KSCE Journal of Civil and Environmental Engineering Research (대한토목학회논문집)

Korean Society of Civil Engeneers (대한토목학회)
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Micromorphological Changes of Rill Development under Simulated Rainfall and Inflow on Steep Slopes

모의 강우와 유입수에 의해 급경사면에서 발달한 세류의 미세지형 변화

  • 신승숙 (강릉원주대학교 방재연구소) ;
  • 심영주 (케이에스엠기술(주)) ;
  • 손상진 (강릉원주대학교 토목공학과) ;
  • 박상덕 (강릉원주대학교 토목공학과)
  • Received : 2022.10.07
  • Accepted : 2022.11.10
  • Published : 2023.02.01
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Abstract

Interrill erosion dominates in forest areas, and the erosion rate in surface-disturbed areas is significantly increased by the development and expansion of rill. In this study, soil erosion experiments using simulated rainfall and inflow were performed to understand the development and the micromorphological changes of rill on steep slopes. The characteristic factors of the micromorphology, such as the rill cross section, rill volume, rill density, rill order, and rill sharpness, were analyzed according to steepness and location (upper or lower) of slope. The head-cut of the simultaneous incised rills by rainfall simulation moved rapidly upslope, and the randomly developed rills expanded deeply and widely with their connection. The rill cross section evolved to downslope gradually increased. The rill volume occupied about 78 % of the sediment volume, confirming that the contribution of the sediment from the rill erosion is greater than that of the interrill erosion. Although the rate of increase in rill order slowed as the slope increased, the total length and density of the rill generally increased. As the slope increased from 15° to 20°, the bed incision of rills became larger than the sidewall expansion, and the rill sharpness increased by 1.6 times. The runoff coefficient on the lower slope decreased by 12.3 % than that on the upper slope. It was evaluated that the subsoil exposures and formation changes by the rill expansion increased the infiltration rate. Although the sediment accompanying the rills generally increased with slope increase, it was directly influenced by the hydraulic velocity of enhanced rill with the local convergence and expansion in the process of the rill evolution.

산림지역은 세류간침식이 지배적인 반면, 지표 교란지역은 세류의 발달과 확장에 의한 침식이 두드러지게 증가한다. 본 연구는 급경사에서 세류 발달과 미세지형 변화의 특성을 파악하고자 강우와 유입수 모의에 따른 토양침식 실험을 수행한 것이다. 세류의 단면과 체적, 세류밀도, 세류차수, 세류예도와 같은 미세지형의 특성인자들은 사면의 경사와 위치(상부 또는 하부)에 따른 분석이 이루어졌다. 강우모의에 의해 동시다발적으로 절개된 세류들의 두부침식은 빠른 속도로 상류로 이동하였고, 무작위으로 발달한 세류들은 서로 연결되면서 깊고 넓게 확장하였다. 세류가 하류방향으로 진화함에 따라 횡단면적은 점차적으로 증가하였다. 세류 체적은 유출토사 체적의 약 78 %를 차지하여, 세류침식이 세류간침식보다 토사유출량 기여도가 큼을 확인하였다. 경사가 증가함에 따라 세류차수의 증가는 둔화되지만, 세류의 총길이와 밀도는 전반적으로 증가하였다. 경사 15°에서 20°로 증가하면서 세류의 측벽확장보다 하상절개가 상대적으로 커지면서 세류예도가 1.6배로 증가하였다. 하사면의 유출계수는 상사면보다 12.3 % 적었으며, 이는 세류 확장에 의한 형상 변화와 심토의 노출이 침투를 증가시켰던 것으로 평가된다. 세류가 수반된 토사유출은 경사가 급할수록 전반적으로 증가하지만, 세류진화 과정에서 국부적인 합류와 확장으로 강화된 세류의 수리학적 유속에 직접적인 영향을 받았다.

Keywords

Acknowledgement

본 연구는 과학기술정보통신부(No. 2019R1A2C1009285)와 교육부(2021R1A6A1A03044326)의 재원으로 한국연구재단의 지원을 받아 수행된 기초연구사업으로 이에 감사를 표합니다.

References

  1. Berger, C., Schulze, M., Rieke-Zapp, D. and Schlunegger, F. (2010). "Rill development and soil erosion: A laboratory study of slope and rainfall intensity." Earth Surface Processes and Landforms, Vol. 35, No. 12, pp. 1456-1467. https://doi.org/10.1002/esp.1989
  2. Bewket, W. and Sterk, G. (2003). "Assessment of soil erosion in cultivated fields using a survey methodology for rills in the Chemoga watershed, Ethiopia." Agriculture, Ecosystems & Environment, Vol. 97, No. 1-3, pp. 81-93. https://doi.org/10.1016/S0167-8809(03)00127-0
  3. Bingner, R. L., Wells, R. R., Momm, H. G., Rigby, J. R. and Theurer, F. D. (2016). "Ephemeral gully channel width and erosion simulation technology." Natural Hazards, Vol. 80, No. 3, pp. 1949-1966. https://doi.org/10.1007/s11069-015-2053-7
  4. Boon, W. and Savat, J. (1981). "A nomogram for the prediction of rill erosion." In Morgan, R., editor, Soil conservation: Problems and prospects, Wiley, Chichester, pp. 303-319.
  5. Brunton, D. A. and Bryan, R. B. (2000). "Rill network development and sediment budgets." Earth Surface Processes and Landforms: The Journal of the British Geomorphological Research Group, Vol. 25, No. 7, pp. 783-800. https://doi.org/10.1002/1096-9837(200007)25:7<783::AID-ESP106>3.0.CO;2-W
  6. Cerdan, O., Le Bissonnais, Y., Couturier, A., Bourennane, H. and Souchere, V. (2002). "Rill erosion on cultivated hillslopes during two extreme rainfall events in Normandy, France." Soil and Tillage Research, Vol. 67, No. 1, pp. 99-108. https://doi.org/10.1016/S0167-1987(02)00045-4
  7. Chen, X., Zhao, Y., Mi, H. and Mo, B. (2016). "Estimating rill erosion process from eroded morphology in flume experiments by volume replacement method." Catena, Vol. 136, pp. 135-140. https://doi.org/10.1016/j.catena.2015.01.013
  8. Gomez, J. A., Darboux, F. and Nearing, M. A. (2003). "Development and evolution of rill networks under simulated rainfall." Water Resources Research, Vol. 39, No. 6, 1148.
  9. Govindaraju, R. S. and Kavvas, M. L. (1994). "A spectral approach for analyzing the rill structure over hillslopes. Part 1. Development of stochastic theory." Journal of Hydrology, Vol. 158, No. 3-4, pp. 333-347. https://doi.org/10.1016/0022-1694(94)90061-2
  10. He, J. J., Sun, L. Y., Gong, H. L. and Cai, Q. G. (2017). "Laboratory studies on the influence of rainfall pattern on rill erosion and its runoff and sediment characteristics." Land Degradation & Development, Vol. 28, No. 5, pp. 1615-1625. https://doi.org/10.1002/ldr.2691
  11. Horton, R. E. (1945). "Erosional development of streams and their drainage basins; hydrophysical approach to quantitative morphology." Geological Society of America Bulletin, Vol. 56, No. 3, pp. 275-370. https://doi.org/10.1130/0016-7606(1945)56[275:edosat]2.0.co;2
  12. Hudson, G. D. (1936). "Unit area method of land classification." Annals of the Association of American Geographers, Vol. 26, No. 2, pp. 99-112. https://doi.org/10.1080/00045603609357083
  13. Hur, S. O., Jung, K. H., Ha, S. K., Kwak, H. K. and Kim, J. G. (2005). "Mathematical description of soil loss by runoff at inclined upland of maize cultivation." Korean Journal of Soil Science and Fertilizer, Vol. 38, No. 2, pp. 66-71 (in Korean).
  14. Kim, C. G., Shin, K. I., Joo, K. Y., Lee, K. S., Shin, S. S. and Choung, Y. S. (2008). "Effects of soil conservation measures in a partially vegetated area after forest fires." Science of the Total Environment, Vol. 399, No. 1-3, pp. 158-164. https://doi.org/10.1016/j.scitotenv.2008.03.034
  15. Kim, S. S., Kim, T. H., Lee, S. M., Park, D. S., Zhu, Y. Z. and Hur, J. H. (2005). "Mobility of pesticides in different slopes and soil collected from Gangwon alpine sloped-land under simulated rainfall conditions." The Korean Journal of Pesticide Science, Vol. 9, No. 4, pp. 316-329 (in Korean).
  16. Loch, R. J. and Donnollan, T. E. (1983). "field rainfall simulator studies on two clay soils of the darling downs, Queensland. I. the effect of plot length and tillage orientation on erosion processes and runoff and erosion rates." Soil Research, Vol. 21, No. 1, pp. 33-46. https://doi.org/10.1071/sr9830033
  17. Mancilla, G. A., Chen, S. and McCool, D. K. (2005). "Rill density prediction and flow velocity distributions on agricultural areas in the pacific northwest." Soil and Tillage Research, Vol. 84, No. 1, pp. 54-66. https://doi.org/10.1016/j.still.2004.10.002
  18. Merritt, W. S., Letcher, R. A. and Jakeman, A. J. (2003). "A review of erosion and sediment transport models." Environmental Modelling & Software, Vol. 18, No. 8-9, pp. 761-799. https://doi.org/10.1016/S1364-8152(03)00078-1
  19. Meyer, L. D., Foster, G. R. and Romkens, M. J. M. (1975). "Source of soil eroded by water from upland slopes." Present and Prospective Technology for Predicting Sediment Yields and Sources, Oxford, Mississippi, pp. 177-189.
  20. Moss, A., Green, P. and Hutka, J. (1982). "Small channels: Their formation, nature and significance." Earth Surface Processes and Landforms, Vol. 7, pp. 401-415. https://doi.org/10.1002/esp.3290070502
  21. Murphy, B. W. and Flewin, T. C. (1993). "Rill erosion on a structurally degraded sandy loam surface soil." Soil Research, Vol. 31, No. 4, pp. 419-436. https://doi.org/10.1071/SR9930419
  22. Nachtergaele, J., Poesen, J., Sidorchuk, A. and Torri, D. (2002). "Prediction of concentrated flow width in ephemeral gully channels." Hydrological Processes, Vol. 16, No. 10, pp. 1935-1953. https://doi.org/10.1002/hyp.392
  23. Nachtergaele, J., Poesen, J., Steegen, A., Takken, I., Beuselinck, L., Vandekerckhove, L. and Govers, G. (2001). "The value of a physically based model versus an empirical approach in the prediction of ephemeral gully erosion for loess-derived soils." Geomorphology, Vol. 40, No. 3-4, pp. 237-252. https://doi.org/10.1016/S0169-555X(01)00046-0
  24. Nam, M. J., Park, S. D., Lee, S. K. and Shin, S. S. (2015). "Interaction between raindrops splash and sheet flow in interrill erosion of steep hillslopes." Journal of Korea Water Resources Association, KWRA, Vol. 48, No. 7, pp. 595-604 (in Korean). https://doi.org/10.3741/JKWRA.2015.48.7.595
  25. Park, S. D., Lee, K. S. and Shin, S. S. (2012). " Statistical soil erosion model for burnt mountain areas in Korea - RUSLE approach." Journal of Hydrologic Engineering, ASCE, Vol. 17, No. 2, pp. 292-304. https://doi.org/10.1061/(ASCE)HE.1943-5584.0000441
  26. Park, S. D., Shin, S. S. and Lee, K. S. (2005). "Sensitivity of runoff and soil erosion in the burnt mountains." Journal of Korea Water Resources Association, KWRA, Vol. 38, No. 1, pp. 59-71 (in Korean). https://doi.org/10.3741/JKWRA.2005.38.1.059
  27. Park, S. D., Shin, S. S., Kim, S. J. and Choi, B. K. (2013). "Effects of surface compaction treatment on soil loss from disturbed bare slopes under simulated rainfalls." Journal of Korea Water Resources Association, KWRA, Vol. 46, No. 5, pp. 559-568 (in Korean). https://doi.org/10.3741/JKWRA.2013.46.5.559
  28. Poesen, J., de Luna, E., Franca, A., Nachtergaele, J. and Govers, G. (1999). "Concentrated flow erosion rates as affected by rock fragment cover and initial soil moisture content." Catena, Vol. 36, No. 4, pp. 315-329. https://doi.org/10.1016/S0341-8162(99)00044-2
  29. Qin, C., Zheng, F., Xu, X., Wu, H. and Shen, H. (2017). "A laboratory study on rill network development and morphological characteristics on loessial hillslope." Journal of Soils and Sediments, Vol. 18, No. 4, pp. 1679-1690.
  30. Raff, D. A., Ramirez, J. A. and Smith, J. L. (2004). "Hillslope drainage development with time: A physical experiment." Geomorphology, Vol. 62, No. 3-4, pp. 169-180. https://doi.org/10.1016/j.geomorph.2004.02.011
  31. Robichaud, P. R., Wagenbrenner, J. W. and Brown, R. E. (2010). "Rill erosion in natural and disturbed forests: 1. Measurements." Water Resources Research, Vol. 46, No. 10.
  32. Shen, H., Zheng, F., Wen, L., Lu, J. and Jiang, Y. (2015). "An experimental study of rill erosion and morphology." Geomorphology, Vol. 231, pp. 193-201. https://doi.org/10.1016/j.geomorph.2014.11.029
  33. Shin, S. S., Park, S. D. and Hwang, Y. H. (2022). "Erodibility evaluation of sandy soils for sheet erosion on steep slopes." Journal of Korea Water Resources Association, KWRA, Vol. 55, No. 4, pp. 291-300 (in Korean).
  34. Shin, S. S., Park, S. D. and Lee, K. S. (2013). "Sediment and hydrological response to vegetation recovery following wildfire on hillslopes and the hollow of a small watershed." Journal of Hydrology, Vol. 499, pp. 154-166. https://doi.org/10.1016/j.jhydrol.2013.06.048
  35. Shin, S. S., Park, S. D., Cho, J. W. and Lee, K. S. (2008). "Effects of vegetation recovery for surface runoff and soil erosion in burned mountains, Yangyang." Journal of the Korean Society of Civil Engineers, KSCE, Vol. 28, No. 4B, pp. 393-403 (in Korean).
  36. Shin, S. S., Park, S. D., Pierson, F. B. and Williams, C. J. (2019). "Evaluation of physical erosivity factor for interrill erosion on steep vegetated hillslopes." Journal of Hydrology, Vol. 571, 559-572. https://doi.org/10.1016/j.jhydrol.2019.01.064
  37. Slattery, M. and Bryan, R. (1992). "Hydraulic conditions for rill incision under simulated rainfall: A laboratory experiment." Earth Surface Processes and Landforms, Vol. 17, pp. 127-146. https://doi.org/10.1002/esp.3290170203
  38. Strahler, A. N. (1952). "Hypsometric (area-altitude) analysis of erosional topography." Geological Society of America Bulletin, Vol. 63, No. 11, pp. 1117-1142. https://doi.org/10.1130/0016-7606(1952)63[1117:haaoet]2.0.co;2
  39. Sun, L., Fang, H., Qi, D., Li, J. and Cai, Q. (2013). "A review on rill erosion process and its influencing factors." Chinese Geographical Science, Vol. 23, No. 4, pp. 389-402. https://doi.org/10.1007/s11769-013-0612-y
  40. Tian, P., Pan, C., Xu, X., Wu, T., Yang, T. and Zhang, L. (2020). "A field investigation on rill development and flow hydrodynamics under different upslope inflow and slope gradient conditions." Hydrology Research, Vol. 51, No. 5, pp. 1201-1220. https://doi.org/10.2166/nh.2020.168
  41. Wang, X. and Fang, D. (1998). "Study on the slope pattern of the slope erosion." Sichuan Hydraulic Electrogeneration, Vol. 17, No. 2, pp. 83-86.
  42. Wirtz, S., Seeger, M. and Ries, J. B. (2012). "Field experiments for understanding and quantification of rill erosion processes." Catena, Vol. 91, pp. 21-34. https://doi.org/10.1016/j.catena.2010.12.002
  43. Yao, C., Lei, T., Elliot, W. J., McCool, D. K., Zhao, J. and Chen, S. (2008). "Critical conditions for rill initiation." Transactions of the ASABE, Vol. 51, No. 1, pp. 107-114.
  44. Zhang, P., Tang, H., Yao, W., Zhang, N. and Xizhi, L. V. (2016). "Experimental investigation of morphological characteristics of rill evolution on loess slope." Catena, Vol. 137, pp. 536-544. https://doi.org/10.1016/j.catena.2015.10.025