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年度	112	專案性質	實驗性質
專案類別	模場試驗	研究主題	調查
申請機構	國立臺灣海洋大學	申請系所	地球科學研究所
專案主持人	邱永嘉	職等/職稱	教授
專案中文名稱	以分散式光纖溫度感測器結合封井材料進行場址地下水流速與流向高解析度調查
中文關鍵字	分散式光纖溫度感測器, TV-DTS, FLUTe, PAG
專案英文名稱	Using FO-DTS combined with well sealing materials to conduct high-resolution surveys of in-situ groundwater flow velocity and direction
英文關鍵字	FO-DTS, TV-DTS, FLUTe, PAG
執行金額	2,851,820元
執行期間	2024/1/1 至 2025/12/31
計畫中文摘要	傳統的水文地質調查方法主要針對大區域進行試驗，然而在地下含水層極為複雜的情況下，由於現場資料的空間解析度不足，往往難以準確掌握水文地質狀況，這可能導致對含水層透水區段及地下水流速、流向的誤判。近年來，利用熱能作為地下水流的示蹤劑，並結合創新的分散式光纖溫度感測器（fiber-optic distributed temperature sensor, FO-DTS）量測技術，已被證明適用於多種水文地質環境的調查工作。有鑒於此，本專案計畫選定屏東潮州新埤鄉的地下水污染場址，藉助分散式光纖溫度感測器在空間與時間上提供的高解析度連續性量測優勢，進行土壤及地下水污染場址的水文地質調查。本計劃今年度將持續進行單井加熱試驗，此外，透過自製的單井流速與流向光纖溫度測定儀（稱為thermal vector DTS, TV-DTS）， 於單井內進行 TV-DTS 加熱試驗，以推估垂直方向上的高解析流速分布，同時解析該地區的地下水流向資訊。今年度已完成四口井（T00571、T00567、T00239與T00226）的單井加熱與TV-DTS之試驗與分析。 單井加熱試驗結果顯示，四口井皆有明顯透水及不透水的區段，井 T00571 位於深度47.5-75 公尺有著較佳的透水性，深度12.5-22.5公尺具有較差的透水性，井T00567於深度50、71-72 及 75-77 公尺有著較高之透水性，而深度 80-90 公尺則有著較差的透水性，井T00239 於深度77.5~80.48 公尺為最透水區段，深度 76~80 公尺則為最不透水，井 T00226則是深度深度37~44和57~60公尺透水性較佳，深度61~69公尺透水性最差。進一步利用單井加熱之溫度資料配合A-DTS Toolbox（Simon et al., 2021）得以推估測量點周圍地層材質之熱傳導係數和地下水流速，結果顯示T00571之流速與熱傳導係數隨著深度有著明顯差異深度44-75公尺為較高流速帶，10-20公尺為較低流速帶；熱傳導係數方面，整體有著明顯差異，深度10-20公尺呈現較低值，深度42~80公尺熱導率係數較高。T00567之流速與熱傳導係數隨著深度同樣有著明顯差異，整體流速可以觀察到深度63~70、80~100公尺區間的低流速帶，以及深度31~50區間的較高流速分佈；熱傳導係數方面，深度25 ~70公尺區間出現較高值，深度80~100 公尺以下熱導率係數開始下降。T00239 的整體流速可以觀察到深度30-37、51~55、69-74公尺區間的低流速帶，以及深度26-29, 40-47.5、60-67.5公尺區間的較高流速分佈；熱傳導系數方面，深度24 ~29公尺區間出現較高值，深度40~75公尺以下係數逐漸趨於穩定，深度78~80公尺區間再次出現較高係數。T00226的整體流速可以觀察到深度20~32、47~56、60~75公尺區間的低流速帶，以及深度36~43、56~59公尺區間的較高流速分佈；熱傳導係數方面，深度20 ~30公尺區間出現較低值，深度30公尺以下開始增加，至深度36公尺以下係數逐漸趨於穩定。 地下水流向則透過TV-DTS 進行量測，試驗結果顯示 T00571 的地下水流向主要為往 E 方位流動，且些微的偏向S方位；井T00239-1則主要往N方位流動，深部位置則為S偏W的方位流動;井T00239-2往N偏W的方位流動，與前人檢測結果大致相符。井T002262 整體地下水流向為往西方流動，結果非常一致；井T00567則因為各方位間的溫度差異不明顯，無法有效判讀。進一步量化TV-DTS之試驗結果，以T00239及T00226進行，其結果顯示，T00239於深度74-76公尺擬合之方位有所偏差，分別是為 35-60°方位 (東偏北)及200°方位(西偏南)，流速方面則差異不大，約為 0.08-0.12m/d。T00226方面，深度38-40公尺流向方位角度十分接近，約為 170-210°方位 (偏西)，流速約為 0.17m/d。 本計劃亦針對柔性襯管(Flexible Liner Underground Technologies, FLUTe)與聚丙烯醯胺(polyacrylamide, PAM)進行室內試驗，測試結果顯示，兩者在阻隔垂直對流的封井成效良好有效降低對流產生的水體混合，改善試驗中的溫度量測。此外，裂隙造成的潛在水流造成的流速差異得以透過FLUTe之設置強化其產生之溫度回饋，顯示明顯的低溫帶狀區間，有助於現地試驗的量測優化。 明年度的工作計劃預計將進外選取四口井，進行TV-DTS 試驗，用於分析其地下水之流向與流速，並選取兩口井進行單井加熱試驗，除了分析井內的流速及地層的熱傳導係數之分佈情形之外，將用於驗證TV-DTS 試驗之結果。本計畫透過所提出之創新方法，研析區域內的含水層透水區段與地下水流向及流速資訊。研究成果所產出的高精度資料可提供後續污染場址調查與整治工作之參考依據。此創新量測方法的精進與應用，冀望未來能對於土壤與地下水污染調查及整治帶來新的契機。
計畫英文摘要	Traditional hydrogeological survey methods primarily focus on large geographical areas. However, in cases where underground aquifers are particularly complex, the insufficient spatial resolution of field data often leads to significant misjudgments regarding the conditions of the aquifers, including permeable sections and the dynamics of groundwater flow. In recent years, the innovative use of thermal energy as a tracer for groundwater flow, combined with fiber-optic distributed temperature sensing (FO-DTS) technology, has demonstrated effectiveness in a variety of hydrogeological environments. Accordingly, this project selected a groundwater contamination site located in Xinpi Township, Chaozhou, Pingtung to demonstrate the proposed methods. The purpose of this study aimed to conduct comprehensive hydrogeological investigations of soil and groundwater contamination by using the high-resolution continuous measurement capabilities of FO-DTS. This year, we conducted the single-well heating tests, and developed a thermal vector DTS (TV-DTS) device to perform heating experiments within the same selected wells. TV-DTS enables us to estimate vertical flow rate distributions and analyze groundwater flow directions simultaneously. To date, we have completed tests and analyses for four wells, i.e., Wells of T00571, T00567, T00239, and T00226. Results from the single-well heating tests indicated that the permeable and impermeable sections in all four wells can be distinguished. Well T00571, at depths of 47.5-75 m, exhibits better permeability, while depths of 12.5-22.5 m show poorer permeability. Well T00567 displays higher permeability at depths of 50, 71-72, and 75-77 m, while depths of 80-90 m exhibit lower permeability. Well T00239 shows the most permeable section at depths of 77.5-80.48 m, while the depths of 76-80 m are the least permeable. Well T00226 has better permeability at depths of 37-44 and 57-60 m, with the worst permeability at depths of 61-69 m. Further analysis of temperature data from the single-well heating tests, combined with the A-DTS Toolbox (Simon et al., 2021), allows us to estimate thermal conductivity coefficients and groundwater flow rates around the measurement points. The results showed that Well T00571 exhibits significant different characteristics in flow rates and thermal conductivity coefficients which were varied with depths. The depth range of 44-75 m corresponded to a higher flow rate zone, while 10-20 m indicated a lower flow rate zone. In terms of thermal conductivity coefficients, there were notable differences overall, with lower values at depths of 10-20 m and higher coefficients at depths of 42-80 m. Similarly, Well T00567 showed clear variations in flow rates and thermal conductivity coefficients with depth, with lower flow rates observed in the ranges of 63-70 and 80-100 m, and higher flow rates in the 31-50 m. The thermal conductivity coefficients are higher between depths of 25-70 m, decreasing below 80-100 m. For Well T00239, low flow rate zones are observed at depths of 3037, 51-55, and 69-74 m, with higher flow rate distributions at depths of 26-29, 40-47.5, and 6067.5 m. The thermal conductivity coefficients show higher values at depths of 24-29 m, stabilizing below 40-75 meters, with another increase at depths of 78-80 m. For Well T00226, low flow rate zones are evident at depths of 20-32, 47-56, and 60-75 m, with higher flow rate distributions at depths of 36-43 and 56-59 m. The thermal conductivity coefficients show lower values at depths of 20-30 m, increasing below 30 meters and stabilizing below 36 m. Groundwater flow directions were measured using TV-DTS, revealing that Well T00571 primarily flowed eastward with a slight inclination toward the south. Well T00239-1 flowed mainly northward, with deeper locations showing a south-southwest direction. Well T00239-2 flowed northwest, aligning with previous detection results. Well T00226-2 showed a consistent westward flow direction, while T00567 exhibited insufficient temperature differences between directions, hindering effective interpretation. Further quantification of TV-DTS results using the analytical solution was conducted for Wells of T00239 and T00226. The results indicated that flow direction at Well T00239 at depths of 74-76 m has a direction corresponding to 35-60° (east-north) and 200° (west-south) orientations, with the flow rates of approximately 0.08-0.12 m/d. For Well T00226 at depths of 38-40 m, the flow direction was very similar, around 170-210° (west), with a flow rate of approximately 0.17 m/d. In addition to field tests, we conducted laboratory experiments on Flexible Liner Underground Technologies (FLUTe) and polyacrylamide (PAM). The results demonstrated that both methods effectively reduce vertical convection, thereby minimizing water mixing and improving the accuracy of temperature measurements. This enhancement is crucial for understanding the thermal dynamics within the aquifer. The future work will focus on selecting additional four wells for TV-DTS testing, two of which will be conducted single-well heating tests for verification, to further analyze groundwater flow directions and rates next year. Through these innovative methods, we aim to provide highprecision data that will inform future investigations and remediation efforts at contaminated sites. The insights gained from this research are expected to significantly enhance our understanding of groundwater dynamics and contribute to more effective management and remediation strategies for soil and groundwater contamination.