隨著人口與產業的發展、用水需求的增加，越是先進的開發國家，在地面水逐漸不敷使用的情形下，地下水由於開發成本低廉、水溫水質穩定、水量固定、污染較少，因此已逐漸成為不可或缺的水資源來源之一。為了永續利用地下水資源，近幾十年來，歐美各先進國家，大都由國家法令政策主導，投注大量的人力與經費，進行地下水保育及污染防治的相關的研究。而觀測井由於可直接接觸地下水含水層與地下水質，因此在各國的地下水相關研究中，均扮演重要的角色，故在數量與品質上，均不斷的提昇。而我國的情形亦是如此，近一、二十年來，隨著一些與地下水有關的重大政策的實施，使得研究調查地下水用的觀測井，在數量與品質上均有顯著的提昇。
本研究主要針對兩項可利用觀測井進行的地下水現場調查工作，就其量測技術及後續資料的加值處理分析，加以探討與研究。包括：一、水平地下水流調查之研究。二、含水層海側邊界調查之研究。希望透過現場調查技術的改善，提供經濟、合理與高品質的基本資料，進而對於地下水應用等相關研究、國內地下水資源管理或保育工作能有所貢獻。
在水平地下水流調查之研究，除了採用國內目前還十分陌生的井中地下水流儀觀測技術外，並針對此一儀器實際應用時，所需解決的「調整因子」問題，設計砂箱試驗及現地小型井場試驗，深入加以研究。研究結果顯示，不同的井體構造及水力條件，對井體中心位置之水平地下水流向，並無明顯之影響，兩者間之誤差大部分低於±10o以下，顯示流向的量測結果具有一定的準確度。至於調整因子 值，當井中地下水流速介於2×10-3m/s至1×10-2m/s間，調整因子 值約介於3至6之間；流速降低至1×10-3m/s時，調整因子 值將提高至10左右。與文獻中前人研究之理論範圍相吻合，但仍無法分離不同影響因子，對調整因子 值之影響程度。另外，利用小型試驗井場現地試驗，探討傳統等值線法與井中地下水流儀量測結果之差異性，以等值線法結合抽水試驗的結果，代表地層中地下水達西流速，則井中地下水流儀量測結果顯示，調整因子約介於3.9至6.0之間；流向的量測誤差，則在±6.36o 以內。此一結果，除了使以往地下水流儀相關的現地試驗，常有調整因子偏高，且範圍極廣的情形，獲得釋疑外，對於往後依環保署公告的「地下水質監測井設置規範」所設置之觀測井，亦提供了類似條件下，合理的調整因子參考範圍。本項研究最後對水平地下水流儀之適用性加以討論，並舉出目前幾個國內極為少見的應用實例，針對現地量測可能遭遇之各項干擾及解決技巧，及地下水流儀實際可能的應用領域，加以說明與探討。
有關含水層海側邊界調查之研究，則是分析單一剖面多觀測井法(多井感潮水位迴歸法)與單一觀測井法(單井感潮水位推估法)的不同，並針對單一觀測井法之適用性，提出檢討與修正。在現場實例計算結果中，以單井感潮水位推估法求得拘限含水層海側的邊界，在距海較近的兩口觀測井，求得海測延伸邊界 L值分別為720.5及734.3公尺。顯示不同位置，亦即距海不同距離的兩口感潮觀測井，推估的含水層海側邊界，有頗為吻合的結果，故此法在實際應用上，應具有一定程度之精確度。至於單井感潮水位推估法之準確度，利用同一斷面上三口感潮水位井之資料，以多井感潮水位迴歸法計算，作為比對。所求得之拘限含水層海側邊界為554公尺，與單井感潮水位法的結果有所差異。其原因可能因本研究多井感潮水位迴歸法，所利用的井數過少(只有三口)，且不同觀測井間的距離，並非十分適當，迴歸可能會造成較明顯的誤差；或是利用單井推估法計算時所需之含水層擴散性，因並非現地試驗值，亦可能造成誤差。至於以何種方法推估較為準確，由本研究所舉之案例，目前並無法斷定，未來如果有實際的海域鑽探資料，將助於此一問題之驗證。

Due to the government’s policies, the quantity and quality of monitoring wells increased gradually in Taiwan in the recent two decades. In this research, we intend to advance some field-investigation techniques on groundwater by using monitoring wells. There are two main parts of this research, including the research of horizontal flows and the research of offshore boundaries of aquifers.
For variations in hydraulic conductivity in different geological formations and well construction, groundwater flows in well bores are typically distinct from flows in the surrounding porous media. Therefore, in order to support application of borehole flowmeters to measure groundwater flows in field sites, differences in groundwater flows must first be explored. In this reseach, a sand tank test and a small-scale field test were designed and performed to explore the problem of accuracy calibration, with the goal of improving the field performance of borehole flowmeters. In the sand tank test, six variables were designed, colloidal borescope meters were used to measure flows in well bores, and responded correction factors for flow velocity were discussed. Based on the test results, the different well construction have no significant effect on the correction factors, which ranged between 3 and 6. When the flow velocity decreased to near or below 2×10-3 m/s, the value of the correction factors increased to equal or exceed 10. In the field test, two different types of flowmeter, colloidal borescope meters and heat-pulse flowmeters, were used as a contrast with a natural gradient and a forced hydraulic gradient, respectively. Field test results showed no differences in correction factors when either type of bolehole meters or hydraulic conditions were used. The correction factors remained between 3.9 and 6.0. The range of correction factors means the possible error of measurement. Sometime this range (3.9 ~ 6.0) has already been acceptable in real application. Besides, the flow directions measured by borehole flowmeters in well bores were consistent with the flow directions in the geological formation. The results of sand tank test indicated the larger well screen diameter and the lower hydraulic gradient seem to have the more accurate flow directions measured by borehole flowmeters. Most of the measurements indicated that the errors of flow direction were below 15o, with a maximum of 21o. For a homogeneous formation maybe some errors are too large but they can be reduced by improving the skill of sand tank test. Finally, the borehole flow meter was applied to the preliminary investigation in three real field sites in taiwan. Due to the accuracy of measurements of groundwater flow direction, the sources of groundwater contaminant sometimes can be found easily. In the worse scenario when the contaminant sources can not be located, the accurate flow direction measured by the borehole flow meter also can reduce the costs and numbers of additional wells in the future detailed investigation works.
In studying many subjects of groundwater in coastal area, such as saltwater intrusion, groundwater resource development and assessment, and groundwater containment transport simulation, determination of the offshore equivalent boundary of an aquifer is the basic task. In previous researches, two methods have been proposed to calculate the offshore equivalent boundary. These two methods, i.e., single well method and multi-well method, also used the relationship between groundwater level response to tidal fluctuation in land and tidal fluctuation.
In this research, the general utilization and limitation of the single well method was discussed and a method to improve it was proposed. Then the two methods also have been applied to the field measured data of a confined aquifer and the results have been analyzed and contrasted. The results of offshore boundaries determined by two different monitoring wells with single well method are 720.5m and 734.3m. It indicates that the single well method is exact and valid. But the verification of the results needs the further data of marine geology exploration.

1.Ando, Y., Tamura, T, Saito, H., Nozawa, A., “Application to groundwater velocimeter using CCD camera”, J. Japan Soc. and Water Resour., 196-199, 1990.（in Japanese）
2.Bidaux, P., Tsang, C.F., “Fluid flow patterns around a well bore or an underground drift with complex skin effects”, Water Resour. Res., 27 (11), 2993-3008, 1991.
3.Barcelona, M. T., J. P. Gibb, and R.A. Miller, “A guide to the Selection of Materials for Monitoring Well Construction and Groundwater Sampling”, USEPA 600/52-84-024, 1983.
4.Bouwer, H.,”Groundwater Hydrology”, Mc McGraw-Hill Book Com., International Edition, 1993.
5.Campbell, M. D. and J. H. Lehr, “Water Well Technology”, McGraw-Hill Book Com., 1973.
6.Carr, P.A., van der Kamp, G., “Determining aquifer characteristics by the tidal methods”, Water Resources Research, 5 (5), 1023-1031, 1969.
7.Carslaw, H.S., Jaeger, J.C., “Conduction of Heat in Solids”, Oxford University Press, New York, 510 pp., 1959.
8.De Wiest, Roger, J. M., Geohydrology, John Wiley, New York, 366 pp., 1965.
9.Driscoll, F.G., “Groundwater and Wells”, Johnson Division,1986.
10.Drost, W., Klotz, D., Koch, A., Moser, H., Neumaier, F., Rauert, W., “Point dilution methods of investigating ground water flow by means of radioisotopes”, Water Resour. Res., 4 (1), 125-146, 1968.
11.Erskine,A.D., “The effect of tidal fluctuation on a coastal aquifer in UK”, Ground Water, 29 (4), 556-562, 1992.
12.Freeze, R.C.,Cherry, J.A., Groundwater, Prentice-Hall. Inc. A Simon & Schuster Company Englewood Cliffs, New Jersey, 1979.
13.Fetter, C. W., Contaminant hydrogeology, Prentice-Hall. , New Jersey, Inc. 2nd ed., 1999.
14.Hess, A. E., “Identifying hydraulically conductive fractures with a slow-velocity borehole flowmeter”, Can. Geotech. J., 23, 69-78, 1986.
15.Jacob, C.E., Flow of groundwater. In: H. Rouse (Editor), Engineering Hydraulics, John Wiley, New York, 321-386 pp., 1950.
16.Kamei, T., Nakamura, Y., “Investigation of groundwater using TV camera and its application to the field measurements”, Tsuchi to Kiso, 40-4, 17-22, 1922. (in Japanese)
17.Kearl, P. M., “Observations of particle movement in a monitoring well using the colloidal borescope”. Journal of Hydrology 200, 323-344, 1997.
18.Kearl, P. M., Roemer K., “Evaluation of groundwater flow directions in a heterogeneous aquifer using the colloidal borescope”, Advance Enviromental Research, 2 (1), 12-23, 1998.
19.Kearl, P. M., Roemer K., Rogoff E. B., Renn, R. M., “Characterization of a fractured aquifer using the colloidal borescope”, Advance Enviromental Research, 3 (1), 49-57, 1998.
20.Kerfoot, W.B., Massard, V. A., “Monitoring well screen influences on direct flowmeter measurements”, Ground Water Monit. Rev., Fall, 74-77, 1985.
21.Kerfoot, W.B., “Monitoring well consruction and recommended procedures for direct groundwater flow measurements using a heat-pulsing flowmeter”, In: Collins, A.G., Johnson, A.I. (Eds.), Groundwater Contamination: Field Methods. Amerucan Society of Testing and Materials, Philadelphia, 146-161, 1988.
22.Li, G.M. and Chen, C.X., “Determining the length of confined aquifer roof extending under the sea by the tidal method”, Journal of Hydrology, Vol. 123, 97-104, 1991.
23.Milne-Thompson, L. M., Theoretical Hydraudynamics. The McMillian Company, Inc., New York, 1968.
24.Momii, K., Jinno, K., Hirano, F., “Laboratory studies on a new laser Doppler velocimeter system for horizontal groundwater velocity measurements in a borehole”, Water Resour. Res., 29 (2), 283-291, 1993.
25.Molz, F. J., Morin, R. H., Hess, A. E., Melville, J. G., Guven, O., “The impeller meter for measuring aquifer permeability variations: evaluation and comparison with other tests”, Water Resour. Res., 25 (7), 1677-1683, 1989.
26.Molz, F. J., Boman, G. K. Young, S. C., Waldrap, W. R., “Bolehole flow meters: field application and data analysis”, J. Hydrol., 163, 347-371, 1994.
27.Ogilvi, N.A., “An electrolytical method of determining the filtration velocity of underground waters”, Bull. Sci-Tech. Inf., 4 (16) Gosgeoltekhisdat, Moscow, 1958.
28.Paillet F., “Borehole flowmeter applications in irregular and large-diameter boreholes”, J. of Applied Geophysics, 55, 39-59, 2004.
29.Serfes, M.E., “Determining the mean hydraulic gradient of ground water affected by tidal fluctuations”, Ground Water, 29 (4), 549-555, 1991.
30.USEPA, “Manual of Water Well Construction Practices”, 570/9-75/001, 1977.
31.Van der Kamp, G., “Tidal Fluctuations in a confined aquifer extending under the sea”, 24th International Geological Congress, Section 11, 101-106, 1972.
32.Wilson, J. T., Mandell, W. A., Paillet F., Bayless, E. R., Hanson, R. T., Kearl, P. M., Kerfoot, W. B., Newhouse, M. W., Pedler, W. H., “An evaluation of borehole flowmeters used to measure horizontal groundwater flow in limestones of Indiana, Kentucky, and Tennessee”, Water-Resource Investigations Report, 01-4139, USGS, 1999.
33.Wheatcraft, S. W., Winterberg, F., “Steady state flow passing through a cylinder of permeability different from the surrounding medium”, Water Resour. Res., 21(12), 1923-1929, 1985.
34.Wu, Y. S., Yu, J. L., Tseng, C. C., Liu, T. K., Hwung, H. H., “Application of groundwater flow measuring techniques : The use of colloidal borescope system(CBS)”, The 4th International Symposium on Environmental Hydraulics and the 14th Congress of Asia and Pacific Division, International Association of Hydraulic Engineering and Research, Hong Kong, 2075-2081, 2005.
35.Wu, Y. S., Lee, C.H., Yu, J. L., ‘’Effects of hydraulic variables and well construction on horizontal borehole flowmeter measurements”, Ground water monitoring and remediation , 28 ( 1) , 2008 .(Accepted)
36.Young, S. C., Waldrop, W. R., “An electromagnetic borehole flowmeter for measuring hydraulic conductivity variability. Proc.:Conference on New Field Techniques for Quantifying the Physical and Chemical Properties of Heterogeneous Aquifers.” Auburn University. Alabama, 1989.
37.台灣糖業公司，”水井手冊 ”，1973。
38.行政院環保署，「台灣省地下水水質監測站網設置實施計畫書」,1992.
39.余進利、吳育生、何信恩、曾建璋, ” 透過分析現地實測資料合理降減地下水水位觀測頻率之研究”，第13屆水利工程研討會，N80-N85，2002.
40.吳育生、余進利、李振誥, “以感潮地下水水位推估拘限含水層海側等效邊界”,台灣水利, 第五十三卷, 第三期, 第17-24 頁,2005.
41.吳育生、余進利、曾建璋, “應用井中攝影技術量測地下水流速流向”, 第6屆地下水資源及水質保護研討會論文集, 第199-206頁, 2004.
42.吳育生、方詠舜、李振誥，”井中與地層中地下水流差異性之探討”，台灣水利，第五十五卷, 第一期, 第32-40 頁,2006.
43.吳育生，”地下水流速流向量測-井中流速流向儀之應用”, 地層下陷防治通訊, 第 5 - 12 頁, 2006.
44.陳崇希、李國敏，”濱海承壓含水層地下水的等效排泄效應，水文地質工程地質”，中國水文地質工程地質勘查院，第17卷，第4期，第147-163頁, 1990.
45.國立成功大學水工試驗所，”「彰化濱海工業區整體開發調查規劃調查研究」，第一部份「現場調查監測及分析」，柒、彰濱工業區及份進地下水水位監測”，研究試驗報告第217號，第8-12~8-13頁，1998.
46.國立成功大學水工試驗所，"雲林縣離島式基礎工業區整體開發規劃調查分析第九年第一部份第八冊”, 研究試驗報告第二四八號，2000.
47.國立成功大學水工試驗所，"彰化濱海工業區整體開發規劃調查研究第十一年第一部份第四冊”, 研究試驗報告第二四九號, 2001a.
48.國立成功大學水工試驗所，"工業區及鄰近區域大地環境監測調查計畫”, 研究試驗報告第二六二號 ,2001b.
49.曹以松, “地下水” ,中國土木水利工程學會,1987.
50.經濟部，”台灣地區地下水觀測網整體計畫書”，1992.
51.經濟部水資源局，”彙編「台灣地區地下水- 濁水溪沖積扇篇」”，第5-1~5-26頁, 1999.