Analysis on Channel Morphology and Rock Resistance by Difference of Bedrock Types between Upper and Lower Reach Gwang-Ryul Lee* 6 GIS : Abstract 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. : fluvial geomorphology, difference of lithology, erosion resistance, channel longitudinal profile, concavity, channel slope, relief Full-time Lecturer Department of Geography Education Kyungpook National University georiver@knu.ac.kr 27
Ritter et al. 1995 Leopold et al. 1992 2006 Gilbert 1877 VanLaningham et al. 2006 Stock and Montgomery 1999 Miller and Gupta 1999 VanLaningham et al. 2006 50 30 20 3 20 2005 2005 GIS GIS 1997 GIS 1998 GIS Clayton and Shamoon 1998 Grid Mills 2003 DEM ERI Meybeck 1987 1 1 3 1 5 2 5 5 12 Kelson and Wells 1989 6 Ahmad et al. 1993 1996 2003 8 Snyder et al. 2003 28
Hodgkinson et al. 2006 Queensland Laceys VanLaningham et al. 2006 Wohl 1999 GIS 6 1 250 000 10 30km 6 1 25,000 ArcGis TIN 5m GRID 1 5,000 S Concavity C Leopold et al. 1992 Goldrick and Bishop 2006 S AD=cot Y A -Y D X A -X D X C AD= B -X A Y B +Y A + X C -X B Y C +Y B + X D -X C Y D +Y C - X D - X A Y D +Y A 29
6 I I A= A-A min A max -A min 0 30km 1 250 000 2 1 30
1 25 6km 110 4km 2 3 14 1km 24 1km 147 2km 2 1 279m 4 11 4km 10 1km 29 6km 2 777m 5 5 5km 18 3km 85 9km 2 1 141m 6 9 6km 13 6km 49 5km 2 1 379m 7 9 7km 18 4km 46 3km 2 544m 10 9km 6 6 2 31
이광률 그림 3. 어룡천 유역분지의 지형과 지질 그림 4. 흥정천 유역분지의 지형과 지질 그림 5. 두학천 유역분지의 지형과 지질 -`32`-
상 하류의 기반암 차이에 따른 하천의 형태와 암석의 저항력 분석 그림 6. 대화천 유역분지의 지형과 지질 그림 7. 남천천 유역분지의 지형과 지질 그림 8. 구룡천 유역분지의 지형과 지질 -`33`-
km km2 m m m km km 2 m 25.6 110.4 0.23 291 19.9 99 0.45 0.16 175.0 1.59 6.017 5.5 427 155 14.1 58.1 0.24 317 18.7 101 0.55 0.15 105.3 1.81 3.178 52.8 226 91 11.5 52.3 0.22 264 21.1 89 0.32 0.21 69.6 1.33 2.839 47.2 246 24.1 147.2 0.16 812 22.4 172 0.71 0.34 139.5 0.95 4.838 3.3 201 584 11.4 84.0 0.14 902 26.2 146 1.06 0.64 67.9 0.81 0.795 16.4 070 495 12.7 63.3 0.20 693 17.0 126 0.40 0.04 71.7 1.13 4.043 83.6 319 10.1 29.6 0.34 349 17.2 106 1.10 0.27 40.8 1.38 2.440 8.2 241 264 5.5 14.3 0.38 427 24.2 101 1.73 0.23 15.5 1.08 0.472 19.3 86 236 4.6 15.3 0.30 278 9.7 39 0.35 0.12 25.3 1.66 1.968 80.7 426 18.3 85.9 0.21 697 24.6 190 0.83 0.18 100.3 1.17 4.567 5.3 249 448 9.6 28.3 0.34 690 21.7 141 1.15 0.10 37.9 1.34 1.537 33.7 160 375 8.8 57.6 0.15 702 25.4 209 0.48 0.06 62.4 1.08 3.030 66.3 346 13 6 49 5 0 27 645 30 3 265 1 58 0 16 71 6 1 45 1 116 2 3 82 232 9 7 32 1 0 30 773 31 0 224 1 76 0 22 43 8 1 36 0 292 26 2 30 156 3 9 17 4 0 22 410 28 9 146 1 13 0 15 27 9 1 60 0 824 73 8 213 18 4 46 3 0 40 122 13 3 88 0 54 0 27 68 6 1 48 5 020 10 8 273 27 10 9 35 3 0 31 150 17 8 81 0 80 0 21 50 7 1 43 1 840 36 7 168 6 7 5 11 0 0 68 33 8 1 25 0 17 0 13 17 9 1 64 3 180 63 3 425 0 16 0 24 0 34 0 20 0 30 0 14 0 30 0 22 0 68 0 38 0 31 0 15 0 22 812m 697m 645m 349m 291m 122m 902m 693m 150m 33m 363m 54m 30 3 13 3 18 7 21 7 17 0 9 7 26 2 31 0 21 1 8 1 34
24 2 17 8 25 4 28 9 265m 88m 101m 141m 126m 39m 146m 224m 89m 25m 101m 81m 209m 146m concave Knighton 1998 Leopold et al. 1992 6 9 0 55 1 15 0 40 0 35 1 06 1 76 0 31 0 17 1 73 0 80 0 48 1 13 convex 11 5km 24km 9 0 34 0 16 0 15 0 10 0 04 0 12 0 64 0 22 35
0 21 0 13 0 23 0 21 0 06 0 15 1 59 0 95 2 1 81 1 34 1 13 1 66 0 81 1 36 1 33 1 64 1 08 1 43 1 08 1 60 10 8 2 3 2 6 30 9 69 1 2 52 8 33 7 83 6 80 7 16 4 26 2 47 2 63 3 19 3 36 7 66 3 73 8 6 6 ( 3), 72%, 5%.,,,,,., Knighton 1998 Wohl 1999 Knighton 1998 Ritter 1995 2006 0 25 0 25 0 69 0 72 0 58 0 51 0 67 0 20 0 05 0 44 0 41 0 41 0 48 0 26 0 86 36
0 24 0 18 0 00 0 46 0 46 0 38 0 29 6 0 09 0 28 0 48 0 54 0 57 0 32 0 38 5 0 56 1 00 1 00 1 00 0 79 0 61 0 83 1 0 14 0 00 0 68 0 00 0 39 0 51 0 29 6 0 98 0 32 0 73 0 96 0 70 0 38 0 68 2 0 11 0 13 0 15 0 04 0 07 0 07 0 10 7 0 62 0 10 0 47 0 74 0 59 0 58 0 52 3 0 19 0 03 0 73 0 26 0 75 0 92 0 48 4 1 00 0 30 0 45 0 86 1 00 1 00 0 77 1 0 60 0 18 0 21 0 14 0 91 0 61 0 44 4 0 40 0 28 0 38 0 70 0 42 0 28 0 41 5 0 00 0 15 0 18 0 30 0 00 0 00 0 10 7 Knighton 1998 Leopold et al. 1992 Knighton 1998 VanLaningham et al. 2006 6 1 0 index 4 10 0 83 0 77 0 10 6 1 2 3 4 5 6 7 37
6 2005 5 38
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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. 702-701 georiver@knu.ac.kr 053 950 5859 Correspondence: Gwang-Ryul Lee, Department of Geography Education, Kyungpook National University, Sankyuk-Dong, Buk-Gu, Daegu, Korea, 702-701(e-mail: georiver@knu.ac.kr, phone: 82-53- 950-5859) 40