Case study:Narborough Rehabilitation Project
Project overview
| Status | Complete |
|---|---|
| Project web site | |
| Themes | Habitat and biodiversity |
| Country | England |
| Main contact forename | Nigel T.H. |
| Main contact surname | Holmes |
| Main contact user ID | |
| Contact organisation | |
| Contact organisation web site | |
| Partner organisations | Environment Agency, River Restoration Centre, Natural England |
| Parent multi-site project | |
| This is a parent project encompassing the following projects |
No |
Project summary
River excavations and modifications took three days, the majority of one of these being import of the gravel to the ‘runs’.
Work was implemented in c1km of river. There was absolutely no gradient within the sections modified, with the river being deep and sluggish throughout. Work carried out:
- created greater diversity of habitat by modifying both the long and cross-sections;
- locally narrowed the channel to improve self-cleansing of the bed in these locations, and accelerated flow into pools created immediately downstream;
- removed the unsightly deflectors by replacing them with ‘living’ features that already are doing a much more effective job than the deflectors were attempting to do;
- the one main difference from the Castle Acre stretch was that some of the upstream ‘runs’ had a thin layer of gravel spread over them too.
Differences in character were primarily determined by the character of the river bed where pools were excavated, and the extent of reed/sedge available from adjacent to the river to add to the channel.
Where the bed was hard, and reed/sedge was plentiful, upstream narrowing could be more extensive. In all cases where the bed was hard (predominantly chalky clay), very distinct pools and upstream ‘runs’ were formed. Where-ever possible the bed of the narrowed channel upstream of the pools was shallowed by adding material dug from the pools – this could only be done where flints or firm clay formed the substrate.
Where the bed was pure soft peat, the distinction between the narrowed channel upstream, and the deepened channel downstream, was much less. Had deflectors not already been present in the channel, it would have been difficult, or impossible, to establish narrowing upstream......the deflectors now form the downstream edges of the shoulders. Without reeds/sedge from adjacent to the river being added to these areas, they could not have been expected to be retained in the long term.
Monitoring surveys and results
Lessons learnt
Image gallery
|
Catchment and subcatchmentSelect a catchment/subcatchment
Catchment
Subcatchment
Other case studies in this subcatchment: Castle Acre Rehabilitation Project, Nar SSSI project, River Nar Castle Acre Common WEG project, River Nar Restoration Project, River Nar, Mileham River Restoration Project, West Lexham Rehabilitation Project
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
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||