The use of PHABSIM in the management of water resources and fisheries in England and Wales

Abstract

The PHABSIM technique enables the quantitative prediction of suitable physical habitat in a river reach for chosen species and lifestages under different river flow scenarios, based on field measurements, hydraulic calibration, and species physical habitat preferences (depth, velocity, and substrate). The technique was recently transferred to the UK from America, and is now being tentatively used by the Environment Agency to support water resources decision making in England and Wales. Applications to date have concentrated mainly on fish habitats, investigating the potential relative impacts of changing reservoir or borehole releases, abstractions, and water transfers. Although the application is both expensive and time consuming, it is nonetheless proving to be a valuable tool, and is the subject of ongoing research to further develop its applicability and transferability. Although taking no account of water quality, sediment transport, or other constraints on habitat suitability and population, the technique appears to have significant potential when used in combination with other habitat protection aids.