ABSTRACT
This chapter concerns the development of an ecological model which attempts to integrate several different aspects of water quality into a single framework, in order to be able to quantify the relative contribution of discharges of various pollutants at selected points to violations of water quality standards wherever they occur. The Quality of the Environment Program at Resources for the Future has, for the last few years, been involved in the development of a residuals management model for the lower Delaware Valley. Although the Delaware Valley Residuals Management Model (DVRMM) as a whole is a fascinating and complicated machine, the linkages between the ecological model and the rest of DVRMM are of more immediate interest. The desired water quality variables which are endogenous variables in the ecosystem model are the concentration of algae, the biomass of fish, and oxygen concentration. Respiration is a function of the biomass consuming oxygen, the temperature, the oxygen concentration, and the concentration of toxic materials.
