Case study:Unit 4 - North Channel Phase 1
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Project overview
| Status | Complete |
|---|---|
| Project web site | http://www.environment-agency.gov.uk |
| Themes | Fisheries, Habitat and biodiversity, Hydromorphology |
| Country | England |
| Main contact forename | Alastair |
| Main contact surname | Maxwell |
| Main contact user ID | |
| Contact organisation | Environment Agency |
| Contact organisation web site | http://www.environment-agency.gov.uk |
| Partner organisations | |
| Parent multi-site project | |
| This is a parent project encompassing the following projects |
No |
Project summary
The North Channel is a distinct channel and unit of the River Frome SSSI. It was historically much smaller and used as part of the water meadow system during the 18th and 19th Centuries within the Moreton Estate. During the 1960’s and 70’s as part of Land Drainage Improvement schemes the channel was enlarged generally through deepening allowing it to carry more flows and act as a flood relief channel. The objective of this scheme was to drain the floodplain more effectively and allow for intensification, principally for dairy farming.
The River Frome Rehabilitation Plan states the main proposals to improve the SSSI condition and WFD objectives of Unit 4 and to incorporate as part of the North Channel project are: a) increase / diversify channel bed profile creating deep pools and gullies and b) to introduce large woody debris to provide in channel habitat and vary bed profiles through scour and deposition.
Monitoring surveys and results
Lessons learnt
This project did pose some issues during its delivery. The generally narrow nature made any changes made to the bed more sensitive than in other reaches of the Frome. The existence of gravels within the river bed was not as extensive as first thought. There were sections that were mostly clays which made it harder to reprofile effectively. The decision made on site was to minimise or exclude any works to the bed if gravel quantities were low.
The banks of the channel were high and steep; they were also quite soft so when trenches were dug to install LWD structures the banks in places seemed quite fragile. This limited the angle which could be dug and did restrict the use of this technique in places on the reach.
The benefit of adding value as described above cannot be under estimated. As described it can give a project additional materials (tree limbs etc) but can also gain acceptance of the project by other stakeholders such as the tenant farmer or river keeper. These can be achieved with minimal additional cost to the project.
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Catchment
Subcatchment
Other case studies in this subcatchment: 2e Lower Woodsford River and Floodplain Enhancement, Bockhampton Enhancement, Hurst Bridge (downstream), Louds Mill (Downstream)m Enhancement, Lower Bockhampton, Lower Woodsford, Martins River Island, Moreton Channel Gravel Reprofiling, North Channel Upper Reach, River Frome Rehabilitation Plan... further results
Site
Project background
Cost for project phases
Reasons for river restoration
Measures
MonitoringHydromorphological quality elements
Biological quality elements
Physico-chemical quality elements
Any other monitoring, e.g. social, economic
Monitoring documents
Additional documents and videos
Additional links and references
Supplementary InformationEdit Supplementary Information
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