Comprehensive Benefit Assessment of the Middle Route of South-to-North Water Diversion Project Based on Markowitz Theory

In order to maximize the water utilization rate of the complex water diversion projects at different times and in different regions, this study takes the actual benefits from 2015 to 2021 in Beijing, Tianjin, Hebei province and Henan province in the water receiving areas of the middle route project as the basis, and selects nine representative indicators regarding social, economic and ecological benefits. Then the Markowitz theory in economics is used to calculate the combination of water allocation for the project to achieve the maximum comprehensive benefits, and a Markowitz model for water conservancy projects is built. The results show that the maximum comprehensive benefits of the project are achieved when 79.9% of the transferred water is used to produce social benefits, 15.8% to produce ecological benefits and 4.5% to produce economic benefits.