https://restorerivers.eu/wiki/api.php?action=feedcontributions&feedformat=atom&user=AimeeThames21 2026-04-07T07:23:06Z User contributions MediaWiki 1.39.7 https://restorerivers.eu/wiki/index.php?title=Case_study:Glenbrook_Wetlands&diff=36538 2016-02-19T13:07:41Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Approved<br /> }}<br /> {{Location<br /> |Location=51.647746622246, -0.11766529030865<br /> }}<br /> {{Project overview<br /> |Status=In progress<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Flood risk management, Habitat and biodiversity, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames 21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Friends of Boxers Lake, Thames Water, Environment Agency,<br /> |Name of parent multi-site project=Case_study:Rewilding Enfield's Urban Rivers<br /> |Multi-site=No<br /> |Project picture=IMAG0001.jpg<br /> |Picture description=Wetland basin 2 - Jan 2016<br /> |Project summary=Thames21 has been working with Enfield Council, The Environment Agency and Thames Water to improve the health of the Salmons Brook and its tributaries. Enfield has a separate sewage system, meaning that surface water eg. rain running off roads and wastewater are carried in two separate pipes. As a result, pollutants enter the Salmons Brook in a number of different ways. Misconnected plumbing contributes nutrients such as phosphates and nitrates and coliform bacteria, road run-off inputs oils and heavy metals such as zinc and copper, and household and industrial waste is dumped into surface water drains. <br /> <br /> With great support from local people we’ve created Sustainable Drainage Systems (SuDS), or ’rainscapes’ to intercept the pollution. As well as filtering pollutants out of water, the SuDS also help reduce local flood risk by slowing the flow, create wildlife habitats and provide new amenities for local people. <br /> <br /> The Glenbrook is a tributary of the Salmons Brook. It flows through underground pipes for much of its length. Hidden away it is damaged, and when it first emerges above ground it is already very badly polluted. Six linked wetlands have been created here to filter pollutants from the stream. The flow is directed through each wetland, being successively cleaned as it is slowed through the basins. Plants use nutrients such as phosphate and nitrate to grow, removing them from the water and stopping them polluting the stream. Bacteria in the soil and root systems break down oils and heavy metals. Once established the planted wetlands not only clean the water, they also add a new dimension to the habitat mosaic for wildlife, and give interest and colour for those passing by.<br /> <br /> The Glenbrook wetlands were complete in September 2014 after three months of construction. Local volunteers helped to plant the wetlands in September 2014 and again in March 2015. The system is designed so that in low flow conditions a series of weirs direct all baseflow into the wetlands, whilst in high flow conditions a large proportion of the flow continues downstream and only the first flush is treated. The headwater of the Glenbrook which feeds this system drains an urban catchment of 42 ha. In addition, 15 gullies have been redirected from the roads that surround the site into the wetland treatment system through a series of swales.<br /> |Monitoring surveys and results=Nitrogen and phosphate are essential for river life but in excess they cause eutrophication. This results in reduced levels of oxygen in the water and may cause toxic algal blooms. Nitrate may be present as ammonia, nitrite or nitrate (measured together as Total Nitrogen), but nitrate is the most stable form. Our water quality monitoring has shown that the SUDS basins are effective at removal of Total nitrogen, nitrates and phosphates. Water quality improves between sampling location 1 (the inflow to the SUDS) and location 2 (outflow from the SUDS), particularly in total nitrogen (dropping from 10mg/l to 6mg/l) and nitrate (dropping from 13mg/l to 7mg/l), bringing water quality within acceptable guideline levels (as defined in EA General Quality Assessment, Water Framework Directive 2014). <br /> <br /> Coliform bacteria derive from faecal waste and are an indicator of pathogens in the aquatic environment. They enter waterways from misconnected toilets, sewage treatment plant overflow, domestic pets and agricultural run off. The SUDS basins are extremely effective at removal of coliform bacteria. Water quality improves between sampling location 1 (the inflow to the SUDS) and location 2 (outflow from the SUDS), with coliform counts dropping from approximately 1400 total coliform colonies to approximately 400 total coliform colonies, bringing water quality within acceptable guideline levels (under EC Bathing Water Directive).<br /> <br /> Invertebrate surveys have also been carried out as part of this project. A masters student from Kings College London (KCL) undertook research into invertebrate populations at each of the project sites. Linking the invertebrate survey results to water quality data, the student predicted the impact/ potential impact of each of the SuDS/wetland schemes on population sizes and diversity over time. There was no existing data on invertebrates for the catchment before research was carried out. As predicted the invertebrate survey confirmed findings of poor water quality, with pollution sensitive taxa very badly represented. The study concluded that the SuDS have the potential to improve water quality and ecological outcomes downstream, but far greater efforts in reducing pollutants from vehicle use and misconnections will be required to resolve the problems of urban diffuse pollution.<br /> |Lessons learn=At this site in particular we came across some levels of reticence from the local community to the project, mainly due to the significant changes to the landscape and lack of familiarity around SuDS, as well as a lack of understanding of why they were desperately needed. We overcame this by being very transparent and available, and in taking care of the site and the stream and making obvious improvements to its health and potential as a wildlife habitat. Regular communications in many forms were key. This became the site at which volunteer days were best attended by local residents. In future projects it would be ideal to spend a time in the build-up to the project engaging the community about water quality issues, rather than to do this simultaneously with planning the SuDS. <br /> <br /> Water quality issues were far more significant than we had anticipated on commencement of the project, particularly in relation to domestic misconnections. Serious pollutant levels damaged the beginning of our SuDS system as Glenbrook. We also found that although we proved our systems had a beneficial impact on water quality, just downstream of each project were outfalls which would bring in yet more pollutants. Therefore SuDS alone could not demonstrate catchment level water improvements needed under WFD. Small scale SuDS have a place in a suite of wider measures that need to be tackled with more drive, especially pollutant impacts from misconnections and vehicle use. <br /> <br /> We experienced some design issues which resulted from a lack of quality data pre-project, for example on flows. It would have been prohibitively expensive for us to get the data needed on this project budget, but it meant that some SuDS elements such as weirs required some costly remediation work.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=Basin 1 creation.JPG<br /> |Caption=Creating basin 1<br /> }}<br /> {{Case study image<br /> |File name=Site of basin 6.JPG<br /> |Caption=Site of basin 6<br /> }}<br /> {{Case study image<br /> |File name=Basin 6 with water.JPG<br /> |Caption=Basin 6 with water<br /> }}<br /> {{Case study image<br /> |File name=Planting in basin 6.JPG<br /> |Caption=Planting in basin 6 - April 2015<br /> }}<br /> {{Case study image<br /> |File name=Drain marking pic.jpg<br /> |Caption=Drain markers installed around site<br /> }}<br /> {{Case study image<br /> |File name=Misconnections pollution.JPG<br /> |Caption=Pollution from misconnections<br /> }}<br /> {{Case study image<br /> |File name=Basin 2 July 2015.JPG<br /> |Caption=Basin 2 July 2015<br /> }}<br /> <br /> {{Case study image<br /> |File name=Planting basin 3.JPG<br /> |Caption=Planting wetland basin 3<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook<br /> }}<br /> {{Site<br /> |Name=Glenbrook<br /> |WFD water body code=GB106038027960<br /> |WFD (national) typology=Type 18: small loess-loam dominated lowland river<br /> |WFD water body name=Salmons Brook<br /> |Heavily modified water body=Yes<br /> |Protected species present=No<br /> |Invasive species present=Yes<br /> |Dominant substrate=London Clay<br /> |River corridor land use=Urban<br /> }}<br /> {{Project background<br /> |Reach length directly affected=220<br /> |Project started=2012/09/01<br /> |Funding sources=Defra, Environment Agency, London Borough of Enfield, Thames Water, <br /> }}<br /> {{Motivations<br /> |Specific mitigation=Poor water quality (urban run off and misconnections), Urbanisation, <br /> |Hydromorphological quality elements=Good status in 2011<br /> |Biological quality elements=In 2011 - Phytobenthos, macrophytes, invertebrates poor and fish moderate<br /> |Physico-chemical quality elements=In 2011 - Ammonia moderate, dissolved oxygen and phosphate poor, annex 8 chem. high<br /> |Other motivation=Improving a public space, flood protection, terrestrial biodiversity improvements<br /> }}<br /> {{Measures<br /> |Bank and bed modifications measure=Overdeepened and incised channel bed raised <br /> |Floodplain / River corridor=Tree works and creation of 6 linked wetland basins, swales taking road run off into basins<br /> |Planform / Channel pattern=n/a<br /> |Other technical measure=n/a<br /> |Management interventions=Opening of tree canopy to encourage varied ground flora<br /> |Social measures=Community consultations, volunteer engagement, education sessions, interpretation, access improvements<br /> |Wider stakeholder / citizen engagement=n/a<br /> }}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Rewilding_Enfield%27s_Urban_Rivers&diff=36537 2016-02-19T13:06:18Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.6522994, -0.08071189999998296<br /> }}<br /> {{Project overview<br /> |Status=In progress<br /> |Themes=Flood risk management, Habitat and biodiversity, Hydromorphology, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames 21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Environment Agency (in an advisory role), Thames Water, Friends of: Boxers Lake, Town Par, Firs Farm, Pymmes Park, Grovelands Park<br /> |Multi-site=Yes<br /> |Project summary=An innovative partnership project to 'rewild' Enfield's urban rivers and renaturalise the water system. The project encompasses 8 sites across the Salmons Brook and Pymmes Brook catchments, themselves part of the Lea catchment. Rivers here suffer from turban pollution, typically from road run off and misconnections. they are often heavily modified or culverted. The project aims to improve water quality, provide flood risk management, improve public spaces, increase good quality habitat and therefore promote biodiversity. Furthermore we aim to increase knowledge of the urban water cycle and how we influence it, and how we can protect our rivers.<br /> <br /> The project is led by the London Borough of Enfield and Thames21, with assistance from Thames Water and advisory input from the Environment Agency. Funders include Defra, Thames Water, the Environment Agency and Greater London Authority.<br /> <br /> Works to the watercourses and their catchments include the creation of wetlands, reedbeds, rain gardens and rain planters, as well as deculverting a stream through a popular park. In addition public engagement and education is key, and interpretation and access enhancements are being carried out on each site. Consulation was carried out before works, and additional project partners include many volunteers and advocates from the local community, as well as Friends groups in parks.<br /> |Monitoring surveys and results=Monitoring has included water quality testing, macroinvertebrate sampling, fixed point photography, questionnaires and ecological surveys. See individual entries for more details.<br /> |Lessons learn=See individual project entries.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=SuDS in Enfield.jpg<br /> |Caption=Wetlands, rain gardens, rain planters in Enfield<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook and Pymmes Brook<br /> }}<br /> {{Site<br /> |Name=Numerous<br /> |WFD water body code=GB106038027960 <br /> |WFD water body name=Salmons Brook<br /> |Heavily modified water body=Yes<br /> |Protected species present=No<br /> |Invasive species present=No<br /> }}<br /> {{Project background<br /> |Project started=2012/08/06<br /> |Funding sources=Defra, Thames Water, EA, GLA<br /> }}<br /> {{Motivations<br /> |Specific mitigation=Poor water quality, Flood risk management, <br /> |Hydromorphological quality elements=Heavily modified waterbodies<br /> |Biological quality elements=Poor ecology due to above and pollution issues<br /> |Physico-chemical quality elements=Urban diffuse and point source pollution from misconnections and road run off<br /> |Other motivation=Improvement to public space and biodiversity<br /> }}<br /> {{Measures<br /> |Bank and bed modifications measure=Daylighting 1.15km of streams<br /> |Floodplain / River corridor=Wetland, raingarden and reedbed creation<br /> |Planform / Channel pattern=Allowing natural re-establishment of channel pattern<br /> |Management interventions=Associated terrestrial habitat improvements, water quality testing and misconnection surveys<br /> |Social measures=Community engagement and education<br /> }}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Rewilding_Enfield%27s_Urban_Rivers&diff=36536 2016-02-19T13:02:09Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.6522994, -0.08071189999998296<br /> }}<br /> {{Project overview<br /> |Status=In progress<br /> |Themes=Flood risk management, Habitat and biodiversity, Hydromorphology, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames 21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Environment Agency (in an advisory role), Thames Water, Friends of: Boxers Lake, Town Par, Firs Farm, Pymmes Park, Grovelands Park<br /> |Multi-site=Yes<br /> |Project summary=An innovative partnership project to 'rewild' Enfield's urban rivers and renaturalise the water system. The project encompasses 8 sites across the Salmons Brook and Pymmes Brook catchments, themselves part of the Lea catchment. Rivers here suffer from turban pollution, typically from road run off and misconnections. they are often heavily modified or culverted. The project aims to improve water quality, provide flood risk management, improve public spaces, increase good quality habitat and therefore promote biodiversity. Furthermore we aim to increase knowledge of the urban water cycle and how we influence it, and how we can protect our rivers.<br /> <br /> The project is led by the London Borough of Enfield and Thames21, with assistance from Thames Water and advisory input from the Environment Agency. Funders include Defra, Thames Water, the Environment Agency and Greater London Authority.<br /> <br /> Works to the watercourses and their catchments include the creation of wetlands, reedbeds, rain gardens and rain planters, as well as deculverting a stream through a popular park. In addition public engagement and education is key, and interpretation and access enhancements are being carried out on each site. Consulation was carried out before works, and additional project partners include many volunteers and advocates from the local community, as well as Friends groups in parks.<br /> |Monitoring surveys and results=Monitoring has included water quality testing, macroinvertebrate sampling, fixed point photography, questionnaires and ecological surveys. See individual entries for more details.<br /> |Lessons learn=See individual project entries.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=SuDS in Enfield.jpg<br /> |Caption=Wetlands, rain gardens, rain planters in Enfield<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook and Pymmes Brook<br /> }}<br /> {{Site<br /> |Name=Numerous<br /> |WFD water body code=GB106038027960 <br /> |WFD water body name=Salmons Brook<br /> |Heavily modified water body=Yes<br /> |Protected species present=No<br /> |Invasive species present=No<br /> }}<br /> {{Project background<br /> |Project started=2012/08/06<br /> |Funding sources=Defra, Thames Water, EA, GLA<br /> }}<br /> {{Motivations<br /> |Specific mitigation=Poor water quality, Flood risk management, <br /> |Hydromorphological quality elements=Heavily modified waterbodies<br /> |Biological quality elements=Poor ecology due to above and pollution issues<br /> |Physico-chemical quality elements=Urban diffuse and point source pollution from misconnections and road run off<br /> |Other motivation=Improvement to public space and biodiversity<br /> }}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Rewilding_Enfield%27s_Urban_Rivers&diff=36390 2016-02-16T11:07:30Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.6522994, -0.08071189999998296<br /> }}<br /> {{Project overview<br /> |Status=In progress<br /> |Themes=Flood risk management, Habitat and biodiversity, Hydromorphology, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames 21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Environment Agency (in an advisory role), Thames Water, Friends of: Boxers Lake, Town Par, Firs Farm, Pymmes Park, Grovelands Park<br /> |Multi-site=Yes<br /> |Project summary=An innovative partnership project to 'rewild' Enfield's urban rivers and renaturalise the water system. The project encompasses 8 sites across the Salmons Brook and Pymmes Brook catchments, themselves part of the Lea catchment. Rivers here suffer from turban pollution, typically from road run off and misconnections. they are often heavily modified or culverted. The project aims to improve water quality, provide flood risk management, improve public spaces, increase good quality habitat and therefore promote biodiversity. Furthermore we aim to increase knowledge of the urban water cycle and how we influence it, and how we can protect our rivers.<br /> <br /> The project is led by the London Borough of Enfield and Thames21, with assistance from Thames Water and advisory input from the Environment Agency. Funders include Defra, Thames Water, the Environment Agency and Greater London Authority.<br /> <br /> Works to the watercourses and their catchments include the creation of wetlands, reedbeds, rain gardens and rain planters, as well as deculverting a stream through a popular park. In addition public engagement and education is key, and interpretation and access enhancements are being carried out on each site. Consulation was carried out before works, and additional project partners include many volunteers and advocates from the local community, as well as Friends groups in parks.<br /> |Monitoring surveys and results=Monitoring has included water quality testing, macroinvertebrate sampling, fixed point photography, questionnaires and ecological surveys. See individual entries for more details.<br /> |Lessons learn=See individual project entries.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=SuDS in Enfield.jpg<br /> |Caption=Wetlands, rain gardens, rain planters in Enfield<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook and Pymmes Brook<br /> }}<br /> {{Site<br /> |Name=Numerous<br /> |WFD water body code=GB106038027960 and GB106038027940<br /> |WFD water body name=Salmons Brook and Pymmes Brook<br /> |Heavily modified water body=Yes<br /> |Protected species present=No<br /> |Invasive species present=No<br /> }}<br /> {{Project background<br /> |Project started=2012/08/06<br /> |Funding sources=Defra, Thames Water, EA, GLA<br /> }}<br /> {{Motivations<br /> |Specific mitigation=Poor water quality, Flood risk management, <br /> |Hydromorphological quality elements=Heavily modified waterbodies<br /> |Biological quality elements=Poor ecology due to above and pollution issues<br /> |Physico-chemical quality elements=Urban diffuse and point source pollution from misconnections and road run off<br /> |Other motivation=Improvement to public space and biodiversity<br /> }}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Glenbrook_Wetlands&diff=36389 2016-02-16T11:06:09Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.647746622246224, -0.11766529030865058<br /> }}<br /> {{Project overview<br /> |Status=In progress<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Flood risk management, Habitat and biodiversity, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames 21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Friends of Boxers Lake, Thames Water, Environment Agency,<br /> |Multi-site=No<br /> |Project picture=IMAG0001.jpg<br /> |Picture description=Wetland basin 2 - Jan 2016<br /> |Project summary=Thames21 has been working with Enfield Council, The Environment Agency and Thames Water to improve the health of the Salmons Brook and its tributaries. Enfield has a separate sewage system, meaning that surface water eg. rain running off roads and wastewater are carried in two separate pipes. As a result, pollutants enter the Salmons Brook in a number of different ways. Misconnected plumbing contributes nutrients such as phosphates and nitrates and coliform bacteria, road run-off inputs oils and heavy metals such as zinc and copper, and household and industrial waste is dumped into surface water drains. <br /> <br /> With great support from local people we’ve created Sustainable Drainage Systems (SuDS), or ’rainscapes’ to intercept the pollution. As well as filtering pollutants out of water, the SuDS also help reduce local flood risk by slowing the flow, create wildlife habitats and provide new amenities for local people. <br /> <br /> The Glenbrook is a tributary of the Salmons Brook. It flows through underground pipes for much of its length. Hidden away it is damaged, and when it first emerges above ground it is already very badly polluted. Six linked wetlands have been created here to filter pollutants from the stream. The flow is directed through each wetland, being successively cleaned as it is slowed through the basins. Plants use nutrients such as phosphate and nitrate to grow, removing them from the water and stopping them polluting the stream. Bacteria in the soil and root systems break down oils and heavy metals. Once established the planted wetlands not only clean the water, they also add a new dimension to the habitat mosaic for wildlife, and give interest and colour for those passing by.<br /> <br /> The Glenbrook wetlands were complete in September 2014 after three months of construction. Local volunteers helped to plant the wetlands in September 2014 and again in March 2015. The system is designed so that in low flow conditions a series of weirs direct all baseflow into the wetlands, whilst in high flow conditions a large proportion of the flow continues downstream and only the first flush is treated. The headwater of the Glenbrook which feeds this system drains an urban catchment of 42 ha. In addition, 15 gullies have been redirected from the roads that surround the site into the wetland treatment system through a series of swales.<br /> |Monitoring surveys and results=Nitrogen and phosphate are essential for river life but in excess they cause eutrophication. This results in reduced levels of oxygen in the water and may cause toxic algal blooms. Nitrate may be present as ammonia, nitrite or nitrate (measured together as Total Nitrogen), but nitrate is the most stable form. Our water quality monitoring has shown that the SUDS basins are effective at removal of Total nitrogen, nitrates and phosphates. Water quality improves between sampling location 1 (the inflow to the SUDS) and location 2 (outflow from the SUDS), particularly in total nitrogen (dropping from 10mg/l to 6mg/l) and nitrate (dropping from 13mg/l to 7mg/l), bringing water quality within acceptable guideline levels (as defined in EA General Quality Assessment, Water Framework Directive 2014). <br /> <br /> Coliform bacteria derive from faecal waste and are an indicator of pathogens in the aquatic environment. They enter waterways from misconnected toilets, sewage treatment plant overflow, domestic pets and agricultural run off. The SUDS basins are extremely effective at removal of coliform bacteria. Water quality improves between sampling location 1 (the inflow to the SUDS) and location 2 (outflow from the SUDS), with coliform counts dropping from approximately 1400 total coliform colonies to approximately 400 total coliform colonies, bringing water quality within acceptable guideline levels (under EC Bathing Water Directive).<br /> <br /> Invertebrate surveys have also been carried out as part of this project. A masters student from Kings College London (KCL) undertook research into invertebrate populations at each of the project sites. Linking the invertebrate survey results to water quality data, the student predicted the impact/ potential impact of each of the SuDS/wetland schemes on population sizes and diversity over time. There was no existing data on invertebrates for the catchment before research was carried out. As predicted the invertebrate survey confirmed findings of poor water quality, with pollution sensitive taxa very badly represented. The study concluded that the SuDS have the potential to improve water quality and ecological outcomes downstream, but far greater efforts in reducing pollutants from vehicle use and misconnections will be required to resolve the problems of urban diffuse pollution.<br /> |Lessons learn=At this site in particular we came across some levels of reticence from the local community to the project, mainly due to the significant changes to the landscape and lack of familiarity around SuDS, as well as a lack of understanding of why they were desperately needed. We overcame this by being very transparent and available, and in taking care of the site and the stream and making obvious improvements to its health and potential as a wildlife habitat. Regular communications in many forms were key. This became the site at which volunteer days were best attended by local residents. In future projects it would be ideal to spend a time in the build-up to the project engaging the community about water quality issues, rather than to do this simultaneously with planning the SuDS. <br /> <br /> Water quality issues were far more significant than we had anticipated on commencement of the project, particularly in relation to domestic misconnections. Serious pollutant levels damaged the beginning of our SuDS system as Glenbrook. We also found that although we proved our systems had a beneficial impact on water quality, just downstream of each project were outfalls which would bring in yet more pollutants. Therefore SuDS alone could not demonstrate catchment level water improvements needed under WFD. Small scale SuDS have a place in a suite of wider measures that need to be tackled with more drive, especially pollutant impacts from misconnections and vehicle use. <br /> <br /> We experienced some design issues which resulted from a lack of quality data pre-project, for example on flows. It would have been prohibitively expensive for us to get the data needed on this project budget, but it meant that some SuDS elements such as weirs required some costly remediation work.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=Basin 1 creation.JPG<br /> |Caption=Creating basin 1<br /> }}<br /> {{Case study image<br /> |File name=Site of basin 6.JPG<br /> |Caption=Site of basin 6<br /> }}<br /> {{Case study image<br /> |File name=Basin 6 with water.JPG<br /> |Caption=Basin 6 with water<br /> }}<br /> {{Case study image<br /> |File name=Planting in basin 6.JPG<br /> |Caption=Planting in basin 6 - April 2015<br /> }}<br /> {{Case study image<br /> |File name=Drain marking pic.jpg<br /> |Caption=Drain markers installed around site<br /> }}<br /> {{Case study image<br /> |File name=Misconnections pollution.JPG<br /> |Caption=Pollution from misconnections<br /> }}<br /> {{Case study image<br /> |File name=Basin 2 July 2015.JPG<br /> |Caption=Basin 2 July 2015<br /> }}<br /> <br /> {{Case study image<br /> |File name=Planting basin 3.JPG<br /> |Caption=Planting wetland basin 3<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook<br /> }}<br /> {{Site<br /> |Name=Glenbrook<br /> |WFD water body code=GB106038027960<br /> |WFD (national) typology=Type 18: small loess-loam dominated lowland river<br /> |WFD water body name=Salmons Brook<br /> |Heavily modified water body=Yes<br /> |Protected species present=No<br /> |Invasive species present=Yes<br /> |Dominant substrate=London Clay<br /> |River corridor land use=Urban<br /> }}<br /> {{Project background<br /> |Reach length directly affected=220<br /> |Project started=2012/09/01<br /> |Funding sources=Defra, Environment Agency, London Borough of Enfield, Thames Water, <br /> }}<br /> {{Motivations<br /> |Specific mitigation=Poor water quality (urban run off and misconnections), Urbanisation, <br /> |Hydromorphological quality elements=Good status in 2011<br /> |Biological quality elements=In 2011 - Phytobenthos, macrophytes, invertebrates poor and fish moderate<br /> |Physico-chemical quality elements=In 2011 - Ammonia moderate, dissolved oxygen and phosphate poor, annex 8 chem. high<br /> |Other motivation=Improving a public space, flood protection, terrestrial biodiversity improvements<br /> }}<br /> {{Measures<br /> |Bank and bed modifications measure=Overdeepened and incised channel bed raised <br /> |Floodplain / River corridor=Tree works and creation of 6 linked wetland basins, swales taking road run off into basins<br /> |Planform / Channel pattern=n/a<br /> |Other technical measure=n/a<br /> |Management interventions=Opening of tree canopy to encourage varied ground flora<br /> |Social measures=Community consultations, volunteer engagement, education sessions, interpretation, access improvements<br /> |Wider stakeholder / citizen engagement=n/a<br /> }}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Grovelands_Park_Wetlands&diff=36388 2016-02-16T11:05:15Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.635654232931394, -0.10910797125688987<br /> }}<br /> {{Project overview<br /> |Status=Complete<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Environmental flows and water resources, Flood risk management, Habitat and biodiversity, Hydromorphology, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Thames Water, Friends of Grovelands Park<br /> |Name of parent multi-site project=Case_study:Rewilding Enfield's Urban Rivers<br /> |Multi-site=No<br /> |Project picture=Thames21-grovelandspk-justinetrickett-1248.jpg<br /> |Picture description=Grovelands Park Wetlands, summer 2015<br /> |Project summary=The water system in Grovelands Park, Enfield, has been artificially engineered over time, with a long stretch of the stream being contained in an underground pipe, hidden from view and useless to wildlife. Here beneath the ground two surface water drains from local roads and homes washed pollutants straight into the stream every time it rained. Plumbing misconnections added to the problem. <br /> <br /> In spring 2014 we worked with the London Borough of Enfield to 'rewild' the water system in Grovelands Park. We created wetlands to intercept pollutants entering the stream in Grovelands Park. Flows in the surface water drains were diverted into shallow ditches, known as swales, and then into a wetland basin. The swales and basin were planted with sedges suitable for the semi-shaded woodland conditions. The plants use excess nutrients such as phosphates and nitrates to grow, preventing them building up in the water which causes the toxic algal blooms. The plants also oxygenate the water. Bacteria growing in the sediment and root systems break down oils and some bacteria can even reduce levels of heavy metals in the water. The clean water then soaks into the ground, as it would naturally, or overflows back into the stream. Rainwater washing off an area the size of 11 rugby fields is cleaned in the wetland. As we completed this project Thames Water ran misconnection surveys on the urban catchment, a vital piece of the jigsaw to ensure optimal results in this project.<br /> <br /> At the same time the London Borough of Enfield naturalised 200m of the stream, breaking it out of its underground pipe and allowing it to find its own course meandering through the woodland. These two projects restored the water system to its natural state, better able to cope with floods and slowing high flows of stormwater, as well as treating pollutants. <br /> <br /> The lake in Grovelands Park, Enfield is the centrepiece of a beautiful and grand garden for the ‘Southgate Grove’ mansion, designed in the 18th century and now a well-loved and popular public park. Sadly the lake is afflicted with pollution from a number of surface water drains, and toxic algal blooms are common in summer. Rainwater running off local streets brings with it oils and heavy metals from the road, as well as detergents and other chemicals such as phosphates and nitrates from misconnected plumbing. This pollution load limits the lake’s potential as a wildlife habitat and its appeal for park visitors.<br /> <br /> In June 2015 we created a reed bed in the south western end of the lake to naturally break down these pollutants and increase oxygen levels in the water, as well as providing a new habitat for birds and insects. Coir rolls and hazel faggots were used to create an area of suitable depth to establish the reed bed. Coir mats pre-planted with reeds, rushes, sedges and colourful purple loosestrife and yellow flag iris were installed across the reed bed area, protected from wildfowl grazing by netting. As in the wetland, the plants use excess nutrients such as phosphates and nitrates to grow, preventing them building up in the water which causes the toxic algal blooms. The plants also oxygenate the water. Bacteria growing in the sediment and root systems break down oils and some bacteria can even reduce levels of heavy metals in the water.<br /> |Monitoring surveys and results=Nitrogen is essential for river life but in excess can cause eutrophication. This results in reduced levels of oxygen in the water and may cause toxic algal blooms. Nitrate may be present as ammonia, nitrite or nitrate (measured together as Total Nitrogen), but nitrate is the most stable form. <br /> <br /> Reed bed: The recently installed reed bed is already proving effective at removing nitrogen compounds from the water. There is a significant difference in water quality between the inflow above the reed bed (sampling location 1) and the sampling location immediately the other side of the reed bed (location 2) in total nitrogen, nitrate and ammonia. Total nitrogen drops from 7mg/l to 5mg/l, nitrate from 13mg/l to 4mg//l and ammonia from 1.6mg/l to 0.5mg/l. The improvement in water quality through the reed bed is greater than the improvement observed in the body of the lake. This is because the difference in water quality is larger between sampling sites 1 and 2 compared to between sites 2 and 3 (the lake outflow). <br /> <br /> Wetland basin: The wetland basin is effective at water quality improvement because it prevents polluted water from two drains (sample locations 5 and 6) from entering the stream at site 4. Water entering the infiltration basin from the de-culverted pipe at sampling site 6 is consistently outside of acceptable concentration ranges specified by the Water Framework Directive. Ammonia is consistently present in levels deemed harmful to aquatic life in both inflow pipes (sample locations 5 and 6). Water only flows out of the wetland basin in storm conditions so it effectively prevents polluted water from entering the stream. <br /> <br /> Coliform bacteria derive from faecal waste and are an indicator of pathogens in the aquatic environment. They enter waterways from misconnected toilets, sewage treatment plant overflow, domestic pets and agricultural run off.<br /> <br /> Reed bed: The reed bed is an effective remover of coliform bacteria, reducing the coliform colony count to within guideline limits (under EC Bathing Water Directive)immediately after the reedbed (sample location 2), dropping from approximately 1100 total coliform colonies to 50 total coliform colonies. <br /> <br /> Wetland basin: Water entering the wetland basin from the culverts at sampling sites 5 and 6 contains high counts of coliform bacteria, that are outside of guideline limits (under EC Bathing Water Directive). This is prevented from entering the stream (sample location 4) because water only flows out of the wetland basin in storm conditions.<br /> |Lessons learn=The wetland basin is quite large, sized for greater flows than have been experienced so far. This means that the water in the treatment basin overflows only during very heavy rainfall events. This is not a significant problem, it just means that the basin is acting more as an infiltration basin rather than a temporary storage basin. The system still functions to prevent polluted water entering the stream. <br /> <br /> The plug planted sedges in the basin are thriving in this environment as the system was not fully activated until the plants were well established. However in the more shaded swales with greater velocity of flows and concentration of pollution the plugs have failed and need to be replanted. <br /> <br /> Sedges have grown lush and verdant in the basin and water is cleaned and returned to the stream as expected or returned to the water table. Although perhaps not as aesthetically pleasing as in the design, the boulder arrangement at the head of the swales has worked well to slow water and prevent excessive erosion in the swales. <br /> <br /> Water quality issues were far more significant than we had anticipated on commencement of the project, particularly in relation to domestic misconnections. High pollutant levels were evident beginning of our swales. We also found that although we proved our systems had a beneficial impact on water quality, just downstream of each project were outfalls which would bring in yet more pollutants. Therefore wetlands and SuDS alone could not demonstrate catchment level water improvements needed under WFD. Small scale interventions have a place in a suite of wider measures that need to be tackled with more drive, especially pollutant impacts from misconnections and vehicle use.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1206.jpg<br /> |Caption=Reedbed summer 2015<br /> }}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1261.jpg<br /> |Caption=Overflow from wetland<br /> }}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1266.jpg<br /> |Caption=Restored stream meandering through woodland<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook<br /> }}<br /> {{Site<br /> |Name=Unnamed tributary of Salmons Brook<br /> |WFD water body name=Salmons Brook<br /> |Pre-project morphology=Closed culvert, <br /> |Desired post project morphology=Actively meandering, <br /> |Heavily modified water body=Yes<br /> |Protected species present=No<br /> |Invasive species present=No<br /> |Dominant substrate=London Clay<br /> |River corridor land use=Urban, <br /> }}<br /> {{Project background<br /> |Reach length directly affected=200<br /> |Project started=2014/02/01<br /> |Project completed=2015/07/10<br /> |Funding sources=Defra, London Borough of Enfield, Thames Water<br /> }}<br /> {{Motivations<br /> |Specific mitigation=Poor water quality, Flood risk management, Urbanisation,<br /> |Hydromorphological quality elements=Good status in 2011<br /> |Biological quality elements= In 2011 - Phytobenthos, macrophytes, invertebrates poor and fish moderate<br /> |Physico-chemical quality elements=In 2011 - Ammonia moderate, dissolved oxygen and phosphate poor, annex 8 chem. high<br /> |Other motivation= Improving a public space, flood protection, terrestrial biodiversity improvements<br /> }}<br /> {{Measures<br /> |Bank and bed modifications measure=Deculverting, <br /> |Floodplain / River corridor=Creation of swales and wetland basin, stream allowed to find new course<br /> |Planform / Channel pattern=Actively meandering<br /> |Social measures=Community consultations, volunteer engagement, education sessions, interpretation, access improvements <br /> |Wider stakeholder / citizen engagement=Reedbed creation in lake<br /> }}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Houndsden_Road_Rain_Gardens&diff=36357 2016-02-15T17:44:30Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.6393116, -0.10710140000003321<br /> }}<br /> {{Project overview<br /> |Status=In progress<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Flood risk management, Habitat and biodiversity, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames 21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Thames Water,<br /> |Name of parent multi-site project=Case_study:Rewilding Enfield's Urban Rivers<br /> |Multi-site=No<br /> |Project picture=Newly planted swale April 2015.JPG<br /> |Picture description=Planted swale April 2015<br /> |Project summary=The Houndsden Gutter is a tributary of the Salmons Brook, a small river running through Enfield which joins the Lea Navigation. Like many urban streams it suffers from pollution. Oils and heavy metals wash off the roads when it rains, flowing into surface water drains which lead straight into our streams and rivers. The plumbing in some homes and businesses is misconnected, sending water from appliances, sinks and sometimes even toilets into watercourses instead of the sewers. <br /> <br /> In 2015 we worked with the London Borough of Enfield to create two rain garden systems to improve the water quality in the stream. They have been designed to treat water that runs off Houndsden Road every time it rains, taking run-off from a busy section of Houndsden Road, which previously flowed directly into the Houndsden Gutter. Water is directed along the verge where it infiltrates into the soil or, in high flow conditions, into the large, natural woodland treatment basin. <br /> <br /> In the first system a two metre wide swale was created along the verge using a low impact digger. A footbridge was created to allow the swale to continue into the natural basin of the spinney. Kerbs were dropped at two points along the verge to allow water to enter the swales from the road. Finally, the road gully just up from the top of the system was filled so water would be redirected into the swales. <br /> Further down same road a second rain garden system was implemented in September 2015, made possible with match funding from LBE. These roadside rain gardens have allowed for another road gully to be filled and more road run-off off to be filtered before entering Houndsden Stream. This scheme consists of a swale and two rain gardens taking water from Houndsden Road. In low rainfall conditions water is temporarily stored in the rain garden basins and slowly infiltrates into the verge. In high rainfall conditions, and when the basins reach a critical limit, water is transferred through a pipe, under the footpath and into the natural woodland basin in the spinney.<br /> <br /> The water treatment occurs in two ways. In the natural woodland basin of the Spinney, chemicals which would pollute the river are naturally and safely used by plants to grow or broken down by bacteria in the soil. The swales have been planted with sedges and native grasses to slow water flow and begin the treatment, and the woodland basin planted with suitable native seed mixes. Water will then naturally soak into the soil, recharging the water table. This is particularly important during times of summer drought. These rain gardens prevent oils and heavy metals washing into the Houndsden Gutter. The stream supports a small fish population, and fish are seriously impacted by such pollutants, so reducing the pollutant levels in the stream is of great importance. <br /> <br /> In addition through this project we flagged up a highly polluting outfall, which was then investigated immediately and rectified, having an enormously positive effect on the health of the stream.<br /> <br /> Interpretation will be created to showcase the benefit of rain gardens for rivers, as well as access improvements in the woodland to allow more people to get close to the stream.<br /> |Monitoring surveys and results=At the Houndsden Spinney it has thus far been impossible to collect road run off, so we have been unable to show an effect on water quality above and below the rain garden at this site. <br /> <br /> Through our work alongside Thames Water and the EA to identify and rectify the misconnections blighting this site a significant improvement in water quality has been seen. We will soon be repeating invertebrate surveys to demonstrate this, along with public questionnaires which we hope will show an improvement in understanding of the urban water cycle and household misconnections.<br /> |Lessons learn=The road inlet designs had to be amended to capture water running along the gully with a road section cut out to allow a deep enough fall into swale. This has been rectified and the majority of run off is now entering the swales as designed.<br /> <br /> The SuDS features are currently drier than anticipated. The resilient sedges are thriving, as are unwanted terrestrial plants. This has additional maintenance implications until replanting of edge species next spring.<br /> <br /> Originally a much larger wetland was planned at this site to clean water in the stream. However the project had to be significantly scaled back as we were unable to provide data needed to the EA to approve the scheme, as collecting this level data would have been prohibitively expensive. It would be better in future to allow for longer lead time on the project and budget far more for pre-project monitoring, however in this case it is still unlikely that we would have been able to fund the data required. Monitoring of schemes such as the Salmons Brook Healthy River Challenge is imperative to provide proof that SuDS are a positive element in the toolkit of approaches to tackle urban diffuse pollution.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=Volunteers planting the swale.JPG<br /> |Caption=Volunteers planting the swale<br /> }}<br /> {{Case study image<br /> |File name=Creating the swales.JPG<br /> |Caption=Creating the swales<br /> }}<br /> {{Case study image<br /> |File name=HS pollution.jpg<br /> |Caption=Misconnection into stream<br /> }}<br /> {{Case study image<br /> |File name=HS pollution 2.jpg<br /> |Caption=Sewage fungus<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook<br /> }}<br /> {{Site<br /> |Name=Houndsden Spinney<br /> |WFD water body code=GB106038027960 <br /> |WFD water body name=Salmons Brook<br /> |Heavily modified water body=Yes<br /> |Protected species present=No<br /> |Invasive species present=No<br /> }}<br /> {{Project background<br /> |Project started=2012/08/06<br /> |Works started=2015/03/02<br /> |Works completed=2015/10/09<br /> |Funding sources=London Borough of Enfield, corporate funder, Defra<br /> }}<br /> {{Motivations<br /> |Specific mitigation=Urban diffuse pollution from road run off<br /> |Hydromorphological quality elements=n/a<br /> |Biological quality elements=Pollution limiting biological potential<br /> |Physico-chemical quality elements=Pollution from misconnections and road run off<br /> |Other motivation=Community demand, education project, interpretation of urban water cycle<br /> }}<br /> {{Measures<br /> |Floodplain / River corridor=Creation of swales and wetland basins<br /> |Management interventions=Opening of tree canopy to encourage ground flora<br /> |Social measures=Community consulation, engagement and interpretation, access enhancements<br /> }}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Houndsden_Road_Rain_Gardens&diff=36356 2016-02-15T17:43:04Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.6393116, -0.10710140000003321<br /> }}<br /> {{Project overview<br /> |Status=In progress<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Flood risk management, Habitat and biodiversity, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames 21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Thames Water,<br /> |Name of parent multi-site project=Case_study:Rewilding Enfield's Urban Rivers<br /> |Multi-site=No<br /> |Project picture=Newly planted swale April 2015.JPG<br /> |Picture description=Planted swale April 2015<br /> |Project summary=The Houndsden Gutter is a tributary of the Salmons Brook, a small river running through Enfield which joins the Lea Navigation. Like many urban streams it suffers from pollution. Oils and heavy metals wash off the roads when it rains, flowing into surface water drains which lead straight into our streams and rivers. The plumbing in some homes and businesses is misconnected, sending water from appliances, sinks and sometimes even toilets into watercourses instead of the sewers. <br /> <br /> In 2015 we worked with the London Borough of Enfield to create two rain garden systems to improve the water quality in the stream. They have been designed to treat water that runs off Houndsden Road every time it rains, taking run-off from a busy section of Houndsden Road, which previously flowed directly into the Houndsden Gutter. Water is directed along the verge where it infiltrates into the soil or, in high flow conditions, into the large, natural woodland treatment basin. <br /> <br /> In the first system a two metre wide swale was created along the verge using a low impact digger. A footbridge was created to allow the swale to continue into the natural basin of the spinney. Kerbs were dropped at two points along the verge to allow water to enter the swales from the road. Finally, the road gully just up from the top of the system was filled so water would be redirected into the swales. <br /> Further down same road a second rain garden system was implemented in September 2015, made possible with match funding from LBE. These roadside rain gardens have allowed for another road gully to be filled and more road run-off off to be filtered before entering Houndsden Stream. This scheme consists of a swale and two rain gardens taking water from Houndsden Road. In low rainfall conditions water is temporarily stored in the rain garden basins and slowly infiltrates into the verge. In high rainfall conditions, and when the basins reach a critical limit, water is transferred through a pipe, under the footpath and into the natural woodland basin in the spinney.<br /> <br /> The water treatment occurs in two ways. In the natural woodland basin of the Spinney, chemicals which would pollute the river are naturally and safely used by plants to grow or broken down by bacteria in the soil. The swales have been planted with sedges and native grasses to slow water flow and begin the treatment, and the woodland basin planted with suitable native seed mixes. Water will then naturally soak into the soil, recharging the water table. This is particularly important during times of summer drought. These rain gardens prevent oils and heavy metals washing into the Houndsden Gutter. The stream supports a small fish population, and fish are seriously impacted by such pollutants, so reducing the pollutant levels in the stream is of great importance. <br /> <br /> In addition through this project we flagged up a highly polluting outfall, which was then investigated immediately and rectified, having an enormously positive effect on the health of the stream.<br /> <br /> Interpretation will be created to showcase the benefit of rain gardens for rivers, as well as access improvements in the woodland to allow more people to get close to the stream.<br /> |Monitoring surveys and results=At the Houndsden Spinney it has thus far been impossible to collect road run off, so we have been unable to show an effect on water quality above and below the rain garden at this site. <br /> <br /> Through our work alongside Thames Water and the EA to identify and rectify the misconnections blighting this site a significant improvement in water quality has been seen. We will soon be repeating invertebrate surveys to demonstrate this, along with public questionnaires which we hope will show an improvement in understanding of the urban water cycle and household misconnections.<br /> |Lessons learn=The road inlet designs had to be amended to capture water running along the gully with a road section cut out to allow a deep enough fall into swale. This has been rectified and the majority of run off is now entering the swales as designed.<br /> <br /> The SuDS features are currently drier than anticipated. The resilient sedges are thriving, as are unwanted terrestrial plants. This has additional maintenance implications until replanting of edge species next spring.<br /> <br /> Originally a much larger wetland was planned at this site to clean water in the stream. However the project had to be significantly scaled back as we were unable to provide data needed to the EA to approve the scheme, as collecting this level data would have been prohibitively expensive. It would be better in future to allow for longer lead time on the project and budget far more for pre-project monitoring, however in this case it is still unlikely that we would have been able to fund the data required. Monitoring of schemes such as the Salmons Brook Healthy River Challenge is imperative to provide proof that SuDS are a positive element in the toolkit of approaches to tackle urban diffuse pollution.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=Volunteers planting the swale.JPG<br /> |Caption=Volunteers planting the swale<br /> }}<br /> {{Case study image<br /> |File name=Creating the swales.JPG<br /> |Caption=Creating the swales<br /> }}<br /> {{Case study image<br /> |File name=HS pollution.jpg<br /> |Caption=Misconnection into stream<br /> }}<br /> {{Case study image<br /> |File name=HS pollution 2.jpg<br /> |Caption=Sewage fungus<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook<br /> }}<br /> {{Site<br /> |Name=Houndsden Spinney<br /> |WFD water body code=GB106038027960 <br /> |WFD water body name=Salmons Brook<br /> |Heavily modified water body=Yes<br /> |Protected species present=No<br /> |Invasive species present=No<br /> }}<br /> {{Project background<br /> |Project started=2012/08/06<br /> |Works started=2015/03/02<br /> |Works completed=2015/10/09<br /> |Funding sources=London Borough of Enfield, corporate funder, Defra<br /> }}<br /> {{Motivations<br /> |Specific mitigation=Urban diffuse pollution from road run off<br /> |Hydromorphological quality elements=n/a<br /> |Biological quality elements=Pollution limiting biological potential<br /> |Physico-chemical quality elements=Pollution from misconnections and road run off<br /> |Other motivation=Community demand, education project, interpretation of urban water cycle<br /> }}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Houndsden_Road_Rain_Gardens&diff=36355 2016-02-15T17:38:58Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.6393116, -0.10710140000003321<br /> }}<br /> {{Project overview<br /> |Status=In progress<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Flood risk management, Habitat and biodiversity, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames 21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Thames Water,<br /> |Name of parent multi-site project=Case_study:Rewilding Enfield's Urban Rivers<br /> |Multi-site=No<br /> |Project picture=Newly planted swale April 2015.JPG<br /> |Picture description=Planted swale April 2015<br /> |Project summary=The Houndsden Gutter is a tributary of the Salmons Brook, a small river running through Enfield which joins the Lea Navigation. Like many urban streams it suffers from pollution. Oils and heavy metals wash off the roads when it rains, flowing into surface water drains which lead straight into our streams and rivers. The plumbing in some homes and businesses is misconnected, sending water from appliances, sinks and sometimes even toilets into watercourses instead of the sewers. <br /> <br /> In 2015 we worked with the London Borough of Enfield to create two rain garden systems to improve the water quality in the stream. They have been designed to treat water that runs off Houndsden Road every time it rains, taking run-off from a busy section of Houndsden Road, which previously flowed directly into the Houndsden Gutter. Water is directed along the verge where it infiltrates into the soil or, in high flow conditions, into the large, natural woodland treatment basin. <br /> <br /> In the first system a two metre wide swale was created along the verge using a low impact digger. A footbridge was created to allow the swale to continue into the natural basin of the spinney. Kerbs were dropped at two points along the verge to allow water to enter the swales from the road. Finally, the road gully just up from the top of the system was filled so water would be redirected into the swales. <br /> Further down same road a second rain garden system was implemented in September 2015, made possible with match funding from LBE. These roadside rain gardens have allowed for another road gully to be filled and more road run-off off to be filtered before entering Houndsden Stream. This scheme consists of a swale and two rain gardens taking water from Houndsden Road. In low rainfall conditions water is temporarily stored in the rain garden basins and slowly infiltrates into the verge. In high rainfall conditions, and when the basins reach a critical limit, water is transferred through a pipe, under the footpath and into the natural woodland basin in the spinney.<br /> <br /> The water treatment occurs in two ways. In the natural woodland basin of the Spinney, chemicals which would pollute the river are naturally and safely used by plants to grow or broken down by bacteria in the soil. The swales have been planted with sedges and native grasses to slow water flow and begin the treatment, and the woodland basin planted with suitable native seed mixes. Water will then naturally soak into the soil, recharging the water table. This is particularly important during times of summer drought. These rain gardens prevent oils and heavy metals washing into the Houndsden Gutter. The stream supports a small fish population, and fish are seriously impacted by such pollutants, so reducing the pollutant levels in the stream is of great importance. <br /> <br /> In addition through this project we flagged up a highly polluting outfall, which was then investigated immediately and rectified, having an enormously positive effect on the health of the stream.<br /> <br /> Interpretation will be created to showcase the benefit of rain gardens for rivers, as well as access improvements in the woodland to allow more people to get close to the stream.<br /> |Monitoring surveys and results=At the Houndsden Spinney it has thus far been impossible to collect road run off, so we have been unable to show an effect on water quality above and below the rain garden at this site. <br /> <br /> Through our work alongside Thames Water and the EA to identify and rectify the misconnections blighting this site a significant improvement in water quality has been seen. We will soon be repeating invertebrate surveys to demonstrate this, along with public questionnaires which we hope will show an improvement in understanding of the urban water cycle and household misconnections.<br /> |Lessons learn=The road inlet designs had to be amended to capture water running along the gully with a road section cut out to allow a deep enough fall into swale. This has been rectified and the majority of run off is now entering the swales as designed.<br /> <br /> The SuDS features are currently drier than anticipated. The resilient sedges are thriving, as are unwanted terrestrial plants. This has additional maintenance implications until replanting of edge species next spring.<br /> <br /> Originally a much larger wetland was planned at this site to clean water in the stream. However the project had to be significantly scaled back as we were unable to provide data needed to the EA to approve the scheme, as collecting this level data would have been prohibitively expensive. It would be better in future to allow for longer lead time on the project and budget far more for pre-project monitoring, however in this case it is still unlikely that we would have been able to fund the data required. Monitoring of schemes such as the Salmons Brook Healthy River Challenge is imperative to provide proof that SuDS are a positive element in the toolkit of approaches to tackle urban diffuse pollution.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=Volunteers planting the swale.JPG<br /> |Caption=Volunteers planting the swale<br /> }}<br /> {{Case study image<br /> |File name=Creating the swales.JPG<br /> |Caption=Creating the swales<br /> }}<br /> {{Case study image<br /> |File name=HS pollution.jpg<br /> |Caption=Misconnection into stream<br /> }}<br /> {{Case study image<br /> |File name=HS pollution 2.jpg<br /> |Caption=Sewage fungus<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook<br /> }}<br /> {{Site}}<br /> {{Project background<br /> |Project started=2012/08/06<br /> |Works started=2015/03/02<br /> |Works completed=2015/10/09<br /> |Funding sources=London Borough of Enfield, corporate funder, Defra<br /> }}<br /> {{Motivations<br /> |Specific mitigation=Urban diffuse pollution from road run off<br /> |Hydromorphological quality elements=n/a<br /> |Biological quality elements=Pollution limiting biological potential<br /> |Physico-chemical quality elements=Pollution from misconnections and road run off<br /> |Other motivation=Community demand, education project, interpretation of urban water cycle<br /> }}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Houndsden_Road_Rain_Gardens&diff=36354 2016-02-15T17:37:29Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.6393116, -0.10710140000003321<br /> }}<br /> {{Project overview<br /> |Status=In progress<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Flood risk management, Habitat and biodiversity, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames 21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Thames Water,<br /> |Name of parent multi-site project=Case_study:Rewilding Enfield's Urban Rivers<br /> |Multi-site=No<br /> |Project picture=Newly planted swale April 2015.JPG<br /> |Picture description=Planted swale April 2015<br /> |Project summary=The Houndsden Gutter is a tributary of the Salmons Brook, a small river running through Enfield which joins the Lea Navigation. Like many urban streams it suffers from pollution. Oils and heavy metals wash off the roads when it rains, flowing into surface water drains which lead straight into our streams and rivers. The plumbing in some homes and businesses is misconnected, sending water from appliances, sinks and sometimes even toilets into watercourses instead of the sewers. <br /> <br /> In 2015 we worked with the London Borough of Enfield to create two rain garden systems to improve the water quality in the stream. They have been designed to treat water that runs off Houndsden Road every time it rains, taking run-off from a busy section of Houndsden Road, which previously flowed directly into the Houndsden Gutter. Water is directed along the verge where it infiltrates into the soil or, in high flow conditions, into the large, natural woodland treatment basin. <br /> <br /> In the first system a two metre wide swale was created along the verge using a low impact digger. A footbridge was created to allow the swale to continue into the natural basin of the spinney. Kerbs were dropped at two points along the verge to allow water to enter the swales from the road. Finally, the road gully just up from the top of the system was filled so water would be redirected into the swales. <br /> Further down same road a second rain garden system was implemented in September 2015, made possible with match funding from LBE. These roadside rain gardens have allowed for another road gully to be filled and more road run-off off to be filtered before entering Houndsden Stream. This scheme consists of a swale and two rain gardens taking water from Houndsden Road. In low rainfall conditions water is temporarily stored in the rain garden basins and slowly infiltrates into the verge. In high rainfall conditions, and when the basins reach a critical limit, water is transferred through a pipe, under the footpath and into the natural woodland basin in the spinney.<br /> <br /> The water treatment occurs in two ways. In the natural woodland basin of the Spinney, chemicals which would pollute the river are naturally and safely used by plants to grow or broken down by bacteria in the soil. The swales have been planted with sedges and native grasses to slow water flow and begin the treatment, and the woodland basin planted with suitable native seed mixes. Water will then naturally soak into the soil, recharging the water table. This is particularly important during times of summer drought. These rain gardens prevent oils and heavy metals washing into the Houndsden Gutter. The stream supports a small fish population, and fish are seriously impacted by such pollutants, so reducing the pollutant levels in the stream is of great importance. <br /> <br /> In addition through this project we flagged up a highly polluting outfall, which was then investigated immediately and rectified, having an enormously positive effect on the health of the stream.<br /> |Monitoring surveys and results=At the Houndsden Spinney it has thus far been impossible to collect road run off, so we have been unable to show an effect on water quality above and below the rain garden at this site. <br /> <br /> Through our work alongside Thames Water and the EA to identify and rectify the misconnections blighting this site a significant improvement in water quality has been seen. We will soon be repeating invertebrate surveys to demonstrate this, along with public questionnaires which we hope will show an improvement in understanding of the urban water cycle and household misconnections.<br /> |Lessons learn=The road inlet designs had to be amended to capture water running along the gully with a road section cut out to allow a deep enough fall into swale. This has been rectified and the majority of run off is now entering the swales as designed.<br /> <br /> The SuDS features are currently drier than anticipated. The resilient sedges are thriving, as are unwanted terrestrial plants. This has additional maintenance implications until replanting of edge species next spring.<br /> <br /> Originally a much larger wetland was planned at this site to clean water in the stream. However the project had to be significantly scaled back as we were unable to provide data needed to the EA to approve the scheme, as collecting this level data would have been prohibitively expensive. It would be better in future to allow for longer lead time on the project and budget far more for pre-project monitoring, however in this case it is still unlikely that we would have been able to fund the data required. Monitoring of schemes such as the Salmons Brook Healthy River Challenge is imperative to provide proof that SuDS are a positive element in the toolkit of approaches to tackle urban diffuse pollution.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=Volunteers planting the swale.JPG<br /> |Caption=Volunteers planting the swale<br /> }}<br /> {{Case study image<br /> |File name=Creating the swales.JPG<br /> |Caption=Creating the swales<br /> }}<br /> {{Case study image<br /> |File name=HS pollution.jpg<br /> |Caption=Misconnection into stream<br /> }}<br /> {{Case study image<br /> |File name=HS pollution 2.jpg<br /> |Caption=Sewage fungus<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook<br /> }}<br /> {{Site}}<br /> {{Project background<br /> |Project started=2012/08/06<br /> |Works started=2015/03/02<br /> |Works completed=2015/10/09<br /> |Funding sources=London Borough of Enfield, corporate funder, Defra<br /> }}<br /> {{Motivations<br /> |Specific mitigation=Urban diffuse pollution from road run off<br /> |Hydromorphological quality elements=n/a<br /> |Biological quality elements=Pollution limiting biological potential<br /> |Physico-chemical quality elements=Pollution from misconnections and road run off<br /> |Other motivation=Community demand, education project, interpretation of urban water cycle<br /> }}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Houndsden_Road_Rain_Gardens&diff=36353 2016-02-15T17:36:52Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.6393116, -0.10710140000003321<br /> }}<br /> {{Project overview<br /> |Status=In progress<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Flood risk management, Habitat and biodiversity, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames 21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Thames Water,<br /> |Name of parent multi-site project=Case_study:Rewilding Enfield's Urban Rivers<br /> |Multi-site=No<br /> |Project picture=Newly planted swale April 2015.JPG<br /> |Picture description=Planted swale April 2015<br /> |Project summary=The Houndsden Gutter is a tributary of the Salmons Brook, a small river running through Enfield which joins the Lea Navigation. Like many urban streams it suffers from pollution. Oils and heavy metals wash off the roads when it rains, flowing into surface water drains which lead straight into our streams and rivers. The plumbing in some homes and businesses is misconnected, sending water from appliances, sinks and sometimes even toilets into watercourses instead of the sewers. <br /> <br /> In 2015 we worked with the London Borough of Enfield to create two rain garden systems to improve the water quality in the stream. They have been designed to treat water that runs off Houndsden Road every time it rains, taking run-off from a busy section of Houndsden Road, which previously flowed directly into the Houndsden Gutter. Water is directed along the verge where it infiltrates into the soil or, in high flow conditions, into the large, natural woodland treatment basin. <br /> <br /> In the first system a two metre wide swale was created along the verge using a low impact digger. A footbridge was created to allow the swale to continue into the natural basin of the spinney. Kerbs were dropped at two points along the verge to allow water to enter the swales from the road. Finally, the road gully just up from the top of the system was filled so water would be redirected into the swales. <br /> Further down same road a second rain garden system was implemented in September 2015, made possible with match funding from LBE. These roadside rain gardens have allowed for another road gully to be filled and more road run-off off to be filtered before entering Houndsden Stream. This scheme consists of a swale and two rain gardens taking water from Houndsden Road. In low rainfall conditions water is temporarily stored in the rain garden basins and slowly infiltrates into the verge. In high rainfall conditions, and when the basins reach a critical limit, water is transferred through a pipe, under the footpath and into the natural woodland basin in the spinney.<br /> <br /> The water treatment occurs in two ways. In the natural woodland basin of the Spinney, chemicals which would pollute the river are naturally and safely used by plants to grow or broken down by bacteria in the soil. The swales have been planted with sedges and native grasses to slow water flow and begin the treatment, and the woodland basin planted with suitable native seed mixes. Water will then naturally soak into the soil, recharging the water table. This is particularly important during times of summer drought. These rain gardens prevent oils and heavy metals washing into the Houndsden Gutter. The stream supports a small fish population, and fish are seriously impacted by such pollutants, so reducing the pollutant levels in the stream is of great importance. <br /> <br /> In addition through this project we flagged up a highly polluting outfall, which was then investigated immediately and rectified, having an enormously positive effect on the health of the stream.<br /> |Monitoring surveys and results=At the Houndsden Spinney it has thus far been impossible to collect road run off, so we have been unable to show an effect on water quality above and below the rain garden at this site. <br /> <br /> Through our work alongside Thames Water and the EA to identify and rectify the misconnections blighting this site a significant improvement in water quality has been seen. We will soon be repeating invertebrate surveys to demonstrate this, along with public questionnaires which we hope will show an improvement in understanding of the urban water cycle and household misconnections.<br /> |Lessons learn=The road inlet designs had to be amended to capture water running along the gully with a road section cut out to allow a deep enough fall into swale. This has been rectified and the majority of run off is now entering the swales as designed.<br /> <br /> The SuDS features are currently drier than anticipated. The resilient sedges are thriving, as are unwanted terrestrial plants. This has additional maintenance implications until replanting of edge species next spring.<br /> <br /> Originally a much larger wetland was planned at this site to clean water in the stream. However the project had to be significantly scaled back as we were unable to provide data needed to the EA to approve the scheme, as collecting this level data would have been prohibitively expensive. It would be better in future to allow for longer lead time on the project and budget far more for pre-project monitoring, however in this case it is still unlikely that we would have been able to fund the data required. Monitoring of schemes such as the Salmons Brook Healthy River Challenge is imperative to provide proof that SuDS are a positive element in the toolkit of approaches to tackle urban diffuse pollution.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=Volunteers planting the swale.JPG<br /> |Caption=Volunteers planting the swale<br /> }}<br /> {{Case study image<br /> |File name=Creating the swales.JPG<br /> |Caption=Creating the swales<br /> }}<br /> {{Case study image<br /> |File name=HS pollution.jpg<br /> |Caption=Misconnection into stream<br /> }}<br /> {{Case study image<br /> |File name=HS pollution 2.jpg<br /> |Caption=Sewage fungus<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook<br /> }}<br /> {{Site}}<br /> {{Project background<br /> |Works started=2015/03/02<br /> |Works completed=2015/10/09<br /> |Funding sources=London Borough of Enfield, corporate funder, Defra<br /> }}<br /> {{Motivations<br /> |Specific mitigation=Urban diffuse pollution from road run off<br /> |Hydromorphological quality elements=n/a<br /> |Biological quality elements=Pollution limiting biological potential<br /> |Physico-chemical quality elements=Pollution from misconnections and road run off<br /> |Other motivation=Community demand, education project, interpretation of urban water cycle<br /> }}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Houndsden_Road_Rain_Gardens&diff=36352 2016-02-15T17:35:03Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.6393116, -0.10710140000003321<br /> }}<br /> {{Project overview<br /> |Status=In progress<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Flood risk management, Habitat and biodiversity, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames 21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Thames Water,<br /> |Name of parent multi-site project=Case_study:Rewilding Enfield's Urban Rivers<br /> |Multi-site=No<br /> |Project picture=Newly planted swale April 2015.JPG<br /> |Picture description=Planted swale April 2015<br /> |Project summary=The Houndsden Gutter is a tributary of the Salmons Brook, a small river running through Enfield which joins the Lea Navigation. Like many urban streams it suffers from pollution. Oils and heavy metals wash off the roads when it rains, flowing into surface water drains which lead straight into our streams and rivers. The plumbing in some homes and businesses is misconnected, sending water from appliances, sinks and sometimes even toilets into watercourses instead of the sewers. <br /> <br /> In 2015 we worked with the London Borough of Enfield to create two rain garden systems to improve the water quality in the stream. They have been designed to treat water that runs off Houndsden Road every time it rains, taking run-off from a busy section of Houndsden Road, which previously flowed directly into the Houndsden Gutter. Water is directed along the verge where it infiltrates into the soil or, in high flow conditions, into the large, natural woodland treatment basin. <br /> <br /> In the first system a two metre wide swale was created along the verge using a low impact digger. A footbridge was created to allow the swale to continue into the natural basin of the spinney. Kerbs were dropped at two points along the verge to allow water to enter the swales from the road. Finally, the road gully just up from the top of the system was filled so water would be redirected into the swales. <br /> Further down same road a second rain garden system was implemented in September 2015, made possible with match funding from LBE. These roadside rain gardens have allowed for another road gully to be filled and more road run-off off to be filtered before entering Houndsden Stream. This scheme consists of a swale and two rain gardens taking water from Houndsden Road. In low rainfall conditions water is temporarily stored in the rain garden basins and slowly infiltrates into the verge. In high rainfall conditions, and when the basins reach a critical limit, water is transferred through a pipe, under the footpath and into the natural woodland basin in the spinney.<br /> <br /> The water treatment occurs in two ways. In the natural woodland basin of the Spinney, chemicals which would pollute the river are naturally and safely used by plants to grow or broken down by bacteria in the soil. The swales have been planted with sedges and native grasses to slow water flow and begin the treatment, and the woodland basin planted with suitable native seed mixes. Water will then naturally soak into the soil, recharging the water table. This is particularly important during times of summer drought. These rain gardens prevent oils and heavy metals washing into the Houndsden Gutter. The stream supports a small fish population, and fish are seriously impacted by such pollutants, so reducing the pollutant levels in the stream is of great importance. <br /> <br /> In addition through this project we flagged up a highly polluting outfall, which was then investigated immediately and rectified, having an enormously positive effect on the health of the stream.<br /> |Monitoring surveys and results=At the Houndsden Spinney it has thus far been impossible to collect road run off, so we have been unable to show an effect on water quality above and below the rain garden at this site. <br /> <br /> Through our work alongside Thames Water and the EA to identify and rectify the misconnections blighting this site a significant improvement in water quality has been seen. We will soon be repeating invertebrate surveys to demonstrate this, along with public questionnaires which we hope will show an improvement in understanding of the urban water cycle and household misconnections.<br /> |Lessons learn=The road inlet designs had to be amended to capture water running along the gully with a road section cut out to allow a deep enough fall into swale. This has been rectified and the majority of run off is now entering the swales as designed.<br /> <br /> The SuDS features are currently drier than anticipated. The resilient sedges are thriving, as are unwanted terrestrial plants. This has additional maintenance implications until replanting of edge species next spring.<br /> <br /> Originally a much larger wetland was planned at this site to clean water in the stream. However the project had to be significantly scaled back as we were unable to provide data needed to the EA to approve the scheme, as collecting this level data would have been prohibitively expensive. It would be better in future to allow for longer lead time on the project and budget far more for pre-project monitoring, however in this case it is still unlikely that we would have been able to fund the data required. Monitoring of schemes such as the Salmons Brook Healthy River Challenge is imperative to provide proof that SuDS are a positive element in the toolkit of approaches to tackle urban diffuse pollution.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=Volunteers planting the swale.JPG<br /> |Caption=Volunteers planting the swale<br /> }}<br /> {{Case study image<br /> |File name=Creating the swales.JPG<br /> |Caption=Creating the swales<br /> }}<br /> {{Case study image<br /> |File name=HS pollution.jpg<br /> |Caption=Misconnection into stream<br /> }}<br /> {{Case study image<br /> |File name=HS pollution 2.jpg<br /> |Caption=Sewage fungus<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook<br /> }}<br /> {{Site}}<br /> {{Project background<br /> |Works started=2015/03/02<br /> |Works completed=2015/10/09<br /> |Funding sources=London Borough of Enfield, corporate funder, Defra<br /> }}<br /> {{Motivations}}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Houndsden_Road_Rain_Gardens&diff=36351 2016-02-15T17:34:36Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.6393116, -0.10710140000003321<br /> }}<br /> {{Project overview<br /> |Status=Complete<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Flood risk management, Habitat and biodiversity, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames 21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Thames Water, <br /> |Name of parent multi-site project=Case_study:Rewilding Enfield's Urban Rivers<br /> |Multi-site=No<br /> |Project picture=Newly planted swale April 2015.JPG<br /> |Picture description=Planted swale April 2015<br /> |Project summary=The Houndsden Gutter is a tributary of the Salmons Brook, a small river running through Enfield which joins the Lea Navigation. Like many urban streams it suffers from pollution. Oils and heavy metals wash off the roads when it rains, flowing into surface water drains which lead straight into our streams and rivers. The plumbing in some homes and businesses is misconnected, sending water from appliances, sinks and sometimes even toilets into watercourses instead of the sewers. <br /> <br /> In 2015 we worked with the London Borough of Enfield to create two rain garden systems to improve the water quality in the stream. They have been designed to treat water that runs off Houndsden Road every time it rains, taking run-off from a busy section of Houndsden Road, which previously flowed directly into the Houndsden Gutter. Water is directed along the verge where it infiltrates into the soil or, in high flow conditions, into the large, natural woodland treatment basin. <br /> <br /> In the first system a two metre wide swale was created along the verge using a low impact digger. A footbridge was created to allow the swale to continue into the natural basin of the spinney. Kerbs were dropped at two points along the verge to allow water to enter the swales from the road. Finally, the road gully just up from the top of the system was filled so water would be redirected into the swales. <br /> Further down same road a second rain garden system was implemented in September 2015, made possible with match funding from LBE. These roadside rain gardens have allowed for another road gully to be filled and more road run-off off to be filtered before entering Houndsden Stream. This scheme consists of a swale and two rain gardens taking water from Houndsden Road. In low rainfall conditions water is temporarily stored in the rain garden basins and slowly infiltrates into the verge. In high rainfall conditions, and when the basins reach a critical limit, water is transferred through a pipe, under the footpath and into the natural woodland basin in the spinney.<br /> <br /> The water treatment occurs in two ways. In the natural woodland basin of the Spinney, chemicals which would pollute the river are naturally and safely used by plants to grow or broken down by bacteria in the soil. The swales have been planted with sedges and native grasses to slow water flow and begin the treatment, and the woodland basin planted with suitable native seed mixes. Water will then naturally soak into the soil, recharging the water table. This is particularly important during times of summer drought. These rain gardens prevent oils and heavy metals washing into the Houndsden Gutter. The stream supports a small fish population, and fish are seriously impacted by such pollutants, so reducing the pollutant levels in the stream is of great importance. <br /> <br /> In addition through this project we flagged up a highly polluting outfall, which was then investigated immediately and rectified, having an enormously positive effect on the health of the stream.<br /> <br /> <br /> <br /> |Monitoring surveys and results=At the Houndsden Spinney it has thus far been impossible to collect road run off, so we have been unable to show an effect on water quality above and below the rain garden at this site. <br /> <br /> Through our work alongside Thames Water and the EA to identify and rectify the misconnections blighting this site a significant improvement in water quality has been seen. We will soon be repeating invertebrate surveys to demonstrate this, along with public questionnaires which we hope will show an improvement in understanding of the urban water cycle and household misconnections.<br /> <br /> <br /> |Lessons learn=The road inlet designs had to be amended to capture water running along the gully with a road section cut out to allow a deep enough fall into swale. This has been rectified and the majority of run off is now entering the swales as designed.<br /> <br /> The SuDS features are currently drier than anticipated. The resilient sedges are thriving, as are unwanted terrestrial plants. This has additional maintenance implications until replanting of edge species next spring.<br /> <br /> Originally a much larger wetland was planned at this site to clean water in the stream. However the project had to be significantly scaled back as we were unable to provide data needed to the EA to approve the scheme, as collecting this level data would have been prohibitively expensive. It would be better in future to allow for longer lead time on the project and budget far more for pre-project monitoring, however in this case it is still unlikely that we would have been able to fund the data required. Monitoring of schemes such as the Salmons Brook Healthy River Challenge is imperative to provide proof that SuDS are a positive element in the toolkit of approaches to tackle urban diffuse pollution. <br /> <br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=Volunteers planting the swale.JPG<br /> |Caption=Volunteers planting the swale<br /> }}<br /> {{Case study image<br /> |File name=Creating the swales.JPG<br /> |Caption=Creating the swales<br /> }}<br /> {{Case study image<br /> |File name=HS pollution.jpg<br /> |Caption=Misconnection into stream<br /> }}<br /> {{Case study image<br /> |File name=HS pollution 2.jpg<br /> |Caption=Sewage fungus<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook<br /> }}<br /> {{Site}}<br /> {{Project background<br /> |Works started=2015/03/02<br /> |Works completed=2015/10/09<br /> |Funding sources=London Borough of Enfield, corporate funder, Defra<br /> }}<br /> {{Motivations}}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Houndsden_Road_Rain_Gardens&diff=36350 2016-02-15T17:33:09Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.6393116, -0.10710140000003321<br /> }}<br /> {{Project overview<br /> |Status=Complete<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Flood risk management, Habitat and biodiversity, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames 21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Thames Water, <br /> |Name of parent multi-site project=Case_study:Rewilding Enfield's Urban Rivers<br /> |Multi-site=No<br /> |Project picture=Newly planted swale April 2015.JPG<br /> |Picture description=Planted swale April 2015<br /> |Project summary=The Houndsden Gutter is a tributary of the Salmons Brook, a small river running through Enfield which joins the Lea Navigation. Like many urban streams it suffers from pollution. Oils and heavy metals wash off the roads when it rains, flowing into surface water drains which lead straight into our streams and rivers. The plumbing in some homes and businesses is misconnected, sending water from appliances, sinks and sometimes even toilets into watercourses instead of the sewers. <br /> <br /> In 2015 we worked with the London Borough of Enfield to create two rain garden systems to improve the water quality in the stream. They have been designed to treat water that runs off Houndsden Road every time it rains, taking run-off from a busy section of Houndsden Road, which previously flowed directly into the Houndsden Gutter. Water is directed along the verge where it infiltrates into the soil or, in high flow conditions, into the large, natural woodland treatment basin. <br /> <br /> In the first system a two metre wide swale was created along the verge using a low impact digger. A footbridge was created to allow the swale to continue into the natural basin of the spinney. Kerbs were dropped at two points along the verge to allow water to enter the swales from the road. Finally, the road gully just up from the top of the system was filled so water would be redirected into the swales. <br /> Further down same road a second rain garden system was implemented in September 2015, made possible with match funding from LBE. These roadside rain gardens have allowed for another road gully to be filled and more road run-off off to be filtered before entering Houndsden Stream. This scheme consists of a swale and two rain gardens taking water from Houndsden Road. In low rainfall conditions water is temporarily stored in the rain garden basins and slowly infiltrates into the verge. In high rainfall conditions, and when the basins reach a critical limit, water is transferred through a pipe, under the footpath and into the natural woodland basin in the spinney.<br /> <br /> The water treatment occurs in two ways. In the natural woodland basin of the Spinney, chemicals which would pollute the river are naturally and safely used by plants to grow or broken down by bacteria in the soil. The swales have been planted with sedges and native grasses to slow water flow and begin the treatment, and the woodland basin planted with suitable native seed mixes. Water will then naturally soak into the soil, recharging the water table. This is particularly important during times of summer drought. These rain gardens prevent oils and heavy metals washing into the Houndsden Gutter. The stream supports a small fish population, and fish are seriously impacted by such pollutants, so reducing the pollutant levels in the stream is of great importance. <br /> <br /> In addition through this project we flagged up a highly polluting outfall, which was then investigated immediately and rectified, having an enormously positive effect on the health of the stream.<br /> <br /> <br /> <br /> |Monitoring surveys and results=At the Houndsden Spinney it has thus far been impossible to collect road run off, so we have been unable to show an effect on water quality above and below the rain garden at this site. <br /> <br /> Through our work alongside Thames Water and the EA to identify and rectify the misconnections blighting this site a significant improvement in water quality has been seen. We will soon be repeating invertebrate surveys to demonstrate this, along with public questionnaires which we hope will show an improvement in understanding of the urban water cycle and household misconnections.<br /> <br /> <br /> |Lessons learn=The road inlet designs had to be amended to capture water running along the gully with a road section cut out to allow a deep enough fall into swale. This has been rectified and the majority of run off is now entering the swales as designed.<br /> <br /> The SuDS features are currently drier than anticipated. The resilient sedges are thriving, as are unwanted terrestrial plants. This has additional maintenance implications until replanting of edge species next spring.<br /> <br /> Originally a much larger wetland was planned at this site to clean water in the stream. However the project had to be significantly scaled back as we were unable to provide data needed to the EA to approve the scheme, as collecting this level data would have been prohibitively expensive. It would be better in future to allow for longer lead time on the project and budget far more for pre-project monitoring, however in this case it is still unlikely that we would have been able to fund the data required. Monitoring of schemes such as the Salmons Brook Healthy River Challenge is imperative to provide proof that SuDS are a positive element in the toolkit of approaches to tackle urban diffuse pollution. <br /> <br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=Volunteers planting the swale.JPG<br /> |Caption=Volunteers planting the swale<br /> }}<br /> {{Case study image<br /> |File name=Creating the swales.JPG<br /> |Caption=Creating the swales<br /> }}<br /> {{Case study image<br /> |File name=HS pollution.jpg<br /> |Caption=Misconnection into stream<br /> }}<br /> {{Case study image<br /> |File name=HS pollution 2.jpg<br /> |Caption=Sewage fungus<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook<br /> }}<br /> {{Site}}<br /> {{Project background}}<br /> {{Motivations}}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Houndsden_Road_Rain_Gardens&diff=36349 2016-02-15T17:31:51Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.6393116, -0.10710140000003321<br /> }}<br /> {{Project overview<br /> |Status=Complete<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Flood risk management, Habitat and biodiversity, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames 21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Thames Water, <br /> |Name of parent multi-site project=Case_study:Rewilding Enfield's Urban Rivers<br /> |Multi-site=No<br /> |Project picture=Newly planted swale April 2015.JPG<br /> |Picture description=Planted swale April 2015<br /> |Project summary=The Houndsden Gutter is a tributary of the Salmons Brook, a small river running through Enfield which joins the Lea Navigation. Like many urban streams it suffers from pollution. Oils and heavy metals wash off the roads when it rains, flowing into surface water drains which lead straight into our streams and rivers. The plumbing in some homes and businesses is misconnected, sending water from appliances, sinks and sometimes even toilets into watercourses instead of the sewers. <br /> <br /> In 2015 we worked with the London Borough of Enfield to create two rain garden systems to improve the water quality in the stream. They have been designed to treat water that runs off Houndsden Road every time it rains, taking run-off from a busy section of Houndsden Road, which previously flowed directly into the Houndsden Gutter. Water is directed along the verge where it infiltrates into the soil or, in high flow conditions, into the large, natural woodland treatment basin. <br /> <br /> In the first system a two metre wide swale was created along the verge using a low impact digger. A footbridge was created to allow the swale to continue into the natural basin of the spinney. Kerbs were dropped at two points along the verge to allow water to enter the swales from the road. Finally, the road gully just up from the top of the system was filled so water would be redirected into the swales. <br /> Further down same road a second rain garden system was implemented in September 2015, made possible with match funding from LBE. These roadside rain gardens have allowed for another road gully to be filled and more road run-off off to be filtered before entering Houndsden Stream. This scheme consists of a swale and two rain gardens taking water from Houndsden Road. In low rainfall conditions water is temporarily stored in the rain garden basins and slowly infiltrates into the verge. In high rainfall conditions, and when the basins reach a critical limit, water is transferred through a pipe, under the footpath and into the natural woodland basin in the spinney.<br /> <br /> The water treatment occurs in two ways. In the natural woodland basin of the Spinney, chemicals which would pollute the river are naturally and safely used by plants to grow or broken down by bacteria in the soil. The swales have been planted with sedges and native grasses to slow water flow and begin the treatment, and the woodland basin planted with suitable native seed mixes. Water will then naturally soak into the soil, recharging the water table. This is particularly important during times of summer drought. These rain gardens prevent oils and heavy metals washing into the Houndsden Gutter. The stream supports a small fish population, and fish are seriously impacted by such pollutants, so reducing the pollutant levels in the stream is of great importance. <br /> <br /> In addition through this project we flagged up a highly polluting outfall, which was then investigated immediately and rectified, having an enormously positive effect on the health of the stream.<br /> <br /> <br /> <br /> |Monitoring surveys and results=At the Houndsden Spinney it has thus far been impossible to collect road run off, so we have been unable to show an effect on water quality above and below the rain garden at this site. <br /> <br /> Through our work alongside Thames Water and the EA to identify and rectify the misconnections blighting this site a significant improvement in water quality has been seen. We will soon be repeating invertebrate surveys to demonstrate this, along with public questionnaires which we hope will show an improvement in understanding of the urban water cycle and household misconnections.<br /> <br /> <br /> |Lessons learn=The road inlet designs had to be amended to capture water running along the gully with a road section cut out to allow a deep enough fall into swale. This has been rectified and the majority of run off is now entering the swales as designed.<br /> <br /> The SuDS features are currently drier than anticipated. The resilient sedges are thriving, as are unwanted terrestrial plants. This has additional maintenance implications until replanting of edge species next spring.<br /> <br /> Originally a much larger wetland was planned at this site to clean water in the stream. However the project had to be significantly scaled back as we were unable to provide data needed to the EA to approve the scheme, as collecting this level data would have been prohibitively expensive. It would be better in future to allow for longer lead time on the project and budget far more for pre-project monitoring, however in this case it is still unlikely that we would have been able to fund the data required. Monitoring of schemes such as the Salmons Brook Healthy River Challenge is imperative to provide proof that SuDS are a positive element in the toolkit of approaches to tackle urban diffuse pollution. <br /> <br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=Volunteers planting the swale.JPG<br /> |Caption=Volunteers planting the swale<br /> }}<br /> {{Case study image<br /> |File name=Creating the swales.JPG<br /> |Caption=Creating the swales<br /> }}<br /> {{Case study image<br /> |File name=HS pollution.jpg<br /> |Caption=Misconnection into stream<br /> }}<br /> {{Case study image<br /> |File name=HS pollution 2.jpg<br /> |Caption=Sewage fungus<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment}}<br /> {{Site}}<br /> {{Project background}}<br /> {{Motivations}}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=File:HS_pollution_2.jpg&diff=36348 2016-02-15T17:29:12Z

<p>AimeeThames21: </p> <hr /> <div></div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=File:HS_pollution.jpg&diff=36347 2016-02-15T17:28:46Z

<p>AimeeThames21: </p> <hr /> <div></div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=File:Creating_the_swales.JPG&diff=36346 2016-02-15T17:28:08Z

<p>AimeeThames21: </p> <hr /> <div></div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=File:Volunteers_planting_the_swale.JPG&diff=36345 2016-02-15T17:26:37Z

<p>AimeeThames21: </p> <hr /> <div></div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Houndsden_Road_Rain_Gardens&diff=36344 2016-02-15T17:24:46Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.6393116, -0.10710140000003321<br /> }}<br /> {{Project overview<br /> |Status=Complete<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Flood risk management, Habitat and biodiversity, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames 21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Thames Water, <br /> |Name of parent multi-site project=Case_study:Rewilding Enfield's Urban Rivers<br /> |Multi-site=No<br /> |Project picture=Newly planted swale April 2015.JPG<br /> |Picture description=Planted swale April 2015<br /> |Project summary=The Houndsden Gutter is a tributary of the Salmons Brook, a small river running through Enfield which joins the Lea Navigation. Like many urban streams it suffers from pollution. Oils and heavy metals wash off the roads when it rains, flowing into surface water drains which lead straight into our streams and rivers. The plumbing in some homes and businesses is misconnected, sending water from appliances, sinks and sometimes even toilets into watercourses instead of the sewers. <br /> <br /> In 2015 we worked with the London Borough of Enfield to create two rain garden systems to improve the water quality in the stream. They have been designed to treat water that runs off Houndsden Road every time it rains, taking run-off from a busy section of Houndsden Road, which previously flowed directly into the Houndsden Gutter. Water is directed along the verge where it infiltrates into the soil or, in high flow conditions, into the large, natural woodland treatment basin. <br /> <br /> In the first system a two metre wide swale was created along the verge using a low impact digger. A footbridge was created to allow the swale to continue into the natural basin of the spinney. Kerbs were dropped at two points along the verge to allow water to enter the swales from the road. Finally, the road gully just up from the top of the system was filled so water would be redirected into the swales. <br /> Further down same road a second rain garden system was implemented in September 2015, made possible with match funding from LBE. These roadside rain gardens have allowed for another road gully to be filled and more road run-off off to be filtered before entering Houndsden Stream. This scheme consists of a swale and two rain gardens taking water from Houndsden Road. In low rainfall conditions water is temporarily stored in the rain garden basins and slowly infiltrates into the verge. In high rainfall conditions, and when the basins reach a critical limit, water is transferred through a pipe, under the footpath and into the natural woodland basin in the spinney.<br /> <br /> The water treatment occurs in two ways. In the natural woodland basin of the Spinney, chemicals which would pollute the river are naturally and safely used by plants to grow or broken down by bacteria in the soil. The swales have been planted with sedges and native grasses to slow water flow and begin the treatment, and the woodland basin planted with suitable native seed mixes. Water will then naturally soak into the soil, recharging the water table. This is particularly important during times of summer drought. These rain gardens prevent oils and heavy metals washing into the Houndsden Gutter. The stream supports a small fish population, and fish are seriously impacted by such pollutants, so reducing the pollutant levels in the stream is of great importance. <br /> <br /> In addition through this project we flagged up a highly polluting outfall, which was then investigated immediately and rectified, having an enormously positive effect on the health of the stream.<br /> <br /> <br /> <br /> |Monitoring surveys and results=At the Houndsden Spinney it has thus far been impossible to collect road run off, so we have been unable to show an effect on water quality above and below the rain garden at this site. <br /> <br /> Through our work alongside Thames Water and the EA to identify and rectify the misconnections blighting this site a significant improvement in water quality has been seen. We will soon be repeating invertebrate surveys to demonstrate this, along with public questionnaires which we hope will show an improvement in understanding of the urban water cycle and household misconnections.<br /> <br /> <br /> |Lessons learn=The road inlet designs had to be amended to capture water running along the gully with a road section cut out to allow a deep enough fall into swale. This has been rectified and the majority of run off is now entering the swales as designed.<br /> <br /> The SuDS features are currently drier than anticipated. The resilient sedges are thriving, as are unwanted terrestrial plants. This has additional maintenance implications until replanting of edge species next spring.<br /> <br /> Originally a much larger wetland was planned at this site to clean water in the stream. However the project had to be significantly scaled back as we were unable to provide data needed to the EA to approve the scheme, as collecting this level data would have been prohibitively expensive. It would be better in future to allow for longer lead time on the project and budget far more for pre-project monitoring, however in this case it is still unlikely that we would have been able to fund the data required. Monitoring of schemes such as the Salmons Brook Healthy River Challenge is imperative to provide proof that SuDS are a positive element in the toolkit of approaches to tackle urban diffuse pollution. <br /> <br /> }}<br /> {{Image gallery}}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment}}<br /> {{Site}}<br /> {{Project background}}<br /> {{Motivations}}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=File:Newly_planted_swale_April_2015.JPG&diff=36343 2016-02-15T17:05:03Z

<p>AimeeThames21: </p> <hr /> <div></div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Houndsden_Road_Rain_Gardens&diff=36342 2016-02-15T17:01:51Z

<p>AimeeThames21: Created page with &quot;{{Case study status |Approval status=Draft }} {{Location |Location=51.6393116, -0.10710140000003321 }} {{Project overview |Project title=Houndsden Road Rain Gardens |Status=Co...&quot;</p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.6393116, -0.10710140000003321<br /> }}<br /> {{Project overview<br /> |Project title=Houndsden Road Rain Gardens<br /> |Status=Complete<br /> |Themes=Flood risk management, Habitat and biodiversity, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames 21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Multi-site=No<br /> |Name of parent multi-site project=Case_study:Rewilding Enfield's Urban Rivers<br /> }}<br /> {{Image gallery}}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment}}<br /> {{Site}}<br /> {{Project background}}<br /> {{Motivations}}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Grovelands_Park_Wetlands&diff=36341 2016-02-15T16:14:09Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.635654232931394, -0.10910797125688987<br /> }}<br /> {{Project overview<br /> |Status=Complete<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Environmental flows and water resources, Flood risk management, Habitat and biodiversity, Hydromorphology, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Thames Water,<br /> |Name of parent multi-site project=Case_study:Rewilding Enfield's Urban Rivers<br /> |Multi-site=No<br /> |Project picture=Thames21-grovelandspk-justinetrickett-1248.jpg<br /> |Picture description=Grovelands Park Wetlands, summer 2015<br /> |Project summary=The water system in Grovelands Park, Enfield, has been artificially engineered over time, with a long stretch of the stream being contained in an underground pipe, hidden from view and useless to wildlife. Here beneath the ground two surface water drains from local roads and homes washed pollutants straight into the stream every time it rained. Plumbing misconnections added to the problem. <br /> <br /> In spring 2014 we worked with the London Borough of Enfield to 'rewild' the water system in Grovelands Park. We created wetlands to intercept pollutants entering the stream in Grovelands Park. Flows in the surface water drains were diverted into shallow ditches, known as swales, and then into a wetland basin. The swales and basin were planted with sedges suitable for the semi-shaded woodland conditions. The plants use excess nutrients such as phosphates and nitrates to grow, preventing them building up in the water which causes the toxic algal blooms. The plants also oxygenate the water. Bacteria growing in the sediment and root systems break down oils and some bacteria can even reduce levels of heavy metals in the water. The clean water then soaks into the ground, as it would naturally, or overflows back into the stream. Rainwater washing off an area the size of 11 rugby fields is cleaned in the wetland. As we completed this project Thames Water ran misconnection surveys on the urban catchment, a vital piece of the jigsaw to ensure optimal results in this project.<br /> <br /> At the same time the London Borough of Enfield naturalised 200m of the stream, breaking it out of its underground pipe and allowing it to find its own course meandering through the woodland. These two projects restored the water system to its natural state, better able to cope with floods and slowing high flows of stormwater, as well as treating pollutants. <br /> <br /> The lake in Grovelands Park, Enfield is the centrepiece of a beautiful and grand garden for the ‘Southgate Grove’ mansion, designed in the 18th century and now a well-loved and popular public park. Sadly the lake is afflicted with pollution from a number of surface water drains, and toxic algal blooms are common in summer. Rainwater running off local streets brings with it oils and heavy metals from the road, as well as detergents and other chemicals such as phosphates and nitrates from misconnected plumbing. This pollution load limits the lake’s potential as a wildlife habitat and its appeal for park visitors.<br /> <br /> In June 2015 we created a reed bed in the south western end of the lake to naturally break down these pollutants and increase oxygen levels in the water, as well as providing a new habitat for birds and insects. Coir rolls and hazel faggots were used to create an area of suitable depth to establish the reed bed. Coir mats pre-planted with reeds, rushes, sedges and colourful purple loosestrife and yellow flag iris were installed across the reed bed area, protected from wildfowl grazing by netting. As in the wetland, the plants use excess nutrients such as phosphates and nitrates to grow, preventing them building up in the water which causes the toxic algal blooms. The plants also oxygenate the water. Bacteria growing in the sediment and root systems break down oils and some bacteria can even reduce levels of heavy metals in the water.<br /> |Monitoring surveys and results=Nitrogen is essential for river life but in excess can cause eutrophication. This results in reduced levels of oxygen in the water and may cause toxic algal blooms. Nitrate may be present as ammonia, nitrite or nitrate (measured together as Total Nitrogen), but nitrate is the most stable form. <br /> <br /> Reed bed: The recently installed reed bed is already proving effective at removing nitrogen compounds from the water. There is a significant difference in water quality between the inflow above the reed bed (sampling location 1) and the sampling location immediately the other side of the reed bed (location 2) in total nitrogen, nitrate and ammonia. Total nitrogen drops from 7mg/l to 5mg/l, nitrate from 13mg/l to 4mg//l and ammonia from 1.6mg/l to 0.5mg/l. The improvement in water quality through the reed bed is greater than the improvement observed in the body of the lake. This is because the difference in water quality is larger between sampling sites 1 and 2 compared to between sites 2 and 3 (the lake outflow). <br /> <br /> Wetland basin: The wetland basin is effective at water quality improvement because it prevents polluted water from two drains (sample locations 5 and 6) from entering the stream at site 4. Water entering the infiltration basin from the de-culverted pipe at sampling site 6 is consistently outside of acceptable concentration ranges specified by the Water Framework Directive. Ammonia is consistently present in levels deemed harmful to aquatic life in both inflow pipes (sample locations 5 and 6). Water only flows out of the wetland basin in storm conditions so it effectively prevents polluted water from entering the stream. <br /> <br /> Coliform bacteria derive from faecal waste and are an indicator of pathogens in the aquatic environment. They enter waterways from misconnected toilets, sewage treatment plant overflow, domestic pets and agricultural run off.<br /> <br /> Reed bed: The reed bed is an effective remover of coliform bacteria, reducing the coliform colony count to within guideline limits (under EC Bathing Water Directive)immediately after the reedbed (sample location 2), dropping from approximately 1100 total coliform colonies to 50 total coliform colonies. <br /> <br /> Wetland basin: Water entering the wetland basin from the culverts at sampling sites 5 and 6 contains high counts of coliform bacteria, that are outside of guideline limits (under EC Bathing Water Directive). This is prevented from entering the stream (sample location 4) because water only flows out of the wetland basin in storm conditions.<br /> |Lessons learn=The wetland basin is quite large, sized for greater flows than have been experienced so far. This means that the water in the treatment basin overflows only during very heavy rainfall events. This is not a significant problem, it just means that the basin is acting more as an infiltration basin rather than a temporary storage basin. The system still functions to prevent polluted water entering the stream. <br /> <br /> The plug planted sedges in the basin are thriving in this environment as the system was not fully activated until the plants were well established. However in the more shaded swales with greater velocity of flows and concentration of pollution the plugs have failed and need to be replanted. <br /> <br /> Sedges have grown lush and verdant in the basin and water is cleaned and returned to the stream as expected or returned to the water table. Although perhaps not as aesthetically pleasing as in the design, the boulder arrangement at the head of the swales has worked well to slow water and prevent excessive erosion in the swales. <br /> <br /> Water quality issues were far more significant than we had anticipated on commencement of the project, particularly in relation to domestic misconnections. High pollutant levels were evident beginning of our swales. We also found that although we proved our systems had a beneficial impact on water quality, just downstream of each project were outfalls which would bring in yet more pollutants. Therefore wetlands and SuDS alone could not demonstrate catchment level water improvements needed under WFD. Small scale interventions have a place in a suite of wider measures that need to be tackled with more drive, especially pollutant impacts from misconnections and vehicle use.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1206.jpg<br /> |Caption=Reedbed summer 2015<br /> }}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1261.jpg<br /> |Caption=Overflow from wetland<br /> }}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1266.jpg<br /> |Caption=Restored stream meandering through woodland<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook<br /> }}<br /> {{Site<br /> |Name=Unnamed tributary of Salmons Brook<br /> |WFD water body name=Salmons Brook<br /> |Pre-project morphology=Closed culvert, <br /> |Desired post project morphology=Actively meandering, <br /> |Heavily modified water body=Yes<br /> |Protected species present=No<br /> |Invasive species present=No<br /> |Dominant substrate=London Clay<br /> |River corridor land use=Urban, <br /> }}<br /> {{Project background<br /> |Reach length directly affected=200<br /> |Project started=2014/02/01<br /> |Project completed=2015/07/10<br /> |Funding sources=Defra, London Borough of Enfield, Thames Water<br /> }}<br /> {{Motivations<br /> |Specific mitigation=Poor water quality, Flood risk management, Urbanisation,<br /> |Hydromorphological quality elements=Good status in 2011<br /> |Biological quality elements= In 2011 - Phytobenthos, macrophytes, invertebrates poor and fish moderate<br /> |Physico-chemical quality elements=In 2011 - Ammonia moderate, dissolved oxygen and phosphate poor, annex 8 chem. high<br /> |Other motivation= Improving a public space, flood protection, terrestrial biodiversity improvements<br /> }}<br /> {{Measures<br /> |Bank and bed modifications measure=Deculverting, <br /> |Floodplain / River corridor=Creation of swales and wetland basin, stream allowed to find new course<br /> |Planform / Channel pattern=Actively meandering<br /> |Social measures=Community consultations, volunteer engagement, education sessions, interpretation, access improvements <br /> |Wider stakeholder / citizen engagement=Reedbed creation in lake<br /> }}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Rewilding_Enfield%27s_Urban_Rivers&diff=36340 2016-02-15T16:12:56Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.6522994, -0.08071189999998296<br /> }}<br /> {{Project overview<br /> |Status=In progress<br /> |Themes=Flood risk management, Habitat and biodiversity, Hydromorphology, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames 21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Environment Agency (in an advisory role), Thames Water, <br /> |Multi-site=Yes<br /> |Project summary=An innovative partnership project to 'rewild' Enfield's urban rivers and renaturalise the water system. The project encompasses 8 sites across the Salmons Brook and Pymmes Brook catchments, themselves part of the Lea catchment. Rivers here suffer from turban pollution, typically from road run off and misconnections. they are often heavily modified or culverted. The project aims to improve water quality, provide flood risk management, improve public spaces, increase good quality habitat and therefore promote biodiversity. Furthermore we aim to increase knowledge of the urban water cycle and how we influence it, and how we can protect our rivers.<br /> <br /> The project is led by the London Borough of Enfield and Thames21, with assistance from Thames Water and advisory input from the Environment Agency. Funders include Defra, Thames Water, the Environment Agency and Greater London Authority.<br /> <br /> Works to the watercourses and their catchments include the creation of wetlands, reedbeds, rain gardens and rain planters, as well as deculverting a stream through a popular park. In addition public engagement and education is key, and interpretation and access enhancements are being carried out on each site. Consulation was carried out before works, and additional project partners include many volunteers and advocates from the local community, as well as Friends groups in parks. <br /> |Monitoring surveys and results=Monitoring has included water quality testing, macroinvertebrate sampling, fixed point photography, questionnaires and ecological surveys. See individual entries for more details. <br /> |Lessons learn=See individual project entries.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=SuDS in Enfield.jpg<br /> |Caption=Wetlands, rain gardens, rain planters in Enfield<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook and Pymmes Brook<br /> }}<br /> {{Site<br /> |Name=Numerous<br /> |WFD water body code=GB106038027960 and GB106038027940<br /> |WFD water body name=Salmons Brook and Pymmes Brook<br /> |Heavily modified water body=Yes<br /> |Protected species present=No<br /> |Invasive species present=No<br /> }}<br /> {{Project background<br /> |Project started=2012/08/06<br /> |Funding sources=Defra, Thames Water, EA, GLA<br /> }}<br /> {{Motivations<br /> |Specific mitigation=Poor water quality, Flood risk management, <br /> |Hydromorphological quality elements=Heavily modified waterbodies<br /> |Biological quality elements=Poor ecology due to above and pollution issues<br /> |Physico-chemical quality elements=Urban diffuse and point source pollution from misconnections and road run off<br /> |Other motivation=Improvement to public space and biodiversity<br /> }}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Rewilding_Enfield%27s_Urban_Rivers&diff=36339 2016-02-15T16:10:56Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.6522994, -0.08071189999998296<br /> }}<br /> {{Project overview<br /> |Status=In progress<br /> |Themes=Flood risk management, Habitat and biodiversity, Hydromorphology, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames 21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Environment Agency (in an advisory role), Thames Water, <br /> |Multi-site=Yes<br /> |Project summary=An innovative partnership project to 'rewild' Enfield's urban rivers and renaturalise the water system. The project encompasses 8 sites across the Salmons Brook and Pymmes Brook catchments, themselves part of the Lea catchment. Rivers here suffer from turban pollution, typically from road run off and misconnections. they are often heavily modified or culverted. The project aims to improve water quality, provide flood risk management, improve public spaces, increase good quality habitat and therefore promote biodiversity. Furthermore we aim to increase knowledge of the urban water cycle and how we influence it, and how we can protect our rivers.<br /> <br /> The project is led by the London Borough of Enfield and Thames21, with assistance from Thames Water and advisory input from the Environment Agency. Funders include Defra, Thames Water, the Environment Agency and Greater London Authority.<br /> <br /> Works to the watercourses and their catchments include the creation of wetlands, reedbeds, rain gardens and rain planters, as well as deculverting a stream through a popular park. In addition public engagement and education is key, and interpretation and access enhancements are being carried out on each site. Consulation was carried out before works, and additional project partners include many volunteers and advocates from the local community, as well as Friends groups in parks. <br /> |Monitoring surveys and results=Monitoring has included water quality testing, macroinvertebrate sampling, fixed point photography, questionnaires and ecological surveys. See individual entries for more details. <br /> |Lessons learn=See individual project entries.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=SuDS in Enfield.jpg<br /> |Caption=Wetlands, rain gardens, rain planters in Enfield<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook and Pymmes Brook<br /> }}<br /> {{Site<br /> |Name=Numerous<br /> |WFD water body code=GB106038027960 and GB106038027940<br /> |WFD water body name=Salmons Brook and Pymmes Brook<br /> |Heavily modified water body=Yes<br /> |Protected species present=No<br /> |Invasive species present=No<br /> }}<br /> {{Project background<br /> |Project started=2012/08/06<br /> |Funding sources=Defra, Thames Water, EA, GLA<br /> }}<br /> {{Motivations}}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Rewilding_Enfield%27s_Urban_Rivers&diff=36338 2016-02-15T16:09:50Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.6522994, -0.08071189999998296<br /> }}<br /> {{Project overview<br /> |Status=In progress<br /> |Themes=Flood risk management, Habitat and biodiversity, Hydromorphology, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames 21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Environment Agency (in an advisory role), Thames Water, <br /> |Multi-site=Yes<br /> |Project summary=An innovative partnership project to 'rewild' Enfield's urban rivers and renaturalise the water system. The project encompasses 8 sites across the Salmons Brook and Pymmes Brook catchments, themselves part of the Lea catchment. Rivers here suffer from turban pollution, typically from road run off and misconnections. they are often heavily modified or culverted. The project aims to improve water quality, provide flood risk management, improve public spaces, increase good quality habitat and therefore promote biodiversity. Furthermore we aim to increase knowledge of the urban water cycle and how we influence it, and how we can protect our rivers.<br /> <br /> The project is led by the London Borough of Enfield and Thames21, with assistance from Thames Water and advisory input from the Environment Agency. Funders include Defra, Thames Water, the Environment Agency and Greater London Authority.<br /> <br /> Works to the watercourses and their catchments include the creation of wetlands, reedbeds, rain gardens and rain planters, as well as deculverting a stream through a popular park. In addition public engagement and education is key, and interpretation and access enhancements are being carried out on each site. Consulation was carried out before works, and additional project partners include many volunteers and advocates from the local community, as well as Friends groups in parks. <br /> |Monitoring surveys and results=Monitoring has included water quality testing, macroinvertebrate sampling, fixed point photography, questionnaires and ecological surveys. See individual entries for more details. <br /> |Lessons learn=See individual project entries.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=SuDS in Enfield.jpg<br /> |Caption=Wetlands, rain gardens, rain planters in Enfield<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook and Pymmes Brook<br /> }}<br /> {{Site<br /> |Name=Numerous<br /> |WFD water body code=GB106038027960 and GB106038027940<br /> |WFD water body name=Salmons Brook and Pymmes Brook<br /> |Heavily modified water body=Yes<br /> |Protected species present=No<br /> |Invasive species present=No<br /> }}<br /> {{Project background}}<br /> {{Motivations}}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Rewilding_Enfield%27s_Urban_Rivers&diff=36337 2016-02-15T16:07:07Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.6522994, -0.08071189999998296<br /> }}<br /> {{Project overview<br /> |Status=In progress<br /> |Themes=Flood risk management, Habitat and biodiversity, Hydromorphology, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames 21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Environment Agency (in an advisory role), Thames Water, <br /> |Multi-site=Yes<br /> |Project summary=An innovative partnership project to 'rewild' Enfield's urban rivers and renaturalise the water system. The project encompasses 8 sites across the Salmons Brook and Pymmes Brook catchments, themselves part of the Lea catchment. Rivers here suffer from turban pollution, typically from road run off and misconnections. they are often heavily modified or culverted. The project aims to improve water quality, provide flood risk management, improve public spaces, increase good quality habitat and therefore promote biodiversity. Furthermore we aim to increase knowledge of the urban water cycle and how we influence it, and how we can protect our rivers.<br /> <br /> The project is led by the London Borough of Enfield and Thames21, with assistance from Thames Water and advisory input from the Environment Agency. Funders include Defra, Thames Water, the Environment Agency and Greater London Authority.<br /> <br /> Works to the watercourses and their catchments include the creation of wetlands, reedbeds, rain gardens and rain planters, as well as deculverting a stream through a popular park. In addition public engagement and education is key, and interpretation and access enhancements are being carried out on each site. Consulation was carried out before works, and additional project partners include many volunteers and advocates from the local community, as well as Friends groups in parks. <br /> |Monitoring surveys and results=Monitoring has included water quality testing, macroinvertebrate sampling, fixed point photography, questionnaires and ecological surveys. See individual entries for more details. <br /> |Lessons learn=See individual project entries.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=SuDS in Enfield.jpg<br /> |Caption=Wetlands, rain gardens, rain planters in Enfield<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook and Pymmes Brook<br /> }}<br /> {{Site}}<br /> {{Project background}}<br /> {{Motivations}}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Rewilding_Enfield%27s_Urban_Rivers&diff=36336 2016-02-15T16:06:19Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.6522994, -0.08071189999998296<br /> }}<br /> {{Project overview<br /> |Status=In progress<br /> |Themes=Flood risk management, Habitat and biodiversity, Hydromorphology, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames 21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Environment Agency (in an advisory role), Thames Water, <br /> |Multi-site=Yes<br /> |Project summary=An innovative partnership project to 'rewild' Enfield's urban rivers and renaturalise the water system. The project encompasses 8 sites across the Salmons Brook and Pymmes Brook catchments, themselves part of the Lea catchment. Rivers here suffer from turban pollution, typically from road run off and misconnections. they are often heavily modified or culverted. The project aims to improve water quality, provide flood risk management, improve public spaces, increase good quality habitat and therefore promote biodiversity. Furthermore we aim to increase knowledge of the urban water cycle and how we influence it, and how we can protect our rivers.<br /> <br /> The project is led by the London Borough of Enfield and Thames21, with assistance from Thames Water and advisory input from the Environment Agency. Funders include Defra, Thames Water, the Environment Agency and Greater London Authority.<br /> <br /> Works to the watercourses and their catchments include the creation of wetlands, reedbeds, rain gardens and rain planters, as well as deculverting a stream through a popular park. In addition public engagement and education is key, and interpretation and access enhancements are being carried out on each site. Consulation was carried out before works, and additional project partners include many volunteers and advocates from the local community, as well as Friends groups in parks. <br /> |Monitoring surveys and results=Monitoring has included water quality testing, macroinvertebrate sampling, fixed point photography, questionnaires and ecological surveys. See individual entries for more details. <br /> |Lessons learn=See individual project entries.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=SuDS in Enfield.jpg<br /> |Caption=Wetlands, rain gardens, rain planters in Enfield<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment}}<br /> {{Site}}<br /> {{Project background}}<br /> {{Motivations}}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=File:SuDS_in_Enfield.jpg&diff=36335 2016-02-15T16:05:21Z

<p>AimeeThames21: </p> <hr /> <div></div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Rewilding_Enfield%27s_Urban_Rivers&diff=36334 2016-02-15T16:03:49Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.6522994, -0.08071189999998296<br /> }}<br /> {{Project overview<br /> |Status=In progress<br /> |Themes=Flood risk management, Habitat and biodiversity, Hydromorphology, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames 21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Environment Agency (in an advisory role), Thames Water, <br /> |Multi-site=Yes<br /> |Project summary=An innovative partnership project to 'rewild' Enfield's urban rivers and renaturalise the water system. The project encompasses 8 sites across the Salmons Brook and Pymmes Brook catchments, themselves part of the Lea catchment. Rivers here suffer from turban pollution, typically from road run off and misconnections. they are often heavily modified or culverted. The project aims to improve water quality, provide flood risk management, improve public spaces, increase good quality habitat and therefore promote biodiversity. Furthermore we aim to increase knowledge of the urban water cycle and how we influence it, and how we can protect our rivers.<br /> <br /> The project is led by the London Borough of Enfield and Thames21, with assistance from Thames Water and advisory input from the Environment Agency. Funders include Defra, Thames Water, the Environment Agency and Greater London Authority.<br /> <br /> Works to the watercourses and their catchments include the creation of wetlands, reedbeds, rain gardens and rain planters, as well as deculverting a stream through a popular park. In addition public engagement and education is key, and interpretation and access enhancements are being carried out on each site. Consulation was carried out before works, and additional project partners include many volunteers and advocates from the local community, as well as Friends groups in parks. <br /> |Monitoring surveys and results=Monitoring has included water quality testing, macroinvertebrate sampling, fixed point photography, questionnaires and ecological surveys. See individual entries for more details. <br /> |Lessons learn=See individual project entries.<br /> }}<br /> {{Image gallery}}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment}}<br /> {{Site}}<br /> {{Project background}}<br /> {{Motivations}}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Rewilding_Enfield%27s_Urban_Rivers&diff=36332 2016-02-15T15:51:31Z

<p>AimeeThames21: Created page with &quot;{{Case study status |Approval status=Draft }} {{Location |Location=51.6522994, -0.08071189999998296 }} {{Project overview |Project title=Rewilding Enfield&#039;s Urban Rivers |Stat...&quot;</p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.6522994, -0.08071189999998296<br /> }}<br /> {{Project overview<br /> |Project title=Rewilding Enfield's Urban Rivers<br /> |Status=In progress<br /> |Themes=Flood risk management, Habitat and biodiversity, Hydromorphology, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames 21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Multi-site=Yes<br /> }}<br /> {{Image gallery}}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment}}<br /> {{Site}}<br /> {{Project background}}<br /> {{Motivations}}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Grovelands_Park_Wetlands&diff=36331 2016-02-15T15:10:09Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.635654232931394, -0.10910797125688987<br /> }}<br /> {{Project overview<br /> |Status=Complete<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Environmental flows and water resources, Flood risk management, Habitat and biodiversity, Hydromorphology, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Thames Water,<br /> |Multi-site=No<br /> |Project picture=Thames21-grovelandspk-justinetrickett-1248.jpg<br /> |Picture description=Grovelands Park Wetlands, summer 2015<br /> |Project summary=The water system in Grovelands Park, Enfield, has been artificially engineered over time, with a long stretch of the stream being contained in an underground pipe, hidden from view and useless to wildlife. Here beneath the ground two surface water drains from local roads and homes washed pollutants straight into the stream every time it rained. Plumbing misconnections added to the problem. <br /> <br /> In spring 2014 we worked with the London Borough of Enfield to 'rewild' the water system in Grovelands Park. We created wetlands to intercept pollutants entering the stream in Grovelands Park. Flows in the surface water drains were diverted into shallow ditches, known as swales, and then into a wetland basin. The swales and basin were planted with sedges suitable for the semi-shaded woodland conditions. The plants use excess nutrients such as phosphates and nitrates to grow, preventing them building up in the water which causes the toxic algal blooms. The plants also oxygenate the water. Bacteria growing in the sediment and root systems break down oils and some bacteria can even reduce levels of heavy metals in the water. The clean water then soaks into the ground, as it would naturally, or overflows back into the stream. Rainwater washing off an area the size of 11 rugby fields is cleaned in the wetland. As we completed this project Thames Water ran misconnection surveys on the urban catchment, a vital piece of the jigsaw to ensure optimal results in this project.<br /> <br /> At the same time the London Borough of Enfield naturalised 200m of the stream, breaking it out of its underground pipe and allowing it to find its own course meandering through the woodland. These two projects restored the water system to its natural state, better able to cope with floods and slowing high flows of stormwater, as well as treating pollutants. <br /> <br /> The lake in Grovelands Park, Enfield is the centrepiece of a beautiful and grand garden for the ‘Southgate Grove’ mansion, designed in the 18th century and now a well-loved and popular public park. Sadly the lake is afflicted with pollution from a number of surface water drains, and toxic algal blooms are common in summer. Rainwater running off local streets brings with it oils and heavy metals from the road, as well as detergents and other chemicals such as phosphates and nitrates from misconnected plumbing. This pollution load limits the lake’s potential as a wildlife habitat and its appeal for park visitors.<br /> <br /> In June 2015 we created a reed bed in the south western end of the lake to naturally break down these pollutants and increase oxygen levels in the water, as well as providing a new habitat for birds and insects. Coir rolls and hazel faggots were used to create an area of suitable depth to establish the reed bed. Coir mats pre-planted with reeds, rushes, sedges and colourful purple loosestrife and yellow flag iris were installed across the reed bed area, protected from wildfowl grazing by netting. As in the wetland, the plants use excess nutrients such as phosphates and nitrates to grow, preventing them building up in the water which causes the toxic algal blooms. The plants also oxygenate the water. Bacteria growing in the sediment and root systems break down oils and some bacteria can even reduce levels of heavy metals in the water.<br /> |Monitoring surveys and results=Nitrogen is essential for river life but in excess can cause eutrophication. This results in reduced levels of oxygen in the water and may cause toxic algal blooms. Nitrate may be present as ammonia, nitrite or nitrate (measured together as Total Nitrogen), but nitrate is the most stable form. <br /> <br /> Reed bed: The recently installed reed bed is already proving effective at removing nitrogen compounds from the water. There is a significant difference in water quality between the inflow above the reed bed (sampling location 1) and the sampling location immediately the other side of the reed bed (location 2) in total nitrogen, nitrate and ammonia. Total nitrogen drops from 7mg/l to 5mg/l, nitrate from 13mg/l to 4mg//l and ammonia from 1.6mg/l to 0.5mg/l. The improvement in water quality through the reed bed is greater than the improvement observed in the body of the lake. This is because the difference in water quality is larger between sampling sites 1 and 2 compared to between sites 2 and 3 (the lake outflow). <br /> <br /> Wetland basin: The wetland basin is effective at water quality improvement because it prevents polluted water from two drains (sample locations 5 and 6) from entering the stream at site 4. Water entering the infiltration basin from the de-culverted pipe at sampling site 6 is consistently outside of acceptable concentration ranges specified by the Water Framework Directive. Ammonia is consistently present in levels deemed harmful to aquatic life in both inflow pipes (sample locations 5 and 6). Water only flows out of the wetland basin in storm conditions so it effectively prevents polluted water from entering the stream. <br /> <br /> Coliform bacteria derive from faecal waste and are an indicator of pathogens in the aquatic environment. They enter waterways from misconnected toilets, sewage treatment plant overflow, domestic pets and agricultural run off.<br /> <br /> Reed bed: The reed bed is an effective remover of coliform bacteria, reducing the coliform colony count to within guideline limits (under EC Bathing Water Directive)immediately after the reedbed (sample location 2), dropping from approximately 1100 total coliform colonies to 50 total coliform colonies. <br /> <br /> Wetland basin: Water entering the wetland basin from the culverts at sampling sites 5 and 6 contains high counts of coliform bacteria, that are outside of guideline limits (under EC Bathing Water Directive). This is prevented from entering the stream (sample location 4) because water only flows out of the wetland basin in storm conditions. <br /> <br /> |Lessons learn=The wetland basin is quite large, sized for greater flows than have been experienced so far. This means that the water in the treatment basin overflows only during very heavy rainfall events. This is not a significant problem, it just means that the basin is acting more as an infiltration basin rather than a temporary storage basin. The system still functions to prevent polluted water entering the stream. <br /> <br /> The plug planted sedges in the basin are thriving in this environment as the system was not fully activated until the plants were well established. However in the more shaded swales with greater velocity of flows and concentration of pollution the plugs have failed and need to be replanted. <br /> <br /> Sedges have grown lush and verdant in the basin and water is cleaned and returned to the stream as expected or returned to the water table. Although perhaps not as aesthetically pleasing as in the design, the boulder arrangement at the head of the swales has worked well to slow water and prevent excessive erosion in the swales. <br /> <br /> Water quality issues were far more significant than we had anticipated on commencement of the project, particularly in relation to domestic misconnections. High pollutant levels were evident beginning of our swales. We also found that although we proved our systems had a beneficial impact on water quality, just downstream of each project were outfalls which would bring in yet more pollutants. Therefore wetlands and SuDS alone could not demonstrate catchment level water improvements needed under WFD. Small scale interventions have a place in a suite of wider measures that need to be tackled with more drive, especially pollutant impacts from misconnections and vehicle use.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1206.jpg<br /> |Caption=Reedbed summer 2015<br /> }}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1261.jpg<br /> |Caption=Overflow from wetland<br /> }}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1266.jpg<br /> |Caption=Restored stream meandering through woodland<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook<br /> }}<br /> {{Site<br /> |Name=Unnamed tributary of Salmons Brook<br /> |WFD water body name=Salmons Brook<br /> |Pre-project morphology=Closed culvert, <br /> |Desired post project morphology=Actively meandering, <br /> |Heavily modified water body=Yes<br /> |Protected species present=No<br /> |Invasive species present=No<br /> |Dominant substrate=London Clay<br /> |River corridor land use=Urban, <br /> }}<br /> {{Project background<br /> |Reach length directly affected=200<br /> |Project started=2014/02/01<br /> |Project completed=2015/07/10<br /> |Funding sources=Defra, London Borough of Enfield, Thames Water<br /> }}<br /> {{Motivations<br /> |Specific mitigation=Poor water quality, Flood risk management, Urbanisation,<br /> |Hydromorphological quality elements=Good status in 2011<br /> |Biological quality elements= In 2011 - Phytobenthos, macrophytes, invertebrates poor and fish moderate<br /> |Physico-chemical quality elements=In 2011 - Ammonia moderate, dissolved oxygen and phosphate poor, annex 8 chem. high<br /> |Other motivation= Improving a public space, flood protection, terrestrial biodiversity improvements<br /> }}<br /> {{Measures<br /> |Bank and bed modifications measure=Deculverting, <br /> |Floodplain / River corridor=Creation of swales and wetland basin, stream allowed to find new course<br /> |Planform / Channel pattern=Actively meandering<br /> |Social measures=Community consultations, volunteer engagement, education sessions, interpretation, access improvements <br /> |Wider stakeholder / citizen engagement=Reedbed creation in lake<br /> }}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Grovelands_Park_Wetlands&diff=36330 2016-02-15T15:07:23Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.635654232931394, -0.10910797125688987<br /> }}<br /> {{Project overview<br /> |Status=Complete<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Environmental flows and water resources, Flood risk management, Habitat and biodiversity, Hydromorphology, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Thames Water,<br /> |Multi-site=No<br /> |Project picture=Thames21-grovelandspk-justinetrickett-1248.jpg<br /> |Picture description=Grovelands Park Wetlands, summer 2015<br /> |Project summary=The water system in Grovelands Park, Enfield, has been artificially engineered over time, with a long stretch of the stream being contained in an underground pipe, hidden from view and useless to wildlife. Here beneath the ground two surface water drains from local roads and homes washed pollutants straight into the stream every time it rained. Plumbing misconnections added to the problem. <br /> <br /> In spring 2014 we worked with the London Borough of Enfield to 'rewild' the water system in Grovelands Park. We created wetlands to intercept pollutants entering the stream in Grovelands Park. Flows in the surface water drains were diverted into shallow ditches, known as swales, and then into a wetland basin. The swales and basin were planted with sedges suitable for the semi-shaded woodland conditions. The plants use excess nutrients such as phosphates and nitrates to grow, preventing them building up in the water which causes the toxic algal blooms. The plants also oxygenate the water. Bacteria growing in the sediment and root systems break down oils and some bacteria can even reduce levels of heavy metals in the water. The clean water then soaks into the ground, as it would naturally, or overflows back into the stream. Rainwater washing off an area the size of 11 rugby fields is cleaned in the wetland. As we completed this project Thames Water ran misconnection surveys on the urban catchment, a vital piece of the jigsaw to ensure optimal results in this project.<br /> <br /> At the same time the London Borough of Enfield naturalised 200m of the stream, breaking it out of its underground pipe and allowing it to find its own course meandering through the woodland. These two projects restored the water system to its natural state, better able to cope with floods and slowing high flows of stormwater, as well as treating pollutants. <br /> <br /> The lake in Grovelands Park, Enfield is the centrepiece of a beautiful and grand garden for the ‘Southgate Grove’ mansion, designed in the 18th century and now a well-loved and popular public park. Sadly the lake is afflicted with pollution from a number of surface water drains, and toxic algal blooms are common in summer. Rainwater running off local streets brings with it oils and heavy metals from the road, as well as detergents and other chemicals such as phosphates and nitrates from misconnected plumbing. This pollution load limits the lake’s potential as a wildlife habitat and its appeal for park visitors.<br /> <br /> In June 2015 we created a reed bed in the south western end of the lake to naturally break down these pollutants and increase oxygen levels in the water, as well as providing a new habitat for birds and insects. Coir rolls and hazel faggots were used to create an area of suitable depth to establish the reed bed. Coir mats pre-planted with reeds, rushes, sedges and colourful purple loosestrife and yellow flag iris were installed across the reed bed area, protected from wildfowl grazing by netting. As in the wetland, the plants use excess nutrients such as phosphates and nitrates to grow, preventing them building up in the water which causes the toxic algal blooms. The plants also oxygenate the water. Bacteria growing in the sediment and root systems break down oils and some bacteria can even reduce levels of heavy metals in the water.<br /> |Monitoring surveys and results=Nitrogen is essential for river life but in excess can cause eutrophication. This results in reduced levels of oxygen in the water and may cause toxic algal blooms. Nitrate may be present as ammonia, nitrite or nitrate (measured together as Total Nitrogen), but nitrate is the most stable form. <br /> <br /> Reed bed: The recently installed reed bed is already proving effective at removing nitrogen compounds from the water. There is a significant difference in water quality between the inflow above the reed bed (sampling location 1) and the sampling location immediately the other side of the reed bed (location 2) in total nitrogen, nitrate and ammonia. Total nitrogen drops from 7mg/l to 5mg/l, nitrate from 13mg/l to 4mg//l and ammonia from 1.6mg/l to 0.5mg/l. The improvement in water quality through the reed bed is greater than the improvement observed in the body of the lake. This is because the difference in water quality is larger between sampling sites 1 and 2 compared to between sites 2 and 3 (the lake outflow). <br /> <br /> Wetland basin: The wetland basin is effective at water quality improvement because it prevents polluted water from two drains (sample locations 5 and 6) from entering the stream at site 4. Water entering the infiltration basin from the de-culverted pipe at sampling site 6 is consistently outside of acceptable concentration ranges specified by the Water Framework Directive. Ammonia is consistently present in levels deemed harmful to aquatic life in both inflow pipes (sample locations 5 and 6). Water only flows out of the wetland basin in storm conditions so it effectively prevents polluted water from entering the stream. <br /> <br /> Coliform bacteria derive from faecal waste and are an indicator of pathogens in the aquatic environment. They enter waterways from misconnected toilets, sewage treatment plant overflow, domestic pets and agricultural run off.<br /> <br /> Reed bed: The reed bed is an effective remover of coliform bacteria, reducing the coliform colony count to within guideline limits (under EC Bathing Water Directive)immediately after the reedbed (sample location 2), dropping from approximately 1100 total coliform colonies to 50 total coliform colonies. <br /> <br /> Wetland basin: Water entering the wetland basin from the culverts at sampling sites 5 and 6 contains high counts of coliform bacteria, that are outside of guideline limits (under EC Bathing Water Directive). This is prevented from entering the stream (sample location 4) because water only flows out of the wetland basin in storm conditions. <br /> <br /> |Lessons learn=The wetland basin is quite large, sized for greater flows than have been experienced so far. This means that the water in the treatment basin overflows only during very heavy rainfall events. This is not a significant problem, it just means that the basin is acting more as an infiltration basin rather than a temporary storage basin. The system still functions to prevent polluted water entering the stream. <br /> <br /> The plug planted sedges in the basin are thriving in this environment as the system was not fully activated until the plants were well established. However in the more shaded swales with greater velocity of flows and concentration of pollution the plugs have failed and need to be replanted. <br /> <br /> Sedges have grown lush and verdant in the basin and water is cleaned and returned to the stream as expected or returned to the water table. Although perhaps not as aesthetically pleasing as in the design, the boulder arrangement at the head of the swales has worked well to slow water and prevent excessive erosion in the swales. <br /> <br /> Water quality issues were far more significant than we had anticipated on commencement of the project, particularly in relation to domestic misconnections. High pollutant levels were evident beginning of our swales. We also found that although we proved our systems had a beneficial impact on water quality, just downstream of each project were outfalls which would bring in yet more pollutants. Therefore wetlands and SuDS alone could not demonstrate catchment level water improvements needed under WFD. Small scale interventions have a place in a suite of wider measures that need to be tackled with more drive, especially pollutant impacts from misconnections and vehicle use.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1206.jpg<br /> |Caption=Reedbed summer 2015<br /> }}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1261.jpg<br /> |Caption=Overflow from wetland<br /> }}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1266.jpg<br /> |Caption=Restored stream meandering through woodland<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook<br /> }}<br /> {{Site<br /> |Name=Unnamed tributary of Salmons Brook<br /> |WFD water body name=Salmons Brook<br /> |Pre-project morphology=Closed culvert, <br /> |Desired post project morphology=Actively meandering, <br /> |Heavily modified water body=Yes<br /> |Protected species present=No<br /> |Invasive species present=No<br /> |Dominant substrate=London Clay<br /> |River corridor land use=Urban, <br /> }}<br /> {{Project background<br /> |Reach length directly affected=200<br /> |Project started=2014/02/01<br /> |Project completed=2015/07/10<br /> |Funding sources=Defra, London Borough of Enfield, Thames Water<br /> }}<br /> {{Motivations<br /> |Specific mitigation=Poor water quality, Flood risk management, Urbanisation,<br /> |Hydromorphological quality elements=Good status in 2011<br /> |Biological quality elements= In 2011 - Phytobenthos, macrophytes, invertebrates poor and fish moderate<br /> |Physico-chemical quality elements=In 2011 - Ammonia moderate, dissolved oxygen and phosphate poor, annex 8 chem. high<br /> |Other motivation= Improving a public space, flood protection, terrestrial biodiversity improvements<br /> }}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Grovelands_Park_Wetlands&diff=36329 2016-02-15T14:41:45Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.635654232931394, -0.10910797125688987<br /> }}<br /> {{Project overview<br /> |Status=Complete<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Environmental flows and water resources, Flood risk management, Habitat and biodiversity, Hydromorphology, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Thames Water,<br /> |Multi-site=No<br /> |Project picture=Thames21-grovelandspk-justinetrickett-1248.jpg<br /> |Picture description=Grovelands Park Wetlands, summer 2015<br /> |Project summary=The water system in Grovelands Park, Enfield, has been artificially engineered over time, with a long stretch of the stream being contained in an underground pipe, hidden from view and useless to wildlife. Here beneath the ground two surface water drains from local roads and homes washed pollutants straight into the stream every time it rained. Plumbing misconnections added to the problem. <br /> <br /> In spring 2014 we worked with the London Borough of Enfield to 'rewild' the water system in Grovelands Park. We created wetlands to intercept pollutants entering the stream in Grovelands Park. Flows in the surface water drains were diverted into shallow ditches, known as swales, and then into a wetland basin. The swales and basin were planted with sedges suitable for the semi-shaded woodland conditions. The plants use excess nutrients such as phosphates and nitrates to grow, preventing them building up in the water which causes the toxic algal blooms. The plants also oxygenate the water. Bacteria growing in the sediment and root systems break down oils and some bacteria can even reduce levels of heavy metals in the water. The clean water then soaks into the ground, as it would naturally, or overflows back into the stream. Rainwater washing off an area the size of 11 rugby fields is cleaned in the wetland. As we completed this project Thames Water ran misconnection surveys on the urban catchment, a vital piece of the jigsaw to ensure optimal results in this project.<br /> <br /> At the same time the London Borough of Enfield naturalised 200m of the stream, breaking it out of its underground pipe and allowing it to find its own course meandering through the woodland. These two projects restored the water system to its natural state, better able to cope with floods and slowing high flows of stormwater, as well as treating pollutants. <br /> <br /> The lake in Grovelands Park, Enfield is the centrepiece of a beautiful and grand garden for the ‘Southgate Grove’ mansion, designed in the 18th century and now a well-loved and popular public park. Sadly the lake is afflicted with pollution from a number of surface water drains, and toxic algal blooms are common in summer. Rainwater running off local streets brings with it oils and heavy metals from the road, as well as detergents and other chemicals such as phosphates and nitrates from misconnected plumbing. This pollution load limits the lake’s potential as a wildlife habitat and its appeal for park visitors.<br /> <br /> In June 2015 we created a reed bed in the south western end of the lake to naturally break down these pollutants and increase oxygen levels in the water, as well as providing a new habitat for birds and insects. Coir rolls and hazel faggots were used to create an area of suitable depth to establish the reed bed. Coir mats pre-planted with reeds, rushes, sedges and colourful purple loosestrife and yellow flag iris were installed across the reed bed area, protected from wildfowl grazing by netting. As in the wetland, the plants use excess nutrients such as phosphates and nitrates to grow, preventing them building up in the water which causes the toxic algal blooms. The plants also oxygenate the water. Bacteria growing in the sediment and root systems break down oils and some bacteria can even reduce levels of heavy metals in the water.<br /> |Monitoring surveys and results=Nitrogen is essential for river life but in excess can cause eutrophication. This results in reduced levels of oxygen in the water and may cause toxic algal blooms. Nitrate may be present as ammonia, nitrite or nitrate (measured together as Total Nitrogen), but nitrate is the most stable form. <br /> <br /> Reed bed: The recently installed reed bed is already proving effective at removing nitrogen compounds from the water. There is a significant difference in water quality between the inflow above the reed bed (sampling location 1) and the sampling location immediately the other side of the reed bed (location 2) in total nitrogen, nitrate and ammonia. Total nitrogen drops from 7mg/l to 5mg/l, nitrate from 13mg/l to 4mg//l and ammonia from 1.6mg/l to 0.5mg/l. The improvement in water quality through the reed bed is greater than the improvement observed in the body of the lake. This is because the difference in water quality is larger between sampling sites 1 and 2 compared to between sites 2 and 3 (the lake outflow). <br /> <br /> Wetland basin: The wetland basin is effective at water quality improvement because it prevents polluted water from two drains (sample locations 5 and 6) from entering the stream at site 4. Water entering the infiltration basin from the de-culverted pipe at sampling site 6 is consistently outside of acceptable concentration ranges specified by the Water Framework Directive. Ammonia is consistently present in levels deemed harmful to aquatic life in both inflow pipes (sample locations 5 and 6). Water only flows out of the wetland basin in storm conditions so it effectively prevents polluted water from entering the stream. <br /> <br /> Coliform bacteria derive from faecal waste and are an indicator of pathogens in the aquatic environment. They enter waterways from misconnected toilets, sewage treatment plant overflow, domestic pets and agricultural run off.<br /> <br /> Reed bed: The reed bed is an effective remover of coliform bacteria, reducing the coliform colony count to within guideline limits (under EC Bathing Water Directive)immediately after the reedbed (sample location 2), dropping from approximately 1100 total coliform colonies to 50 total coliform colonies. <br /> <br /> Wetland basin: Water entering the wetland basin from the culverts at sampling sites 5 and 6 contains high counts of coliform bacteria, that are outside of guideline limits (under EC Bathing Water Directive). This is prevented from entering the stream (sample location 4) because water only flows out of the wetland basin in storm conditions. <br /> <br /> |Lessons learn=The wetland basin is quite large, sized for greater flows than have been experienced so far. This means that the water in the treatment basin overflows only during very heavy rainfall events. This is not a significant problem, it just means that the basin is acting more as an infiltration basin rather than a temporary storage basin. The system still functions to prevent polluted water entering the stream. <br /> <br /> The plug planted sedges in the basin are thriving in this environment as the system was not fully activated until the plants were well established. However in the more shaded swales with greater velocity of flows and concentration of pollution the plugs have failed and need to be replanted. <br /> <br /> Sedges have grown lush and verdant in the basin and water is cleaned and returned to the stream as expected or returned to the water table. Although perhaps not as aesthetically pleasing as in the design, the boulder arrangement at the head of the swales has worked well to slow water and prevent excessive erosion in the swales. <br /> <br /> Water quality issues were far more significant than we had anticipated on commencement of the project, particularly in relation to domestic misconnections. High pollutant levels were evident beginning of our swales. We also found that although we proved our systems had a beneficial impact on water quality, just downstream of each project were outfalls which would bring in yet more pollutants. Therefore wetlands and SuDS alone could not demonstrate catchment level water improvements needed under WFD. Small scale interventions have a place in a suite of wider measures that need to be tackled with more drive, especially pollutant impacts from misconnections and vehicle use.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1206.jpg<br /> |Caption=Reedbed summer 2015<br /> }}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1261.jpg<br /> |Caption=Overflow from wetland<br /> }}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1266.jpg<br /> |Caption=Restored stream meandering through woodland<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook<br /> }}<br /> {{Site<br /> |Name=Unnamed tributary of Salmons Brook<br /> |WFD water body name=Salmons Brook<br /> |Pre-project morphology=Closed culvert, <br /> |Desired post project morphology=Actively meandering, <br /> |Heavily modified water body=Yes<br /> |Protected species present=No<br /> |Invasive species present=No<br /> |Dominant substrate=London Clay<br /> |River corridor land use=Urban, <br /> }}<br /> {{Project background<br /> |Reach length directly affected=200<br /> |Project started=2014/02/01<br /> |Project completed=2015/07/10<br /> |Funding sources=Defra, London Borough of Enfield, Thames Water<br /> }}<br /> {{Motivations<br /> |Specific mitigation=Poor water quality, Flood risk management, Urbanisation, <br /> }}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Glenbrook_Wetlands&diff=36328 2016-02-15T14:09:32Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.647746622246224, -0.11766529030865058<br /> }}<br /> {{Project overview<br /> |Status=In progress<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Flood risk management, Habitat and biodiversity, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames 21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Thames Water, Environment Agency,<br /> |Multi-site=No<br /> |Project picture=IMAG0001.jpg<br /> |Picture description=Wetland basin 2 - Jan 2016<br /> |Project summary=Thames21 has been working with Enfield Council, The Environment Agency and Thames Water to improve the health of the Salmons Brook and its tributaries. Enfield has a separate sewage system, meaning that surface water eg. rain running off roads and wastewater are carried in two separate pipes. As a result, pollutants enter the Salmons Brook in a number of different ways. Misconnected plumbing contributes nutrients such as phosphates and nitrates and coliform bacteria, road run-off inputs oils and heavy metals such as zinc and copper, and household and industrial waste is dumped into surface water drains. <br /> <br /> With great support from local people we’ve created Sustainable Drainage Systems (SuDS), or ’rainscapes’ to intercept the pollution. As well as filtering pollutants out of water, the SuDS also help reduce local flood risk by slowing the flow, create wildlife habitats and provide new amenities for local people. <br /> <br /> The Glenbrook is a tributary of the Salmons Brook. It flows through underground pipes for much of its length. Hidden away it is damaged, and when it first emerges above ground it is already very badly polluted. Six linked wetlands have been created here to filter pollutants from the stream. The flow is directed through each wetland, being successively cleaned as it is slowed through the basins. Plants use nutrients such as phosphate and nitrate to grow, removing them from the water and stopping them polluting the stream. Bacteria in the soil and root systems break down oils and heavy metals. Once established the planted wetlands not only clean the water, they also add a new dimension to the habitat mosaic for wildlife, and give interest and colour for those passing by.<br /> <br /> The Glenbrook wetlands were complete in September 2014 after three months of construction. Local volunteers helped to plant the wetlands in September 2014 and again in March 2015. The system is designed so that in low flow conditions a series of weirs direct all baseflow into the wetlands, whilst in high flow conditions a large proportion of the flow continues downstream and only the first flush is treated. The headwater of the Glenbrook which feeds this system drains an urban catchment of 42 ha. In addition, 15 gullies have been redirected from the roads that surround the site into the wetland treatment system through a series of swales.<br /> |Monitoring surveys and results=Nitrogen and phosphate are essential for river life but in excess they cause eutrophication. This results in reduced levels of oxygen in the water and may cause toxic algal blooms. Nitrate may be present as ammonia, nitrite or nitrate (measured together as Total Nitrogen), but nitrate is the most stable form. Our water quality monitoring has shown that the SUDS basins are effective at removal of Total nitrogen, nitrates and phosphates. Water quality improves between sampling location 1 (the inflow to the SUDS) and location 2 (outflow from the SUDS), particularly in total nitrogen (dropping from 10mg/l to 6mg/l) and nitrate (dropping from 13mg/l to 7mg/l), bringing water quality within acceptable guideline levels (as defined in EA General Quality Assessment, Water Framework Directive 2014). <br /> <br /> Coliform bacteria derive from faecal waste and are an indicator of pathogens in the aquatic environment. They enter waterways from misconnected toilets, sewage treatment plant overflow, domestic pets and agricultural run off. The SUDS basins are extremely effective at removal of coliform bacteria. Water quality improves between sampling location 1 (the inflow to the SUDS) and location 2 (outflow from the SUDS), with coliform counts dropping from approximately 1400 total coliform colonies to approximately 400 total coliform colonies, bringing water quality within acceptable guideline levels (under EC Bathing Water Directive).<br /> <br /> Invertebrate surveys have also been carried out as part of this project. A masters student from Kings College London (KCL) undertook research into invertebrate populations at each of the project sites. Linking the invertebrate survey results to water quality data, the student predicted the impact/ potential impact of each of the SuDS/wetland schemes on population sizes and diversity over time. There was no existing data on invertebrates for the catchment before research was carried out. As predicted the invertebrate survey confirmed findings of poor water quality, with pollution sensitive taxa very badly represented. The study concluded that the SuDS have the potential to improve water quality and ecological outcomes downstream, but far greater efforts in reducing pollutants from vehicle use and misconnections will be required to resolve the problems of urban diffuse pollution.<br /> |Lessons learn=At this site in particular we came across some levels of reticence from the local community to the project, mainly due to the significant changes to the landscape and lack of familiarity around SuDS, as well as a lack of understanding of why they were desperately needed. We overcame this by being very transparent and available, and in taking care of the site and the stream and making obvious improvements to its health and potential as a wildlife habitat. Regular communications in many forms were key. This became the site at which volunteer days were best attended by local residents. In future projects it would be ideal to spend a time in the build-up to the project engaging the community about water quality issues, rather than to do this simultaneously with planning the SuDS. <br /> <br /> Water quality issues were far more significant than we had anticipated on commencement of the project, particularly in relation to domestic misconnections. Serious pollutant levels damaged the beginning of our SuDS system as Glenbrook. We also found that although we proved our systems had a beneficial impact on water quality, just downstream of each project were outfalls which would bring in yet more pollutants. Therefore SuDS alone could not demonstrate catchment level water improvements needed under WFD. Small scale SuDS have a place in a suite of wider measures that need to be tackled with more drive, especially pollutant impacts from misconnections and vehicle use. <br /> <br /> We experienced some design issues which resulted from a lack of quality data pre-project, for example on flows. It would have been prohibitively expensive for us to get the data needed on this project budget, but it meant that some SuDS elements such as weirs required some costly remediation work.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=Basin 1 creation.JPG<br /> |Caption=Creating basin 1<br /> }}<br /> {{Case study image<br /> |File name=Site of basin 6.JPG<br /> |Caption=Site of basin 6<br /> }}<br /> {{Case study image<br /> |File name=Basin 6 with water.JPG<br /> |Caption=Basin 6 with water<br /> }}<br /> {{Case study image<br /> |File name=Planting in basin 6.JPG<br /> |Caption=Planting in basin 6 - April 2015<br /> }}<br /> {{Case study image<br /> |File name=Drain marking pic.jpg<br /> |Caption=Drain markers installed around site<br /> }}<br /> {{Case study image<br /> |File name=Misconnections pollution.JPG<br /> |Caption=Pollution from misconnections<br /> }}<br /> {{Case study image<br /> |File name=Basin 2 July 2015.JPG<br /> |Caption=Basin 2 July 2015<br /> }}<br /> <br /> {{Case study image<br /> |File name=Planting basin 3.JPG<br /> |Caption=Planting wetland basin 3<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook<br /> }}<br /> {{Site<br /> |Name=Glenbrook<br /> |WFD water body code=GB106038027960<br /> |WFD (national) typology=Type 18: small loess-loam dominated lowland river<br /> |WFD water body name=Salmons Brook<br /> |Heavily modified water body=Yes<br /> |Protected species present=No<br /> |Invasive species present=Yes<br /> |Dominant substrate=London Clay<br /> |River corridor land use=Urban<br /> }}<br /> {{Project background<br /> |Reach length directly affected=220<br /> |Project started=2012/09/01<br /> |Funding sources=Defra, Environment Agency, London Borough of Enfield, Thames Water, <br /> }}<br /> {{Motivations<br /> |Specific mitigation=Poor water quality (urban run off and misconnections), Urbanisation, <br /> |Hydromorphological quality elements=Good status in 2011<br /> |Biological quality elements=In 2011 - Phytobenthos, macrophytes, invertebrates poor and fish moderate<br /> |Physico-chemical quality elements=In 2011 - Ammonia moderate, dissolved oxygen and phosphate poor, annex 8 chem. high<br /> |Other motivation=Improving a public space, flood protection, terrestrial biodiversity improvements<br /> }}<br /> {{Measures<br /> |Bank and bed modifications measure=Overdeepened and incised channel bed raised <br /> |Floodplain / River corridor=Tree works and creation of 6 linked wetland basins, swales taking road run off into basins<br /> |Planform / Channel pattern=n/a<br /> |Other technical measure=n/a<br /> |Management interventions=Opening of tree canopy to encourage varied ground flora<br /> |Social measures=Community consultations, volunteer engagement, education sessions, interpretation, access improvements<br /> |Wider stakeholder / citizen engagement=n/a<br /> }}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Grovelands_Park_Wetlands&diff=36327 2016-02-15T14:07:48Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.635654232931394, -0.10910797125688987<br /> }}<br /> {{Project overview<br /> |Status=Complete<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Environmental flows and water resources, Flood risk management, Habitat and biodiversity, Hydromorphology, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Thames Water,<br /> |Multi-site=No<br /> |Project picture=Thames21-grovelandspk-justinetrickett-1248.jpg<br /> |Picture description=Grovelands Park Wetlands, summer 2015<br /> |Project summary=The water system in Grovelands Park, Enfield, has been artificially engineered over time, with a long stretch of the stream being contained in an underground pipe, hidden from view and useless to wildlife. Here beneath the ground two surface water drains from local roads and homes washed pollutants straight into the stream every time it rained. Plumbing misconnections added to the problem. <br /> <br /> In spring 2014 we worked with the London Borough of Enfield to 'rewild' the water system in Grovelands Park. We created wetlands to intercept pollutants entering the stream in Grovelands Park. Flows in the surface water drains were diverted into shallow ditches, known as swales, and then into a wetland basin. The swales and basin were planted with sedges suitable for the semi-shaded woodland conditions. The plants use excess nutrients such as phosphates and nitrates to grow, preventing them building up in the water which causes the toxic algal blooms. The plants also oxygenate the water. Bacteria growing in the sediment and root systems break down oils and some bacteria can even reduce levels of heavy metals in the water. The clean water then soaks into the ground, as it would naturally, or overflows back into the stream. Rainwater washing off an area the size of 11 rugby fields is cleaned in the wetland. As we completed this project Thames Water ran misconnection surveys on the urban catchment, a vital piece of the jigsaw to ensure optimal results in this project.<br /> <br /> At the same time the London Borough of Enfield naturalised 200m of the stream, breaking it out of its underground pipe and allowing it to find its own course meandering through the woodland. These two projects restored the water system to its natural state, better able to cope with floods and slowing high flows of stormwater, as well as treating pollutants. <br /> <br /> The lake in Grovelands Park, Enfield is the centrepiece of a beautiful and grand garden for the ‘Southgate Grove’ mansion, designed in the 18th century and now a well-loved and popular public park. Sadly the lake is afflicted with pollution from a number of surface water drains, and toxic algal blooms are common in summer. Rainwater running off local streets brings with it oils and heavy metals from the road, as well as detergents and other chemicals such as phosphates and nitrates from misconnected plumbing. This pollution load limits the lake’s potential as a wildlife habitat and its appeal for park visitors.<br /> <br /> In June 2015 we created a reed bed in the south western end of the lake to naturally break down these pollutants and increase oxygen levels in the water, as well as providing a new habitat for birds and insects. Coir rolls and hazel faggots were used to create an area of suitable depth to establish the reed bed. Coir mats pre-planted with reeds, rushes, sedges and colourful purple loosestrife and yellow flag iris were installed across the reed bed area, protected from wildfowl grazing by netting. As in the wetland, the plants use excess nutrients such as phosphates and nitrates to grow, preventing them building up in the water which causes the toxic algal blooms. The plants also oxygenate the water. Bacteria growing in the sediment and root systems break down oils and some bacteria can even reduce levels of heavy metals in the water.<br /> |Monitoring surveys and results=Nitrogen is essential for river life but in excess can cause eutrophication. This results in reduced levels of oxygen in the water and may cause toxic algal blooms. Nitrate may be present as ammonia, nitrite or nitrate (measured together as Total Nitrogen), but nitrate is the most stable form. <br /> <br /> Reed bed: The recently installed reed bed is already proving effective at removing nitrogen compounds from the water. There is a significant difference in water quality between the inflow above the reed bed (sampling location 1) and the sampling location immediately the other side of the reed bed (location 2) in total nitrogen, nitrate and ammonia. Total nitrogen drops from 7mg/l to 5mg/l, nitrate from 13mg/l to 4mg//l and ammonia from 1.6mg/l to 0.5mg/l. The improvement in water quality through the reed bed is greater than the improvement observed in the body of the lake. This is because the difference in water quality is larger between sampling sites 1 and 2 compared to between sites 2 and 3 (the lake outflow). <br /> <br /> Wetland basin: The wetland basin is effective at water quality improvement because it prevents polluted water from two drains (sample locations 5 and 6) from entering the stream at site 4. Water entering the infiltration basin from the de-culverted pipe at sampling site 6 is consistently outside of acceptable concentration ranges specified by the Water Framework Directive. Ammonia is consistently present in levels deemed harmful to aquatic life in both inflow pipes (sample locations 5 and 6). Water only flows out of the wetland basin in storm conditions so it effectively prevents polluted water from entering the stream. <br /> <br /> Coliform bacteria derive from faecal waste and are an indicator of pathogens in the aquatic environment. They enter waterways from misconnected toilets, sewage treatment plant overflow, domestic pets and agricultural run off.<br /> <br /> Reed bed: The reed bed is an effective remover of coliform bacteria, reducing the coliform colony count to within guideline limits (under EC Bathing Water Directive)immediately after the reedbed (sample location 2), dropping from approximately 1100 total coliform colonies to 50 total coliform colonies. <br /> <br /> Wetland basin: Water entering the wetland basin from the culverts at sampling sites 5 and 6 contains high counts of coliform bacteria, that are outside of guideline limits (under EC Bathing Water Directive). This is prevented from entering the stream (sample location 4) because water only flows out of the wetland basin in storm conditions. <br /> <br /> |Lessons learn=The wetland basin is quite large, sized for greater flows than have been experienced so far. This means that the water in the treatment basin overflows only during very heavy rainfall events. This is not a significant problem, it just means that the basin is acting more as an infiltration basin rather than a temporary storage basin. The system still functions to prevent polluted water entering the stream. <br /> <br /> The plug planted sedges in the basin are thriving in this environment as the system was not fully activated until the plants were well established. However in the more shaded swales with greater velocity of flows and concentration of pollution the plugs have failed and need to be replanted. <br /> <br /> Sedges have grown lush and verdant in the basin and water is cleaned and returned to the stream as expected or returned to the water table. Although perhaps not as aesthetically pleasing as in the design, the boulder arrangement at the head of the swales has worked well to slow water and prevent excessive erosion in the swales. <br /> <br /> Water quality issues were far more significant than we had anticipated on commencement of the project, particularly in relation to domestic misconnections. High pollutant levels were evident beginning of our swales. We also found that although we proved our systems had a beneficial impact on water quality, just downstream of each project were outfalls which would bring in yet more pollutants. Therefore wetlands and SuDS alone could not demonstrate catchment level water improvements needed under WFD. Small scale interventions have a place in a suite of wider measures that need to be tackled with more drive, especially pollutant impacts from misconnections and vehicle use.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1206.jpg<br /> |Caption=Reedbed summer 2015<br /> }}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1261.jpg<br /> |Caption=Overflow from wetland<br /> }}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1266.jpg<br /> |Caption=Restored stream meandering through woodland<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook<br /> }}<br /> {{Site<br /> |Name=Unnamed tributary of Salmons Brook<br /> |WFD water body name=Salmons Brook<br /> |Pre-project morphology=Closed culvert, <br /> |Desired post project morphology=Actively meandering, <br /> |Heavily modified water body=Yes<br /> |Protected species present=No<br /> |Invasive species present=No<br /> |Dominant substrate=London Clay<br /> |River corridor land use=Urban, <br /> }}<br /> {{Project background<br /> |Reach length directly affected=200<br /> |Project started=2014/02/01<br /> |Project completed=2015/07/10<br /> |Funding sources=Defra, London Borough of Enfield, Thames Water<br /> }}<br /> {{Motivations}}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Grovelands_Park_Wetlands&diff=36326 2016-02-15T14:06:23Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.635654232931394, -0.10910797125688987<br /> }}<br /> {{Project overview<br /> |Status=Complete<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Environmental flows and water resources, Flood risk management, Habitat and biodiversity, Hydromorphology, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Thames Water,<br /> |Multi-site=No<br /> |Project picture=Thames21-grovelandspk-justinetrickett-1248.jpg<br /> |Picture description=Grovelands Park Wetlands, summer 2015<br /> |Project summary=The water system in Grovelands Park, Enfield, has been artificially engineered over time, with a long stretch of the stream being contained in an underground pipe, hidden from view and useless to wildlife. Here beneath the ground two surface water drains from local roads and homes washed pollutants straight into the stream every time it rained. Plumbing misconnections added to the problem. <br /> <br /> In spring 2014 we worked with the London Borough of Enfield to 'rewild' the water system in Grovelands Park. We created wetlands to intercept pollutants entering the stream in Grovelands Park. Flows in the surface water drains were diverted into shallow ditches, known as swales, and then into a wetland basin. The swales and basin were planted with sedges suitable for the semi-shaded woodland conditions. The plants use excess nutrients such as phosphates and nitrates to grow, preventing them building up in the water which causes the toxic algal blooms. The plants also oxygenate the water. Bacteria growing in the sediment and root systems break down oils and some bacteria can even reduce levels of heavy metals in the water. The clean water then soaks into the ground, as it would naturally, or overflows back into the stream. Rainwater washing off an area the size of 11 rugby fields is cleaned in the wetland. As we completed this project Thames Water ran misconnection surveys on the urban catchment, a vital piece of the jigsaw to ensure optimal results in this project.<br /> <br /> At the same time the London Borough of Enfield naturalised 200m of the stream, breaking it out of its underground pipe and allowing it to find its own course meandering through the woodland. These two projects restored the water system to its natural state, better able to cope with floods and slowing high flows of stormwater, as well as treating pollutants. <br /> <br /> The lake in Grovelands Park, Enfield is the centrepiece of a beautiful and grand garden for the ‘Southgate Grove’ mansion, designed in the 18th century and now a well-loved and popular public park. Sadly the lake is afflicted with pollution from a number of surface water drains, and toxic algal blooms are common in summer. Rainwater running off local streets brings with it oils and heavy metals from the road, as well as detergents and other chemicals such as phosphates and nitrates from misconnected plumbing. This pollution load limits the lake’s potential as a wildlife habitat and its appeal for park visitors.<br /> <br /> In June 2015 we created a reed bed in the south western end of the lake to naturally break down these pollutants and increase oxygen levels in the water, as well as providing a new habitat for birds and insects. Coir rolls and hazel faggots were used to create an area of suitable depth to establish the reed bed. Coir mats pre-planted with reeds, rushes, sedges and colourful purple loosestrife and yellow flag iris were installed across the reed bed area, protected from wildfowl grazing by netting. As in the wetland, the plants use excess nutrients such as phosphates and nitrates to grow, preventing them building up in the water which causes the toxic algal blooms. The plants also oxygenate the water. Bacteria growing in the sediment and root systems break down oils and some bacteria can even reduce levels of heavy metals in the water.<br /> |Monitoring surveys and results=Nitrogen is essential for river life but in excess can cause eutrophication. This results in reduced levels of oxygen in the water and may cause toxic algal blooms. Nitrate may be present as ammonia, nitrite or nitrate (measured together as Total Nitrogen), but nitrate is the most stable form. <br /> <br /> Reed bed: The recently installed reed bed is already proving effective at removing nitrogen compounds from the water. There is a significant difference in water quality between the inflow above the reed bed (sampling location 1) and the sampling location immediately the other side of the reed bed (location 2) in total nitrogen, nitrate and ammonia. Total nitrogen drops from 7mg/l to 5mg/l, nitrate from 13mg/l to 4mg//l and ammonia from 1.6mg/l to 0.5mg/l. The improvement in water quality through the reed bed is greater than the improvement observed in the body of the lake. This is because the difference in water quality is larger between sampling sites 1 and 2 compared to between sites 2 and 3 (the lake outflow). <br /> <br /> Wetland basin: The wetland basin is effective at water quality improvement because it prevents polluted water from two drains (sample locations 5 and 6) from entering the stream at site 4. Water entering the infiltration basin from the de-culverted pipe at sampling site 6 is consistently outside of acceptable concentration ranges specified by the Water Framework Directive. Ammonia is consistently present in levels deemed harmful to aquatic life in both inflow pipes (sample locations 5 and 6). Water only flows out of the wetland basin in storm conditions so it effectively prevents polluted water from entering the stream. <br /> <br /> Coliform bacteria derive from faecal waste and are an indicator of pathogens in the aquatic environment. They enter waterways from misconnected toilets, sewage treatment plant overflow, domestic pets and agricultural run off.<br /> <br /> Reed bed: The reed bed is an effective remover of coliform bacteria, reducing the coliform colony count to within guideline limits (under EC Bathing Water Directive)immediately after the reedbed (sample location 2), dropping from approximately 1100 total coliform colonies to 50 total coliform colonies. <br /> <br /> Wetland basin: Water entering the wetland basin from the culverts at sampling sites 5 and 6 contains high counts of coliform bacteria, that are outside of guideline limits (under EC Bathing Water Directive). This is prevented from entering the stream (sample location 4) because water only flows out of the wetland basin in storm conditions. <br /> <br /> |Lessons learn=The wetland basin is quite large, sized for greater flows than have been experienced so far. This means that the water in the treatment basin overflows only during very heavy rainfall events. This is not a significant problem, it just means that the basin is acting more as an infiltration basin rather than a temporary storage basin. The system still functions to prevent polluted water entering the stream. <br /> <br /> The plug planted sedges in the basin are thriving in this environment as the system was not fully activated until the plants were well established. However in the more shaded swales with greater velocity of flows and concentration of pollution the plugs have failed and need to be replanted. <br /> <br /> Sedges have grown lush and verdant in the basin and water is cleaned and returned to the stream as expected or returned to the water table. Although perhaps not as aesthetically pleasing as in the design, the boulder arrangement at the head of the swales has worked well to slow water and prevent excessive erosion in the swales. <br /> <br /> Water quality issues were far more significant than we had anticipated on commencement of the project, particularly in relation to domestic misconnections. High pollutant levels were evident beginning of our swales. We also found that although we proved our systems had a beneficial impact on water quality, just downstream of each project were outfalls which would bring in yet more pollutants. Therefore wetlands and SuDS alone could not demonstrate catchment level water improvements needed under WFD. Small scale interventions have a place in a suite of wider measures that need to be tackled with more drive, especially pollutant impacts from misconnections and vehicle use.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1206.jpg<br /> |Caption=Reedbed summer 2015<br /> }}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1261.jpg<br /> |Caption=Overflow from wetland<br /> }}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1266.jpg<br /> |Caption=Restored stream meandering through woodland<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook<br /> }}<br /> {{Site<br /> |Name=Unnamed tributary of Salmons Brook<br /> |WFD water body name=Salmons Brook<br /> |Pre-project morphology=Closed culvert, <br /> |Desired post project morphology=Actively meandering, <br /> |Heavily modified water body=Yes<br /> |Protected species present=No<br /> |Invasive species present=No<br /> |Dominant substrate=London Clay<br /> |River corridor land use=Urban, <br /> }}<br /> {{Project background<br /> |Reach length directly affected=200<br /> |Project started=2014/02/01<br /> |Project completed=2015/07/10<br /> }}<br /> {{Motivations}}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Grovelands_Park_Wetlands&diff=36325 2016-02-15T14:04:19Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.635654232931394, -0.10910797125688987<br /> }}<br /> {{Project overview<br /> |Status=Complete<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Environmental flows and water resources, Flood risk management, Habitat and biodiversity, Hydromorphology, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Thames Water,<br /> |Multi-site=No<br /> |Project picture=Thames21-grovelandspk-justinetrickett-1248.jpg<br /> |Picture description=Grovelands Park Wetlands, summer 2015<br /> |Project summary=The water system in Grovelands Park, Enfield, has been artificially engineered over time, with a long stretch of the stream being contained in an underground pipe, hidden from view and useless to wildlife. Here beneath the ground two surface water drains from local roads and homes washed pollutants straight into the stream every time it rained. Plumbing misconnections added to the problem. <br /> <br /> In spring 2014 we worked with the London Borough of Enfield to 'rewild' the water system in Grovelands Park. We created wetlands to intercept pollutants entering the stream in Grovelands Park. Flows in the surface water drains were diverted into shallow ditches, known as swales, and then into a wetland basin. The swales and basin were planted with sedges suitable for the semi-shaded woodland conditions. The plants use excess nutrients such as phosphates and nitrates to grow, preventing them building up in the water which causes the toxic algal blooms. The plants also oxygenate the water. Bacteria growing in the sediment and root systems break down oils and some bacteria can even reduce levels of heavy metals in the water. The clean water then soaks into the ground, as it would naturally, or overflows back into the stream. Rainwater washing off an area the size of 11 rugby fields is cleaned in the wetland. As we completed this project Thames Water ran misconnection surveys on the urban catchment, a vital piece of the jigsaw to ensure optimal results in this project.<br /> <br /> At the same time the London Borough of Enfield naturalised 200m of the stream, breaking it out of its underground pipe and allowing it to find its own course meandering through the woodland. These two projects restored the water system to its natural state, better able to cope with floods and slowing high flows of stormwater, as well as treating pollutants. <br /> <br /> The lake in Grovelands Park, Enfield is the centrepiece of a beautiful and grand garden for the ‘Southgate Grove’ mansion, designed in the 18th century and now a well-loved and popular public park. Sadly the lake is afflicted with pollution from a number of surface water drains, and toxic algal blooms are common in summer. Rainwater running off local streets brings with it oils and heavy metals from the road, as well as detergents and other chemicals such as phosphates and nitrates from misconnected plumbing. This pollution load limits the lake’s potential as a wildlife habitat and its appeal for park visitors.<br /> <br /> In June 2015 we created a reed bed in the south western end of the lake to naturally break down these pollutants and increase oxygen levels in the water, as well as providing a new habitat for birds and insects. Coir rolls and hazel faggots were used to create an area of suitable depth to establish the reed bed. Coir mats pre-planted with reeds, rushes, sedges and colourful purple loosestrife and yellow flag iris were installed across the reed bed area, protected from wildfowl grazing by netting. As in the wetland, the plants use excess nutrients such as phosphates and nitrates to grow, preventing them building up in the water which causes the toxic algal blooms. The plants also oxygenate the water. Bacteria growing in the sediment and root systems break down oils and some bacteria can even reduce levels of heavy metals in the water.<br /> |Monitoring surveys and results=Nitrogen is essential for river life but in excess can cause eutrophication. This results in reduced levels of oxygen in the water and may cause toxic algal blooms. Nitrate may be present as ammonia, nitrite or nitrate (measured together as Total Nitrogen), but nitrate is the most stable form. <br /> <br /> Reed bed: The recently installed reed bed is already proving effective at removing nitrogen compounds from the water. There is a significant difference in water quality between the inflow above the reed bed (sampling location 1) and the sampling location immediately the other side of the reed bed (location 2) in total nitrogen, nitrate and ammonia. Total nitrogen drops from 7mg/l to 5mg/l, nitrate from 13mg/l to 4mg//l and ammonia from 1.6mg/l to 0.5mg/l. The improvement in water quality through the reed bed is greater than the improvement observed in the body of the lake. This is because the difference in water quality is larger between sampling sites 1 and 2 compared to between sites 2 and 3 (the lake outflow). <br /> <br /> Wetland basin: The wetland basin is effective at water quality improvement because it prevents polluted water from two drains (sample locations 5 and 6) from entering the stream at site 4. Water entering the infiltration basin from the de-culverted pipe at sampling site 6 is consistently outside of acceptable concentration ranges specified by the Water Framework Directive. Ammonia is consistently present in levels deemed harmful to aquatic life in both inflow pipes (sample locations 5 and 6). Water only flows out of the wetland basin in storm conditions so it effectively prevents polluted water from entering the stream. <br /> <br /> Coliform bacteria derive from faecal waste and are an indicator of pathogens in the aquatic environment. They enter waterways from misconnected toilets, sewage treatment plant overflow, domestic pets and agricultural run off.<br /> <br /> Reed bed: The reed bed is an effective remover of coliform bacteria, reducing the coliform colony count to within guideline limits (under EC Bathing Water Directive)immediately after the reedbed (sample location 2), dropping from approximately 1100 total coliform colonies to 50 total coliform colonies. <br /> <br /> Wetland basin: Water entering the wetland basin from the culverts at sampling sites 5 and 6 contains high counts of coliform bacteria, that are outside of guideline limits (under EC Bathing Water Directive). This is prevented from entering the stream (sample location 4) because water only flows out of the wetland basin in storm conditions. <br /> <br /> |Lessons learn=The wetland basin is quite large, sized for greater flows than have been experienced so far. This means that the water in the treatment basin overflows only during very heavy rainfall events. This is not a significant problem, it just means that the basin is acting more as an infiltration basin rather than a temporary storage basin. The system still functions to prevent polluted water entering the stream. <br /> <br /> The plug planted sedges in the basin are thriving in this environment as the system was not fully activated until the plants were well established. However in the more shaded swales with greater velocity of flows and concentration of pollution the plugs have failed and need to be replanted. <br /> <br /> Sedges have grown lush and verdant in the basin and water is cleaned and returned to the stream as expected or returned to the water table. Although perhaps not as aesthetically pleasing as in the design, the boulder arrangement at the head of the swales has worked well to slow water and prevent excessive erosion in the swales. <br /> <br /> Water quality issues were far more significant than we had anticipated on commencement of the project, particularly in relation to domestic misconnections. High pollutant levels were evident beginning of our swales. We also found that although we proved our systems had a beneficial impact on water quality, just downstream of each project were outfalls which would bring in yet more pollutants. Therefore wetlands and SuDS alone could not demonstrate catchment level water improvements needed under WFD. Small scale interventions have a place in a suite of wider measures that need to be tackled with more drive, especially pollutant impacts from misconnections and vehicle use.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1206.jpg<br /> |Caption=Reedbed summer 2015<br /> }}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1261.jpg<br /> |Caption=Overflow from wetland<br /> }}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1266.jpg<br /> |Caption=Restored stream meandering through woodland<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook<br /> }}<br /> {{Site<br /> |Name=Unnamed tributary of Salmons Brook<br /> |WFD water body name=Salmons Brook<br /> |Pre-project morphology=Closed culvert, <br /> |Desired post project morphology=Actively meandering, <br /> |Heavily modified water body=Yes<br /> |Protected species present=No<br /> |Invasive species present=No<br /> |Dominant substrate=London Clay<br /> |River corridor land use=Urban, <br /> }}<br /> {{Project background}}<br /> {{Motivations}}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Grovelands_Park_Wetlands&diff=36324 2016-02-15T13:59:55Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.635654232931394, -0.10910797125688987<br /> }}<br /> {{Project overview<br /> |Status=Complete<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Environmental flows and water resources, Flood risk management, Habitat and biodiversity, Hydromorphology, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Thames Water,<br /> |Multi-site=No<br /> |Project picture=Thames21-grovelandspk-justinetrickett-1248.jpg<br /> |Picture description=Grovelands Park Wetlands, summer 2015<br /> |Project summary=The water system in Grovelands Park, Enfield, has been artificially engineered over time, with a long stretch of the stream being contained in an underground pipe, hidden from view and useless to wildlife. Here beneath the ground two surface water drains from local roads and homes washed pollutants straight into the stream every time it rained. Plumbing misconnections added to the problem. <br /> <br /> In spring 2014 we worked with the London Borough of Enfield to 'rewild' the water system in Grovelands Park. We created wetlands to intercept pollutants entering the stream in Grovelands Park. Flows in the surface water drains were diverted into shallow ditches, known as swales, and then into a wetland basin. The swales and basin were planted with sedges suitable for the semi-shaded woodland conditions. The plants use excess nutrients such as phosphates and nitrates to grow, preventing them building up in the water which causes the toxic algal blooms. The plants also oxygenate the water. Bacteria growing in the sediment and root systems break down oils and some bacteria can even reduce levels of heavy metals in the water. The clean water then soaks into the ground, as it would naturally, or overflows back into the stream. Rainwater washing off an area the size of 11 rugby fields is cleaned in the wetland. As we completed this project Thames Water ran misconnection surveys on the urban catchment, a vital piece of the jigsaw to ensure optimal results in this project.<br /> <br /> At the same time the London Borough of Enfield naturalised 200m of the stream, breaking it out of its underground pipe and allowing it to find its own course meandering through the woodland. These two projects restored the water system to its natural state, better able to cope with floods and slowing high flows of stormwater, as well as treating pollutants. <br /> <br /> The lake in Grovelands Park, Enfield is the centrepiece of a beautiful and grand garden for the ‘Southgate Grove’ mansion, designed in the 18th century and now a well-loved and popular public park. Sadly the lake is afflicted with pollution from a number of surface water drains, and toxic algal blooms are common in summer. Rainwater running off local streets brings with it oils and heavy metals from the road, as well as detergents and other chemicals such as phosphates and nitrates from misconnected plumbing. This pollution load limits the lake’s potential as a wildlife habitat and its appeal for park visitors.<br /> <br /> In June 2015 we created a reed bed in the south western end of the lake to naturally break down these pollutants and increase oxygen levels in the water, as well as providing a new habitat for birds and insects. Coir rolls and hazel faggots were used to create an area of suitable depth to establish the reed bed. Coir mats pre-planted with reeds, rushes, sedges and colourful purple loosestrife and yellow flag iris were installed across the reed bed area, protected from wildfowl grazing by netting. As in the wetland, the plants use excess nutrients such as phosphates and nitrates to grow, preventing them building up in the water which causes the toxic algal blooms. The plants also oxygenate the water. Bacteria growing in the sediment and root systems break down oils and some bacteria can even reduce levels of heavy metals in the water.<br /> |Monitoring surveys and results=Nitrogen is essential for river life but in excess can cause eutrophication. This results in reduced levels of oxygen in the water and may cause toxic algal blooms. Nitrate may be present as ammonia, nitrite or nitrate (measured together as Total Nitrogen), but nitrate is the most stable form. <br /> <br /> Reed bed: The recently installed reed bed is already proving effective at removing nitrogen compounds from the water. There is a significant difference in water quality between the inflow above the reed bed (sampling location 1) and the sampling location immediately the other side of the reed bed (location 2) in total nitrogen, nitrate and ammonia. Total nitrogen drops from 7mg/l to 5mg/l, nitrate from 13mg/l to 4mg//l and ammonia from 1.6mg/l to 0.5mg/l. The improvement in water quality through the reed bed is greater than the improvement observed in the body of the lake. This is because the difference in water quality is larger between sampling sites 1 and 2 compared to between sites 2 and 3 (the lake outflow). <br /> <br /> Wetland basin: The wetland basin is effective at water quality improvement because it prevents polluted water from two drains (sample locations 5 and 6) from entering the stream at site 4. Water entering the infiltration basin from the de-culverted pipe at sampling site 6 is consistently outside of acceptable concentration ranges specified by the Water Framework Directive. Ammonia is consistently present in levels deemed harmful to aquatic life in both inflow pipes (sample locations 5 and 6). Water only flows out of the wetland basin in storm conditions so it effectively prevents polluted water from entering the stream. <br /> <br /> Coliform bacteria derive from faecal waste and are an indicator of pathogens in the aquatic environment. They enter waterways from misconnected toilets, sewage treatment plant overflow, domestic pets and agricultural run off.<br /> <br /> Reed bed: The reed bed is an effective remover of coliform bacteria, reducing the coliform colony count to within guideline limits (under EC Bathing Water Directive)immediately after the reedbed (sample location 2), dropping from approximately 1100 total coliform colonies to 50 total coliform colonies. <br /> <br /> Wetland basin: Water entering the wetland basin from the culverts at sampling sites 5 and 6 contains high counts of coliform bacteria, that are outside of guideline limits (under EC Bathing Water Directive). This is prevented from entering the stream (sample location 4) because water only flows out of the wetland basin in storm conditions. <br /> <br /> |Lessons learn=The wetland basin is quite large, sized for greater flows than have been experienced so far. This means that the water in the treatment basin overflows only during very heavy rainfall events. This is not a significant problem, it just means that the basin is acting more as an infiltration basin rather than a temporary storage basin. The system still functions to prevent polluted water entering the stream. <br /> <br /> The plug planted sedges in the basin are thriving in this environment as the system was not fully activated until the plants were well established. However in the more shaded swales with greater velocity of flows and concentration of pollution the plugs have failed and need to be replanted. <br /> <br /> Sedges have grown lush and verdant in the basin and water is cleaned and returned to the stream as expected or returned to the water table. Although perhaps not as aesthetically pleasing as in the design, the boulder arrangement at the head of the swales has worked well to slow water and prevent excessive erosion in the swales. <br /> <br /> Water quality issues were far more significant than we had anticipated on commencement of the project, particularly in relation to domestic misconnections. High pollutant levels were evident beginning of our swales. We also found that although we proved our systems had a beneficial impact on water quality, just downstream of each project were outfalls which would bring in yet more pollutants. Therefore wetlands and SuDS alone could not demonstrate catchment level water improvements needed under WFD. Small scale interventions have a place in a suite of wider measures that need to be tackled with more drive, especially pollutant impacts from misconnections and vehicle use.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1206.jpg<br /> |Caption=Reedbed summer 2015<br /> }}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1261.jpg<br /> |Caption=Overflow from wetland<br /> }}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1266.jpg<br /> |Caption=Restored stream meandering through woodland<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook<br /> }}<br /> {{Site}}<br /> {{Project background}}<br /> {{Motivations}}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Grovelands_Park_Wetlands&diff=36323 2016-02-15T13:59:21Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.635654232931394, -0.10910797125688987<br /> }}<br /> {{Project overview<br /> |Status=Complete<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Environmental flows and water resources, Flood risk management, Habitat and biodiversity, Hydromorphology, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Thames Water,<br /> |Multi-site=No<br /> |Project picture=Thames21-grovelandspk-justinetrickett-1248.jpg<br /> |Picture description=Grovelands Park Wetlands, summer 2015<br /> |Project summary=The water system in Grovelands Park, Enfield, has been artificially engineered over time, with a long stretch of the stream being contained in an underground pipe, hidden from view and useless to wildlife. Here beneath the ground two surface water drains from local roads and homes washed pollutants straight into the stream every time it rained. Plumbing misconnections added to the problem. <br /> <br /> In spring 2014 we worked with the London Borough of Enfield to 'rewild' the water system in Grovelands Park. We created wetlands to intercept pollutants entering the stream in Grovelands Park. Flows in the surface water drains were diverted into shallow ditches, known as swales, and then into a wetland basin. The swales and basin were planted with sedges suitable for the semi-shaded woodland conditions. The plants use excess nutrients such as phosphates and nitrates to grow, preventing them building up in the water which causes the toxic algal blooms. The plants also oxygenate the water. Bacteria growing in the sediment and root systems break down oils and some bacteria can even reduce levels of heavy metals in the water. The clean water then soaks into the ground, as it would naturally, or overflows back into the stream. Rainwater washing off an area the size of 11 rugby fields is cleaned in the wetland. As we completed this project Thames Water ran misconnection surveys on the urban catchment, a vital piece of the jigsaw to ensure optimal results in this project.<br /> <br /> At the same time the London Borough of Enfield naturalised 200m of the stream, breaking it out of its underground pipe and allowing it to find its own course meandering through the woodland. These two projects restored the water system to its natural state, better able to cope with floods and slowing high flows of stormwater, as well as treating pollutants. <br /> <br /> The lake in Grovelands Park, Enfield is the centrepiece of a beautiful and grand garden for the ‘Southgate Grove’ mansion, designed in the 18th century and now a well-loved and popular public park. Sadly the lake is afflicted with pollution from a number of surface water drains, and toxic algal blooms are common in summer. Rainwater running off local streets brings with it oils and heavy metals from the road, as well as detergents and other chemicals such as phosphates and nitrates from misconnected plumbing. This pollution load limits the lake’s potential as a wildlife habitat and its appeal for park visitors.<br /> <br /> In June 2015 we created a reed bed in the south western end of the lake to naturally break down these pollutants and increase oxygen levels in the water, as well as providing a new habitat for birds and insects. Coir rolls and hazel faggots were used to create an area of suitable depth to establish the reed bed. Coir mats pre-planted with reeds, rushes, sedges and colourful purple loosestrife and yellow flag iris were installed across the reed bed area, protected from wildfowl grazing by netting. As in the wetland, the plants use excess nutrients such as phosphates and nitrates to grow, preventing them building up in the water which causes the toxic algal blooms. The plants also oxygenate the water. Bacteria growing in the sediment and root systems break down oils and some bacteria can even reduce levels of heavy metals in the water.<br /> |Monitoring surveys and results=Nitrogen is essential for river life but in excess can cause eutrophication. This results in reduced levels of oxygen in the water and may cause toxic algal blooms. Nitrate may be present as ammonia, nitrite or nitrate (measured together as Total Nitrogen), but nitrate is the most stable form. <br /> <br /> Reed bed: The recently installed reed bed is already proving effective at removing nitrogen compounds from the water. There is a significant difference in water quality between the inflow above the reed bed (sampling location 1) and the sampling location immediately the other side of the reed bed (location 2) in total nitrogen, nitrate and ammonia. Total nitrogen drops from 7mg/l to 5mg/l, nitrate from 13mg/l to 4mg//l and ammonia from 1.6mg/l to 0.5mg/l. The improvement in water quality through the reed bed is greater than the improvement observed in the body of the lake. This is because the difference in water quality is larger between sampling sites 1 and 2 compared to between sites 2 and 3 (the lake outflow). <br /> <br /> Wetland basin: The wetland basin is effective at water quality improvement because it prevents polluted water from two drains (sample locations 5 and 6) from entering the stream at site 4. Water entering the infiltration basin from the de-culverted pipe at sampling site 6 is consistently outside of acceptable concentration ranges specified by the Water Framework Directive. Ammonia is consistently present in levels deemed harmful to aquatic life in both inflow pipes (sample locations 5 and 6). Water only flows out of the wetland basin in storm conditions so it effectively prevents polluted water from entering the stream. <br /> <br /> Coliform bacteria derive from faecal waste and are an indicator of pathogens in the aquatic environment. They enter waterways from misconnected toilets, sewage treatment plant overflow, domestic pets and agricultural run off.<br /> <br /> Reed bed: The reed bed is an effective remover of coliform bacteria, reducing the coliform colony count to within guideline limits (under EC Bathing Water Directive)immediately after the reedbed (sample location 2), dropping from approximately 1100 total coliform colonies to 50 total coliform colonies. <br /> <br /> Wetland basin: Water entering the wetland basin from the culverts at sampling sites 5 and 6 contains high counts of coliform bacteria, that are outside of guideline limits (under EC Bathing Water Directive). This is prevented from entering the stream (sample location 4) because water only flows out of the wetland basin in storm conditions. <br /> <br /> |Lessons learn=The wetland basin is quite large, sized for greater flows than have been experienced so far. This means that the water in the treatment basin overflows only during very heavy rainfall events. This is not a significant problem, it just means that the basin is acting more as an infiltration basin rather than a temporary storage basin. The system still functions to prevent polluted water entering the stream. <br /> <br /> The plug planted sedges in the basin are thriving in this environment as the system was not fully activated until the plants were well established. However in the more shaded swales with greater velocity of flows and concentration of pollution the plugs have failed and need to be replanted. <br /> <br /> Sedges have grown lush and verdant in the basin and water is cleaned and returned to the stream as expected or returned to the water table. Although perhaps not as aesthetically pleasing as in the design, the boulder arrangement at the head of the swales has worked well to slow water and prevent excessive erosion in the swales. <br /> <br /> Water quality issues were far more significant than we had anticipated on commencement of the project, particularly in relation to domestic misconnections. High pollutant levels were evident beginning of our swales. We also found that although we proved our systems had a beneficial impact on water quality, just downstream of each project were outfalls which would bring in yet more pollutants. Therefore wetlands and SuDS alone could not demonstrate catchment level water improvements needed under WFD. Small scale interventions have a place in a suite of wider measures that need to be tackled with more drive, especially pollutant impacts from misconnections and vehicle use.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1206.jpg<br /> |Caption=Reedbed summer 2015<br /> }}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1261.jpg<br /> |Caption=Overflow from wetland<br /> }}<br /> {{Case study image<br /> |File name=Thames21-grovelandspk-justinetrickett-1266.jpg<br /> |Caption=Restored stream meandering through woodland<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment}}<br /> {{Site}}<br /> {{Project background}}<br /> {{Motivations}}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=File:Thames21-grovelandspk-justinetrickett-1266.jpg&diff=36322 2016-02-15T13:58:33Z

<p>AimeeThames21: </p> <hr /> <div></div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=File:Thames21-grovelandspk-justinetrickett-1261.jpg&diff=36321 2016-02-15T13:57:56Z

<p>AimeeThames21: </p> <hr /> <div></div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=File:Thames21-grovelandspk-justinetrickett-1206.jpg&diff=36320 2016-02-15T13:56:50Z

<p>AimeeThames21: </p> <hr /> <div></div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Grovelands_Park_Wetlands&diff=36319 2016-02-15T13:55:47Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.635654232931394, -0.10910797125688987<br /> }}<br /> {{Project overview<br /> |Status=Complete<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Environmental flows and water resources, Flood risk management, Habitat and biodiversity, Hydromorphology, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Thames Water,<br /> |Multi-site=No<br /> |Project picture=Thames21-grovelandspk-justinetrickett-1248.jpg<br /> |Picture description=Grovelands Park Wetlands, summer 2015<br /> |Project summary=The water system in Grovelands Park, Enfield, has been artificially engineered over time, with a long stretch of the stream being contained in an underground pipe, hidden from view and useless to wildlife. Here beneath the ground two surface water drains from local roads and homes washed pollutants straight into the stream every time it rained. Plumbing misconnections added to the problem. <br /> <br /> In spring 2014 we worked with the London Borough of Enfield to 'rewild' the water system in Grovelands Park. We created wetlands to intercept pollutants entering the stream in Grovelands Park. Flows in the surface water drains were diverted into shallow ditches, known as swales, and then into a wetland basin. The swales and basin were planted with sedges suitable for the semi-shaded woodland conditions. The plants use excess nutrients such as phosphates and nitrates to grow, preventing them building up in the water which causes the toxic algal blooms. The plants also oxygenate the water. Bacteria growing in the sediment and root systems break down oils and some bacteria can even reduce levels of heavy metals in the water. The clean water then soaks into the ground, as it would naturally, or overflows back into the stream. Rainwater washing off an area the size of 11 rugby fields is cleaned in the wetland. As we completed this project Thames Water ran misconnection surveys on the urban catchment, a vital piece of the jigsaw to ensure optimal results in this project.<br /> <br /> At the same time the London Borough of Enfield naturalised 200m of the stream, breaking it out of its underground pipe and allowing it to find its own course meandering through the woodland. These two projects restored the water system to its natural state, better able to cope with floods and slowing high flows of stormwater, as well as treating pollutants. <br /> <br /> The lake in Grovelands Park, Enfield is the centrepiece of a beautiful and grand garden for the ‘Southgate Grove’ mansion, designed in the 18th century and now a well-loved and popular public park. Sadly the lake is afflicted with pollution from a number of surface water drains, and toxic algal blooms are common in summer. Rainwater running off local streets brings with it oils and heavy metals from the road, as well as detergents and other chemicals such as phosphates and nitrates from misconnected plumbing. This pollution load limits the lake’s potential as a wildlife habitat and its appeal for park visitors.<br /> <br /> In June 2015 we created a reed bed in the south western end of the lake to naturally break down these pollutants and increase oxygen levels in the water, as well as providing a new habitat for birds and insects. Coir rolls and hazel faggots were used to create an area of suitable depth to establish the reed bed. Coir mats pre-planted with reeds, rushes, sedges and colourful purple loosestrife and yellow flag iris were installed across the reed bed area, protected from wildfowl grazing by netting. As in the wetland, the plants use excess nutrients such as phosphates and nitrates to grow, preventing them building up in the water which causes the toxic algal blooms. The plants also oxygenate the water. Bacteria growing in the sediment and root systems break down oils and some bacteria can even reduce levels of heavy metals in the water.<br /> |Monitoring surveys and results=Nitrogen is essential for river life but in excess can cause eutrophication. This results in reduced levels of oxygen in the water and may cause toxic algal blooms. Nitrate may be present as ammonia, nitrite or nitrate (measured together as Total Nitrogen), but nitrate is the most stable form. <br /> <br /> Reed bed: The recently installed reed bed is already proving effective at removing nitrogen compounds from the water. There is a significant difference in water quality between the inflow above the reed bed (sampling location 1) and the sampling location immediately the other side of the reed bed (location 2) in total nitrogen, nitrate and ammonia. Total nitrogen drops from 7mg/l to 5mg/l, nitrate from 13mg/l to 4mg//l and ammonia from 1.6mg/l to 0.5mg/l. The improvement in water quality through the reed bed is greater than the improvement observed in the body of the lake. This is because the difference in water quality is larger between sampling sites 1 and 2 compared to between sites 2 and 3 (the lake outflow). <br /> <br /> Wetland basin: The wetland basin is effective at water quality improvement because it prevents polluted water from two drains (sample locations 5 and 6) from entering the stream at site 4. Water entering the infiltration basin from the de-culverted pipe at sampling site 6 is consistently outside of acceptable concentration ranges specified by the Water Framework Directive. Ammonia is consistently present in levels deemed harmful to aquatic life in both inflow pipes (sample locations 5 and 6). Water only flows out of the wetland basin in storm conditions so it effectively prevents polluted water from entering the stream. <br /> <br /> Coliform bacteria derive from faecal waste and are an indicator of pathogens in the aquatic environment. They enter waterways from misconnected toilets, sewage treatment plant overflow, domestic pets and agricultural run off.<br /> <br /> Reed bed: The reed bed is an effective remover of coliform bacteria, reducing the coliform colony count to within guideline limits (under EC Bathing Water Directive)immediately after the reedbed (sample location 2), dropping from approximately 1100 total coliform colonies to 50 total coliform colonies. <br /> <br /> Wetland basin: Water entering the wetland basin from the culverts at sampling sites 5 and 6 contains high counts of coliform bacteria, that are outside of guideline limits (under EC Bathing Water Directive). This is prevented from entering the stream (sample location 4) because water only flows out of the wetland basin in storm conditions. <br /> <br /> |Lessons learn=The wetland basin is quite large, sized for greater flows than have been experienced so far. This means that the water in the treatment basin overflows only during very heavy rainfall events. This is not a significant problem, it just means that the basin is acting more as an infiltration basin rather than a temporary storage basin. The system still functions to prevent polluted water entering the stream. <br /> <br /> The plug planted sedges in the basin are thriving in this environment as the system was not fully activated until the plants were well established. However in the more shaded swales with greater velocity of flows and concentration of pollution the plugs have failed and need to be replanted. <br /> <br /> Sedges have grown lush and verdant in the basin and water is cleaned and returned to the stream as expected or returned to the water table. Although perhaps not as aesthetically pleasing as in the design, the boulder arrangement at the head of the swales has worked well to slow water and prevent excessive erosion in the swales. <br /> <br /> Water quality issues were far more significant than we had anticipated on commencement of the project, particularly in relation to domestic misconnections. High pollutant levels were evident beginning of our swales. We also found that although we proved our systems had a beneficial impact on water quality, just downstream of each project were outfalls which would bring in yet more pollutants. Therefore wetlands and SuDS alone could not demonstrate catchment level water improvements needed under WFD. Small scale interventions have a place in a suite of wider measures that need to be tackled with more drive, especially pollutant impacts from misconnections and vehicle use.<br /> }}<br /> {{Image gallery}}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment}}<br /> {{Site}}<br /> {{Project background}}<br /> {{Motivations}}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Glenbrook_Wetlands&diff=36317 2016-02-15T13:32:45Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.647746622246224, -0.11766529030865058<br /> }}<br /> {{Project overview<br /> |Status=In progress<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Flood risk management, Habitat and biodiversity, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames 21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Thames Water, Environment Agency,<br /> |Multi-site=No<br /> |Project picture=IMAG0001.jpg<br /> |Picture description=Wetland basin 2 - Jan 2016<br /> |Project summary=Thames21 has been working with Enfield Council, The Environment Agency and Thames Water to improve the health of the Salmons Brook and its tributaries. Enfield has a separate sewage system, meaning that surface water eg. rain running off roads and wastewater are carried in two separate pipes. As a result, pollutants enter the Salmons Brook in a number of different ways. Misconnected plumbing contributes nutrients such as phosphates and nitrates and coliform bacteria, road run-off inputs oils and heavy metals such as zinc and copper, and household and industrial waste is dumped into surface water drains. <br /> <br /> With great support from local people we’ve created Sustainable Drainage Systems (SuDS), or ’rainscapes’ to intercept the pollution. As well as filtering pollutants out of water, the SuDS also help reduce local flood risk by slowing the flow, create wildlife habitats and provide new amenities for local people. <br /> <br /> The Glenbrook is a tributary of the Salmons Brook. It flows through underground pipes for much of its length. Hidden away it is damaged, and when it first emerges above ground it is already very badly polluted. Six linked wetlands have been created here to filter pollutants from the stream. The flow is directed through each wetland, being successively cleaned as it is slowed through the basins. Plants use nutrients such as phosphate and nitrate to grow, removing them from the water and stopping them polluting the stream. Bacteria in the soil and root systems break down oils and heavy metals. Once established the planted wetlands not only clean the water, they also add a new dimension to the habitat mosaic for wildlife, and give interest and colour for those passing by.<br /> <br /> The Glenbrook wetlands were complete in September 2014 after three months of construction. Local volunteers helped to plant the wetlands in September 2014 and again in March 2015. The system is designed so that in low flow conditions a series of weirs direct all baseflow into the wetlands, whilst in high flow conditions a large proportion of the flow continues downstream and only the first flush is treated. The headwater of the Glenbrook which feeds this system drains an urban catchment of 42 ha. In addition, 15 gullies have been redirected from the roads that surround the site into the wetland treatment system through a series of swales.<br /> |Monitoring surveys and results=Nitrogen and phosphate are essential for river life but in excess they cause eutrophication. This results in reduced levels of oxygen in the water and may cause toxic algal blooms. Nitrate may be present as ammonia, nitrite or nitrate (measured together as Total Nitrogen), but nitrate is the most stable form. Our water quality monitoring has shown that the SUDS basins are effective at removal of Total nitrogen, nitrates and phosphates. Water quality improves between sampling location 1 (the inflow to the SUDS) and location 2 (outflow from the SUDS), particularly in total nitrogen (dropping from 10mg/l to 6mg/l) and nitrate (dropping from 13mg/l to 7mg/l), bringing water quality within acceptable guideline levels (as defined in EA General Quality Assessment, Water Framework Directive 2014). <br /> <br /> Coliform bacteria derive from faecal waste and are an indicator of pathogens in the aquatic environment. They enter waterways from misconnected toilets, sewage treatment plant overflow, domestic pets and agricultural run off. The SUDS basins are extremely effective at removal of coliform bacteria. Water quality improves between sampling location 1 (the inflow to the SUDS) and location 2 (outflow from the SUDS), with coliform counts dropping from approximately 1400 total coliform colonies to approximately 400 total coliform colonies, bringing water quality within acceptable guideline levels (under EC Bathing Water Directive).<br /> <br /> Invertebrate surveys have also been carried out as part of this project. A masters student from Kings College London (KCL) undertook research into invertebrate populations at each of the project sites. Linking the invertebrate survey results to water quality data, the student predicted the impact/ potential impact of each of the SuDS/wetland schemes on population sizes and diversity over time. There was no existing data on invertebrates for the catchment before research was carried out. As predicted the invertebrate survey confirmed findings of poor water quality, with pollution sensitive taxa very badly represented. The study concluded that the SuDS have the potential to improve water quality and ecological outcomes downstream, but far greater efforts in reducing pollutants from vehicle use and misconnections will be required to resolve the problems of urban diffuse pollution.<br /> |Lessons learn=At this site in particular we came across some levels of reticence from the local community to the project, mainly due to the significant changes to the landscape and lack of familiarity around SuDS, as well as a lack of understanding of why they were desperately needed. We overcame this by being very transparent and available, and in taking care of the site and the stream and making obvious improvements to its health and potential as a wildlife habitat. Regular communications in many forms were key. This became the site at which volunteer days were best attended by local residents. In future projects it would be ideal to spend a time in the build-up to the project engaging the community about water quality issues, rather than to do this simultaneously with planning the SuDS. <br /> <br /> Water quality issues were far more significant than we had anticipated on commencement of the project, particularly in relation to domestic misconnections. Serious pollutant levels damaged the beginning of our SuDS system as Glenbrook. We also found that although we proved our systems had a beneficial impact on water quality, just downstream of each project were outfalls which would bring in yet more pollutants. Therefore SuDS alone could not demonstrate catchment level water improvements needed under WFD. Small scale SuDS have a place in a suite of wider measures that need to be tackled with more drive, especially pollutant impacts from misconnections and vehicle use. <br /> <br /> We experienced some design issues which resulted from a lack of quality data pre-project, for example on flows. It would have been prohibitively expensive for us to get the data needed on this project budget, but it meant that some SuDS elements such as weirs required some costly remediation work.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=Basin 1 creation.JPG<br /> |Caption=Creating basin 1<br /> }}<br /> {{Case study image<br /> |File name=Site of basin 6.JPG<br /> |Caption=Site of basin 6<br /> }}<br /> {{Case study image<br /> |File name=Basin 6 with water.JPG<br /> |Caption=Basin 6 with water<br /> }}<br /> {{Case study image<br /> |File name=Planting in basin 6.JPG<br /> |Caption=Planting in basin 6 - April 2015<br /> }}<br /> {{Case study image<br /> |File name=Drain marking pic.jpg<br /> |Caption=Drain markers installed around site<br /> }}<br /> {{Case study image<br /> |File name=Misconnections pollution.JPG<br /> |Caption=Pollution from misconnections<br /> }}<br /> {{Case study image<br /> |File name=Basin 2 July 2015.JPG<br /> |Caption=Basin 2 July 2015<br /> }}<br /> <br /> {{Case study image<br /> |File name=Planting basin 3.JPG<br /> |Caption=Planting wetland basin 3<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook<br /> }}<br /> {{Site<br /> |Name=Glenbrook<br /> |WFD water body code=GB106038027960<br /> |WFD (national) typology=Type 18: small loess-loam dominated lowland river<br /> |WFD water body name=Salmons Brook<br /> |Heavily modified water body=Yes<br /> |Protected species present=No<br /> |Invasive species present=Yes<br /> |Dominant substrate=London Clay<br /> |River corridor land use=Urban<br /> }}<br /> {{Project background<br /> |Reach length directly affected=220<br /> |Project started=2012/09/01<br /> |Funding sources=Defra, Environment Agency, London Borough of Enfield, Thames Water, <br /> }}<br /> {{Motivations<br /> |Specific mitigation=Poor water quality (urban run off and misconnections)<br /> |Hydromorphological quality elements=Good status in 2011<br /> |Biological quality elements=In 2011 - Phytobenthos, macrophytes, invertebrates poor and fish moderate<br /> |Physico-chemical quality elements=In 2011 - Ammonia moderate, dissolved oxygen and phosphate poor, annex 8 chem. high<br /> |Other motivation=Improving a public space, flood protection, terrestrial biodiversity improvements<br /> }}<br /> {{Measures<br /> |Bank and bed modifications measure=Overdeepened and incised channel bed raised <br /> |Floodplain / River corridor=Tree works and creation of 6 linked wetland basins, swales taking road run off into basins<br /> |Planform / Channel pattern=n/a<br /> |Other technical measure=n/a<br /> |Management interventions=Opening of tree canopy to encourage varied ground flora<br /> |Social measures=Community consultations, volunteer engagement, education sessions, interpretation, access improvements<br /> |Wider stakeholder / citizen engagement=n/a<br /> }}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Grovelands_Park_Wetlands&diff=36316 2016-02-15T13:29:17Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.635654232931394, -0.10910797125688987<br /> }}<br /> {{Project overview<br /> |Status=Complete<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Environmental flows and water resources, Flood risk management, Habitat and biodiversity, Hydromorphology, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Thames Water, <br /> |Multi-site=No<br /> |Project picture=Thames21-grovelandspk-justinetrickett-1248.jpg<br /> |Picture description=Grovelands Park Wetlands, summer 2015<br /> |Project summary=The water system in Grovelands Park, Enfield, has been artificially engineered over time, with a long stretch of the stream being contained in an underground pipe, hidden from view and useless to wildlife. Here beneath the ground two surface water drains from local roads and homes washed pollutants straight into the stream every time it rained. Plumbing misconnections added to the problem. <br /> <br /> In spring 2014 we worked with the London Borough of Enfield to 'rewild' the water system in Grovelands Park. We created wetlands to intercept pollutants entering the stream in Grovelands Park. Flows in the surface water drains were diverted into shallow ditches, known as swales, and then into a wetland basin. The swales and basin were planted with sedges suitable for the semi-shaded woodland conditions. The plants use excess nutrients such as phosphates and nitrates to grow, preventing them building up in the water which causes the toxic algal blooms. The plants also oxygenate the water. Bacteria growing in the sediment and root systems break down oils and some bacteria can even reduce levels of heavy metals in the water. The clean water then soaks into the ground, as it would naturally, or overflows back into the stream. Rainwater washing off an area the size of 11 rugby fields is cleaned in the wetland. As we completed this project Thames Water ran misconnection surveys on the urban catchment, a vital piece of the jigsaw to ensure optimal results in this project.<br /> <br /> At the same time the London Borough of Enfield naturalised 200m of the stream, breaking it out of its underground pipe and allowing it to find its own course meandering through the woodland. These two projects restored the water system to its natural state, better able to cope with floods and slowing high flows of stormwater, as well as treating pollutants. <br /> <br /> The lake in Grovelands Park, Enfield is the centrepiece of a beautiful and grand garden for the ‘Southgate Grove’ mansion, designed in the 18th century and now a well-loved and popular public park. Sadly the lake is afflicted with pollution from a number of surface water drains, and toxic algal blooms are common in summer. Rainwater running off local streets brings with it oils and heavy metals from the road, as well as detergents and other chemicals such as phosphates and nitrates from misconnected plumbing. This pollution load limits the lake’s potential as a wildlife habitat and its appeal for park visitors.<br /> <br /> In June 2015 we created a reed bed in the south western end of the lake to naturally break down these pollutants and increase oxygen levels in the water, as well as providing a new habitat for birds and insects. Coir rolls and hazel faggots were used to create an area of suitable depth to establish the reed bed. Coir mats pre-planted with reeds, rushes, sedges and colourful purple loosestrife and yellow flag iris were installed across the reed bed area, protected from wildfowl grazing by netting. As in the wetland, the plants use excess nutrients such as phosphates and nitrates to grow, preventing them building up in the water which causes the toxic algal blooms. The plants also oxygenate the water. Bacteria growing in the sediment and root systems break down oils and some bacteria can even reduce levels of heavy metals in the water. <br /> <br /> |Lessons learn=The wetland basin is quite large, sized for greater flows than have been experienced so far. This means that the water in the treatment basin overflows only during very heavy rainfall events. This is not a significant problem, it just means that the basin is acting more as an infiltration basin rather than a temporary storage basin. The system still functions to prevent polluted water entering the stream. <br /> <br /> The plug planted sedges in the basin are thriving in this environment as the system was not fully activated until the plants were well established. However in the more shaded swales with greater velocity of flows and concentration of pollution the plugs have failed and need to be replanted. <br /> <br /> Sedges have grown lush and verdant in the basin and water is cleaned and returned to the stream as expected or returned to the water table. Although perhaps not as aesthetically pleasing as in the design, the boulder arrangement at the head of the swales has worked well to slow water and prevent excessive erosion in the swales. <br /> <br /> Water quality issues were far more significant than we had anticipated on commencement of the project, particularly in relation to domestic misconnections. High pollutant levels were evident beginning of our swales. We also found that although we proved our systems had a beneficial impact on water quality, just downstream of each project were outfalls which would bring in yet more pollutants. Therefore wetlands and SuDS alone could not demonstrate catchment level water improvements needed under WFD. Small scale interventions have a place in a suite of wider measures that need to be tackled with more drive, especially pollutant impacts from misconnections and vehicle use. <br /> }}<br /> {{Image gallery}}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment}}<br /> {{Site}}<br /> {{Project background}}<br /> {{Motivations}}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=File:Thames21-grovelandspk-justinetrickett-1248.jpg&diff=36315 2016-02-15T13:11:56Z

<p>AimeeThames21: </p> <hr /> <div></div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Grovelands_Park_Wetlands&diff=36260 2016-02-10T17:02:17Z

<p>AimeeThames21: Created page with &quot;{{Case study status |Approval status=Draft }} {{Location |Location=51.635654232931394, -0.10910797125688987 }} {{Project overview |Project title=Grovelands Park Wetlands |Stat...&quot;</p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.635654232931394, -0.10910797125688987<br /> }}<br /> {{Project overview<br /> |Project title=Grovelands Park Wetlands<br /> |Status=In progress<br /> |Themes=Environmental flows and water resources, Flood risk management, Habitat and biodiversity, Hydromorphology, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Multi-site=No<br /> }}<br /> {{Image gallery}}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment}}<br /> {{Site}}<br /> {{Project background}}<br /> {{Motivations}}<br /> {{Measures}}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=Case_study:Glenbrook_Wetlands&diff=36255 2016-02-09T16:34:03Z

<p>AimeeThames21: </p> <hr /> <div>{{Case study status<br /> |Approval status=Draft<br /> }}<br /> {{Location<br /> |Location=51.647746622246224, -0.11766529030865058<br /> }}<br /> {{Project overview<br /> |Status=In progress<br /> |Project web site url=http://www.thames21.org.uk/salmons-brook/<br /> |Themes=Flood risk management, Habitat and biodiversity, Monitoring, Social benefits, Water quality, Urban<br /> |Country=England<br /> |Main contact forename=Aimee<br /> |Main contact surname=Felus<br /> |Main contact id=AimeeThames21<br /> |Contact organisation=Thames 21<br /> |Contact organisation url=www.thames21.org.uk<br /> |Partner organisations=London Borough of Enfield, Thames Water, Environment Agency,<br /> |Multi-site=No<br /> |Project picture=IMAG0001.jpg<br /> |Picture description=Wetland basin 2 - Jan 2016<br /> |Project summary=Thames21 has been working with Enfield Council, The Environment Agency and Thames Water to improve the health of the Salmons Brook and its tributaries. Enfield has a separate sewage system, meaning that surface water eg. rain running off roads and wastewater are carried in two separate pipes. As a result, pollutants enter the Salmons Brook in a number of different ways. Misconnected plumbing contributes nutrients such as phosphates and nitrates and coliform bacteria, road run-off inputs oils and heavy metals such as zinc and copper, and household and industrial waste is dumped into surface water drains. <br /> <br /> With great support from local people we’ve created Sustainable Drainage Systems (SuDS), or ’rainscapes’ to intercept the pollution. As well as filtering pollutants out of water, the SuDS also help reduce local flood risk by slowing the flow, create wildlife habitats and provide new amenities for local people. <br /> <br /> The Glenbrook is a tributary of the Salmons Brook. It flows through underground pipes for much of its length. Hidden away it is damaged, and when it first emerges above ground it is already very badly polluted. Six linked wetlands have been created here to filter pollutants from the stream. The flow is directed through each wetland, being successively cleaned as it is slowed through the basins. Plants use nutrients such as phosphate and nitrate to grow, removing them from the water and stopping them polluting the stream. Bacteria in the soil and root systems break down oils and heavy metals. Once established the planted wetlands not only clean the water, they also add a new dimension to the habitat mosaic for wildlife, and give interest and colour for those passing by.<br /> <br /> The Glenbrook wetlands were complete in September 2014 after three months of construction. Local volunteers helped to plant the wetlands in September 2014 and again in March 2015. The system is designed so that in low flow conditions a series of weirs direct all baseflow into the wetlands, whilst in high flow conditions a large proportion of the flow continues downstream and only the first flush is treated. The headwater of the Glenbrook which feeds this system drains an urban catchment of 42 ha. In addition, 15 gullies have been redirected from the roads that surround the site into the wetland treatment system through a series of swales.<br /> |Monitoring surveys and results=Nitrogen and phosphate are essential for river life but in excess they cause eutrophication. This results in reduced levels of oxygen in the water and may cause toxic algal blooms. Nitrate may be present as ammonia, nitrite or nitrate (measured together as Total Nitrogen), but nitrate is the most stable form. Our water quality monitoring has shown that the SUDS basins are effective at removal of Total nitrogen, nitrates and phosphates. Water quality improves between sampling location 1 (the inflow to the SUDS) and location 2 (outflow from the SUDS), particularly in total nitrogen (dropping from 10mg/l to 6mg/l) and nitrate (dropping from 13mg/l to 7mg/l), bringing water quality within acceptable guideline levels (as defined in EA General Quality Assessment, Water Framework Directive 2014). <br /> <br /> Coliform bacteria derive from faecal waste and are an indicator of pathogens in the aquatic environment. They enter waterways from misconnected toilets, sewage treatment plant overflow, domestic pets and agricultural run off. The SUDS basins are extremely effective at removal of coliform bacteria. Water quality improves between sampling location 1 (the inflow to the SUDS) and location 2 (outflow from the SUDS), with coliform counts dropping from approximately 1400 total coliform colonies to approximately 400 total coliform colonies, bringing water quality within acceptable guideline levels (under EC Bathing Water Directive).<br /> <br /> Invertebrate surveys have also been carried out as part of this project. A masters student from Kings College London (KCL) undertook research into invertebrate populations at each of the project sites. Linking the invertebrate survey results to water quality data, the student predicted the impact/ potential impact of each of the SuDS/wetland schemes on population sizes and diversity over time. There was no existing data on invertebrates for the catchment before research was carried out. As predicted the invertebrate survey confirmed findings of poor water quality, with pollution sensitive taxa very badly represented. The study concluded that the SuDS have the potential to improve water quality and ecological outcomes downstream, but far greater efforts in reducing pollutants from vehicle use and misconnections will be required to resolve the problems of urban diffuse pollution.<br /> |Lessons learn=At this site in particular we came across some levels of reticence from the local community to the project, mainly due to the significant changes to the landscape and lack of familiarity around SuDS, as well as a lack of understanding of why they were desperately needed. We overcame this by being very transparent and available, and in taking care of the site and the stream and making obvious improvements to its health and potential as a wildlife habitat. Regular communications in many forms were key. This became the site at which volunteer days were best attended by local residents. In future projects it would be ideal to spend a time in the build-up to the project engaging the community about water quality issues, rather than to do this simultaneously with planning the SuDS. <br /> <br /> Water quality issues were far more significant than we had anticipated on commencement of the project, particularly in relation to domestic misconnections. Serious pollutant levels damaged the beginning of our SuDS system as Glenbrook. We also found that although we proved our systems had a beneficial impact on water quality, just downstream of each project were outfalls which would bring in yet more pollutants. Therefore SuDS alone could not demonstrate catchment level water improvements needed under WFD. Small scale SuDS have a place in a suite of wider measures that need to be tackled with more drive, especially pollutant impacts from misconnections and vehicle use. <br /> <br /> We experienced some design issues which resulted from a lack of quality data pre-project, for example on flows. It would have been prohibitively expensive for us to get the data needed on this project budget, but it meant that some SuDS elements such as weirs required some costly remediation work.<br /> }}<br /> {{Image gallery}}<br /> {{Case study image<br /> |File name=Basin 1 creation.JPG<br /> |Caption=Creating basin 1<br /> }}<br /> {{Case study image<br /> |File name=Site of basin 6.JPG<br /> |Caption=Site of basin 6<br /> }}<br /> {{Case study image<br /> |File name=Basin 6 with water.JPG<br /> |Caption=Basin 6 with water<br /> }}<br /> {{Case study image<br /> |File name=Volunteers planting basin 6.JPG<br /> |Caption=Volunteers planting basin 6 - April 2015<br /> }}<br /> {{Case study image<br /> |File name=Planting in basin 6.JPG<br /> |Caption=Planting in basin 6 - April 2015<br /> }}<br /> {{Case study image<br /> |File name=Drain marking pic.jpg<br /> |Caption=Drain markers installed around site<br /> }}<br /> {{Case study image<br /> |File name=Misconnections pollution.JPG<br /> |Caption=Pollution from misconnections<br /> }}<br /> {{Case study image<br /> |File name=Basin 2 July 2015.JPG<br /> |Caption=Basin 2 July 2015<br /> }}<br /> {{Case study image<br /> |File name=Planting basin 3.JPG<br /> |Caption=Planting wetland basin 3<br /> }}<br /> {{Image gallery end}}<br /> {{Toggle button}}<br /> {{Toggle content start}}<br /> {{Case study subcatchment<br /> |Subcatchment=Salmons Brook<br /> }}<br /> {{Site<br /> |Name=Glenbrook<br /> |WFD water body code=GB106038027960<br /> |WFD (national) typology=Type 18: small loess-loam dominated lowland river<br /> |WFD water body name=Salmons Brook<br /> |Heavily modified water body=Yes<br /> |Protected species present=No<br /> |Invasive species present=Yes<br /> |Dominant substrate=London Clay<br /> |River corridor land use=Urban<br /> }}<br /> {{Project background<br /> |Reach length directly affected=220<br /> |Project started=2012/09/01<br /> |Funding sources=Defra, Environment Agency, London Borough of Enfield, Thames Water, <br /> }}<br /> {{Motivations<br /> |Specific mitigation=Poor water quality (urban run off and misconnections)<br /> |Hydromorphological quality elements=Good status in 2011<br /> |Biological quality elements=In 2011 - Phytobenthos, macrophytes, invertebrates poor and fish moderate<br /> |Physico-chemical quality elements=In 2011 - Ammonia moderate, dissolved oxygen and phosphate poor, annex 8 chem. high<br /> |Other motivation=Improving a public space, flood protection, terrestrial biodiversity improvements<br /> }}<br /> {{Measures<br /> |Bank and bed modifications measure=Overdeepened and incised channel bed raised <br /> |Floodplain / River corridor=Tree works and creation of 6 linked wetland basins, swales taking road run off into basins<br /> |Planform / Channel pattern=n/a<br /> |Other technical measure=n/a<br /> |Management interventions=Opening of tree canopy to encourage varied ground flora<br /> |Social measures=Community consultations, volunteer engagement, education sessions, interpretation, access improvements<br /> |Wider stakeholder / citizen engagement=n/a<br /> }}<br /> {{Hydromorphological quality elements header}}<br /> {{End table}}<br /> {{Biological quality elements header}}<br /> {{End table}}<br /> {{Physico-chemical quality elements header}}<br /> {{End table}}<br /> {{Other responses header}}<br /> {{End table}}<br /> {{Monitoring documents}}<br /> {{Monitoring documents end}}<br /> {{Additional Documents}}<br /> {{Additional Documents end}}<br /> {{Additional links and references header}}<br /> {{Additional links and references footer}}<br /> {{Supplementary Information}}<br /> {{Toggle content end}}</div>

AimeeThames21 https://restorerivers.eu/wiki/index.php?title=File:Planting_basin_3.JPG&diff=36254 2016-02-09T16:33:42Z

<p>AimeeThames21: </p> <hr /> <div></div>

AimeeThames21