Abstract: Since the 1990s, seasonal emergency of water pollution has occurred frequently in reservoirs on Maotiao River. To understand the mechanism of water quality deterioration, the investigation of Baihua Reservoir was carried out from July 2007 to June 2008. Water temperature, dissolved oxygen (DO) and nutrients were monitored once a month. The water quality analysis simulation program (WASP) was used to simulate water temperature, DO and NH⁺ ₄ . Simulation results fitted well with the monitoring values, indicating applicability of the model. Furthermore, the inflow of the reservoir was regulated within the model. The result shows that efficient seasonal flow regulation plays an important role on the improvement of DO level in the seasonal oxygen-deficiency period.

Key words: flow regulation, seasonal emergency pollution incident, water quality simulation, water stratification, Baihua Reservior