Case study:Long Eau (Great Eau): Difference between revisions
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{{Case study status | {{Case study status | ||
|Approval status= | |Approval status=Approved | ||
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{{Location | {{Location | ||
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|Main contact forename=Nick | |Main contact forename=Nick | ||
|Main contact surname=Elbourne | |Main contact surname=Elbourne | ||
|Contact organisation=Lincolnshire Chalk Streams | |||
|Contact organisation url=www.lincswolds.org.uk/chalk-streams/lincolnshire-chalk-streams | |||
|Multi-site=No | |Multi-site=No | ||
|Project picture=DSC02373.JPG | |||
|Picture description=Long Eau floodplain 2005 | |||
|Project summary=Flowing from the Lincolnshire Wolds to the North Sea, the Long Eau drains a small catchment of 22.3 km2, but together with the Great Eau has a catchment area of 112.3 km2. | |Project summary=Flowing from the Lincolnshire Wolds to the North Sea, the Long Eau drains a small catchment of 22.3 km2, but together with the Great Eau has a catchment area of 112.3 km2. | ||
Before restoration, the river had become embanked and channelised to protect adjacent agricultural land from flooding. The flood banks were steeply sloped directly into the channel. Dredging and removal of bankside vegetation was part of the maintenance regime, which had removed morphological features, in channel habitats and natural substrate. Historically the Long Eau had a history of washlands, regularly flooding the land adjacent to the river. | Before restoration, the river had become embanked and channelised to protect adjacent agricultural land from flooding. The flood banks were steeply sloped directly into the channel. Dredging and removal of bankside vegetation was part of the maintenance regime, which had removed morphological features, in channel habitats and natural substrate. Historically the Long Eau had a history of washlands, regularly flooding the land adjacent to the river. | ||
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Performance 1995-2001- | Performance 1995-2001- | ||
Since completion flood protection has increased, as water spills onto new floodplain when channel reaches 2.6m or above. Below this level 75% of floodplain will retain water up to 0.5m for up to 4 months. This provides an important habitat for wetland birds. Lapwing and redshank have bred at the site. | Since completion flood protection has increased, as water spills onto new floodplain when channel reaches 2.6m or above. Below this level 75% of floodplain will retain water up to 0.5m for up to 4 months. This provides an important habitat for wetland birds. Lapwing and redshank have bred at the site. | ||
The Environment Agency estimates a saving of £400-500 a year on the previous maintenance regime. | The Environment Agency estimates a saving of £400-500 a year on the previous maintenance regime. | ||
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{{Case study subcatchment | {{Case study subcatchment | ||
|Subcatchment= | |Subcatchment=Long Eau | ||
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{{Site | {{Site | ||
|Name=Long Eau at Manby | |Name=Long Eau at Manby | ||
|WFD water body code=GB105029061670 | |||
|WFD water body name=Long Eau | |||
|Pre-project morphology=Embanked, Over-widened, Over deepened, | |Pre-project morphology=Embanked, Over-widened, Over deepened, | ||
|Reference morphology=Set back defence, | |Reference morphology=Set back defence, | ||
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|Protected species present=No | |Protected species present=No | ||
|Invasive species present=No | |Invasive species present=No | ||
|Dominant hydrology=Artificially regulated, | |Dominant hydrology=Artificially regulated, | ||
|River corridor land use=Intensive agriculture (arable), Improved/semi-improved grassland/pasture, | |River corridor land use=Intensive agriculture (arable), Improved/semi-improved grassland/pasture, | ||
}} | }} | ||
{{Project background | {{Project background | ||
|Reach length directly affected=900 | |Reach length directly affected=900 | ||
|Project started=1992 | |||
|Works started=1995/05/01 | |Works started=1995/05/01 | ||
|Works completed=1995/07/01 | |Works completed=1995/07/01 | ||
|Project completed=1996/01/01 | |||
|Total cost category=50 - 100 k€ | |Total cost category=50 - 100 k€ | ||
|Funding sources=environmental stewardship scheme | |Funding sources=environmental stewardship scheme | ||
|Works1 and supervision cost category=50 - 100 k€ | |Works1 and supervision cost category=50 - 100 k€ | ||
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{{Measures | {{Measures | ||
|Floodplain / River corridor= | |Floodplain / River corridor=Displacement of flood defences, Lowering of embankments, | ||
|Planform / Channel pattern= | |Planform / Channel pattern=Creation of backwater, | ||
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{{Hydromorphological quality elements header}} | {{Hydromorphological quality elements header}} | ||
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{{Monitoring documents}} | {{Monitoring documents}} | ||
{{Monitoring documents end}} | {{Monitoring documents end}} | ||
{{Additional Documents}} | {{Additional Documents}} | ||
{{Additional Documents end}} | {{Additional Documents end}} | ||
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{{Additional links and references footer}} | {{Additional links and references footer}} | ||
{{Supplementary Information}} | {{Supplementary Information}} | ||
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Latest revision as of 16:21, 2 January 2019
Location: 53° 21' 22.58" N, 0° 6' 55.08" E
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Project overview
| Status | Complete |
|---|---|
| Project web site | |
| Themes | Flood risk management, Habitat and biodiversity, Land use management - agriculture |
| Country | England |
| Main contact forename | Nick |
| Main contact surname | Elbourne |
| Main contact user ID | |
| Contact organisation | Lincolnshire Chalk Streams |
| Contact organisation web site | http://www.lincswolds.org.uk/chalk-streams/lincolnshire-chalk-streams |
| Partner organisations | |
| Parent multi-site project | |
| This is a parent project encompassing the following projects |
No |
Project summary
Edit project overview to modify the project summary.
Flowing from the Lincolnshire Wolds to the North Sea, the Long Eau drains a small catchment of 22.3 km2, but together with the Great Eau has a catchment area of 112.3 km2.
Before restoration, the river had become embanked and channelised to protect adjacent agricultural land from flooding. The flood banks were steeply sloped directly into the channel. Dredging and removal of bankside vegetation was part of the maintenance regime, which had removed morphological features, in channel habitats and natural substrate. Historically the Long Eau had a history of washlands, regularly flooding the land adjacent to the river.
Three sites were chosen along the Little ands Great Eau to demonstrate the relocation of flood banks and the provision of flood storage areas on neighbouring land. A secondary objective was to enhance habitats.
An environmental stewardship scheme offered a ten year grant scheme to farmers/landowners, some of whom were already supportive of the idea of nature conservation.
Long Eau at Manby-
Left floodbank was lowered to just above ground level. The adjacent field was widened and flattened to act as an over spill area (1 in 10 slope). Material generated from embankment removal was used to infill and Internal Drainage Board drain which ran through flood storage area. This drain was re located behind the new embankment to maintain land drainage. The new embankment slopes were 3:1 to a height of 2.5-2.7 meters.
Ledges and berms were created along the channel to increased habitat potential.
Performance 1995-2001-
Since completion flood protection has increased, as water spills onto new floodplain when channel reaches 2.6m or above. Below this level 75% of floodplain will retain water up to 0.5m for up to 4 months. This provides an important habitat for wetland birds. Lapwing and redshank have bred at the site.
The Environment Agency estimates a saving of £400-500 a year on the previous maintenance regime.
Monitoring surveys and results
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Lessons learnt
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Measures
MonitoringHydromorphological quality elements
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Supplementary InformationEdit Supplementary Information
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