Occurrence and control of soil erosion and fluvial sedimentation in selected basins of the Thames River watershed
This report summarizes results from the application of the soil-loss/ sediment-delivery model GAMES to selected small watersheds in the Avon River and lower Thames River basins. GAMES was developed to describe and predict soil loss by water erosion and the subsequent delivery of suspended solids from field to stream and downstream in agricultural areas. The modelling analysis indicates that it is well to consider the rolling upland watersheds such as the Avon basin somewhat differently than the level watersheds of the lower Thames basin when assessing soil erosion and stream sediment problems. In the upland watersheds, average soil loss rates may not be considered excessive though there is evidence of localized erosion problems. Sediment sources are even more localized than the erosion-prone sites. Erosion and sediment delivery can therefore be effectively achieved by the application of remedial measures to site-specific problem areas. The level lowland watersheds, on the other hand, present neither general nor local soil erosion problems, the estimated soil-loss rates being relatively low. If either the low erosion rates or the sediment delivery rates are to be controlled for reasons of agricultural productivity or water quality, then widespread control measures would be required. These would involve extensive changes in soil and crop management systems.