Simulation of water resource balance in Golmud River Basin based on mathematical models

This study develops an integrated HEC-RAS-MODFLOW model coupled with a nonlinear evaporation module to simulate the water resource balance of the Golmud River Basin, an arid inland basin on the Tibetan Plateau, from 1990 to 2017. The model addresses limitations of previous linear evaporation approaches and isolated surface–groundwater simulations by incorporating dynamic exchange processes and multi-decadal climate variability. Results indicate that river seepage constitutes 63.0% of total groundwater recharge, while groundwater levels decline at an average rate of 0.10 m/year due to combined climatic variability and anthropogenic extraction. The nonlinear evaporation module reduced simulation errors by over 15% compared to conventional linear models. Sensitivity analysis identifies hydraulic conductivity and evaporation coefficients as key parameters influencing model reliability. Under current extraction trends, groundwater discharge to terminal wetlands is projected to decrease by 50% by 2030, threatening local ecosystems. The study provides a robust modeling framework for sustainable water management in arid basins, emphasizing the need for controlled groundwater extraction, water-saving irrigation practices, and maintenance of ecological flows to mitigate aquifer depletion and wetland degradation under climate and anthropogenic pressures.