QUANTIFYING THE EFFECTS OF WATER MANAGEMENT DECISIONS ON STREAMBANK STABILITY

Streambank erosion contributes significantly to total watershed sediment yields, resulting in sedimentation of downstream reservoirs, contamination of streams, loss of productive land, and damage to infrastructure. Streambank erosion results from both natural processes and human activities, including water management activities that alter the hydrological conditions of the stream and, subsequently, the erosive forces operating on the streambank. Despite this connection, there is still little research that considers the relationship between water management and streambank erosion. Recent work developed an integrated hydrological modeling framework that can simulate both surface water operations and hydraulic erosion and applied it to the Lower Republican River Basin (LRRB), USA. Here, we extend this work to couple the established integrated hydrologic model to a module that estimates streambank stability using a factor of safety to quantify how water management decisions, particularly reservoir operations, affect streambank stability. We used hydrological and geological data from a combination of previously reported values and field measurements to verify and test this model. Once verified, this modeling framework was used to demonstrate the role water management decisions in streambank stability through different scenarios in the LRRB.