Case study:Houghton 'trout stream' enhancements - Revision history

Hazel Wilson at 11:54, 3 November 2015

2015-11-03T11:54:10Z

← Older revision		Revision as of 11:54, 3 November 2015
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	}}		}}
	{{Site		{{Site
			\|WFD water body code=GB105033047921
	\|Heavily modified water body=No		\|Heavily modified water body=No
	\|Protected species present=No		\|Protected species present=No

Hazel Wilson at 10:00, 2 November 2015

2015-11-02T10:00:08Z

← Older revision		Revision as of 10:00, 2 November 2015
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	}}		}}
	{{Site		{{Site
	~~\|WFD water body code=GB105033037920~~
	~~\|WFD water body name=Ouse~~
	\|Heavily modified water body=No		\|Heavily modified water body=No
	\|Protected species present=No		\|Protected species present=No

Hazel Wilson at 09:56, 2 November 2015

2015-11-02T09:56:34Z

← Older revision		Revision as of 09:56, 2 November 2015
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	\|Subcatchment=Ouse (Roxton to Earith)		\|Subcatchment=Ouse (Roxton to Earith)
	}}		}}
	{{Site}}		{{Site
			\|WFD water body code=GB105033037920
			\|WFD water body name=Ouse
			\|Heavily modified water body=No
			\|Protected species present=No
			\|Invasive species present=No
			}}
	{{Project background		{{Project background
	\|Project completed=2014/05/01		\|Project completed=2014/05/01

Robclapham at 11:30, 22 December 2014

2014-12-22T11:30:25Z

← Older revision		Revision as of 11:30, 22 December 2014
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	\|Lessons learn=Wood for construction of deflectors was sourced locally and work was undertaken by hand. Therefore the size of deflectors were limited to what could be manoeuvred by hand. Despite their size, careful consideration of the prevailing flow and sediment conditions meant they could be placed to achieve optimum benefit.		\|Lessons learn=Wood for construction of deflectors was sourced locally and work was undertaken by hand. Therefore the size of deflectors were limited to what could be manoeuvred by hand. Despite their size, careful consideration of the prevailing flow and sediment conditions meant they could be placed to achieve optimum benefit.

	In November 2014 some of the wooden posts, used to hold deflectors in place, had to be replaced. The posts were 75 mm diameter and it is thought that the staples and screws used in these posts were too large ~~and caused~~ the post to be weakened and split under load. We have since replaced posts with 20 mm re-bar drilled through the deflectors. Post diameter and staple size should be considered when planning how to secure LWD.		In November 2014 some of the wooden posts, used to hold deflectors in place, had to be replaced. The posts were 75 mm diameter and it is thought that the staples and screws used to secure wire to these posts were too large, causing the post to be weakened and split under load. We have since replaced posts with 20 mm re-bar drilled through the deflectors. Post diameter and staple size should be considered when planning how to secure LWD.
	}}		}}
	{{Image gallery}}		{{Image gallery}}

Robclapham at 11:28, 22 December 2014

2014-12-22T11:28:47Z

← Older revision		Revision as of 11:28, 22 December 2014
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	Follow link for YouTube video of spawning gravel enhancements: http://www.youtube.com/watch?v=ubVX4pla10Y&list=UU8XLubOua8P9B1hT0Qb5Tbg		Follow link for YouTube video of spawning gravel enhancements: http://www.youtube.com/watch?v=ubVX4pla10Y&list=UU8XLubOua8P9B1hT0Qb5Tbg

	\|Monitoring surveys and results=Pre-enhancement fish surveys have been undertaken<br>		\|Monitoring surveys and results=Pre-enhancement fish surveys have been undertaken<br>

	The Environment Agency will continue to monitor this site through electric fishing surveys.		The Environment Agency will continue to monitor this site through electric fishing surveys.
	\|Lessons learn=Wood for construction of deflectors was sourced locally and work was undertaken by hand. Therefore the size of deflectors were limited to what could be manoeuvred by hand. Despite their size, careful consideration of the prevailing flow and sediment conditions meant they could be placed to achieve optimum benefit.		\|Lessons learn=Wood for construction of deflectors was sourced locally and work was undertaken by hand. Therefore the size of deflectors were limited to what could be manoeuvred by hand. Despite their size, careful consideration of the prevailing flow and sediment conditions meant they could be placed to achieve optimum benefit.

			In November 2014 some of the wooden posts, used to hold deflectors in place, had to be replaced. The posts were 75 mm diameter and it is thought that the staples and screws used in these posts were too large and caused the post to be weakened and split under load. We have since replaced posts with 20 mm re-bar drilled through the deflectors. Post diameter and staple size should be considered when planning how to secure LWD.
	}}		}}
	{{Image gallery}}		{{Image gallery}}

JoshRRC at 08:53, 30 October 2014

2014-10-30T08:53:49Z

← Older revision		Revision as of 08:53, 30 October 2014
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	}}		}}
	{{Site}}		{{Site}}
	{{Project background}}		{{Project background
			\|Project completed=2014/05/01
			}}
	{{Motivations		{{Motivations
	\|Specific mitigation=Land drainage,		\|Specific mitigation=Land drainage,

Robclapham at 13:39, 29 October 2014

2014-10-29T13:39:48Z

← Older revision		Revision as of 13:39, 29 October 2014
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	\|File name=Finished deflector 2.jpg		\|File name=Finished deflector 2.jpg
	\|Caption=Finished deflector in May 2014		\|Caption=Finished deflector in May 2014
			}}
			{{Case study image
			\|File name=Houghton large paired.jpg
			\|Caption=large paired deflector
	}}		}}
	{{Image gallery end}}		{{Image gallery end}}

Robclapham at 07:29, 27 May 2014

2014-05-27T07:29:21Z

← Older revision		Revision as of 07:29, 27 May 2014
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	This project demonstrates that correctly targeted low-cost measures, undertaken in partnership with committed stakeholders, can make significant improvement to river channel habitat and fisheries value.		This project demonstrates that correctly targeted low-cost measures, undertaken in partnership with committed stakeholders, can make significant improvement to river channel habitat and fisheries value.

			Follow link for YouTube video of spawning gravel enhancements: http://www.youtube.com/watch?v=ubVX4pla10Y&list=UU8XLubOua8P9B1hT0Qb5Tbg

	\|Monitoring surveys and results=Pre-enhancement fish surveys have been undertaken<br>		\|Monitoring surveys and results=Pre-enhancement fish surveys have been undertaken<br>

Robclapham at 14:18, 22 May 2014

2014-05-22T14:18:25Z

← Older revision		Revision as of 14:18, 22 May 2014
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	This project demonstrates that correctly targeted low-cost measures, undertaken in partnership with committed stakeholders, can make significant improvement to river channel habitat and fisheries value.		This project demonstrates that correctly targeted low-cost measures, undertaken in partnership with committed stakeholders, can make significant improvement to river channel habitat and fisheries value.

	\|Monitoring surveys and results=Pre-enhancement fish surveys have been undertaken<br>		\|Monitoring surveys and results=Pre-enhancement fish surveys have been undertaken<br>

	The Environment Agency will continue to monitor this site through electric fishing surveys~~, and will continue to support the Angling club in making further enhancements~~.		The Environment Agency will continue to monitor this site through electric fishing surveys.
	\|Lessons learn=Wood for construction of deflectors was sourced locally and work was undertaken by hand. Therefore the size of deflectors were limited to what could be manoeuvred by hand. Despite their size, careful consideration of the prevailing flow and sediment conditions meant they could be placed to achieve optimum benefit.		\|Lessons learn=Wood for construction of deflectors was sourced locally and work was undertaken by hand. Therefore the size of deflectors were limited to what could be manoeuvred by hand. Despite their size, careful consideration of the prevailing flow and sediment conditions meant they could be placed to achieve optimum benefit.
	}}		}}

Robclapham at 14:17, 22 May 2014

2014-05-22T14:17:44Z

← Older revision		Revision as of 14:17, 22 May 2014
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	\|Project picture=Mid V.JPG		\|Project picture=Mid V.JPG
	\|Picture description=Installation of a mid-channel 'v' deflector to create and maintain clean gravels		\|Picture description=Installation of a mid-channel 'v' deflector to create and maintain clean gravels
	\|Project summary=The ~~Houghton ’trout’ stream is an important~~ side channel of the Great Ouse ~~providing many habitat types that are not present in the navigable main channel~~.		\|Project summary=The Environment Agency worked with local stakeholders to improve habitat quality on a side-channel of the Great Ouse.

	~~Over~~ the ~~last decade there~~ has been ~~a decline in the number of fish species present in the stream~~. ~~This is likely a result of historic over-widening~~, ~~catchment sediment issues~~ and ~~flow regulation which~~ have ~~changed or degraded~~ the ~~habitat~~.		Like many of our rivers, the Houghton 'trout' stream, has been significantly modified over many years. These modifications include impoundment, channelization and tree clearance. These pressures have reduced the resilience of the channel to wider catchment scale pressures from water quality and sediment.

	~~The Environment Agency worked with~~ the ~~local fishing club~~ and ~~landowners to improve~~ the ~~status~~ of the ~~stream putting in place a number~~ of ~~measures to address pressures~~ and ~~improve habitat~~.		As a result of these modifications, there is insufficient flow and energy within the channel at many times of the year to move and redistribute sediment within the channel. This has meant that this 'naturally' gravelly river has an overlying layer of fine sediment. This significantly reduces the likelihood of successful spawning by species such as chub, dace and barbel, the latter of which has not been seen on the river for over a decade.

			Such habitats are particularly important to retain on this side channel, as the main river is navigable, heavily impounded, and cannot provide the diversity of habitats found on this channel, all of which are vital to many species at different points in their life cycle. Furthermore, due to navigation on the main channel, options to enhance or restore it are limited.

	These ~~measures include~~:		The Environment Agency surveyed the side channel and put together a series of enhancement options to address the deterioration, which were then shared and discussed with the local Angling club and landowners. These included: Improving flow over an upstream weir, tree planting, retaining woody material, fencing, gravel jetting, and installing deflectors to keep areas of spawning gravels free from silt and excessive vegetation growth. Both landowners and Angling Club were keen to see these improvements made and offered both their time and money to see them implemented.

	- ~~Gravel Cleaning has been carried out to improve spawning gravels~~. ~~Limited flows in an over-wide channel~~ have ~~resulted in a lot~~ of ~~fine sediment to drop out~~ of ~~suspension and smother~~ the ~~gravels~~. ~~High powered jets of water are used to remove silt between gravels~~ and ~~improve the chances of successful fish spawning~~.		Partnership was vital to success of the project. Very little money was spent on these enhancements with most contributions coming from volunteer time. The angling club have helped with planting of trees (willow whips sourced from local trees), gravel jetting (using agency equipment), and will share the cost of installing fencing with the local landowners Smith & Smith. The Agencies Fisheries and biodiversity team cleared vegetation blocking an upstream weir and installed flow deflectors, again using wood sourced from locally fallen tree that identified for removal as it was blocking a nearby drainage channel.

	~~- Tree Planting has been started in various locations. Trees~~ will ~~provide~~ shelter and ~~shade for various fish species as well as habitat for macroinvertebrates. In future years they will provide~~ woody material to the channel ~~which will help create~~ in-channel ~~habitat. They are also important for moderating river water temperatures~~.		While enhancements such as tree planting will take many years until benefits from increased cover, shelter shading, and supply of woody material to the channel are realized. Already, the benefits of the gravel jetting and flow deflectors can be seen. Following the work, the areas of clean gravels have remained, while other areas in the channel (not yet enhanced) have become covered with sediment and clogged with reed growth.

	~~- Wooden flow deflectors~~ have been ~~installed~~ in ~~a number of locations on the stream~~. ~~These increase flow velocities over the spawning gravel preventing build up~~ of ~~fine sediment in slow flows. These should be self sustaining and reduce~~ the ~~need to gravel~~ clean ~~by hand each year~~.		For the first time in many years, large numbers of fish have been seen congregating around the deflectors in preparation to spawn, including many large chub. Furthermore, we have also seen River Lamprey (a formerly declining species) making use of the clean gravels for spawning.

	- ~~Flow~~ improvement ~~works have been carried out at the weir. Overhanging and submerged trees, and vegetation has been removed~~ to ~~improve flows and prevent further build up of materials~~ and ~~sediment~~.		This project demonstrates that correctly targeted low-cost measures, undertaken in partnership with committed stakeholders, can make significant improvement to river channel habitat and fisheries value.

	~~- Fencing will be installed in summer 2014 to protect trees from cattle and prevent in-channel access close to enhanced spawning riffles~~
	\|Monitoring surveys and results=Pre-enhancement fish surveys have been undertaken<br>		\|Monitoring surveys and results=Pre-enhancement fish surveys have been undertaken<br>
	~~Post-enhancement fish~~ surveys will ~~be carried out~~ in ~~subsequent years~~
			The Environment Agency will continue to monitor this site through electric fishing surveys, and will continue to support the Angling club in making further enhancements.
	\|Lessons learn=Wood for construction of deflectors was sourced locally and work was undertaken by hand. Therefore the size of deflectors were limited to what could be manoeuvred by hand. Despite their size, careful consideration of the prevailing flow and sediment conditions meant they could be placed to achieve optimum benefit.		\|Lessons learn=Wood for construction of deflectors was sourced locally and work was undertaken by hand. Therefore the size of deflectors were limited to what could be manoeuvred by hand. Despite their size, careful consideration of the prevailing flow and sediment conditions meant they could be placed to achieve optimum benefit.
	}}		}}