Seminar Series
CEE Graduate Seminars 2012
Friday, April 20, 2012, 2 PM
120 Olsson Hall
Simulation-Optimization Approach for the Design of Outlet Control
Structures for Ecological Detention Ponds
John Mobley
Abstract
This presentation will introduce a novel simulation-optimization modeling approach to modify the design of detention ponds to preserve the natural ecological flows, while satisfying the requisite regulatory flow requirements. This work utilizes an innovative ecological flow paradigm: the eco-flow statistics. The eco-flow statistics consist of nine hydrological flow statistics that have been shown to be particularly relevant to ecological quality. The statistics include annual and seasonal ecodeficits and ecosurplus, calculated using median annual and seasonal flow duration curves, and the total seasonal ecochange. A new metric called the ‘ecodifference’ is defined as the weighted sum of the nine eco-flow statistics and represents the hydrologic alteration in the stream. The ecodifference in a receiving stream can be calculated using the outflow hydrograph from a detention pond hydrologic simulator. First, a design approach- using a hydrologic model, detention pond model, and the ecodifference metric- is introduced to design a series of flow controls in a detention pond outlet control structure that reduces the ecological impact to the stream caused by development, while meeting current design regulations. Then, a simulation-optimization strategy that incorporates a Genetic Algorithm with the design approach is used to design an outlet control structure that best minimizes the ecological impact to the stream. For a case study site, optimized designs have demonstrated that improvements in ecological flows can be achieved while meeting design regulations. By introducing this approach for eco-detention ponds, demonstrating its performance, and then extending the concept to other Best Management Practices, this work has the potential to significantly impact stormwater management design practice.
The Civil Engineering seminar series is open to the University community.
Civil Engineering undergraduate students are especially invited to attend.