Regime theory and the stability of straight channels with bankfull and overbank flow

Experiments have been carried out at a large laboratory scale to test a rational regime theory and to study the development of regime channel morphology for straight loose-boundary channels (bed and banks) in fixed flood plains for a range of flow conditions. Results are presented for straight channels which have been developed with bankfull flows and then subjected to overbank flows, and include friction and sediment transport data. These indicate reasonable theoretical agreement with the friction data but the sediment transport rate is underestimated. Stability of the main channel was assessed in response to bedforms, bank erosion and hydraulic friction and sediment transport. For overbank flows, rates of bank erosion have been measured. These measurements constitute unique overbank widening data for the main channel.