Rivers and streams are being restored to allow pre-industrial levels of bio-diversity to recover by the building of fish passes.
The passes – also known as fish ladders – allow free movement of fish along water courses. Migratory fish, such as salmon and sea trout, are able to travel freely upriver to their breeding grounds and non-migratory fish can re-colonise areas that were previously inaccessible because of weirs.
Recent European and UK legislation places greater obligations on the owners of river structures to take account of fish passage. The legislation also aims to protect eel populations whose numbers have dropped dramatically in recent years.
Halcrow has wide experience of developing and designing fish passes. All our new river projects in the UK give automatic consideration to allowing fish passage while maintaining the key functions of river structures.
We tailor our design and management plans to suit individual local needs. A recent innovation in the UK is the combined use of a brush type pass for both fish and canoes.
Halcrow’s expertise in hydraulic modelling and environment projects enables us to advise on every stage of a fish pass project from survey to construction. Our key capabilities are:
- river basin management plans
- eel management plans
- water framework directive assessments
- hydrological analysis
- hydraulic modelling
- geomorphological assessments
- design of fish passes
- design of fish screens