Linear programming applied to water quality management

Linear programming is applied to the management of water quality in a river basin. The charge is to select the efficiencies of the treatment plants on the river that will achieve the dissolved oxygen standards at a minimum cost. The objective function is structured in terms of the costs of the treatment plants. The principal constraints prevent violation of the dissolved oxygen standards. A simplified version of the Willamette River in Oregon is studied, using the linear programming formulation, and the results are compared with those obtained by dynamic programming. The effects of changes in the dissolved oxygen standards are explored by use of the dual variables.