The weir maintains levels to allow navigation along the Calder and Hebble Navigation and onto the Huddersfield Broad Canal. It is undergoing a £2m overhaul to install a new 40 metre weir and new fish pass.
Following a major failure of the weir in 2009, this section of waterway has been forced to close on two occasions as emergency temporary repairs were undertaken which led to the navigations being closed.
Project Manager Linda Milton said: "This is the largest project happening anywhere on the waterway system during this maintenance period and is really important for these navigations. The weir is a completely new structure with a heavily reinforced base around four metres below the crest level. The remaining structure is constructed with fibre mesh concrete 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 weir also includes a bywash facility for fish migrating downstream. The main fish pass is a Larinier type and also incorporates an elver pass.
"The river cannot be closed fully and so extensive temporary works in the way of steel sheet piles have had to be driven into the river bed to form two cofferdams so the works can be carried out in two halves across the river; some of the piles are 13m in length. This enables the works to be constructed in the dry and at the same time maintain the river flow. However, due to all the heavy rainfall in 2012 this has proven a real challenge and several major floods to the river have caused delays as levels have been so high they have flooded the cofferdams out.
"The aim has been to install a new durable, robust, low maintenance structure that safeguards the navigations. Because of the nature of this river system, there is a high probability that these failures would have kept occurring so it’s important we’ve taken this action to avoid any further disruption to the three navigable waterways which rely on this weir."
Work is due to be completed by the end of January.
Cooper Bridge Weir [Photo: Canal & River Trust]