Case study:New Forest LIFE project
Project overview
Status | Complete |
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Project web site | http://www.newforestlife.org.uk/ |
Themes | Flood risk management, Habitat and biodiversity, Land use management - forestry, Monitoring |
Country | England |
Main contact forename | Nick |
Main contact surname | Elbourne |
Main contact user ID | User:NickRRC |
Contact organisation | River Restoration Centre |
Contact organisation web site | http://www.therrc.co.uk |
Partner organisations | Forestry Comission, Environment Agency, University of Southampton |
This is a parent project encompassing the following projects |
Highland Water at Warwickslade Lawn, Holmsley Inclosure Stream Restoration, Markway Stream Restoration |
Project summary
In the past, the Highland Water and Blackwater channels have been straightened and cleared of large woody debris (LWD), leading to disconnection of the channel from its floodplain, increased headward erosion and downcutting, high sediment transport rates and rapid progression of flood peaks.
The New Forest LIFE III project was proposed to improve the ecological potential of the catchments, increase habitat diversity and mitigate flood risk. Restoration began in 2003, with a 'test restoration' on the Blackwater, followed by Highland Water, reaching completion in 2006. The project involved remeandering of the channel and the introduction of LWD dams and CWD - providing habitats for fish and macroinvertebrates, while increasing flow resistance and the frequency/magnitude of overbank flow (which in turn would supply additional LWD for dam creation. LWD dams also increase the frequency of pool-riffle sequences - improving bed complexity.
Many aspects of the projects were deemed to be a success, with a clear increase in delay of the flood peak, post-restoration. The frequency and duration of overbank flow was also observed to increase appreciably.
Monitoring surveys and results
Lessons learnt
Catchment and subcatchment
Edit the catchment and subcatchment details
(affects all case studies in this subcatchment)
Catchment
River basin district | South East |
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River basin | New Forest |
Subcatchment
River name | Black Water |
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Area category | 10 - 100 km² |
Area (km2) | |
Maximum altitude category | 100 - 200 m |
Maximum altitude (m) | 119119 m <br />0.119 km <br />11,900 cm <br /> |
Dominant geology | Siliceous |
Ecoregion | Great Britain |
Dominant land cover | Broadleaved Woodland |
Waterbody ID | GB107042016710 |
Site
Name | Highland Water/Blackwater |
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WFD water body codes | GB107042016720 |
WFD (national) typology | Low, Small, Siliceous |
WFD water body name | Highland Water |
Pre-project morphology | Straight |
Reference morphology | Sinuous, Pool-riffle |
Desired post project morphology | |
Heavily modified water body | Yes |
National/international site designation | EU - Special Area of Conservation |
Local/regional site designations | SSSI (Site of Special Scientific Interest) |
Protected species present | No |
Invasive species present | No |
Species of interest | |
Dominant hydrology | Quick run-off |
Dominant substrate | Barton clays and plateau gravels. |
River corridor land use | Plantation forestry, Woodland |
Average bankfull channel width category | 2 - 5 m |
Average bankfull channel width (m) | |
Average bankfull channel depth category | 0.5 - 2 m |
Average bankfull channel depth (m) | |
Mean discharge category | |
Mean annual discharge (m3/s) | |
Average channel gradient category | |
Average channel gradient | 0.0066 |
Average unit stream power (W/m2) |
Project background
Reach length directly affected (m) | 3000 m3 km <br />300,000 cm <br /> |
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Project started | 2003/06/01 |
Works started | 2005/06/01 |
Works completed | 2006/08/01 |
Project completed | |
Total cost category | more than 10000 k€ |
Total cost (k€) | |
Benefit to cost ratio | |
Funding sources | EU LIFE III |
Cost for project phases
Phase | cost category | cost exact (k€) | Lead organisation | Contact forename | Contact surname |
---|---|---|---|---|---|
Investigation and design | |||||
Stakeholder engagement and communication | |||||
Works and works supervision | |||||
Post-project management and maintenance | |||||
Monitoring |
Reasons for river restoration
Measures
Structural measures
| |
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Bank/bed modifications | Introduction of LWD to increase flow resistance - increasing frequency/magnitude of overbank flow, delaying flood peaks for flood mitigation and creating habitat for aquatic organisms. Bed-level raising with gravel addition. |
Floodplain / River corridor | See above - increased channel:floodplain connectivity. |
Planform / Channel pattern | Re-meandering of channel to increase capacity. |
Other | |
Non-structural measures
| |
Management interventions | |
Social measures (incl. engagement) | |
Other |
Monitoring
Hydromorphological quality elements
Element | When monitored | Type of monitoring | Control site used | Result | ||
---|---|---|---|---|---|---|
Before measures | After measures | Qualitative | Quantitative | |||
Width & depth variation | Yes | Yes | Yes | No | No | Improvement |
Flow velocities | Yes | Yes | Yes | No | No | Improvement |
Biological quality elements
Element | When monitored | Type of monitoring | Control site used | Result | ||
---|---|---|---|---|---|---|
Before measures | After measures | Qualitative | Quantitative | |||
Fish | Yes | Yes | No | Yes | Yes | Inconclusive |
Physico-chemical quality elements
Element | When monitored | Type of monitoring | Control site used | Result | ||
---|---|---|---|---|---|---|
Before measures | After measures | Qualitative | Quantitative |
Any other monitoring, e.g. social, economic
Element | When monitored | Type of monitoring | Control site used | Result | ||
---|---|---|---|---|---|---|
Before measures | After measures | Qualitative | Quantitative | |||
Frequency of overbank flow | Yes | Yes | No | Yes | No | Improvement |
Lag in propagation of flood peak | Yes | Yes | No | Yes | No | Improvement |
Monitoring documents
Image gallery
Additional documents and videos
Additional links and references
Link | Description |
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http://www.newforestlife.org.uk/life3/PDFs/PDFs/LaymansReport.pdf | Layman's Report |
http://www.newforestlife.org.uk/life3/PDFs/PDFs/C-V2EndofProjectHydroRpt.pdf | Hydrological Report |
http://www.geog.soton.ac.uk/school/staff/profiles/das/Life.pdf | New Forest LIFE III Monitoring Report |
http://www.natura.org/DOC/uk newforest panels.pdf | Sustainable Wetland Creation in the New Forest |
http://www.coastms.co.uk/resources/6a99ddc3-5955-4605-9f30-76f182f80153.pdf | Presentation: Practice and impacts of wet woodland restoration in lowland headwater streams in the New Forest SAC. |