River corridors in urban areas have recieved scant attention from ecologists, so the discovery of unusually rich habitats on the banks of the River Don in central Sheffield encouraged the Nature Conservancy Council to grant-aid a detailed survey of wildlife along the most urban stretches. The project was seen as a contribution to the planning process to help ensure that during the current wave of redevlopment, involving the opening up of previously secluded areas, ecological richness would be regarded as an asset to be incorporated into the new post-industrial landscape.