四重溪溫泉區區內溫泉旅館林立，溫泉業者為取得足夠的溫泉資源，紛紛以鑿井抽水增加溫泉水，致使溫泉水超抽。2010年溫泉水位已下降至地面下75m，可能導致溫泉區附近的地表水或淺層地下水補注，改變溫泉水之水質，對溫泉產業造成威脅。本研究之目的在探討四重溪溫泉水質近年來的改變，以做為未來溫泉資源管理的依據。
本研究針對四重溪溫泉井、地下水井及地表水進行採樣分析、長期監測，以測得其導電度、pH值、氧化還原電位、化學成分，進而了解四重溪溫泉泉質近年來的改變。
其結果發現，四重溪溫泉化學成分以碳酸氫根及鈉離子為主，兩者約占總比例95％以上，其他成分均低；地表水及淺層地下水成分以碳酸氫鈣鎂為主。2002~2009年水位、導電度有逐年下降的趨勢；pH值、氧化還原電位較無明顯變化。若溫泉水混入地表及地下水，依照導電度、碳酸氫根及鈉離子之推算，其混入比例為48~53％，亦即2009年四重溪溫泉水，為原先一半之濃度。
2009年後由於屏東縣政府實施總量管制，超抽逐漸改善，水位、導電度、pH值、氧化還原電位有逐漸回復的趨勢。 Many hot spring hotels in Szuchungchi, southern Taiwan, in order to support their hot spring water supply, are increasing the amount of hot spring water by over-pumping, which resulting the decline of hot spring water level. In 2009, the water level has dropped to 75m from ground surface. The decline of the hot spring water level could lead to surface water and shallow groundwater recharging to the hot spring aquifer. This will result in changes of water quality and pose a threat to the hotels and spa industry. The purpose of this study is to investigate the chemistry changes of hot spring waters in Szuchungchi and to provide suggestions to the management of the hot spring water resources.
In this study, I take samples from hot spring wells, stream waters and shallow wells. The electrical conductivity (EC), pH, oxidation/reduction potential of waters are analyzed on site. An EC sensor and data logger were also set to long-term monitoring in a public bath house.
The results of my study show that water level and EC in hot spring wells were all decline from 2002 to 2009. The values of pH, oxidation/reduction potential didn’t change. The composition of hot spring water is mainly by sodium bicarbonate which is 95% of the major ion concentration. Stream water and shallow groundwater are composed by calcium and magnesium bicarbonate. The decline of water level in hot spring aquifer should cause the intrusion of shallow groundwater that results the EC decreased of hot spring waters.
After 2009, the decline of water level in hot spring wells were hold and recovered after the enforced of pumping restriction on the hot spring wells by the Pingtung County Government. The EC values of the hot spring waters were also increased after 2009.
