Abstract: The governance and protection of lake and river water environment require the consideration of both the quantity and quality of water to preserve ecological flow. In this study we examine the Xinzhou segment of the Jushui River, a tributary of the Yangtze River, using the MIKE11 software to develop a water quantity and quality model. The model was calibrated using measured data and data from pollution source investigations. The model measured the main pollutants including COD, NH₃-N, TN, and TP, and established the water demand for control sections to meet water quality standards on a monthly basis with consideration of current sewage discharge levels. In addition, we utilized the Tennant method and flow frequency curve method to calculate the ecological water demand to ensure the basic stability of the river ecosystem. By comparing and analyzing the results of Tennant method, flow frequency curve method, and the proposed model, we obtained the monthly ecological water flow for the Xinzhou segment of Jushui River.

Key words: ecological flow, MIKE11 software, Tennant method, flow frequency curve method, Xinzhou segment of Jushui River