A management model for water quality control.

The urgency of the nation's water quality problem has compelled agencies responsible for river basin management to seek rational policies for pollution control. One essential aspect of es tablishing pollution control policies involves the determination of the de gree of treatment that should be re quired of each party discharging waste water to the river basin. Systems analysis is especially adaptable to this situation since it can be approached as a problem involving the allocation of scarce resources, viz., the assimilative capacity of the river system and the investment of capital in waste treat ment facilities. Previous solutions to this problem have been presented in various ways, but in general each study attempted to determine the degree of treatment re quired of each wastewater discharger that results in a minimum cost for the basin, while maintaining prescribed levels of water quality (i.e., dissolved oxygen). Deininger (1) has structured the problem as a linear programming model, utilizing the Thomas "step method" (2) approximation of the Streeter-Phelps equation for oxygen deficit (3). Kerri (4) has utilized mathematical programming and the concept of a critical reach to deal with the problem. Sobel (5) also used linear