屏東平原地下水鹽化情形探討

Abstract

隨著國內經濟結構發展的轉變，水資源的需求量大幅攀升，卻因降雨分配不均、水庫庫容因淤沙問題日益減少，及河川污染嚴重而使水資源供需失衡，許多民眾遂以地下水來補其不足，長期超抽的結果，沿海地區之地下含水層多已遭受海水入侵之情事，雲嘉南地區及屏東平原即為典型海水入侵的代表。 本研究以屏東平原為範圍，根據經濟部推動「地下水觀測網整體計畫」之調查資料為基礎，透過美國地質調查所研發之地下水模式－PMWIN，進行平原地區地下含水層氯鹽分佈範圍之模擬，模擬結果顯示，研究區域南端近海岸地區之地下含水層氯鹽濃度較高，接近海水之氯鹽含量，顯示確有海水入侵現象，若能減少地下水抽取量，將有助於減緩地下水鹽化情形。

Along with domestic economic structure development change, the water resources demand climbs largely. Actually due to the distribution of rainfalls to be unevenly; the storage capacity of reservoir has been reduced because of the silt deposit question and the river pollution seriously causes the water resources supply and demand to be unbalanced. Many populace then make up theirs insufficiency by the ground water. The aquifer along the coastal area are suffered the seawater intrusion under the circumstances of long-term ultra pumps out result. Yunlin, Chiayi, Tainan area and Pingtung plain are namely for typical sea water intrusion representative. This research take the Pingtung plain as a scope, According to the 'Plane of the groundwater monitoring network' impetus by Ministry Economy Affairs the released investigation material is a foundation. Furthermore, throughout the model of groundwater software－PMWIN (Processing Modflow for Windows) developed by the United States Geological Survey to carry on simulation of the Cl- distribution scope of the aquifer under plain area. The simulation result demonstrating the southern part of the studied region which close to offshore area, the concentration of Cl- in the aquifer are higher, this indicating the region where approaching the Cl- quantity contained in seawater. Seawater intrusion phenomenon is likely proven to be true. If the extracting volume of the groundwater can be reduced dramatically, this will be helpful to relief the worsen situation of the salinization of groundwater.