Restoring the Hammer Stream in Kent, UK

River restoration is a service that has become increasingly important as the risk of flooding has increased over the past few years. Ensuring rivers and their tributaries are responsibly and sensibly managed can have persistent effects by reducing flood risks and benefitting the natural environment.

Following a competitive tendering process, RSK Habitat Management was awarded the contract to carry out the restoration of a 750-m stretch of the Hammer Stream on Ayleswade Farm, Kent. The Hammer Stream forms part of the Beault catchment and is managed by the Upper Medway Internal Drainage Board.

The stream through Ayleswade Farm had been managed for land drainage and flood defence; years of clearance and dredging had resulted in a deeply incised channel with vertical banks and an almost complete disconnection from the flood plain in all but high flow conditions.

Work to restore the stream required a complex approach, including modifying the existing cross-section to create a two stage channel, re-grading the banks to create a maximum 1 in 3 slope, re-meandering the channel to help increase morphological and flow diversity, and narrowing the steam using the excavated material to create low-level margins and berms. In addition to the river modification, HM offered an additional service supplying, installing and constructing four 10-m riffles at strategic locations along the river channel as well as supplying and installing a replacement 900-mm culvert crossing. This provided the client with a one-stop service for their needs.

These works had multiple successful outcomes in addition to successfully narrowing the Hammer Stream and significantly increasing in-channel velocity and diversity of flows. A fish spawning habitat was created and water holding capacity was increased, which will have a knock-on effect, helping to reduce the likelihood of flood events further downstream.

The client was delighted with the work that RSK Habitat Management undertook, especially in light of the difficult ground conditions. They communicated that the work was done to a high standard and any issues that arose were dealt with promptly.