Water voles and brown trout are expected to thrive in the River Mermaid after some extensive restoration work.
The Norfolk Rivers Internal Drainage Board (IDB) undertook river restoration works on 700m of the River Mermaid at Burgh in 2017.
Before the restoration works were completed the channel was over widened and deepened in places, which made the water flow slow down and the stream bed fill with deposited silt covering gravels. The slow flow meant that freshwater plants such as bur reed were growing at an exponential rate, blocking the channel, backing up the water and increasing the flood risk as well as reducing flow and species diversity. This stream was regularly maintained mechanically removing the reed to allow the water to flow.
The work involved importing gravel to the stream to raise the bed level of previously over-deepened parts. Woody features were also installed using locally felled trees to enhance and meander the water flow, creating a more dynamic and varied channel.
This work has made the channel shallower and narrower in places resulting in a faster flowing river along this stretch. This in turn will improve in-stream habitats for plants, invertebrates and fish populations that prefer the faster water flow. In particular it is hoped to increase the number of brown trout in the Mermaid.
Water voles are present and as the restoration develops and establishes it will provide more cover and food plants for them to thrive. The need to undertake routine maintenance has also been reduced as a result of these works.
The works are next to the public footpath and it is hoped the resulting improvements in the local habitat and wildlife will make the walk a more interesting and enjoyable experience in this beautiful part of the Bure Valley.
This scheme demonstrates how changes to drainage systems can make a significant difference to the local environment. The work was completed in partnership with the Environment Agency, and was part funded by the Water Environment Improvement Fund.
Courtesy of the Norfolk Rivers Internal Drainage Board
The third edition of the Upper Bure Valley Newsletter is now available. It provides a snapshot of activities across the Upper Bure water catchment and the stories linked to the precious streams, rivers, ponds and wetlands within.