Extraction of water quality information from field data using mathematical models

The purpose of this study was to develop mathematical models which can be used to extend limited field data on water circulation and effluent dispersion. Two models were developed and tested; the "Circulation Model" and "Effluent-Dispersion Model." The Circulation Model predicts the currents throughout a specified time and throughout a vertically well-mixed two-dimensional embayment from a knowledge of the tide heights or currents at the open boundaries of the embayment. The Effluent Dispersion Model predicts the concentration of wastes in space and time using the quantities of wastes discharged at the source locations and using the circulation currents in the embayment. For the case in which insufficient current data exists, the capability of using the two models in tandem (i.e. the outputs of the Circulation Model used directly as inputs to the Effluent Dispersion Model) was developed. Both models were applied to a pilot waterway, the West Passage of Narragansett Bay, to identify their operating characteristics and to demonstrate the veracity of their predictions. Results of these tests are presented, and demonstrate encouraging evidence that the models give accurate predictions.