Tyne Rivers Trust
NEC 3 Short Form
Scheme comprised the construction of a new fish pass to aid the passage of fish up the River Derwent. Lintzford Weir is a significant masonry structure and was a major barrier to the upstream migration of salmon and sea trout.
|The new fish pass (15m x 4m) was constructed on the corner of the existing weir structure. We created a working area by diverting the River using large sand bags, supplemented by the use of pumping equipment. The fish pass was constructed by the creation of rock armour (1 – 2 tonnes each) ramps to create a series of pools, each roughly 200mm lower than the one immediately upstream.
The rock armour stones were fixed to the masonry weir structure and pinned to the river bed to ensure stability.
The works required close consultation with the Environment Agency and the Rivers Trust to gain understanding of how best to form the turbulence required from the rock pools, to initially attract and then allow fish to move through the rock pools to the river upstream of the weir.