The Environment Agency project was aimed to help fish and eels navigate safely over the weir structure on the River Colne while ensuring that the flood risk and water resources data collected by the Earls Colne gauging station was unaffected.
However given the unusual shape of the gauging weir, it was a complicated fish pass to design, with the added issue of having to dry a section of the river out for the work to be completed.
Despite a setback during the construction, where some vital tools and a JCB was stolen, the design was still successfully completed in just four weeks.
Contractors carried out the work, which involved fixing low cost baffles (a structure to redirect the flow of water) and eel tiles to the weir. However to ensure this was done accurately and safely, the work area had to be dried out for the duration of the work.
A dam was constructed upstream and downstream and large pumps were used to bypass the structure. As the water levels were slowly lowered while the work area was being dried out, the contractor safely relocated the fish and eels that remained by the weir.