Document Type



Virginia Institute of Marine Science

Publication Date



Two water quality models of the Pagan River were developed in the 1970s by the Virginia Institute of Marine Science. The first model was developed under the CSA (cooperative state agencies) program (Kuo, Lewis and Fang, 1976). It simulated the oxidation of organic matter and the effect that, and reaeration, had on the dissolved oxygen regime of the river. The model included four water quality parameters: salinity, dissolved oxygen, carbonaceous oxygen demand and nitrogenous oxygen demand. A later model, developed as part of the Hampton Roads 208 studies, was an expansion of the first one. It included the nitrogen and phosphorus cycles, algal dynamics, and fecal coliform bacteria. It was calibrated and verified with field data collected in the summer of 1976 (Rosenbaum, Kuo and Neilson, 1977). Both models have been used by the Virginia Water Control Board in the establishment of permit limits for point source discharges to the river.

Since the model study, the two major point source dischargers, the Smithfield Packing and Gwaltney, have improved their waste treatment facilities. As a result, it is expected that the river water quality condition should be significantly different fran that in 1976, with which the model was last calibrated



Water quality -- Virginia -- Pagan River -- Mathematical models