Simulation-Optimization Methodology for the Design of Outlet Control Structures for Ecological Detention Ponds: Fid-Bau Portal

Simulation-Optimization Methodology for the Design of Outlet Control Structures for Ecological Detention Ponds

Mobley, John T. / Culver, Teresa B. / Hall, Thomas E.

This work presents a new paradigm for the design of stormwater detention basins. Through simulation and optimization, this work seeks to find the design of a detention basin outlet control structure that reduces the ecological impairment to downstream water bodies. Ecological impairment is measured using the ecodifference, a metric that represents the hydrologic alteration in the stream. The ecodifference is defined as the weighted sum of the eco-flow statistics, nine hydrological flow statistics that have been shown to be particularly relevant to ecological quality. In this simulation-optimization methodology, a genetic algorithm (GA) is combined with a hydrologic simulator of a detention pond. The GA is used to design the openings in the outlet control structure that minimizes the ecodifference. Constraints are used to meet current municipality design regulations. The simulation-optimization methodology is been applied to a case study site, and resulting designs demonstrate that improvements in ecological flows can be achieved via alteration of two to four outlet control openings, while meeting design regulations. The ecodetention ponds designed here primary improve the low flow series. Applying this ecological design approach to alternative volume-reducing best management practices could further improve the ecological flow series.