]> 2026-04-09T05:24:05+00:00 Case study:River Alt at Knowsley 500 en RRC Manual of River Restoration Techniques entry Approved Embankment lowering Yes No No Improvement No Invertebrates,No,Yes,No,Yes,No,Improvement Invertebrates Yes Creation of braided channel Channel naturalisation Environment Agency Yes No Yes false Prior to works.jpg Vegetated channel.jpg Vegetation structure.jpg Excavated flooplain area.jpg 2012Nov23 Woolfall H Reedbed area cropped.jpg March 2012 comparative photo.JPG Sept 2012.jpg River Alt prior to works Vegetated channel threads Diverse vegetation structure Newly excavated floodplain area Floodplain area - 2012 One of choked braided side channels - 2012 Issues with urban litter evident - 2012 No 53.427515266745,-2.8546632360667 Sue Environment Agency Slamon Tree management works and re-opening of choked side channels is planned as part of 'Knowsley 2020' project. The site would have benefited from a long term tailored management plan. Embankment lowering,,Floodplain reconnection, Protect/restore riparian zone, Riparian planting,,Creation of braided channel, Channel naturalisation, ,Tree management works and re-opening of choked side channels is planned as part of 'Knowsley 2020' project. The site would have benefited from a long term tailored management plan.,Improved public access, Engagement with schools,,Community engagement, Yes No No Awaiting results Yes Public perceptions,No,Yes,Yes,No,No,Awaiting results No Public perceptions 6041 Yes Yes No Improvement No ,Yes,Yes,No,No,No,Improvement No Cross section of new floodplain and braided channels 2006-10-01Z 2454009.5 Alt newchannelXsection.jpg 2006-02-01Z 2453767.5 Complete The Alt is a small, low energy urban river which had been historically re-sectioned, straightened and over deepened. The river flows beside a road and was constrained within a trapezoidal channel. Improved water quality had seen fish return to parts of the river but further improvements to the riverine habitat were desired. Consultation with local authorities, community groups and local schools took place during the design and construction phases. Options were limited by planning permissions on parts of the site and the existence of a wildflower meadow. Improving public access to the river was a very important element of the scheme. The 1.5m, 30 degree banks were excavated back on either side of the existing course and up to 30m width of 'floodplain' was created. This comprises a mix of a main and braided channels separated by marginal berms. The new course was approximately 25% larger and deeper than the braided channels to encourage the majority of low flows along this route. Initial earthworks have delivered access and recreation improvements along this stretch of the Alt. Reedbed habitat has established reinstating a locally rare habitat. However, this has also has some negative impacts in that biodiversity has been limited by reedbed monoculture and encroachment of the reedbed has reduced velocities increasing siltation and reducing flow variation as a result. Minimal management has been undertaken since the project work and as a result the site has become overgrown with vegetation and some of the braided side channels have become choked. Tree work is underway as is work to re-open the braided channels (part of Knowsley 2020 Project). The project would have benefited from a tailored long term management plan. Water quality appears to have improved with the number and density of pollution sensitive invertebrates increasing since the works were carried out. Anecdotal evidence suggests that people are happy with the scheme. Knowsley MBC is undertaking further works to open up the riparian corridor and is currently installing a cycle path. Community involvement - Consultation with local authorities, community groups and local schools took place during the design and construction phases. River Alt at Knowsley river alt at knowsley No 140 Alt Floodplain reconnection Protect/restore riparian zone Riparian planting River Alt river alt River Alt, Knowsley river alt, knowsley Improved public access Engagement with schools River Alt Fisheries Flood risk management Habitat and biodiversity Water quality 46.3 10 - 50 k€ GB112069060580 Community engagement 2013-07-17T12:15:01Z 2456491.0104282 2019-01-02T15:53:49Z 2458486.1623727 River Alt at Knowsley 500 1 plainlist 5 [[Category:Case study]] [[Project title::!River Alt at Knowsley]] [[Subcatchment title::River Alt]] River Alt at Knowsley# QUERYfc1021a299084a5e9ffc1666407018f6