降水、河流径流量与开采对西安地区潜水流场影响分析

An analysis of the variation in groundwater flow field affected by precipitation,runoff and exploitation in Xi'an

为定量分析降水、径流和开采对西安地区潜水流场影响程度,应用小波变换、最小二乘相关分析等研究方法,对区域平均地下水位,水源地漏斗中心水位及漏斗面积与降水、径流和开采变化之间的特征进行了研究。结果表明:1986—2010年期间,平均地下水位随降水量的增大呈线性函数递增趋势,降水量每增加100 mm,平均水位上升0.77 m,漏斗中心水位变化速率随降水量的增大呈直线下降趋势,年均降水量每增加100 mm,漏斗中心水位上升0.7 m(灞河水源地)、0.27 m(沣皂河水源地)和0.14 m(渭滨水源地);1986—2010年期间,径流量每增加1×10~8m^3,区域平均水位上升0.9~1.98 m,漏斗中心水位上升0.32~2.36 m,漏斗面积减小0.019~13.2 km2;1998—2010年期间,地下水开采量每增加0.1×10~8m^3,区域平均水位降幅达1.14~5.37 m,水源地漏斗中心水位降幅0.94~5.76 m,漏斗面积扩大0.44~27 km2;关联度分析表明,降水、开采是西安地区潜水流场变异的主导因素。

In order to accurately identify the influence degree of precipitation, runoff and exploitation on the groundwater flow filed in Xi＇ an, methods of Wavelet Transform and correlation analysis of least square are used to examine the interactive features between the average groundwater levels, the central levels of groundwater wellfields and the area of groundwater depression cones, and the precipitation, runoff and groundwater exploitation in the study area. The results indicate that during the period of 1986--2010, the average groundwater level shows a linear increase trend with the increasing precipitation. Every increase in precipitation by 100 mm results in a raise of the average groundwater level by 0. 77 m. The central level shows a linear downward trend with the increasing precipitation, every rise in precipitation by 100 mm results in a raise in the drawdown of the central level by 0.7 m （the Bahe wellfield） , 0.27 m （the Fengzao wellfiled） , and 0. 14 m （the Weibin wellfield）. During the period of 1986--2010, evey increase in runoff by 1 billion cubic meters results in a rise of 0.9 - 1.98 m in the average groundwater level, a rise of 0.32 - 2.36 m in the central level and a decline of 0. 019 - 13.2 km2 in the area of groundwater depression cone. During the period of 1998--2010, every increase in groundwater exploitation by 0. 1 billion cubic meters results in a decline in the average groundwater level by 1.14 - 5.37 m, a decline of 0.94-5.76 m in the central level and a increase of 0.44 - 27 km^2 in the area of groundwater depression cone. Precipitation and exploitation are identified as the main influence factors for the changes in the water flow field by using grey relational analyses.