Dynamics of Groundwater in Changwu Loess Tableland and Its Determiants

Abstract

【Objective】 Groundwater is the predominant water resource for agricultural and other sectors in the loess tableland in northwestern China. Understanding its response to management and environmental changes is important to elucidate the mechanisms underlying groundwater recharges and help improve groundwater resource management. The purpose of this paper is to present a method to analyze the determinants of groundwater change in the loess tableland. 【Method】 The analysis is based on data measured from 1976 to 2017 from five boreholes in the Changwu loess tableland. Change in groundwater depth and its determinants are identified using the cross-correlation and multiple linear regression methods. 【Result】 The groundwater depth in Changwu varied between 25 and 95 m, with the variation depending on boreholes due to the difference in hydrogeological conditions and human activity between them. On average, the groundwater table had fallen from 1976 to 2017 at 0.08-0.21 m/a, with the falling rate depending on boreholes. Meteorology, vegetation and anthropogenic activities are the factors affecting both monthly and inter-annually change in groundwater depth, though the relative dominance of these factors varies with boreholes. Interannually, anthropogenic activities affected groundwater more, contributing to 74% of its depth change. Monthly, vegetation was the factor predominantly affecting groundwater, contributing to 40% of its depth change. 【Conclusion】 Increase in population, economic development and expansion of apple orchards is the factors underlying the groundwater depth change in the studied area. Our results have an important implication for sustainable development of agriculture and other industries sectors in this region.

Keywords

• changwu loess tableland
• groundwater depth
• influencing factors
• contribution