The River Wensum Restoration & Floodplain Enhancement Project
The Project began in 2012 and was facilitated by the Catchment Restoration Fund and was completed in early 2016 with the restoration of the entire stretch of the Wensum running through Pensthorpe. A previous successful restoration of the Meander Loop was completed in 2010 by the Environment Agency with great success.
The River Wensum is considered one of the most important lowland chalk rivers and has both EU Special Area of Conservation (SAC) status and Site of Special Scientific Interest (SSSI) status yet it is in unfavourable ecological condition. This is as a result of pollution from both agricultural and urban run-off and reduced functionality due to extensive dredging and straightening.
The extensive design and planning stage allowed the Project team including Dr Rob Dryden and Adam Thurtle both from the Environment Agency, project designer Robin Chase from Atkins and Tim Nevard from Pensthorpe Conservation Trust to ensure that the needs of the river laid out in the River Wensum Restoration Strategy would be achieved.
Rivers are not uniform in depth, speed or width, therefore one of the key areas of river restoration is returning the river to a more natural sinuosity and with variable depths. Different features naturally found in rivers will be used to restore the river and create suitable habitat for several key species.
Gravel Glides are raised areas of washed gravel due to a faster flow, they create ideal habitat for key species such as water crowfoot and spawning sites for fish such as bullhead and brown trout.
Deflectors occur when a large tree falls into the river, this feature creates a build up of silt on the deflector side and a faster river speed on the opposite side, it provides species such as brook lamprey vital habitat at different life stages.
Composite Berms mimic a build up of silt at areas of bank-side vegetation they are at a level that allows water to flow over them during flooding.
Brushwood Berms work in a similar way to composite berms, they are created using staked brushwood, the slower flow rate through the brushwood creates the perfect cover for young fish and invertebrate.