상.하류의 기반암 차이에 따른 하천의 형태와 암석의 저항력 분석

Analysis on Channel Morphology and Rock Resistance by Difference of Bedrock Types between Upper and Lower Reach

  • 이광률 (경북대학교 사범대학 지리교육과)
  • Lee, Gwang-Ryul (Department of Geography Education, Kyungpook National University)
  • 발행 : 2007.03.31

초록

하천은 암석의 저항력, 구조 운동, 퇴적물, 유량 등에 의해 다양한 형태로 발전한다 본 연구는 이러한 요인 중에서도, 암석의 침식 저항력에 초점을 두었다. 상 하류간 기반암의 차이가 뚜렷한 어룡천, 흥정천, 두학천, 대화천, 남천천, 구룡천의 6개 하천을 대상으로, GIS를 이용하여, 유역분지 상 하류의 평면 및 종단면 특성을 분석하였다. 화강암 유역은 완만한 경사, 낮은 요형도, 넓은 하곡 면적을 이루며, 편마암 유역은 급한 경사, 높은 요형도, 좁은 하곡 면적을 나타내며, 퇴적암 유역은 본류 경사도와 기복량은 크지만, 나머지는 하천별로 차이가 있다. 여러 가지 형태적 특성 중 상 하류 암석간의 차이가 분명한 본류의 경사, 본류의 요형도, 하계밀도, 하곡의 면적비, 유역의 평균 경사, 유역의 평균 기복을 대상으로, 그 값을 지수화하여, 상 하류 암석의 침식 저항력을 판단하였다. 그 결과, 편마암으로 이루어진 하천의 상류는 침식에 대한 저항력이 높으며, 퇴적암은 상 하류에 관계없이 중간 정도의 저항력을 나타내고, 화강암은 퇴적암과 접한 상류의 경우를 제외하면, 대체로 침식 저항력이 낮다.

The streams evolve to diverse forms influenced by various factors such as rock resistance tectonic process, sediments and discharge. This study focuses on erosion resistance of rocks among these factors. The morphology of plane and longitudinal profile has been analysed in upper and lower reach of 6 streams using GIS; Yeoryong-cheon, Heungjeong-cheon, Duhak-cheon, Daehwa-cheon, Namcheon-cheon, Guryong-cheon, having distinct bedrock types between upper and lower reach. While the basins of granite have gentle slope, low concavity and wide valley area, those of gneiss form steep slope, high concavity and narrow valley area. However, the basins of sedimentary rock make steep slope and high relief in main channel, the other features show some differences in each stream. Among the various morphological features, the indices on slope and concavity of main channel, drainage density, ratio of valley area, average slope and average relief of the basin which have clear differences between rocks in upper and lower reach are calculated to interpret the erosion resistance of rocks in upper and lower reach. As a result, the upper reaches composed of gneiss have the highest erosion resistance, sedimentary rocks in upper and lower reaches show moderate resistance, and granite reaches generally have the lowest resistance except the upper reaches bordered by sedimentary rock.

키워드

참고문헌

  1. 권혁재, 2006, 지형학, 법문사, 서울
  2. 권혁재, 2005, 한국지리, 법문사, 서울
  3. 김우관.임용호, 1997, 'GIS를 이용한 거제도 지형 및 하 계 분석,' 한국지역지리학회지, 3(2), 19-35
  4. 이광률.윤순옥, 2003, '북한강 유역분지 하천의 평면 및 종단면 특성,' 한국지형학회지, 10(2), 207-219
  5. 이금삼.조화룡, 1998, '경상도 지역에 있어서 지질별 지 형 특성 분석,' 한국지형학회지, 5(1), 1-19
  6. 황상일, 1996, '하계망패턴의 특색으로 구분한 중국의 자 연지역,' 한국지역지리학회지, 2, 151-164
  7. Ahmad, R., Scatene, F. N., and Gupta, A., 1993, Morphology and sedimentation in Caribbean montane streams: examples from Jamaica and Puerto Rico, Sedimentary Geology, 85, 157-169 https://doi.org/10.1016/0037-0738(93)90080-O
  8. Clayton, K. and Shammon, N., 1998, A new approach to the relief of Great Britain II. A classification of rocks based on relative resistance to denudation, Geomorphology, 25, 155-171 https://doi.org/10.1016/S0169-555X(98)00038-5
  9. Gilbert, G.K., 1877, Report on the Geology of the Henry Mountains: U.S. Geographical and Geological Survey of the Rocky Mountain Region, Government Printing Office, Washington, D.C
  10. Goldrick, G. and Bishop, P., 2006, Regional analysis of bedrock stream long profiles: evaluation of Hack's SL form, and formulation and assessment of an alternative (the DS form), Earth Surface Processes and Landforms, pulished on line(in press), DOI: 10.1002/esp.1413
  11. Goudie, A., 1995, The Changing Earth, Blackwel, New York
  12. Hodgkinson, J. H., McLoughlin, S., and Cox, M, 2006, The influence of geological fabric and scale on drainage pattern analysis in catchment of metamorphic terrain: Laceys Creek, southeast Queensland, Australia, Geomorphology, 81, 394- 407 https://doi.org/10.1016/j.geomorph.2006.04.019
  13. Kelson, K. I. and Wells, S. G., 1989, Geologic influences on fluvial hydrology and bedload transport in small mountainous watersheds, Northern New Mexico, U.S.A., Earth Surface Processes and Landforms, 14(8), 671-690 https://doi.org/10.1002/esp.3290140803
  14. Knighton, D., 1998, Fluvial Forms and Processes, Oxford University Press, New York
  15. Leopold, L. B., Wolman, M. G., and Miller, J. P., 1992, Fluvial Processes in Geomorphology, Dover Publication, New York
  16. Meybeck, M., 1987, Global chemical weathering of surficial rocks estimated from river dissolved loads, American Journal of Science, 287, 401- 428 https://doi.org/10.2475/ajs.287.5.401
  17. Miller, A. J. and Gupta, A., 1999, Varieties of Fluvial Form, John Wiley & Sons
  18. Mills, H. H., 2003, Inferring erosional resistance of bedrock units in the east Tennessee mountains from digital elevation data, Geomorphology, 55, 263-281 https://doi.org/10.1016/S0169-555X(03)00144-2
  19. Ritter, D. F., Kochel, R. C., and Miller, J. R, 1995, Process Geomorphology, Wm. C. Brown Publishers. Dubuque
  20. Snyder, N. P., Whipple, K. X., Tucker, G. E., and Merritts, D. J., 2003, Channel response to tectonic forcing: field analysis of stream morphology and hydrology in the Mendocino triple junction region, northern California, Geomorphology, 53, 97-127 https://doi.org/10.1016/S0169-555X(02)00349-5
  21. Stock, J. D. and Montgomery, D. R., 1999, Geologic constraints on bedrock river incision using the stream power law, Journal of Geophysical Research, 104, 4983-4993 https://doi.org/10.1029/98JB02139
  22. VanLaningham, S., Meigs, A., and Goldfinger, C., 2006, The effect of rock uplift and rock resistance on river morphology in a subduction zone forearc, Oregon, USA, Earth Surface Processes and Landforms, 31, 1257-1279 https://doi.org/10.1002/esp.1326
  23. Wohl, E. E., 1999, Incised bedrock channels, in Darby, S. E. and Simon, A.(eds.), Incised River Channels: Processes, Forms, Engineering and Management, John Wiley & Sons, Chichester, 187-218