Integrated approach of hydrological and water quality dynamic simulation for anthropogenic disturbance assessment in the Huai River Basin, China.

Detailed depiction of hydrological process and its associated pollution processes plays a critical role in environment improvement and management at basin scale. It also provides a useful tool to assess impact of potential factors on hydrological and water quality conditions. However, it was still difficult to well capture some typical characteristics of these complicated processes including built-in nonlinearity and time-variation, water infrastructure regulations, particularly for highly regulated basins. In this study, an integrated approach of hydrological and water quality dynamic simulation was proposed to solve these difficulties and assess the impacts of several anthropogenic disturbances. The Huai River Basin which was highly disturbed and seriously polluted, was selected as the study area. The main anthropogenic activities considered were point source pollution emissions, diffuse pollutant losses and dam regulations. Results showed that the integrated simulation could well capture the variations in water level, water discharge, concentrations of permanganate index (COD) and ammonia nitrogen (NH-N) in high (2007), normal (2008) and low (2004) flow years at 15 stations in the upper and middle streams of Huai River Basin. The regulation rules of downstream sluices played negative roles on water quality improvement if keeping current pollution sources, while those of middle stream sluices played positive roles on water quality improvement. However, the water quality deterioration was mainly attributed to emission of point source pollution (12%-43%), followed by diffuse pollutant loss (0-23%) and water quantity-oriented dam regulation (-29%-20%). The study was expected to provide technical supports for the implementation of water pollution control and sustainable water resources management in the Huai River Basin, and give a reference of integrated hydrological and hydrodynamic simulation.