Effects of the water level change of Poyang Lake on characteristics of water quality

By analyzing the hydrologic and water quality monitoring data of typical stations of Poyang Lake, the objectives were to describe the characteristics of water quality in water level changes. The results indicated that: the average water level of Poyang Lake showed downward trend, further more, water level amplitude of Poyang Lake was increasing in recent years; the concentrations of NH₃-N and COD_Mn at typical stations were obviously negative correlation with the level change, the water quality of dry season was worse than rainy season. Based on the Hydrodynamic and water quality coupled model of Poyang lake modeling the water quality in stable water level, it´s showed that in the situation of stable stage pollutants enrich in estuary easily and are difficult to discharge to the downstream.