1:5万冲洪积扇含水层水质调查方法探讨

以豫北山前冲洪积扇含水层为研究对象,探讨1:5万冲洪积扇含水层水质调查方法。该方法由工作量预部署、野外调查和取样点布设3个阶段组成。工作量预部署阶段,以前期调查资料为基础,编制工作区地形地貌、潜在污染源、地下水流场和水化学类型演变图,并赋值叠加形成不同调查点密度分区的野外工作图,宏观控制调查工作量; 野外调查阶段,重视pH值、溶解氧、电导率和氧化还原电位的测定与质量控制,根据调查区块环境状况调整调查点密度,布点兼顾地下水点与非地下水点及不同深度水点间的比例; 取样点布设阶段,以地质环境对含水层进行分区,以不同深度水井地下水功能对含水层进行分层。利用调查点现场水化学参数,识别并圈定水质变异区,分别采用判断法和均布法布设水质变异区和水质正常演化区取样点。该方法可为类似地区开展高精度地下水水质或污染调查提供参考。

Discussion on water quality survey method for 1:50 000 alluvial-proluvial fan aquifer survey

With the object of alluvial-proluvial fan aquifer in Northern Henan, the authors have set up a 1:50 000 water quality survey approach for alluvial-proluvial fan aquifer. This method consists of three stages: workload pre-deployment, field survey and sampling points setting. At pre-deployment stage, based on the preliminary survey, the authors have made research on geomorphologic landscape, pollution potential sources, groundwater flow field and hydrogeochemical type evolution and formed a field survey work map with different density zones by means of assignment and superposition, which is used for macro control survey workload. At field survey stage, measurement and quality control of the pH value, dissolved oxygen, electrical conductivity, redox, and other current hydrochemistry parameters are paid much attention to. And survey points density was adjusted according to the environment of the study area and the number of survey points was also considered with the proportion of groundwater points and non-groundwater points and different depth of water points. At the sampling points setting stage, aquifer stratifying was based on geological environment and the groundwater function of different depth wells. The water chemical parameter information of the surveyed points was also made full use of to identify and delineate the water quality variation area. The sampling points of the water quality variation area and the normal evolution area of the water quality were respectively set by judgment method and uniform method. This water quality survey method can provide some technical reference for the development of high-precision groundwater quality or pollution survey in similar areas.