CONTROL-UNIT-BASED ANALYSIS OF THE ECOLOGICAL RESTORATION MEASURE SYSTEM AND ARRANGEMENT OF THE XIAONANHAI LAKE WATERSHED IN HUBEI PROVINCE, CHINA

Abstract

To deal with the water environmental degradation and ecological damage of the Xiaonanhai Lake watershed in Songzi City of Hubei Province, China, this study first divided the watershed into 32 control units according to the administrative division and catchment zones, then analyzed the pollution source and load and calculated the water environmental capacity of the watershed with the water environment system model coupled by the Soil and Water Assessment Tool model and the MIKE 21 model. To better deal with different pollutants and divide the responsibility more efficiently, the study proposed a control-unit-based system of five ecological restoration measures including the three-stage constructed wetland, the natural wetland, the clean water corridor, the Lakeshore buffer zone, and the emerged and floating plant belt. Finally, the performance evaluation of these measures was conducted under the "Dual Control" system of concentration control and total load control of pollutants. The result proved that the five measures could effectively reduce the total amount of COD, TN, TP, and NH3-N to improve the water quality, meeting the Surface Water Class III Standard.