A Cost-Optimization Tool for Stormwater Management Plans Using Green Infrastructure Practices

Green infrastructure practices (GIPs) are a set of design principles, practices, and engineered devices that capture and treat stormwater runoff at its source using natural processes such as infiltration and evapotranspiration. Green infrastructure can reduce the effects of increased impervious area associated with land development by reducing the amount of runoff generated on a site and improving the water quality of the runoff. A methodology was developed using the runoff reduction method to size media-based GIPs and select the minimum cost site design. For most developments, green infrastructure practices alone are not adequate for attenuation of peak runoff flows to pre-development levels for large rain events and conventional stormwater management devices such as detention basins must be used to control runoff flows. The storm water management model (SWMM) was used to generate pre-development and post-development hydrographs for an example application and calculate design criteria for a detention basin. A cost optimization model was developed using the general algebraic modeling system (GAMS) for the design of a detention basin. This analysis was part of an ongoing research effort to develop techniques for green infrastructure cost optimizations, and the results were consequential in the development of a planning-level optimization tool for stormwater management.