Three-Dimensional Modeling of the Hydraulic Function and Channel Stability of Regenerative Stormwater Conveyances

Abstract

Regenerative stormwater conveyances (RSCs) are an innovative approach to repairing local channel incision at stormwater outfalls while simultaneously treating stormwater runoff, providing groundwater recharge, and establishing floodplain connectivity. Although RSCs are increasingly being utilized for watershed restoration, little research has been performed on these systems. This study uses the commercially available computational fluid dynamics program, FLOW-3D version 1.1 developed by Flow Science, Inc., and hypothesizes that RSC system design can be improved to maximize velocity and energy dissipation while minimizing erosion potential. Results found that it is possible to create a strategically designed system that maximizes velocity and energy reductions, providing insight that is currently lacking regarding the design of RSCs. Overall it was determined that lower length to width (L/W) ratios are preferred for reducing velocities and energies, and study results suggest designing with a L/W pool ratio of .7. It was also found that the design of the first two pools of the system appears to be most critical for dissipating erosive flows and that a minimum number of pools is necessary to adequately reduce velocities and energy before discharging to the receiving stream. These findings are beneficial to the design community as they allow a better understanding of how RSCs function and how manipulation of system geomorphology can improve stability.