Available Quantity of Transferable Water and Risk Analysis

Abstract

The area of the Western Route Project for South-to-North Water Transfer (WRP) in China, located in the upper reaches of the Yangtze River and the marginal area of the Qinghai-Tibet Plateau, has sufficient water resources that transfers could be considered. However, potential transfers are limited due to a fragile eco-environment. The eco-environmental water demand is the key constraint for determining the available quantity of water that could be transferred in view of the existing water demand for local social and economic development. Considering the effect on the eco-environment, this study investigates the available quantity of transferable water in the WRP for the dual purpose of protecting the local eco-environment and decreasing the crisis of water resources in the western areas by considering the water demand for river channel eco-environment downstream of the dams as the main constraint. In order to estimate the eco-environmental water demand, the low runoff and Tennant methods are studied. According to the results of risk analysis, the proposed schemes for water transfer have high reliability and low risk. The risk will be further reduced if in the future reservoirs are operated jointly.