Probabilistic models for predicting stream quality

Abstract

Mathematical models are developed to predict the probability distribution of minimum dissolved oxygen concentrations occurring downstream from any particular wastewater treatment facility. Each of the models is based on different assumptions of average daily stream and sewage flow conditions. Using a hypothetical example, distributions of minimum dissolved oxygen concentrations in a stream are determined for 1, 2, and 3 consecutive‐day periods. Knowledge of the cost required to reduce the probability of having less than some desired level of stream quality for various consecutive‐day periods can be used as a basis for selecting the degree of wastewater treatment as well as for establishing more realistic stream quality standards. (Key words: Quality of streams; probabilistic models) Copyright 1966 by the American Geophysical Union.