Using Computational Fluid Dynamics (CFD) and a one-dimensional lake model (DYRESM-WQ), Flow Science assisted in designing a second inlet structure for the Diamond Valley Reservoir in Riverside County, California.The design effort was focused on designing an inlet that would meet hydraulic requirements, while maximizing water quality in the reservoir. By building a submerged inlet, the analysis showed that the nutrient-rich inflow could be sequestered in the lower strata of the reservoir, thus minimizing algal growth.Flow Science evaluated several different inlet alternatives for the reservoir. The chosen design was selected on the basis of functionality, cost, flexibility, and water quality enhancement.