Evaluating Groundwater Resource and its Distribution in Jinghe Basin Using the SWAT Model

Abstract

【Background and objective】 Continuously pumping groundwater over the past half century for crop production in northern China has resulted in a series of environmental and ecological issues. The shortage of freshwater resources has become a bottleneck in socioeconomic development of this region. Improving groundwater management is important not only to its sustainable use but also to keeping ecosystems in this region function. Achieving this goal needs to understand how groundwater dynamics responds to environmental changes, as well as its consequent spatial distribution. The objective of this paper is to demonstrate how the SWAT model can be used to evaluate groundwater resource and its spatial distribution at regional scale. 【Method】 We took Jinghe basin as an example. Groundwater flow, surface runoff and their underlying driving factors were simulated using the SWAT model. Monthly measured runoff from hydrological stations at Jingchuan, Yangjiaping and Zhangjiashan was used to calibrated the model parameters; the calibrated model was then used to evaluate changes in groundwater depth, shallow groundwater resource, as well as extractable groundwater in the basin. 【Result】 The calibrated model correctly reproduced the groundwater dynamics in the basin, with R2 and NS between the measured and simulated runoff being 0.83 and 0.71, respectively. The distribution of shallow groundwater depth varied widely in the basin, but it has been in decline. From 2009 to 2016, the shallow groundwater resource had reduced by 6.59 billion m3, decreasing at an average rate of 0.051 billion m3/month. We found that the average recharge rate to the groundwater in the basin was 0.344 billion m3/a, the average subsurface runoff modulus was 0.21 L/(s·km2), and the extractable groundwater resource was 0.189 billion m3/a. 【Conclusion】 The SWAT model is capable of modelling regional surface runoff and shallow groundwater dynamics. It can be used to evaluate groundwater resources and the response of groundwater dynamics to environmental change.

Keywords

• jinghe river basin
• swat model
• spatial groundwater distribution
• groundwater resource evaluation