Quantifying the Effects of Water Management Decisions on Streambank Stability

Abstract

Streams continuously change due to natural processes and human activities, significantly affecting streambank erosion and stability. These changes cause severe environmental issues, including sedimentation of reservoirs, contamination of streams, loss of productive land, and damage to infrastructure. Many factors affect streambank erosion and stability, including hydrological conditions of the stream and streambank environment, which are often controlled by environmental structures and water management decisions. Much is known about hydrology and water management, as well as hydrology and streambank stability. However, there is still little research that considers the connection between water management and streambank stability. The objective of this work is to quantify how water management decisions, particularly reservoir operations, affect streambank stability. A module was developed to estimate streambank stability using a factor of safety approach and uses results from an established integrated hydrologic model to characterize hydrologic conditions. This module is validated and then demonstrated using model results from the Lower Republican River Basin in Kansas, USA. Results applied at the LRRB indicated that several water management decisions may negatively affect streambank stability by changing pore water pressure, the weight of the streambank soil, and the status of erosion.