台灣東北部的蘭陽平原居民廣泛使用地下水作為飲用、灌溉與養殖所需用水。根據經濟部水利署的調查顯示蘭陽平原沿海地區有超抽地下水所造成的地層下陷與海水入侵問題，此外，經濟部水利署的長期地下水水質監測也顯示部分地區有地下水水質超過飲用、灌溉與養殖標的用水的水質標準的問題，使得地下水資源的永續使用與水質安全面臨極大的挑戰。 本研究的目標為建立蘭陽平原多標的用水的地下水使用分區管理計畫，整個多標的地下水使用管理計畫建立將考量地下水水質、地下水抽取所造成的含水層衝擊(洩降)與現有土地使用資訊。首先，利用將現有的地下水井水質參數的監測資料利用地質統計方法建立水質參數的空間分布，然後根據飲用水、灌溉水與養殖水的水質標準決定三個不同標的用水的水質安全區，接著利用實際地下水抽取量與流通係數的比值決定低含水層衝擊區，最後，整合飲用水、灌溉水與養殖水三個用水標的安全區與低含水層衝擊區的分區管理地圖，此地圖可提供做為改進水質安全與永續地下水使用的基礎以達到蘭陽平原多標的地下水使用的需求。 ;Groundwater is widely extracted for meeting the demands of drinking, irrigation and aquaculture in the Lanyang Plain. A long-term groundwater quality survey in northeastern Taiwan’s Lanyang Plain has revealed obvious contamination of some part of the groundwater, with some measured hydrochemical parameters in excess of the levels recommended by Taiwan Environmental Protection Administration. In addition, land subsidence and seawater intrusion caused by overexploitation of groundwater are also found in the Lanyang Plain. Thus, establishing a sound plan for groundwater resource management that considers groundwater quality and the aquifer impact by pumping in Lanyang Plain is important. This study aims to present a zonal management plan for the multi-purpose groundwater utilization in the Lanyang Plain based on the groundwater quality and aquifer impact by pumping. The Kriging approach is used evaluate spatial distribution of groundwater quality and the safe zones are determined based on the water quality standards for the three groundwater utilization sectors. The suitable zone for the aquifer impact by pumping is then spatially determined based on the ratio of actual groundwater utilization to the transmissivity. Integrating the evaluation results showing the safe water quality zones for the three different purposes of groundwater utilization demands and suitable zones for the low impact on aquifer. Integrating the evaluation results showing the safe water quality zones for the three different purposes of groundwater utilization demands and suitable zones for the low aquifer impact by pumping can create groundwater management map for multi-purpose groundwater utilization. Ultimately, the obtained groundwater management map is compared with the current land use information to provide a basis for evaluating current land use practices and establishing a water resource management strategy for safe and sustainable use of groundwater to meet multi-purpose groundwater utilization requirements in the Lanyang Plain.
