基于地下水流数值模型的改进DRASTIC方法

A Groundwater-Model-Based DRASTIC for assessing aquifer vulnerability

地下水脆弱性评价作为地下水资源保护和地下水开发利用规划的一个重要工具,被广泛的应用于实际工作中。尝试利用地下水数值模型为改进的DRASTIC方法提供数据支持,并以北京市平原区为例探讨地下水脆弱性评价方法。评价结果与传统方法在高值区和低值区具有很好的对应性,而基于模型的方法在地下水水位计算、含水层介质和水力传导系数确定上较传统方法更具优势,如地下水位的计算上较传统方法更为客观地体现含水介质对地下水运动的影响,且能够方便地获得模拟期内任意时间的流场数据;经由模型调试后的含水层参数数据,较传统方法更为准确。评价结果分区之间的变化较传统方法更为平滑,更符合水文地质条件渐变的特性。

Assessment of groundwater vulnerability as an essential tool for protection and management of groundwater resources is widely used. This article uses a modified DRASTIC model, in which a groundwater flow model is used as a data supplier, to evaluate the vulnerability of the Beijing plain aquifer, and discuss the pros and cons of this new method. The results of this method and ordinary one are familiar in high-value and low-value regions. However, the new method is more competitive in calculating water table, hydraulic conductivity and mapping aquifer media. The groundwater-model-based way is more objective in describing the influence of the aquifer media on groundwater movement and the time-based water table is available. The parameters describing the aquifer media of a calibrate groundwater model is more precise than the statistics- based way. The values between the estimated regions are more smooth than the ordinary one, which is accordance with the continuity of hydrogeological conditions.