The purpose of the project was to reinstate the failed weir across the river Calder at Cooper Bridge near Mirfield. To comply with Environment Agency, it was also necessary to include a fish pass as part of the works.
Cooper Bridge Weir is located at Cooper Bridge Junction where the Huddersfield Broad canal joins the Calder and Hebble Navigation from the south. The function of the weir is to maintain the upstream water levels of the Calder and Hebble and the Huddersfield Broad canals. Approximately two thirds of the original weir structure have failed in the past and had since been replaced with other materials over the years.
The principal structures to be constructed were a new 40m long reinforced concrete weir to replace the existing one and a Larinier fish pass and an elver pass. The weir included a concrete crest with steel sheet piles up and downstream tying into a sloping concrete apron to the upstream and a stepped concrete apron to the downstream.
The river Calder is a fast-flowing river which has a high flash flood risk. Maintaining the flow of the river whilst constructing the new Weir and Fish Pass in the river was going to require advanced programming and temporary works installation.
For more information see the Canal and River Trusts article and waterways blog below.