Case study:Aubourn Rock Ramp and Habitat Works

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: 53° 9' 7.49" N, 0° 38' 10.62" W

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 Aubourn Rock Ramp and Habitat Works\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":"Aubourn Rock Ramp and Habitat Works","link":"","lat":53.152080986039,"lon":-0.63628317482514,"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	Fisheries, Habitat and biodiversity
Country	England
Main contact forename	Matt
Main contact surname	Parr
Main contact user ID
Contact organisation	Environement Agency
Contact organisation web site	http://Environement%20Agency
Partner organisations
Parent multi-site project	Upper Witham Restoration
This is a parent project encompassing the following projects	No

Constructed Rock Ramp.

Project summary

Edit project overview to modify the project summary.

Aubourn Weir, located in the lower reaches of the Upper River Witham, presented a major barrier to upstream fish and eel passage and the heavily-modified channel in the vicinity, lacked morphological and habitat diversity resulting in poor fish populations. Also affected by high levels of phosphates, the overall Ecological Status of this section of the river is classified as Moderate.

The key objectives of the Aubourn project were to enable fish and eel passage at the weir and to undertake additional enhancements to improve the channel diversity. The wider project, from Bassingham Bridge to beyond Aubourn Weir, sought to enhance the heavily-modified channel using existing riverside trees to create in-stream deadwood habitat, improve flow variation and provide valuable refuges for fish and invertebrates.

There were two parts to the project: construction of the rock ramp fish pass and associated bed enhancements in the vicinity of Aubourn Weir, and extensive woody habitat creation from Bassingham downstream to beyond Aubourn Weir.

Rock Ramp - Using large rocks and steel sheet piling to maintain the water levels, a series of stepped pools, rising c1m in c20cm increments, were constructed to create the “rock ramp” which now enables fish and eels to negotiate the former obstruction.

Pools – Five pools were excavated in the river bed, three above the new rock ramp and two below it. The excavated material was deposited against the bank immediately upstream of each pool to narrow the channel and speed up the flow - a technique known as “dig-and-dump”.

Woody habitat - Riverside trees, in particular those that had collapsed in to the river or were in imminent danger of doing so, were selectively hinged and/or secured into the channel and along the bank throughout the whole of the 3.25km reach. The large woody material creates flow variation and provides refuges for fish and invertebrates as the river level and speed of flow changes.

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.

Image gallery

Edit Image gallery

Weir Pre-works

Tree Works

Catchment and subcatchment Select a catchment/subcatchment Site Edit site Name WFD water body codes WFD (national) typology WFD water body name Pre-project morphology Reference morphology Desired post project morphology Heavily modified water body National/international site designation Local/regional site designations Protected species present Invasive species present 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 Additional documents and videos Upload additional documents Additional links and references Edit links and references Link Description Supplementary Information Edit Supplementary Information