Accounting of Transboundary Ecocompensation Standards Based on Water Quantity Allocation and Water Quality Control Targets

In China, under the premise that the water quantity allocation and water quality control targets for transboundary rivers have been determined, ecocompensation between upstream and downstream areas is urgently needed in management practice when targets cannot be met in the transboundary section. A dynamic accounting method for ecocompensation standards needs to be established at the scientific level. However, the accounting method of the existing ecocompensation standards is not sufficient. The purpose of this study is to propose a transboundary compensation standard accounting method based on water quantity allocation and water quality control targets and to establish ecocompensation standard accounting formulas for the Shaying River watershed. The accounting process is as follows: the water quantity compensation standard in different water quantity scenarios is calculated from the perspective of the water resource value. By using the comprehensive pollution index method, the water quality compensation standard is calculated in different water quality scenarios, and the ecocompensation standard calculation formulas for watersheds are determined. As an application, 27 types of ecocompensation standard formulas for the Shaying River watershed were determined for 3 hydrological frequencies (50%, 75% and 95%), 3 water quantity scenarios (equal-quantity, excess-quantity and reduced-quantity discharging) and 3 water quality levels (equal-quality, inferior-quality and better-quality discharging). The results not only provide a compensation standard for the Shaying River but also provide a reference for the calculation of ecocompensation standards for other transboundary rivers in China with definite water quantity and water quality management objectives.