Estimation of long-term river discharge and benefits evaluation of ecological water conveyance in Ertanggou basin from 2000 to 2020

Given the current ecological degradation in the inland arid river basins of our country, ecological water conveyance has increasingly become a critical measure to alleviate the pressures of water scarcity on ecosystems and to promote regional sustainable development. The Ertanggou watershed in Xinjiang was selected as the study area. This study utilized Remote Sensing Hydrological Station (RSHS) technology to calculate river discharge for typical cross-sections in the Tulufan Ertanggou basin from 2000 to 2020. The study also analyzed the impact of ecological water conveyance on different land types using land cover type data to assess the benefits of ecological water conveyance. RSHS technology offers reliable data support for estimating river discharge and evaluating ecological water conveyance. The average annual growth rates of the river basin discharge at the study sections are 0.36%, 1.2%, and 0.77% respectively from 2000-2016. All monitored river sections were glacial meltwater-dominated, and the accelerated melting of glaciers caused by climate warming was the main reason for the increasing trend. From 2016 to 2020, ecological water conveyance provided an average of 0.61 × 108 m3 of ecological water per year, with up to 10% water conveyance efficiency. Reservoir development and river training have significantly increased this efficiency. The ecological water supply was significantly correlated with changes in landscape patterns, such as cultivated land, grassland, and water bodies in the downstream area. The water area expanded by 6.14 × 105 m2, while cultivated land increased by 32.98%. It is evident that ecological water conveyance effectively promotes land use optimization and ecological balance. This study will provide new ideas for evaluating the benefits of ecological water conveyance in inland arid basins with limited data, offering theoretical support for future ecological water conveyance projects.