Salmon Habitat Improvements
We were contracted by South West Water to conduct an evaluation of the in-river engineering options for two rivers. Both river systems were subject to enhanced flows to support downstream abstraction, and offered unique opportunities for fish habitat improvements in a relatively stable and managed flow regime. Detailed fish habitat assessments were undertaken via a walkover survey, together with a thorough evaluation of existing fisheries data. The two data sets were combined to identify habitat related fish production 'bottlenecks'. A range of in-stream and riparian fish habitat improvement techniques were identified and their potential to improve populations modelled using GIS techniques. A Cost Benefit Analysis was carried out to identify the most economically beneficial approach for each system. Recommended solutions included spawning channels to overcome a lack of spawning gravel below each reservoir, and boulder additions and bank modifications to overcome the homogenous flow environment.
