| Abstract: | Atmospheric reaeration is a natural mechanism of oxygen transfer from the atmosphere to a water body. In practice, stream water quality models are developed with reaeration coefficients (K2) estimated by predictive equations. This leads to uncertainties in modeling analysis because these equations are empirical in nature and may yield greatly different K2 values for the same stream. Values of K2 may be adjusted in model calibration, but unfortunately, values of other model parameters are no less easy to identify and require adjustment in model calibration as well. Therefore, validity of a stream model would be enhanced significantly if K2 could be determined directly and reliably. In this research, values of K2 in the Canandaiqua Outlet in Central New York have been measured by using a gas tracer method. A successful modeling analysis was conducted using these K2 values. As a result, effluent limitations of several waste water discharges into the Outlet were established. It was concluded that field measurements of reaeration rate would improve modeling results significantly, and that the gas tracer method can be easily incorporated into intensive water quality surveys normally required for stream modeling. |
