On the Monetary Value of an Ecological River Quality Model

A problem widely discussed in the field of water resources research is the degree of complexity a water quality model should have if it is used for water quality management. In the present work this problem is investigated by means of an example: An optimal control problem for river quality is solved for both a simple Streeter-Phelps model and a more complex ecological model. Through decision theoretical arguments it is shown how the two optimal solutions can be compared in a rational way. As in previous IIASA reports on the application of systems theory and operations research to river quality management, the methodologies described are applied to a section of the Rhine River in the Federal Republic of Germany