Cross-regional ecological compensation under the composite index of water quality and quantity: A case study of the Yellow River Basin

The calculation of ecological compensation (EC) constitutes the core element of the EC mechanism, which is related to the practicability of the mechanism. Based on the comprehensive index of water quality and quantity, this study establishes a measurement method for EC across administrative divisions. First, the improved Nemerow pollution index (NPI) is adopted to assess the water quality of specific sections, while the water rights and GDP indicators are employed to characterize the water quantity of each section. Secondly, given the spatial relationship of each region within the basin, two compensation allocation schemes are established referring to the water intake and grey water footprint indicators. Finally, the EC amounts of each region in the Yellow River Basin from 2016 to 2021 are calculated using the proposed method. The results show that: (1) the improved NPI is significantly higher in the upstream than in the downstream, implying better water quality in the upstream region; (2) From 2016 to 2021, both Gansu and Ningxia exhibit negative EC coefficients, suggesting superior water quality in the upper section of these regions, while Henan Province demonstrates the opposite trend; (3) During the same period, Qinghai, Gansu, Shanxi, Shaanxi, and Shandong experience an EC deficit, while Ningxia, Inner Mongolia, Henan, and Yellow River Conservancy Commission exhibit an EC surplus. Using water quality and quantity indicators, this study includes the implementation of basin unification and regional environmental comprehensive management into the scope of responsibility of the basin government, which can effectively solve the drawbacks of unclear responsibilities of stakeholders and ineffective implementation of compensation in the basin EC.