Case study:River Quaggy- Chinbrook meadows: Difference between revisions
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|Picture description=Chinbrook Meadows soon after the works had been completed | |Picture description=Chinbrook Meadows soon after the works had been completed | ||
|Project summary=This project is an excellent example of a partnership initiative that has not only restored the river and floodplain, but has also paid careful attention to improving the park amenities. The channel work was completed in spring 2002 and by September that year there had already been considerable movement of gravels. Natural geomorphological features including a pool/riffle sequence, gravel bars and steeper banks had formed. The pond has been colonised by invertebrates and the vegetation planted along the banks is now providing good cover in both the planted and unplanted sections. | |Project summary=This project is an excellent example of a partnership initiative that has not only restored the river and floodplain, but has also paid careful attention to improving the park amenities. The channel work was completed in spring 2002 and by September that year there had already been considerable movement of gravels. Natural geomorphological features including a pool/riffle sequence, gravel bars and steeper banks had formed. The pond has been colonised by invertebrates and the vegetation planted along the banks is now providing good cover in both the planted and unplanted sections. | ||
'''Site background''' | |||
This section of the River Quaggy, with a flashy flow regime, was channelised and straightened between 1960-1970 as | |||
part of a flood alleviation scheme. Prior to restoration it was encased in concrete with fences and high privet hedges | |||
near to each bank. It could neither be accessed nor viewed by the public and was devoid of natural fauna and flora. | |||
'''Objectives''' | |||
To reintroduce the floodplain as a natural flood storage area as part of a larger catchment flood alleviation plan; to enable the River Quaggy to become accessible to the public and hence create a local amenity; to create an environment where native fauna and flora could colonise and allow for natural channel processes. | |||
'''Design''' | |||
*The concrete channel in the park was replaced by a sinuous channel, allowing easy | |||
access. It was (except where the cost of moving existing sewage drains prevented | |||
this) cut to follow its path prior to channelisation. | |||
*Whilst cutting the channel old gravels were evacuated and sufficient ‘room’ was left | |||
along the river corridor to allow for natural adjustment. | |||
*The margins of the channel were planted using a reputable source of native wetland | |||
plants (including iris, water mint and reeds), a wetland grass and wild flower mix was | |||
also sown. One section downstream has not been planted since there was a request | |||
from the local group to allow natural colonisation. | |||
*Flood storage ponds were included in the scheme and at the upstream section a | |||
boardwalk, pond dipping and educational area, were incorporated to attract local | |||
school children. | |||
}} | }} | ||
{{Case_study_subcatchment | {{Case_study_subcatchment | ||
Revision as of 10:18, 5 June 2013
Project overview
| Status | Complete |
|---|---|
| Project web site | |
| Themes | Habitat and biodiversity, Social benefits, Water quality |
| Country | England |
| Main contact forename | Dave |
| Main contact surname | Webb |
| Main contact user ID | |
| Contact organisation | Environment Agency |
| Contact organisation web site | http://www.environment-agency.gov.uk |
| Partner organisations | QWAG, Lewisham Council |
| Parent multi-site project | |
| This is a parent project encompassing the following projects |
No |
Project summary
This project is an excellent example of a partnership initiative that has not only restored the river and floodplain, but has also paid careful attention to improving the park amenities. The channel work was completed in spring 2002 and by September that year there had already been considerable movement of gravels. Natural geomorphological features including a pool/riffle sequence, gravel bars and steeper banks had formed. The pond has been colonised by invertebrates and the vegetation planted along the banks is now providing good cover in both the planted and unplanted sections.
Site background This section of the River Quaggy, with a flashy flow regime, was channelised and straightened between 1960-1970 as part of a flood alleviation scheme. Prior to restoration it was encased in concrete with fences and high privet hedges near to each bank. It could neither be accessed nor viewed by the public and was devoid of natural fauna and flora.
Objectives To reintroduce the floodplain as a natural flood storage area as part of a larger catchment flood alleviation plan; to enable the River Quaggy to become accessible to the public and hence create a local amenity; to create an environment where native fauna and flora could colonise and allow for natural channel processes.
Design
- The concrete channel in the park was replaced by a sinuous channel, allowing easy
access. It was (except where the cost of moving existing sewage drains prevented this) cut to follow its path prior to channelisation.
- Whilst cutting the channel old gravels were evacuated and sufficient ‘room’ was left
along the river corridor to allow for natural adjustment.
- The margins of the channel were planted using a reputable source of native wetland
plants (including iris, water mint and reeds), a wetland grass and wild flower mix was also sown. One section downstream has not been planted since there was a request from the local group to allow natural colonisation.
- Flood storage ponds were included in the scheme and at the upstream section a
boardwalk, pond dipping and educational area, were incorporated to attract local school children.
Monitoring surveys and results
Lessons learnt
Catchment and subcatchment
Edit the catchment and subcatchment details
(affects all case studies in this subcatchment)
Site
| Name | River Quaggy |
|---|---|
| WFD water body codes | GB106039023290 |
| WFD (national) typology | Calcareous |
| WFD water body name | Quaggy |
| Pre-project morphology | Straight, Revetments |
| Reference morphology | Sinuous |
| Desired post project morphology | |
| Heavily modified water body | Yes |
| National/international site designation | |
| Local/regional site designations | |
| Protected species present | No |
| Invasive species present | No |
| Species of interest | |
| Dominant hydrology | Artificially regulated, Quick run-off |
| Dominant substrate | Bedrock |
| River corridor land use | Urban |
| 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 | 0.3 |
| Average unit stream power (W/m2) |
Project background
| Reach length directly affected (m) | 300 m0.3 km <br />30,000 cm <br /> |
|---|---|
| Project started | 2002/03/01 |
| Works started | |
| Works completed | 2002/10/01 |
| Project completed | 2002/04/02 |
| Total cost category | 50 - 100 k€ |
| Total cost (k€) | 100 k€100,000 € <br /> |
| Benefit to cost ratio | |
| Funding sources | Environment Agency |
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
| |
|---|---|
| Bank/bed modifications | Removal of revetments, Introduction of gravels, Planting of native species |
| Floodplain / River corridor | Removal of embankments, Creation of wetlands, Creation of ponds |
| Planform / Channel pattern | Introduction of sinuosity |
| Other | |
Non-structural measures
| |
| Management interventions | |
| Social measures (incl. engagement) | |
| Other | Information provision, Consultation |
Monitoring
Hydromorphological quality elements
| Element | When monitored | Type of monitoring | Control site used | Result | ||
|---|---|---|---|---|---|---|
| Before measures | After measures | Qualitative | Quantitative | |||
Biological quality elements
| Element | When monitored | Type of monitoring | Control site used | Result | ||
|---|---|---|---|---|---|---|
| Before measures | After measures | Qualitative | Quantitative | |||
| Invertebrates | Yes | Yes | Yes | Improvement | ||
| Macrophytes | Yes | Yes | Yes | Improvement | ||
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 | |||
Monitoring documents
Image gallery
Additional documents and videos
Additional links and references
| Link | Description |
|---|---|
| http://www.therrc.co.uk/case studies/chinbrook meadows.pdf | RRC site description |
| http://www.restorerivers.eu/Publications/tabid/2624/mod/11083/articleType/ArticleView/articleId/3123/Chinbrook-Meadows----A-better-place-to-play.aspx | Video on Chinbrook meadows |
| http://www.qwag.org.uk/quaggy/restoration.php | Quaggy Waterways Action Plan link |
| http://www.lewisham.gov.uk/inmyarea/openspaces/parks/Pages/chinbrook-meadows.aspx | Lewisham Council's link |
| http://en.wikipedia.org/wiki/Chinbrook Meadows | Wikipedia link |
| http://www.greenchain.com/learning/sites/chinbrook-meadows.php | Green chain link |