EVOLUTION CHARACTERISTICS OF GOLMUD RIVER RUNOFF BASED ON SWAT MODEL

The arid northwestern China is fragile in ecological environment and is one of the most sensitive areas to global climate change. In recent years, the hydrological and ecological issues induced by the change of regional surface water runoff producing pattern have been more and more significant under the global warming. The present research took the hyper-arid Golmud River Basin on Tibetan Plateau as an example to get insights into the spatio-temporal characteristics of surface water runoff quantity evolution and its seepage infiltrating into the groundwater system of arid watershed under climate warming. It further conducted the SWAT simulation and the in-situ hydrological observed data analysis. The results show that the surface water runoff quantity of Golmud river at the mountain pass had a significant increasing trend from 1976 to 2014 with the annual average increasing rate up to 0.38 (m³·s^-1)·a^-1. The annual average increasing quantity of the surface water runoff at the mountain pass is approximately 1.66×10⁸m³. The increase of surface water runoff quantity is more significant during the summer compared to the winter. Precipitation and temperature are the dominant meteorological factors governing the surface runoff quantity in the Golmud watershed. The increase of surface water runoff quantity has significantly changed the seepage condition of surface water into the groundwater system. The annual average seepage water quantity can be up to 9.89×10⁸m³. The increase of river seepage water quantity would break the water balance of the regional groundwater system and trigger a series of hydrological and ecological issues, and furtherly threaten the sustainable development of the watershed. This study can provide scientific supports for our country to cope with the challenges of water resources and ecological environment in arid regions by global climate change.