本研究透過兩年的地表水和淺層地下水的氫氧同位素、水位高度和雙井的溴化鈉示蹤劑試驗，來瞭解大屯火山地區地下水的補注機制與可能傳輸行為。利用每兩周一次的採樣頻率收集水樣和量測水位並分析氫氧同位素。地表水的採樣位置從北至南有鹿角坑溪、小油坑、竹子湖以及中正山。地下水監測井各別位在七星山的南麓與北麓，南麓有TB-MW-25、TB-MW-21、TB-MW-20、TB-MW-08、TB-MW-17和TB-MW-18；北麓則有TB-MW-30、TB-MW-29、TB-MW-26和TB-MW-11共10口。地表水和地下水之δ18O和δD在時間上的變化，顯示在北側地表水入滲到地下水水面的平均時間相對南側較長。另外，結合降雨事件和地下水的D-excess，其結果也指出北麓的D-excess變化所需時間最短而且夏季相對於冬季低顯示氣團來源的季節性變化。一般來說，地表水氫氧同位素越往南越輕，地下水北麓平均較南麓重，顯示主要地下水補助來源的不同。另外，七星山北麓的TB-MW-30、TB-MW-29和TB-MW-11的氫氧同位素值有隨著監測井的海拔增加而變輕的高度效應。另外，在七星山南麓的自然梯度溴化鈉示蹤劑試驗結果顯示TB-MW-08的地下水大約在3天以內將示蹤劑帶到TB-MW-17。兩次的溴化鈉濃度變化曲線皆有2-3個峰值，表示TB-MW-08和TB-MW-17可能存在著2-3條裂隙。
Stable isotopes of surface water, groundwater, hydraulic head and tracer test were used to investigate the recharge mechanism and flow path in the shallow groundwater system in the Tatun volcano group. The total data duration is two years, August, 2012 to December, 2014, with sampling frequency once evert other week. Sampling locations of surface water are located at Lujiaokeng creek, Xiaoyoukeng, Zhuzihu and Zhongzhengshan from north to south. Monitor wells in the south of Cising Mountain are TB-MW-25、TB-MW-21、TB-MW-20、TB-MW-08、TB-MW-17 and TB-MW-18, while in the north of Cising Mountain are TB-MW-30、TB-MW-29、TB-MW-26 and TB-MW-11. Results show that the north of Cising Mountain where surface water infiltrated into groundwater is faster than that of the south. Geological deposits also play a role of infiltration, pyrclastic in the north with faster infiltration. On the other hand, the relationship between precipitation events and D-excess of groundwater variations indicated that the same pattern. The δ18O and δD values increase with elevation in the north of Cising.
Natural gradient trace tests conducted in the south of Cising Mountain to investigate the local fractures. It takes less than three days to flowed from TB-MW-08 to TB-MW-17. And two breakthrough curves possess two to three peaks indicating between TB-MW-08 and TB-MW-17 at least three flow paths exist.
