Just over a year ago the Environment Agency reinstated a meander loop at Great Ryburgh Common that had been bypassed and left high and dry by engineering works in the 1950s. Once the bypass channel was plugged and the old channel de-silted, the river flowed again along its original winding course.
Electric-fishing surveys in the meander loop channel have shown excellent results, with 384 fish of 11 species captured. These included good numbers of native brown trout, as well as legally protected species such as bullhead and brook lamprey.
The previous year’s electric-fishing results from the old straightened channel yielded only 31 fish representing eight species.
Great improvements in the river ecosystem have also been seen, with a number of typical chalk stream plant species having colonised the new channel in just over a year. These include water starwort, lesser water-parsnip and whorl-grass, plants for which the river is designated.
At the same time, the gravel bed of the river was restored after much of it had been removed by past dredging. Wildlife in the gravel now includes species typical of “natural” free flowing gravel bed sections which are rare on a local scale. The aquatic life stages of over 15 species of mayfly, caddisfly and stonefly were found, indicating a healthy invertebrate community, good water quality and, importantly, good habitat variability as a result of the restoration works.
Dr Rob Dryden, Technical Specialist for the Environment Agency’s Fisheries and Biodiversity Team, said:
“We are delighted with the monitoring results, which show clearly how river restoration can improve local habitat quality for a wide range of fish, plants and other wildlife”.
Tim Nevard, a Trustee at Pensthorpe said:
“We’re thrilled with the outcomes of reinstating the ‘Meander Loop’. The Wensum is internationally important and the Environment Agency is to be commended for planning and implementing this exemplary project, entirely in keeping with the philosophy of our nature reserve”.
The River Wensum Restoration Strategy, developed by Natural England in partnership with the Environment Agency, to remedy the physical modifications the Wensum has experienced as a result of past land drainage and industrial activities. The strategy aims to work with landowners and other partners to return the river, which is nationally and internationally designated for its wildlife, to a state which can sustain the wildlife and fisheries typical of a Norfolk chalk stream.
The strategy links to other initiatives which aim to improve the ecological condition of the river by tackling the impacts of siltation and water abstraction.
