臺灣地勢陡峻、河川坡陡流急且地質構造複雜；臺灣之氣候屬於海島型氣候，故雨量豐沛，加上近年來由於氣候變遷，極端氣候之影響，豪雨、颱風事件所帶來之雨量，在降雨強度及降雨延時與過去資料比較起來有漸增之趨勢。由於臺灣之地文、水文條件影響，主要天然災害由地震、豪雨及颱風所引發，其中包括崩塌、地滑、土石流及天然壩等災害。於民國88年9月21日發生之集集大地震及民國98年8月8日莫拉克颱風事件中形成多處堰塞湖，天然壩形成至潰決之歷程可能極為短暫，造成天然壩之災害應變時間極短，壩體一旦潰壞，大量水流挾砂可能造成下游居民傷亡及財產損失且天然壩形成位置大多位於山區之中，因此，如何於第一時間內找出堰塞湖天然壩形成位置，於此類災害緊急應變過程中是非常重要的一環。
本研究利用室內物理模型實驗模擬天然壩於上游形成，阻斷水流向下游流動之現象，並觀測下游水位變化歷程，藉由實驗水位變化歷程，驗證簡單波公式於此類問題之可行性。簡單波公式係由特徵曲線法簡化而得。確立理論公式後，進而利用水位觀測資料來推估上游壩體形成位置，以達到本研究之目的。
本研究所得之結果為，於室內物理模型實驗之水位觀測資料回推上游壩體位置時，水位觀測值與理論值之誤差會影響推測距離之誤差，其水位誤差小於10%，推測距離誤差可在15%之內；而推測距離誤差與水位誤差之比值，會隨著時間而改變，約於0.3倍總退水時間有著最小之比值。於實驗水位觀測資料與理論值檢核時，會發現不論初始水位或是退水過程中，水位越低會使理論值較實際量測值來的低，因此水位於0.4倍初始水位以下，水位誤差會變大，由於簡單波公式中忽略的底床摩擦之影響，於後續研究中可考慮底床摩擦之影響，進而改善其成果，並且更進一步應用於現場資料之推算。

Sediment disaster is triggered by typhoons, extremely heavy rainfall and earthquake frequently in Taiwan, such as debris flow, landslide, collapse and landslide dam. In 2009, a landslide dam where was located nearby Siao-Lin village was reform in Chi-Shan river by deep-seated landslide, which was triggered by typhoon Morakot. After the landslide was crashed, many properties, which were closed river bank, and many bridges, which were built along with downstream, were destroyed by dam-break wave. In order to mitigate damage from landslide dam, the researchers have studied in landslide dam deform and break for many years. For example, there are some theories which are developed to understand landslide dam’s deform and break, landslide dam’s materials, dam’s stability, dam’s formation conditions, dam-break wave propagation, dam-break mechanism. However, it wasn’t easy to find a method for estimating landslide dam forming location. Therefore, this thesis develops a method for estimating landslide dam forming location by water-level hydrograph in downstream after landslide dam is formed. It hypothesis that water-level hydrograph after landslide dam is formed is a negative surge propagation. Depending on this condition, analytic solution of negative surge propagation can be derived from de-Saint-Venant equation of one dimensional by the method of characteristics. It’s also called simple wave equation which is used to estimate landslide dam forming location depend on water-level hydrograph. Then, the thesis reappear phenomenon of dam-break wave by the physical model experiments. And database of experiments is used to verify accuracy of estimating landslide dam forming location by simple wave equation. In the conclusion, it’s less 30% error rate to estimate landslide dam forming location, and the method will be very helpful for warming system of landslide dam.

1. 田畑茂清、水山高久、井上公夫，天然壩災害，古今書院，2002。
2. 呂明鴻，堰塞湖天然壩形狀預測，國立成功大學水利及海洋工程研究碩士論文，2010。
3. 柯欽彬，擬似定量流與變量流模擬在台灣河川之適用性探討，逢甲大學土木及水利工程研究碩士論文，2003。
4. 陳樹群，彭思顯，潰壩瞬間急變流之數值演算，水土保持學報，34(4)：293-304，2002。
5. 陳樹群、許中立，莫拉克颱風形成之堰塞湖及危險度評估，地工技術，第122期，第77-86頁，2009。
6. 曾皇銘，小林村潰壩研究，國立成功大學水利及海洋工程研究碩士論文，2011。
7. 黃建朝，潰壩引致之洪峰傳播之試驗，國立成功大學水利及海洋工程研究碩士論文，2010。
8. 鐘浩榮，二次流效應影響下湧波傳遞之模擬研究，國立交通大學土木工程研究所碩士論文，2006。
9. A. Ritter, Die Fortpflanzung der Wasserwellen, Zeitschriftdes Vereines Deutscher Ingenieure, Vol. 36, NO. 24, pp.947-954, 1892.
10. Barré de Saint Venant, A. J. C., “Théorie et Equations Générales du Mouvement Non Permanent des Eaux, avec Application aux Crues des Rivières et à l’Introduction des Marées dans leur Lit(2ème Note)[Theory and equation of unsteady open channel flows, with applications to river floods and tidal influence(2nd Note)],Comptes Rendus des séances de ’Académie des Sciences, Paris, France.” Séance, 73,237–240.,1871.
11. Bellos, C. V., Soulis, J. V. and Sakkas, J. G.,1-D Dam-Break Flow-Wave Propagation on Dry Bed, J. Hydr. Div., ASCE, 113(12),1510-1524, 1987.
12. Bellos, C.V., Soulis, J.V. and Sakkas, J.G., Experimental investigation of two-dimensional dam-break induced flows, Journal of Hydraulic Research, IAHR, 30(2), pp.255-252, 1992.
13. Brufau, P. and P. García-Navarro, Two-dimensional dam-break flow simulation, Methods Fluids, Vol.33, pp.35-57, 2000.
14. Chanson, H., Environmental Hydraulics of Open Channel Flows, Elsevier-butterworth-Institution, London, 1943.
15. Chanson, H., Environmental Hydraulics of Open Channel Flows, Elsevier-butterworth-Institution, London, 1943.
16. Costa, J.E. and Schuster, R.L., The formation and failure of natural dams. Geological Society of America Bulletin 100, 1054-68, 1988.
17. Favre, H., Etude Théorique et Expérimentale des Ondes de Translation dans les Canaux Découverts(Theoretical and Experimental Study of Travelling Surges in Open Channels) Dunod, Paris, France, 1935.
18. Fennema, R. J., and Chaudhry, M. H., Explicit Methods for 2-D Transient Free-Surface Flows., J. Hydr. Engrg., ASCE, 116(8), 1479-1495, 1990.
19. Fraccarollo, L. and Toro, E.F., Experimental and numerical assessment of the Shallow water model for two dimensional dan-break type problems, J. Hydraulic Research, IAHR, 33(6),843-862, 1995.
20. G.B. Whitham, The effects of hydraulic resistance on dam-break problem, J. Hydraulic Research, IAHR,33(6),843-861, 1955.
21. Garcia, R. and Kahawita, R. A.,Numerical Solution of the St.Venant Equations with the MacCormack Finite Difference Scheme. ,International Journal for Numerical Methods in Fluids,6, 259-274, 1986.
22. Henderson, F.M., Open Channel Flow, MacMillan Company, New York, USA, 1966.
23. Hubert Chanson, Application of the method of characteristics to the dam break wave problem, Journal of Hydraulic Research, 47(1), pp.41-49, 2009.
24. Imre M. Ja´nosi,Dominique Jan, K. Gab´or Szabo´, Tama´s Te´l,Turbulent drag reduction in dam-break flows, Experiments in Fluids, 37, pp.219-229, 2004.
25. J.A. Liggett, Fluid mechanics, McGraw-Hill, New York,USA, 1994.
26. J.D. Wang, and H.R. Ansari, Dynamics of surge run-up on dry bed, Internal report, Division of Applied Marine Physics, Rosentiel School of Marine and Atmospheric Science, University of Miami, 1986.
27. Jaeger, C., Engineering Fluid Mechanics, Blackie & Son, Glasow, Uk, pp.529, 1956.
28. Martina Reichstetter and Hubert Chanson, Negative Surges in Open Channels: Physical and Numerical Modelling, Journal of Hydraulic Engineering, online(doi:10.1061/(ASCE)HY.1943-7900.0000674), 2012.
29. Martina Reichstetter and Hubert Chanson, Physical and Numerical Modelling of Surges in Open Channels, School of Civil Engineering, The University of Quwwnsland, 2011.
30. Montes, J.S., Hydraulics of Open Channel Flow, ASCE press, New-York, USA, pp.697, 1998.
31. Moussa, R. and Claude B., Criteria for the choice of flood-routing methods in natural channels, Journal of Hydrology, 186, pp.1-30, 1996.
32. R.H. Cross, Tsunami surge force, Journal of Waterways and Harbor Division, ASCE, Vol.93, NO.4, pp.201-231, 1967.
33. Rayleigh, L.,Note on tidal bores, Proc. Royal Soc. of London, Series A Containing Papers of a Mathematical and Physical Character, 81(541), pp.448-449, 1908.
34. Stoker, J.J., Water waves, Interscience Publishers, pp.291-341, 1957.
35. Sturm, T.W., Open Channel Hydraulics, McGraw Hill, Boston, USA, Water Resources and Environmental Engineering Series, pp.493, 2001.
36. Subramanya, K., Flow in Open Channels, McGraw-Hill, pp.437-482, 1985.
37. Valian A., Caleffi V., Zanni A.,Case Study:“Malpasset dam-break Simulation using a two-dimensional Finite Volume Method”, Journal of Hydraulic Engineering, 128(5), pp.460-472, 2002.