Analyzing Hydrological Regime Variability and Optimizing Environmental Flow Allocation to Lake Ecosystems in a Sustainable Water Management Framework: Model Development and a Case Study for China’s Baiyangdian Watershed

Abstract

This study analyzed the variability of the hydrological regime in a Chinese watershed and in the available water resources and used this data to develop an optimal environmental flow allocation model that lets decision-makers work towards sustainable management of the watershed’s water resources. First, historical hydrological data was analyzed to determine its statistical parameters, flow duration characteristics, and trends based on data from two gauging stations (at the West Dayang and Wangkuai reservoirs) from 1956 to 2000 and data for Baiyangdian Lake from 1950 to 2005. The monthly and annual inflows and lake water levels were found to be highly variable. The optimization model that was developed for environmental flow allocation to the lake seeks a rational balance of providing appropriate environmental water to the lake, maximizing economic returns for humans, and minimizing agricultural yield losses. The appropriate quantity of environmental water was defined by minimizing the difference between the regulated and natural flow regimes. Scenario analysis then provided a range of potential management strategies for the socioeconomic, agricultural, and environmental water uses in the watershed surrounding the lake and revealed the effects of assigning different weights to these three objectives. The optimal results will help the lake’s managers to develop aquatic ecosystem restoration strategies, establish sustainable water regimes, and perform environmentally and economically sound management.