Abstract:

It is important to further explore the nature features before the SouthNorth Water Transfer Project and hydraulic control measures on ecology protection after the project. This paper used IHA method to analyze the discharge data in Daduhe River transfer area before project,then took the monthly low flows as the characteristic flows,which was important to maintain the basic ecological river system,and used Tennant method to assess them.With taking the characteristic flow as a reference,the paper concerned the advantage to the ecosystem of the monthly average flows postproject in the stations reaches.It also calculated indirectly the monthly low flows downstream the dams and discussed the advantage to the ecosystem of monthly average flows in the dams reaches.The results show that with the restoration of flow along the way,the discharge in Chuosijia station and Zumuzu station had been restored so that the monthly mean discharge was better to the river ecology after the fist stage water transfer project.While,the monthly mean discharge downstream the dams were too low to support the normal river ecology.The river ecological conditions in the downstream of the Zhu’anda dam and the Huona dam were“very poor”under the situation of the monthly mean discharge in June after the project