MATHEMATICAL MODEL FOR DISSOLVED OXYGEN IN THREE SOUTHERN ONTARIO RESERVOIRS

A mathematical model for dissolved oxygen has been developed and applied to three reservoirs in the Grand River System in Southern Ontario. The modelling approach is to calibrate its predictions of vertical transport using temperature and its predictions of dissolved oxygen using biochemical data from one reservoir and then to attempt model verification using the remaining two reservoirs. Input-output material and hydrological budgets were made for two years. Measurements of hypolimnetic water column respiration (WCR) and sediment oxygen demand (SOD) were made for one year. WCR is approximately 0.2 mg/L-day while SOD is approximately 0.5 mg O2/m2-day. Using a vertical one-dimensional, wind-driven temperature model, model predictions agreed with observations to within 2 °C during stratification in 1978. During 1979, predictions are significantly improved due to the use of better wind data. Estimation of decay in the oxygen model is based upon mass inputs of phosphorus to the reservoirs and internal phospho...