大安市地下水时空动态变化分析及预测

Analysis and prediction of temporal and spatial variation of groundwater in Da'an City

为掌握大安市地下水的动态变化规律,更好地为社会经济服务,本文利用2000—2013年现有21口承压井水位埋深数据资料,采用ArcGIS空间分析及主成分分析法对研究区地下水动态变化规律进行分析,运用BP神经网络对地下水位进行预测。结果表明:大安市动态类型为入渗—蒸发型和入渗—开采型; 2000—2010年枯水期水位变幅较小,丰水期前五年的变幅小,后五年北部和南部部分地区的水位下降变幅较大,这表明近些年以来,大安市大规模地开采地下水,导致地下水位逐年下降且变幅较大,局部已形成较明显的降落漏斗。通过主成分分析法得到的地下水驱动力最大为农业灌溉开采,采用BP神经网络预测得出地下水水位仍然呈现一定的下降趋势,因此在农作物灌溉时期要发展地下水灌溉与地表水渠灌相结合的方式,提高水资源综合利用效率,严格控制地下水超采的行为,合理开发地下水资源。

In order to understand the law of the dynamic change of groundwater in Da an City,the law of the dynamic change of groundwater within the study area is analyzed with the methods of ArcGIS spatial analysis and principal component analysis in accordance with the data of the water level buried depths of the existing 21 artesian wells from 2000 to 2013,and then the groundwater level therein is predicted with BP neural network.The result shows that the dynamic types of groundwater in Da an City are the type of infiltration-evaporation and the type of infiltration-exploitation.From 2000 to 2010,the amplitudes of the variation of the groundwater level are smaller during dry seasons,while the amplitudes are smaller during the wet seasons in the first five years and larger in some of the northern and southern parts of the city in the last five years.It is indicated that the large scale groundwater exploitation in Da an City leads to the continuous decline of groundwater level with larger amplitude of variation year by year,while more obvious cones of depression are locally formed.The largest driving force of the variation of groundwater obtained through the relevant principal component analysis is the exploitation for agricultural irrigation,while the groundwater level predicted from BP neural network still exhibits a certain trend of decline.Therefore,not only the mode of combining groundwater irrigation with surface water irrigation is necessary to be developed during the irrigation of agricultural crop,but the efficiency of the comprehensive utilization of water resources is necessary to be enhanced along with strict control of the excessive exploitation of groundwater and reasonable development of groundwater resources.