Background Information
Somerset Bridge is located on the River Wey between Elstead and Eashing. There is a small weir immediately upstream of the bridge which is impassable to most fish species during normal flow conditions. The purpose of the weir is not known but on initial investigations there didn’t appear to be any features, e.g. ponds/channels that benefited from the weir.
Scope of the Project
The objective of this project was to remove the weir to ensure that it was passable to all fish species at all flows. This project builds on a strategic programme of works to get the River Wey and its tributaries to ‘good ecological status’ and to improve populations of both migratory and coarse fish. To date this programme of works, known as the Wey FWD, has secured mec hanisms for the delivery of fish passes from the confluence with the Thames at Weybridge upstream to Somerset Bridge. Removing the weir will open up fish passage for approximately 100km and ensure that fish are able to reach good quality spawning grounds in the catchment’s headwaters. This project addresses one of only a few remaining priority barriers on the River Wey catchment and will help move fish populations towards good ecological status.
Our Solution
Aquamaintain Ltd worked closely with EA Fisheries officers to determine the appropriate methodology for the removal of the weir. Consideration was given to minimise downstream erosion. Before works commenced a silt curtain consisting of hazel faggots secured with hazel stakes was installed downstream of the site to prevent the escape of sediments. An 8T excavator fitted with breaker attachment was used to breakout the weir structure and allow a gradual release of water downstream. Once water levels had settled a small ramp was constructed with bog mats to allow access for a 3T wheeled dumper into the channel. The excavator fitted with grab attachment was then used to load the dumper with waste weir material away. This was then stockpiled at the sit e entrance and grabbed away by a licensed waste carrier. Once the weir was fully removed the bed and banks were graded to a natural gradient that allow ed the passing of all fish species to the upper reach of the river.
