Selecting Non-Point Source Pollution Treatment Practices Using Linear Optimization

This paper provides a case study application of a linear optimization program as a water quality management tool. The optimization program seeks to minimize the cost of nonpoint source pollution control by selecting the best combination of pollution control management practices for Hampton, Virginia. The management practice options are grass swale roadways, porous pavers, ponds, detention basins and fertilizer management education. Management practice selection is limited by constraints on land-use and water quality. Pollutants evaluated are total nitrogen, total phosphorus, suspended solids, fecal coliforms and biochemical oxygen demand (five-day). The value in the water quality constraints for pollution loading on all the land area is reduced in 10 percent increments from 10 percent to 60 percent pollution removal. Each pollution reduction level produced a set of optimum management practices and costs. The data for each pollutant are examined for diminishing marginal returns and management practice selection trends. The cost for each percent of pollution removed increases between 40 percent and 50 percent removal levels for all pollutants except biochemical oxygen demand. The management practice and land-use combinations recommended for each pollutant are similar