Horizontal ecological compensation for strategic water resource reserve in the Miyun Reservoir Basin

Beijing is an area with extremely scarce water resources, and the contradiction between water supply and demand is prominent. As an important surface drinking water source and strategic water resource reserve base in Beijing, it is of great significance to conduct a study on horizontal ecological compensation in the Miyun Reservoir Basin from the perspective of strategic water resource reserve in the basin. Using the synthetic storage capacity method and combining data such as the inflow volume from 2000 to 2020 and the South-to-North Water Diversion volume from 2017 to 2021, this paper calculates the water volume for strategic reserve emergency under different inflow volumes of the South-to-North Water Diversion and water supply guarantee rates. Based on the relevant values and costs of the generation, protection, and use of emergency water volume, this paper constructs a compensation index system and a corresponding model. Based on the data in 2020, this paper calculates the upper and lower limits of horizontal ecological compensation in the basin, and compares the results of willingness to pay with the spillover value of the basin. The research results show that the water volume for the strategic reserve emergency that the Miyun Reservoir should store annually should be no less than 1 billion m³. Based on the data in 2020, the lower limit of horizontal ecological compensation in the basin is calculated to be CNY 2.3663 billion, and the upper limit is CNY 11.275 billion. Haidian District and Chaoyang District have the highest sharing ratios due to their large GDP scale and high water consumption, with the lower limits of compensation being CNY 683.9 million and CNY 565.5 million, respectively, and the upper limits being CNY 3.2585 billion and CNY 2.6947 billion, respectively. The willingness to pay for ecological compensation in the beneficiary areas is still at a relatively low level, which should be improved.