Water quality control is similar in many ways to other managerial enterprises in our society. In particular, costs as well as benefits are associated with every program for water quality management. If such programs are to be planned rationally, costs and benefits should be analyzed whenever possible. The Delaware Estuary is an example of such an environment. It is studded with tributaries, waste discharges, reaches whose volumes can be changed by dredging, other factors which affect water quality and other alternatives to control water quality.