Abstract: The discharge of waste water and sewage in many cities in China continues to increase along with the rapid economic and social development, resulting in excessive pollutants in rivers and lakes and the deteriorating water ecological environment, which in turn hinders economic and social development. The basic theories and key technologies for water system connectivity in Zhongshun Protection Demonstration Site as a case study are studied in this paper with flood control and storage, agricultural water supply and water environment improvement as targets. Results demonstrate that: 1) with flood control and storage as major target, scheme 1 is the optimal with its average inrush capacity 100 000 m³ smaller than the current situation; 2) with agricultural water supply as major target, scheme 3 is the optimal solution with the water diversion volume increasing by 3.81 times; 3) with water quality improvement as major target, scheme 2 and scheme 3 are the optimal, with 90% of the overall water exchange period shortened by 58.17%. In addition, countermeasures and suggestions are put forward corresponding to the flood control and drainage safety in Zhongshun Protection, the water environmental problem brought about by urbanization, and the lack of unified dispatch and management of water conservancy projects. The research findings offer theoretical basis and technical support for the comprehensive improvement and restoration of Zhongshun Protection, water ecological protection and other projects.

Key words: water system connection, flood control and storage, agricultural water supply, water environment improvement, Zhongshun Protection