臨海離島式工業區地下水鹽化現象研析

本研究藉由水質濃度關係式運算與三維數值模式GMS-Modflow&MT3DMS模擬離島式基礎工業區地下水層水質鹽化之流佈情境，探討該區之鹽化指標變化特性。此研究區域屬於全新世之新三角洲沖積層，其地層組成主要以黏土、粉砂、砂和礫石為主；水位高程約為0.15～1.96 m，各監測井之相對水位高程相差不大，流場與海邊邊界具相關性。由模式運算結果得知地下水流速約為2.7×10^(-7) cm/sec，場區北方與中央位置之水位較高，地下水流多由中間位置往四週海邊方向流動，符合島嶼型地下水位凸透鏡狀分佈。該區域地下水無側向補注，主要地下水來源為降雨，在無抽用地下水促使海水入侵之情形下，其歷年地下水水質之鹽化指標測值顯示，雖海淡水介面溶質交換會影響鹽化指標降低之速率，離海較遠之地下水淡化速率較快；較靠近海邊之地下水淡化速率較慢，但無論是臨近海邊或遠離海邊之地下水，至今約經過10多年之降雨淋洗，地下水均淡化至接近淡水，氯離子濃度約為3000 mg/L。

關鍵字

鹽化指標；濃度關係式運算；數值模擬

並列摘要

The salinization process was investigated with hydrogeochemical tools to evaluate the new Delta Holocene alluvium, and the zone components are based on the formation of clay, silt, sand and gravel-based. Water level elevation vary between 0.15~1.96 m. The results of the research show that, the groundwater flow rate of approximately 2.7 × 10^(-7) cm/sec, water level high block locate at the north and central location field area, by the middle of the groundwater flow direction to flow around the beach, in line with the island-type-like distribution of groundwater lens.The purpose of this study was to assess aquifer salinization in the coastal area of the Offshore Industrial Park in Taiwan by using GMS-Modflow & MT3DMS simulation and Calculated salinization concentration. When fresh water was recharged into the shallow aquifers, the ascended groundwater levels reduced chlorine concentrations and remedied aquifer salinization. The results showed that although the sea and fresh water interface solute exchange will impact to reduce the rate of salinization indicators from groundwater desalination of sea far faster rate than close to the sea shore groundwater desalination slower rate; whether it is close to the sea or away from the beach groundwater aroundafter 10 years of rainfall leaching, are dilute to near fresh water, the chloride ion concentration of about 3,000 mg/L.

並列關鍵字

Numerical simulation ； Salinization indicators ； Concentration in a well changes at a rate equation

國際替代計量

臨海離島式工業區地下水鹽化現象研析

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