Property:Project summary
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R
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 suffered from urban 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.
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.
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. +
W
Another milestone in revitalization for via donau in 2009: completion of construction of a riverbank restoration project at Witzelsdorf in the Donau-Auen National Park. The Witzelsdorf section of the river had been one of the most heavily built-up along the entire Danube. Thus ideal conditions prevailed here for a restoration aiming to improve the overall ecological situation: to encourage the momentum and formative power of the Danube and to initiate the natural development of the shore. Project measures included:
* Removal of eight old groynes and field experiments involving novel, ecologically-optimized groyne structures
* Lowering of existing retaining walls to 0.5 meters above the low navigable water level (LNWL)
* Riverbank restoration on a stretch nearly two kilometres long between river kilometres 1891.7 and 1893.4 with preservation of bank revetments to just over LNWL in areas of strong currents.
Approximately 30,000 m3 stone material was removed from the banks and transported away by ship. The National Park provided professional support for this project in collaboration with the project team. The Witzelsdorf restoration project was co-financed by the Federal Ministry of Transport, Innovation and Technology (BMVIT) and the trans-European networks of the European Union.
Meanwhile, the Danube has been busy forming her newly-won natural banks. The second riverbank restoration project in the Donau-Auen National Park is thus a veritable success story. +
C
Area has been identified as one which can be developed as a New Nature Reserve, by Enfield BC who have produced an action plan to enhance land include a ditch and pond as well as the bankside habitat. This will include control of Floating Pennywort and other invasives as well as enhancing the morphological features of the bank. Area is currently grazed by a couple of horse and contains little ecological value - area is boarded by the backloops of the river Lea which are reported to support a population of water voles. +
R
Around 96km of the River Soar and River Trent in Leicestershire and Nottinghamshire have in the past been choked by the non-native plant Floating Pennywort.
The plant was first identified in Leicestershire in 2004, thought to be an escapee from a private garden. It soon got a hold, growing fast in our waterways and out-competing our native plants. It can grow up to 20cm a day and spreads to block out light for other aquatic plants. The problem is so extensive that we have been carrying out annual herbicide spraying and some removal of the plant since 2007, with regular herbicide spraying from 2010.
The project will continue with spraying and undertake aerial surveys. It has been noticed that the weed has entered off line waterbodies after flooding events. Therefore we will also be contacting the owners of these waterbodies to highlight the presence of this invasive weed to see how these waterbodies can be tackled. Continue to spray on the Barrow Gravel Pits SSSI which will address one of its reasons for being in unfavourable condition. +
H
As part of a EU Life project there was a programme of habitat restoration in SSSIs, into which the Highland Water at Warwickslade fell. The project looked to return the river to it's historical course (determined through the study of historical maps), including re-meandering. A number of work measures were undertaken to reduce the speed of the flow, subsequently reducing bank erosion, and to improve the habitat quality.
Highland Water is a small headwater sub-catchment (0.25m3) of the Lymington River. Prior to restoration the channel was up to 1.2m deep and 4m wide restricting the natural seasonal flooding of the surrounding forest. The previously wet woodland and mire habitat had dried out and the increased channel size presented a barrier to freely roaming animals across the forest due to channelization in the 1850’s. Construction was carried out using an innovative tramway system to import material to the site, removing the need to drive heavy machinery across the fragile forest environment, which helped to achieve rapid visual recovery once works were complete.
A variety of morphological features and in stream habitats have re-established and floodplain connection has been restored through more regular bank overtopping, which has helped to re-wet the surrounding woodland habitats. These enhancements have been quantified by a recorded improvement in SSSI condition scores for the area.
The work has been well received by the local communities with excellent media coverage. The success of the scheme has facilitated negotiations for future works at other locations across the New Forest. +
K
As part of a larger biodiversity project for Stormont Estate, enhancement works were required for the Knock Burn. The burn had been overwidened in past years, resulting in a shallow, slow flowing channel, which required regular maintenance due to silt accumulation. It was decided to cretae a sinuous low flow channel, using the silt and bed material to creat a narrower, faster flowing channel. No additional materials were added to the channel, and land drainage was picked up during the new channel creation. All 200m of the project was completed in one day, using a mini digger. The planform of the channel was designed on site, by working downstream and trying to follow the flow patterns as they appeared. +
R
As part of a programme in the Saone River, an assessment was run in
2003 to identify problems along the river and propose
solutions adapted to the local issues.
The assessment pinpointed the areas suitable for
ecological development work, with a low topographic
level, without any major projects or issues
nearby, and having worthwhile ecological potential
(alluvial areas, etc.). It also identified areas of interest
for tourism infrastructure along the river (boating
sites, etc.).
Subsequently, VNF, the managing authority for the
waterway, decided to work on the wetlands that
were filling in along the Saône in the town of Jassans-Riottier.
This project was part of the contract for
the floodable Saône valley and met one of its objectives,
namely to restore and protect natural environments.
Works were done on the remains of wetlands that
still existed along the Saône. In 2007, secondary
channels and ponds that were continuously or intermittently
linked to the Saône were restored by moving
12,000 m³ of earth.
Then the worked and graded sites and banks were
planted with 8 000 clumps of helophytes comprising
a total of ten species.
The foot of the bank at the connection point with
the Saône was bio-engineered over a distance of
40 metres to limit erosion and the effects of ships’
wakes on the restored alluvial zone.
A sluice ensures continuous connection between the
river bed and the side channel.
In 2008, all the worked surfaces, not including the
low areas, were planted with grass and the service
road was restored with a stone surface. +
As part of the National River Restoration (ENRR), it has been selected 10 river reaches of the Confederation Júcar (CHJ), in which restoration projects will be developed. One of these sections corresponds to the Turia River in a stretch of 15.6 km upstream of the Turia Natural Park. The purpose of the restoration of that reach is the recovery of good ecological status, required for the WFD by 2015. Thus, the actions proposed are targets in the short and long term, all framed in ENRR and the WFD.
The main project objectives are, in short term, conditioning of DPH to improve the functioning natural hydraulic channel; increase river mobility space; conservation of riparian ecosystems; maintenance and improvement of current vegetation conditions; control of exotic vegetation; increased diversity of plant cover; improving the mobility of fish fauna; landscaping adjustment and environmental restoration of degraded areas; social use.
Long term: Improve the river dynamics; enhancement of riparian forest development; improving the aquatic environment and associated land to allow regeneration and diversification of the fauna; promoting social use of the river more attractive and environmentally; promote integration of use policies and land management with the use and management of rivers, with sustainability criteria. +
B
As part of the Thames21 project "the Salmons Brook Healthy River Challenge", it is proposed to create a flood storage area incorporating a wetland nature reserve, possibly involving the re-alignment of Salmons Brook. The site is on council owned land, and occupies a former depot. Works include the construction of wetlands and a swale treating runoff from the A10 before it enters the Salmons Brook, designed by the London Borough of Enfield's watercourses team. The site could accommodate up to 5,000m3 of flood waters, benefitting properties downstream. The use of reeds and other aquatic plant species would serve to improve water quality in Salmons Brook by filtering out sediments and absorbing nutrients. Thus at the same time providing an area of educational interest and recreation by sensitively landscaping the area into an ecologically interesting site with habitat creation. Allowing use by a neighbouring school and as a safe linkage between two neighbouring communities as part of the creation of a green transport link along Salmons Brook from Little Bury Street right through to Edmonton Green. The key benefits include: • Reduction in flood risk to properties in Edmonton Green area downstream<br>• Enhanced wildlife habitat in the park and along the river corridor<br>• Creation of a new resource for the local community<br>• Improved water quality to Salmons Brook<br>• Provision footpath/cycleway along river would improve green transport links across the borough +
C
Asset management planning identifying environmental enhancements. +
W
Associated British Ports (ABP) constructed a new Roll-on Roll-off terminal at Immingham Outer Harbour (opened in July 2006), which resulted in the direct loss of 22ha of intertidal mudflat area and potentially up to 5ha of indirect losses in a proposed Special Protection Area (pSPA) and a proposed Special Area of Conservation (pSAC). In consultation with regulatory bodies and local nature conservation interest groups, the two managed realignment schemes at Welwick and Chowder Ness were identified as contributing to a potentially acceptable compensation package for the impacts of the Immingham development.
The objective of Welwick was to create between 15 and 38 ha of intertidal mudflat, between 12ha and 28ha of saltmarsh and between 4 ha and 10ha of grassland.
Welwick was undertaken for the same purpose as another realignment on the Humber, Chowder Ness, which is presented as a separate case study. Both schemes were designed and implemented by the same organisations (Associated British Ports (ABP) and ABPmer), and to very similar timescales and principles. To inform the final design of these sites, numerical modelling was
undertaken based on LiDAR elevation data. This was designed to ensure the correct balance of habitats would be achieved. As mudflat creation was the main objective of the schemes, and as the sites were largely too high for this to occur, the land was re-profiled to increase the extent of lower areas where mudflat could develop (i.e. below Mean High Water Neap (MHWN)) (see Plates 2 and 3 for an illustration of the design steps undertaken). Prior to these works, the land at Welwick had an approximate elevation of 2.8mODN, some 0.4m below the level of the Mean High Water Spring (MHWS) tides. The reprofiling included the creation of a gentle slope from the fronting, existing, mudflats to the rear of the sites.
New flood defences were created at the rear of the 54ha Welwick site to a minimum height of 6.1m Ordnance Datum Newlyn (ODN); designed to withstand a 1 in 50 year design event. A strip of saltmarsh was expected to develop in front of the new defences. The 70,000m3 of material needed for these defences was obtained from within the site from a combination of reprofiling and creation of temporary borrow pits. The new embankment was seeded and left to stabilise for one year.
The existing seawall was removed over a length of 1,400m, and the approximately 20,000m3 of material gained was used to fill the temporary borrow pits. The wholesale removal, rather than the creation of solitary breaches, was chosen for a number of reasons: it improves connectivity with the wider estuary; it more closely recreates the type of environments that existed prior to the land claim; it enables the whole cross sectional area of estuary including the realignment site, to respond to estuary wide changes; and it increases energy levels within the site, thereby improving the likelihood that mudflat
habitat will be maintained.
The old defence was removed in a series of stages:
*(1) removing the rear of the embankment;
*(2) the rock gabions, and
*(3) the overall lowering of the embankment. Following this, breaches were created in the existing saltmarsh in front of site. These were required as the fronting marsh is designated, and could thus not be removed completely to increase wave energy even further. As the typical elevation of this marsh was 3.2mODN, which coincides with the MHWS level, these breaches were necessary to allow the site to flood and drain sufficiently. The location of the breaches was chosen to minimise marsh losses (approximately 0.4ha). Their width had been assessed by calculating the discharge and considering the critical threshold for erosion of sediment. The suggested breach size was considered large enough for the velocities to be below the critical threshold for erosion.
As Welwick was considered relatively small-scale in relation to the estuary as a whole any predicted changes to the hydrodynamics and sediment dynamics were expected be extremely localised and relatively small in magnitude (ABPmer, 2003).
C
Associated British Ports (ABP) constructed a new Roll-on Roll-off terminal at Immingham Outer Harbour (opened in July 2006), which resulted in the direct loss of 22ha of intertidal mudflat area and potentially up to 5ha of indirect losses in a proposed Special Protection Area (pSPA) and a proposed Special Area of Conservation (pSAC). In consultation with regulatory bodies and local nature conservation interest groups, the two managed realignment schemes at Chowder Ness and Welwick were identified as contributing to a compensation package for the impacts of the above development. The initial objective of Chowder Ness was to create 10.5ha of mud and 0.8ha of saltmarsh to support a variety of invertebrate and bird species.
Chowder Ness was undertaken for the same purpose as another realignment on the Humber, Welwick, which is presented as a separate case study. Both schemes were designed and implemented by the same organisations (Associated British Ports (ABP) and ABPmer), and to very similar timescales and principles. To inform the final design of these sites, numerical modelling was undertaken based on LiDAR elevation data. This was to ensure the correct balance of habitats would be achieved. As mudflat creation was the main objective of the schemes, and as the sites were largely too high for this to occur, the land was re-profiled to increase the extent of lower areas where mudflat could develop (i.e. below Mean High Water Neap (MHWN)). These works included the creation of a gentle slope from the fronting, existing, mudflats to the rear of the sites to assist drainage.
At the 15ha Chowder Ness site, new flood defences were created at the rear of the site to a minimum height of 6.7m above Ordnance Datum Newlyn (ODN). Material for these defences was obtained from within the site from a combination of reprofiling and creation of temporary borrow pits (these were later infilled with material obtained from the seawall removal).
The existing seawall was removed over a length of 570m (some 200m remain), to a level of around 1.6 to 2mODN. This removal, rather than the creation of solitary breaches, was chosen for a number of reasons: it improves connectivity with the wider estuary; it more closely recreates the type of environments that existed prior to the land claim; it enables the whole cross sectional area of the estuary including the realignment site, to respond to estuary wide changes; and it increases energy levels within the site, thereby improving the likelihood that mudflat habitat will be maintained (as mudflat creation was the main objective of the site).
As Chowder Ness was considered relatively small-scale in relation to the estuary as a whole any predicted changes to the hydrodynamics and sediment dynamics were expected be extremely localised and relatively small in magnitude (ABPmer, 2004).
The old defence was removed in a series of stages: (1) removing the rear of the embankment, (2) the concrete wave return, the bitumen and rock face, and (3) the overall lowering of the embankment (to levels around 1.6 to 2mODN).
W
At Watercress Farm, which lies on the very northern edge of the Somerset Levels, Ecosulis worked with Belmont Estate on the creation of a new wetland. The intention was to enable the river to reclaim its former floodplain, creating a new, more sinuous path, which will deliver benefits for both people and nature. The project was designed to trap runoff sediment, pollutants and nutrients, while this degraded former arable field develops into a biodiverse wetland, supporting abundant wildlife.
Our main objectives for the Watercress Wetland creation project were to re-connect the flood plain at the Watercress Farm landholding, maximize the area of semi-permanent and ephemeral water and improve the hydro morphology and biodiversity of the Land Yeo River.
The project was set out to achieve these objectives through creation of a new 400m wetland stream and 1.74hectares of wetland scrapes, blocking existing straight/steep sided ditches, the creation of numerous ephemeral scrapes of varying sizes and shapes, and the creation of numerous areas of permanent water, either within a scrape or as backwater ponds with shallow gradients.
Between June and September 2023, Ecosulis undertook extensive transformative works, focusing on the Land Yeo River channel and its surroundings. The west side of Watercress Wood saw the elevation of water levels in the existing channel, with the creation of four clay and gravel riffle impoundments, diverting flows into a newly designed 400m optimized wetland stream. This stream, boasting various river restoration techniques, now functions as the primary channel, bypassing the re-purposed longitudinal wetland ponds.
Ten wetland scrapes, excavated into arable land on both banks of the wetland stream, offer over 7,800m² of habitat to the Land Yeo River catchment. These features, connected to the wetland stream, adjust water levels based on flow conditions. Gravels extracted on-site were used for bed dressing, bed raising, and gravel riffle installations.
Wetland scrapes upstream of Watercress Wood, both within and outside the floodplain, intercept agricultural runoff, fostering approximately 18,000m² of vital wet meadow habitat. Field ditches have been strategically plugged to maximise marshy wet meadow habitat. Spoil from wetland excavation formed butterfly banks and bunds, enhancing breeding habitat for insects and reptiles across 13,000m².
Land drains were intentionally broken or blocked to retain water on-site, mitigating runoff into the Land Yeo River and neighbouring areas. This comprehensive approach showcases a commitment to environmental restoration, providing diverse habitats while addressing water management and runoff concerns within the catchment.
A
Aubourn Weir, located in the lower reaches of the Upper River Witham, presented a major barrier to upstream fish and eel passage and the heavily-modified channel in the vicinity, lacked morphological and habitat diversity resulting in poor fish populations. Also affected by high levels of phosphates, the overall Ecological Status of this section of the river is classified as Moderate.
The key objectives of the Aubourn project were to enable fish and eel passage at the weir and to undertake additional enhancements to improve the channel diversity. The wider project, from Bassingham Bridge to beyond Aubourn Weir, sought to enhance the heavily-modified channel using existing riverside trees to create in-stream deadwood habitat, improve flow variation and provide valuable refuges for fish and invertebrates.
There were two parts to the project: construction of the rock ramp fish pass and associated bed enhancements in the vicinity of Aubourn Weir, and extensive woody habitat creation from Bassingham downstream to beyond Aubourn Weir.
*Rock Ramp - Using large rocks and steel sheet piling to maintain the water levels, a series of stepped pools, rising c1m in c20cm increments, were constructed to create the “rock ramp” which now enables fish and eels to negotiate the former obstruction.
*Pools – Five pools were excavated in the river bed, three above the new rock ramp and two below it. The excavated material was deposited against the bank immediately upstream of each pool to narrow the channel and speed up the flow - a technique known as “dig-and-dump”.
*Woody habitat - Riverside trees, in particular those that had collapsed in to the river or were in imminent danger of doing so, were selectively hinged and/or secured into the channel and along the bank throughout the whole of the 3.25km reach. The large woody material creates flow variation and provides refuges for fish and invertebrates as the river level and speed of flow changes. +
E
Avant de procéder à l’effacement du seuil,
l’équipe technique du CRE a réalisé un entretien
de la ripisylve en coupant tous les
arbres pouvant gêner l’accès au seuil ou menaçant
de tomber suite à l’effacement de la
retenue. Un chenal de dérivation a ensuite
été mis en place afin de pouvoir travailler à
sec. Une partie du sable abondamment présent
dans la retenue a été régalée sur les
berges. Enfin, le seuil de pierre a été totalement
supprimé jusqu’au niveau de ses fondations,
les blocs le constituant ont été en
partie mis en dépôt sur les berges ou utilisés
pour diversifier les écoulements dans le lit
mineur du cours d’eau. +
R
Background: The River Skerne is a tributary of the River Tees in North East England. The restored reach lies in a sub-urban area on the outskirts of Darlington, County Durham. During the last 150 years, the River Skerne has been heavily modified as a result of industrialisation and urbanisation. Between 1850 and 1945 the river was straightened and channelized, and the river corridor was markedly narrowed. Widening and deepening was undertaken in the 1950s and the 1970s, and new housing developments were built along the entire north side of the river. The area has a rich industrial heritage including the first railway company Stockton and Darlington. The Skerne (railway) Bridge, which can be found just downstream of the site, was pictured on the old five pound notes.
Restoration: The River Skerne was included in a joint initiative between England and Denmark to demonstrate best practice in urban and rural river rehabilitation and encourage river restoration in Europe. The wider aim was to promote further river restoration and demonstrate how river restoration could provide multiple benefits such as enhancement in wildlife, landscape, recreation, water quality, fisheries, amenities and other local interests.
The River Skerne Restoration Project was supported by European Commission LIFE funding with matched financial and in-kind support from the Environment Agency, Darlington Borough Council, Northumbrian Water English Nature and the Countryside Commission. The project also attracted additional Heritage Lottery Fund support to complete the original 'full scheme' aspirations. The project was managed by the River Restoration Project (the precursor to the River Restoration Centre) with significant additional partner management input from Northumbrian Water and The Environment Agency in leading the project and working group.
The restoration of 2 km of the Skerne was initiated in July 1995. Much of the floodplain had been raised by old industrial waste tipping, with gas and sewer pipes running alongside the river. As a result of these constraints, restoration opportunities were severely limited - typical of urban rivers elsewhere. At the upstream end, instream deflectors and a coarse sediment riffle were installed to enhance flow variability and habitat diversity. Further downstream four new meanders were cut across the old channel, which was used to create two backwaters.
Soft revetments – such as willow mattress, willow spiling, underwater rock layer, fibre rolls, and geotextiles – were used on the outer meander bends to prevent erosion towards the gas main. As a flood water retention measure, about 25,000 m3 of spoil was removed from the river banks. This also aimed to increase the lateral connectivity between the river and the adjacent floodplain. The spoil was later used for landscaping purposes.
Hundreds of nearby properties were checked for misconnections by Northumbrian Water and thirteen ugly surface water outfalls were replaced with underground inspection /collection chambers that firstly intercept pollution and then discharge the water into the river below water level. New footpaths were constructed and a planting scheme engaging local residents carried out. At the downstream end of the restored section a new footbridge was constructed, designed to resemble a locomotive as a tribute to the historical significance of the Skerne Bridge.
M
Bank and bed naturalisation; introduction of meanders; associated wetland creation; inclusion of riffles and pools. The Beddington branch is a straight, concrete channel through an area of amenity grassland. There is an opportunity to create a natural river through the area of open space with associated habitat creation. The benefits would also include slowing the flow into the Wandle at Poulter park. +
R
Bank naturalisation and enhancements; tree works; backwater enhancement. The river through the park has hard edges which could be enhanced to create more of a marginal edge. Several channels run through the park which could be enhanced to improve their value as wildlife corridors. +
P
Bank naturalisation and re-profiling, replacing and re-surfacing adjacent footpath. The banks of the river in this location are reinforced with concrete slabs. Some sections have eroded and are in poor condition. There is a need to improve marginal habitats to enable the spread of future water voles released in Watermeads. Targeted species include River water crowfoot, brown trout and European eel. +
C
Bank re-profiling, beach creation and gravel recharge as part of bank repair and navigation maintenance works.<br>Littoral habitat enhancement of lowland regulated river.<br> Neglected area of the river Thames +