太平洋典型海岛淡水透镜体特征与地下水开发利用关系分析——以Saipan海岛Ocean Vista Resort项目为例  

Analysis of the relationship between the characteristics of the freshwater lens of typical islands in the Pacific Ocean and the development and utilization of groundwater——Take the Ocean Vista Resort project of Saipan Island as an example

作　　者：赵斌 张明科 杨圣安 张雪丽 ZHAO Bin;ZHANG Ming-ke;YANG Sheng-an;ZHANG Xue-li(North China Nonferrous Engineering Survey Institute Co.,Ltd.,Shijiazhuang,Hebei 050021,China)

机构地区：[1]华北有色工程勘察院有限公司,河北石家庄050021

出　　处：《地下水》2022年第5期94-96,共3页Ground water

摘　　要：淡水透镜体是位于岛屿的地下像凸透镜一样,中间厚四周薄的淡水层,是岛礁环境的重要组成部分。以位于西太平洋北马里亚纳群岛的Saipan岛为研究区域,基于为Ocean Vista Resort酒店项目寻找稳定水源中的相关地层与构造勘探成果,综合岛上现有水文地质资料,合理概化该岛屿的水文地质概念模型,对淡水透镜体的赋存状态、取水井中氯化物的浓度变化与井位选取、淡水透镜体厚度变化规律进行分析,在此基础上对岛屿商业开发供水水源类型及供水潜力进行评价,明确限制饮用水开发可利用性的主要因素,提出Ocean Vista Resort项目水源地的开发建议。结果认为:Saipan岛上地下淡水唯一补给为大气降水,降雨随高渗透性的礁灰岩渗透到地下,并在地下向海边运移,最终在海岸带排出,形成悬浮在咸水上的淡水透镜体,淡水透镜体的形状呈凸圆状,其厚度的变化受季节性交替,岛中心位置厚,朝向海岸线方向相当薄,研究区限制饮用水可利用性的因素主要是海水入侵、井群干扰导致的地下水位降低和向海洋排泄;在为Ocean Vista Resort项目进行地下水开发时应合理布置钻孔,找出饮用淡水透镜体最厚的井的位置,确认井深没有揭穿相邻的淡水与咸水过渡带,合理选用不会造成咸水入侵的井中泵的速率。研究结果为同类型岛屿的供水水源开发提供了科学依据。The freshwater lens is located in the underground of the island like a convex lens, with a thick and thin freshwater layer in the middle, and it is an important part of the island reef environment.Taking Saipan Island in the Northern Mariana Islands in the western Pacific as the research area, based on the relevant stratigraphic and structural exploration results in finding a stable water source for the Ocean Vista Resort hotel project, and synthesizing the existing hydrogeological data on the island, a reasonable generalization of the island’s Hydrogeological Conceptual Model. The occurrence state of the freshwater lens, the change of chloride concentration in the water intake well and the selection of the well location, and the change law of the thickness of the freshwater lens are analyzed.On this basis, the water source types and water supply potential for commercial development of the island are evaluated, the main factors limiting the availability of drinking water development are clarified, and the water source development suggestions for the Ocean Vista Resort project are put forward.The results suggest that the only supply of underground freshwater on Saipan Island is atmospheric precipitation, which infiltrates into the ground with the high permeability reef limestone, migrates underground to the sea, and finally discharges in the coastal zone, forming a freshwater lens suspended in salt water.The freshwater lens is cabochon in shape and its thickness varies seasonally, thick at the center of the island and rather thin towards the coastline. The factors limiting the availability of drinking water in the study area are mainly seawater intrusion, groundwater level reduction due to well group disturbance, and discharge to the ocean.When conducting groundwater development for the Ocean Vista Resort project, drill holes should be arranged reasonably, and the position of the well with the thickest drinking freshwater lens should be located, and the depth of the well should not be exposed to the adjacent fre

关 键 词：水文地质 淡水透镜体 氯化物浓度 水源地 

分 类 号：P641.8[天文地球—地质矿产勘探]