Case study:Narborough Rehabilitation Project

This case study is pending approval by a RiverWiki administrator.

Approve case study

 

0.00

(0 votes)

To discuss or comment on this case study, please use the discussion page.

Location: 52° 41' 15.58" N, 0° 34' 41.21" E

Edit location

Loading map...

{"format":"googlemaps3","type":"HYBRID","minzoom":false,"maxzoom":false,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"limit":50,"offset":0,"link":"all","sort":[""],"order":[],"headers":"show","mainlabel":"","intro":"","outro":"","searchlabel":"... further results","default":"","import-annotation":false,"width":"auto","height":"400px","centre":false,"title":"","label":"","icon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"visitedicon":"","wmsoverlay":false,"zoom":14,"layers":[],"controls":["pan","zoom","type","scale","streetview","rotate"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"resizable":false,"kmlrezoom":false,"poi":true,"cluster":false,"clustergridsize":60,"clustermaxzoom":20,"clusterzoomonclick":true,"clusteraveragecenter":true,"clusterminsize":2,"imageoverlays":[],"kml":[],"gkml":[""],"searchmarkers":"","fullscreen":false,"scrollwheelzoom":false,"showtitle":false,"hidenamespace":true,"template":"Location map popup","userparam":"","activeicon":"","pagelabel":false,"ajaxcoordproperty":"","ajaxquery":"","locations":[{"text":"\u003Cp\u003E\u003Cbr /\u003E\n\u003C/p\u003E\u003Cp\u003E\u003Cb\u003EProject Title:\u003C/b\u003E Narborough Rehabilitation Project\n\u003C/p\u003E\u003Cp\u003E\u003Cb\u003ECountry:\u003C/b\u003E \u003Ca href=\"/wiki/index.php?title=England\" title=\"England\"\u003EEngland\u003C/a\u003E\n\u003C/p\u003E\u003Cp\u003E\u003Cb\u003EProject Status:\u003C/b\u003E Complete\n\u003C/p\u003E\u003Cp\u003E\u003Cb\u003EThemes:\u003C/b\u003E Habitat and biodiversity\n\u003C/p\u003E\u003Cp\u003E\u003Cbr /\u003E\n\u003C/p\u003E","title":"Narborough Rehabilitation Project","link":"","lat":52.687660411953,"lon":0.57811260223389,"icon":"/wiki/images/a/af/Red_marker.png"}]}

Left click to look around in the map, and use the wheel of your mouse to zoom in and out.

Project overview

Edit 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

just post works

Project summary

Edit project overview to modify the 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

This case study hasn’t got any Monitoring survey and results, you can add some by editing the project overview.

Lessons learnt

This case study hasn’t got any lessons learnt, you can add some by editing the project overview.

Catchment and subcatchment

Select a catchment/subcatchment

Edit the catchment and subcatchment details
(affects all case studies in this subcatchment)

Catchment

River basin district	Anglian
River basin	North West Norfolk

Subcatchment

River name	Nar
Area category
Area (km2)
Maximum altitude category
Maximum altitude (m)
Dominant geology
Ecoregion
Dominant land cover
Waterbody ID

Site

Edit site

Name	Narborough
WFD water body codes
WFD (national) typology
WFD water body name
Pre-project morphology	Single channel, Straightened
Reference morphology	Single channel, Pool-riffle, Sinuous
Desired post project morphology
Heavily modified water body	No
National/international site designation
Local/regional site designations
Protected species present	No
Invasive species present	No
Species of interest
Dominant hydrology
Dominant substrate
River corridor land use
Average bankfull channel width category
Average bankfull channel width (m)
Average bankfull channel depth category
Average bankfull channel depth (m)
Mean discharge category
Mean annual discharge (m3/s)
Average channel gradient category
Average channel gradient
Average unit stream power (W/m2)

Project background

Edit project background

Reach length directly affected (m)
Project started
Works started
Works completed
Project completed
Total cost category
Total cost (k€)
Benefit to cost ratio
Funding sources

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

Edit reasons for restoration

Mitigation of a pressure
Hydromorphology
Biology
Physico-chemical
Other reasons for the project

Measures

Edit Measures

Structural measures
Bank/bed modifications
Floodplain / River corridor
Planform / Channel pattern
Other
Non-structural measures
Management interventions
Social measures (incl. engagement)
Other

Monitoring

Hydromorphological quality elements

Edit Hydromorphological
quality elements

Element	When monitored		Type of monitoring		Control site used	Result
	Before measures	After measures	Qualitative	Quantitative

Biological quality elements

Edit biological
quality elements

Element	When monitored		Type of monitoring		Control site used	Result
	Before measures	After measures	Qualitative	Quantitative

Physico-chemical quality elements

Edit 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

Edit Other responses

Element	When monitored		Type of monitoring		Control site used	Result
	Before measures	After measures	Qualitative	Quantitative

Monitoring documents

Upload monitoring documents

Image gallery

Edit Image gallery

Additional documents and videos

Upload additional documents

River Nar Rehabilitation summary by Nigel Holmes

Additional links and references

Edit links and references

Link	Description

Supplementary Information

Edit Supplementary Information