Impacts of Climate Change and Human Activities on Groundwater in Spatial-Temporal Scales in Guanzhong Basin, China

Guanzhong Basin, which is located in the heartland of China, is the center for politics, economics and culture of Shaanxi Province, as well as one of the largest basins in Yellow River Basin. In Guanzhong Basin, there are many natural advantages, fertile land, developed cultural education and gathered industrial estates. In total, 13 dynasties set their capitals in Guangzhong Basin in Chinese history. However, the drought and water shortage are very severe within Guangzhong Basin especially the area of this study and groundwater plays a significant role in maintaining the production and domestic water, ecological balance, etc. According to more than 500 observed groundwater level data of the study area in nearly 30 years, the law of groundwater cycle and the evolution of stream-groundwater were analysed. Afterwards, with the application of mathematical statistics, comparison of hydrographic curves and numerical simulation technique, analysis and research were conducted on spatial-temporal evolution of groundwater dynamic field and its driving factors. The results showed that, the evolution of groundwater hydrodynamic filed, which is controlled by local stratum, geography and hydrogeological conditions, can be divided into three distinct sections in spatial scale, i.e. piedmont pluvial fan area, area near by stream and irrigation area. In temporal scale, the evolution of groundwater hydrodynamic field is affected by climate change, hydrological variation and human activity. Moreover, the factors of groundwater evolution were identified by numerical simulation, statistical analysis and other techniques. It was found that climate change dominates the evolution direction of groundwater hydrodynamic field, and the evolution progress and its variation intensity are aggravated by hydrological variation and human activity. On this basis, the negative eco-environment effects induced by evolution of groundwater hydrodynamic field were further analysed, including land subsidence and ground fissure, variation of river baseflow, change of groundwater quality, landslide and collapse, etc. All the above research findings provide not only significance for deepening research about related environmental concerns of groundwater, but also methods for analysing groundwater circulation and evolution on a basin scale.