Assignment #6

Behera, P, Papa, F., Adams, B (1999) “Optimization of Regional Storm-Water Management Systems” Journal of Water Resources Planning and Management, 125(2) pp. 107-114

Summary:
In this study, the authors developed a methodology (using dynamic programming) to optimize the design and configuration of a storm-water management system for single-storm events in land development applications, primarily with the use of detention basins that regulate flows. Overall, the objective of the model is to determine a way to minimize the cost associated with the development of the storm-water management plan while still meeting environmental constraints such as peak discharge requirements and water quality parameters. The model is applied on an entire watershed basis such that the optimal locations and configurations of many detention basins can be applied such that the overall discharge from the watershed meets the requirements. Decision variables in the model include the active volume of water contained in each detention basin, the volumetric release rate from the pond, and the depth of the pond. The objective function is applied with associated costs for construction of the basin and land area taken by the pond (which relate to the decision variables). Finally, the system constraints were applied such that the water quality/quantity parameters could be met.

The initial simulation, the modeling considered only a single catchment of the watershed with one detention basin (and meeting optimum water quality/quantity parameters). Subsequent to this operation, the authors considered overall basin configurations with multiple basins (in this case a three catchment configuration). For this application, they added quality and quantity constraints such that the total outflow from all basins would meet requirements. In this application, they utilized a dynamic programming model that would allow for them to determine the overall minimum cost by considering each basin (stage) separately in decision making.

Discussion:
Overall, I thought the approach of the authors seemed to be valid for the system. It was interesting to see a direct application for linear programming, and reading the article can help me think of other applicable situations, such as river water quality modeling for point sources (determining where to force waste generators to meet higher levels of treatment).