View source for Case study:Narborough Rehabilitation Project

{{Case study status
|Approval status=Approved
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{{Location
|Location=52.68766041195301, 0.5781126022338867
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{{Project overview
|Status=Complete
|Themes=Habitat and biodiversity
|Country=England
|Main contact forename=Nigel T.H.
|Main contact surname=Holmes
|Partner organisations=Environment Agency, River Restoration Centre, Natural England,
|Multi-site=No
|Project picture=Nar.png
|Picture description=just post works
|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.
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{{Case study subcatchment
|Subcatchment=Nar to confl with Blackborough Drain
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{{Site
|Name=Narborough
|WFD water body code=GB105033047791
|WFD water body name=Nar to confl with Blackborough Drain
|Pre-project morphology=Single channel, Straightened
|Reference morphology=Single channel, Pool-riffle, Sinuous
|Heavily modified water body=No
|Protected species present=No
|Invasive species present=No
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{{Monitoring documents}}
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{{Additional Documents}}
{{Case study documents
|File name=NAR Spring 2011 - as built project report.pdf
|Description=River Nar Rehabilitation summary by Nigel Holmes
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