The role of water management and river morphology on stranding pool formation

Fish can be stranded in pools during flow recessions that may occur naturally or as a result of dam operations. Past studies have recommended dam operation guidelines that only consider water surface elevation (WSE) recession rate to reduce fish stranding potential. Here, we holistically consider the role of flow, WSE recession rate, and river-floodplain topography under unregulated and regulated flow regimes to predict the potential of stranding pool formation. The proposed methodology leverages advances in two-dimensional (2D) surface hydraulic (HD) modeling and high-resolution topobathymetric LiDAR surveys. We applied this method to the South Fork Boise River (SFBR), Idaho, USA. We developed a 2D HD model supported by meter-resolution topobathymetric data to simulate channel and floodplain hydraulics and stranding pool formation for different flow scenarios.