[关键词]
[摘要]
为实现石川河地下水位的有效回升进而维持采补平衡,需在该区实施地下水人工补给工程,并确定合理的 补给位置及有效的补给方式。选取地下水埋深、坡度、含水层厚度、含水层渗透系数、与环境敏感区距离和给水 度 6 个指标,运用空间分析技术对人工补给地下水地点适宜性进行评价;在此基础上建立三维地质模型分析典型 人工补给潜力区的地层结构,探索可行的地下水人工补给方式。结果表明:适宜进行人工补给的高潜力和较高潜 力区域主要分布在研究区中部及东南部,面积达 48.01?km2,占研究区总面积的 32.0%。建议:在石川河河道中上 游高潜力和较高潜力区域的北部修建地表入渗池或渗坑;在河道中上游高潜力和较高潜力区域南部和河道中下 游的较高潜力区域布设反滤回灌井群;可沿石川河河道中上游高潜力与较高潜力区域之间布置一条长约 4.5?km 的渗渠,利用河道进行入渗补给。研究结果可为地下水库的修建提供参考。
[Key word]
[Abstract]
The Shichuan River Valley is located in the hinterland of Guanzhong, and due to the shortage of surface water resources, groundwater is an important source of supply for the area. The long-term imbalance of groundwater extraction and replenishment led to multiple landing funnels in the area, resulting in the drying up of submerged aquifers on a large scale and the loss of ecological service function value of rivers. Artificial recharge is an important measure to solve the contradiction between water supply and demand in the area, prevent and control groundwater overdraft, and conserve water resources. The large underground storage space in the area provides favorable conditions for artificial groundwater recharge. The study relies on the Shaanxi Water Conservancy Science and Technology Project, through field investigation and collection of information covering topography and geomorphology, hydro-meteorology, river system, stratigraphic lithology, hydrogeological conditions and current status of groundwater development and utilization in the study area to provide a supporting basis for the subsequent study of artificial groundwater recharge.The artificial recharge conditions in the study area were comprehensively analyzed, and according to the basic principles of index selection, six indexes of groundwater table depth of burial, slope, aquifer thickness, distance to environmentally sensitive areas, aquifer permeability coefficient, and water supply degree were selected for graded scoring. Then, the AHP method was used to calculate the subjective weights and the CRITIC method to calculate the objective weights, respectively. After that, the subjective weights and objective weights of each index were combined using the formula to obtain the coupling weights. Based on the determination of weights, the raster data of each index was overlaid and calculated using ArcGIS spatial analysis technology to obtain the recharge potential scores of each area of the Shichuan River groundwater reservoir, and established a recharge suitability evaluation system that fit the characteristics of the area to determine the site selection of the recharge area. On this basis, a three-dimensional geological model of the study area was established by combining the borehole data and geological profiles, and the spatial structure and stratigraphic characteristics of the regional submerged aquifer were analyzed and studied to determine the characteristics and layout requirements of each recharge process and to select the most suitable recharge mode for the area. The results showed that the high potential area suitable for artificial recharge was concentrated in the central and western parts of the study area, with an area of 16.49 km2, accounting for 10.99%; the higher potential area was scattered, mainly in the northeast and southwest of the high potential area and the southeast of the study area, with an area of 31.52 km2, accounting for 21.01%; the medium potential area was widely distributed, mainly in the northwest and most of the southeast of the study area, with an area of 68.75 km2, accounting for 45.83%. Both high potential and higher potential areas can be the primary choice for recharge sites for recharge, with medium potential as a supplemental area. Among them, it was appropriate to construct surface infiltration ponds or seepage pits in the northern part of the high potential and higher potential area in the middle and upper reaches of the Shichuan River channel; reverse filtration recharge well clusters can be placed in the southern part of the high potential and higher potential areas in the middle and upper reaches of the river and in the higher potential areas in the middle and lower reaches of the river; a seepage canal about 4.5 km long can be arranged along the middle and upper reaches of the Shichuan River channel between the high potential and higher potential areas to use the river channel for infiltration recharge. The results of the study can provide a reference for the construction of underground reservoirs.
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[基金项目]