近年來地下水質監測資料顯示，高雄平原地區之總溶解固體物和砷離子濃度是超出飲用水法規標準。本研究藉由DRASTIC模式建立高雄平原汙染潛勢分佈圖，透過層級分析法（Analytic hierarchy process, AHP）修正DRASTIC中的參數權重，藉此達到更高的預測準確率；在考慮未來氣候條件變異的影響下，假設部分自來水廠將大量抽用地下水，本研究利用MODFLOW地下水流模式，模擬大規模抽用地下水的情況下，汙染潛勢變異情形。由DRASTIC模式分析結果顯示：中高-高潛勢(140 DI 180)多集中於東部的大寮、大樹與林園區域；低-中汙染潛勢(102 DI 120)則集中於近山區部分的田寮、旗山與美濃區。根據層級分析法模式的結果顯示，相關性由原先23%提升至72.5%，效果相當顯著。以AHP的權重修正模式為基礎下，發現大社、仁武與林園區因抽水，平均水位下降約3公尺，材質的判釋上均屬於較細質顆粒材質使得潛勢有降低的現象；大樹區則在材質判釋上隸屬粗顆粒材質，使得該區潛勢提升。本研究由各觀測井位置附近加入抽水井模擬，高潛勢分佈則由東部轉移至西南部區域，其高潛勢上升8%。故地下水的抽用，對於整體潛勢有著一定的重要程度的影響。 Recent groundwater quality monitoring data show that the total dissolved solids and arsenic ions concentrations in many of Kaohsiung plain areas are higher than that of drinking water standards. This study uses DRASTIC model to create groundwater vulnerability maps for the Kaohsiung plain area. The analytic hierarchy process (AHP) was employed to modify the DRASTIC weightings to improve the prediction accuracy of the DRASTIC model. Based on the modified DRASTIC model this study then uses MODFLOW model to evaluate the groundwater vulnerability induced by pumping events. The DRASTIC model results show that the medium high to high groundwater vulnerability (140 ? DI ? 180) areas for Kaohsiung plain are Daliao, Dashu, and Lin Yuan districts. The low to medium groundwater vulnerability (102 ? DI ? 120) areas are near Tianliao, Qishan and Mino districts. The AHP modified model results show that the correlation of vulnerability maps are improved significantly from 23% to 72.5%. The results of MODFLOW model show that the large pumping rates will lead to 3 m drawdown in average near the Tashe, Ren Wu, Lin Yuan, and Dashu districts. However, the different aquifer materials in these areas will either decrease (Tashe, Ren Wu, and Lin Yuan districts) or increase (Dashu district) the groundwater vulnerability. The average increase of groundwater vulnerability in the Kaohsiung area is about 8% and the high vulnerability areas are mainly located in southwest regions in the Kaohsiung plain.
