Optimization model to determine cost-effective, low impact development strategies to achieve designated stormwater flows.

摘要

he research developed a tool that engineers and developers can use to optimize the use of low impact development (LID) strategies to reduce urban runoff at the lowest cost. LID is an alternative comprehensive approach to stormwater management that incorporates best management practices (BMP) that reduce the impacts of runoff on surface water quantity and quality. LID has the goal of maintaining and enhancing the hydrologic regime of developing urban watersheds and can be used to address a wide range of runoff issues. For this research, a pilot study was conducted on a sub watershed inside the campus of Tennessee Technological University (TTU), Cookeville, Tennessee. This area was analyzed for watershed catchments, discharge points, and the various types of development such as sidewalks, parking lots, buildings, parks, etc. Data were collected for rainfall and runoff volumes for the campus. The objectives of this research were develop a program to determine the optimized combination of LID practices applied to the TTU campus to reduce flow of stormwater runoff at the lowest cost. The simulated annealing algorithm (Kirckpatrick, 1983) was used as the optimization component for the program. The hydrologic model selected for the study catchment was HEC-HMS and the NRCS Curve Number (CN) method was used for the loss method in the hydrologic model. The modified CN method, developed by McCuen (MDE, 1983), was used to determine the CN for land uses applied with an LID treatment. The CN constraint set for the study watershed was a CN of 78, which was based on reducing the stormwater runoff depth by an average of one inch (25.4 mm) for a wide range of storm events. The LID optimization model was run for the study watershed and produced the amount of LID strategies to implement to achieve the CN constraint of 78 at an estimated capital cost of