HESS Hydrology and Earth System Sciences HESS Hydrol. Earth Syst. Sci. 1607-7938 Copernicus Publications Göttingen, Germany 10.5194/hess-13-935-2009 Dye staining and excavation of a lateral preferential flow network Anderson A. E. 1 Weiler M. 2 Alila Y. 3 Hudson R. O. 3 Sustainable Resource Development, Calgary, Alberta, Canada Institute of Hydrology, Albert-Ludwigs University, Freiburg, Germany Department of Forest Resources Management, University of British Columbia Vancouver, British Columbia, Canada 29 06 2009 13 6 935 944 Copyright: © 2009 A. E. Anderson et al. 2009 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://hess.copernicus.org/articles/13/935/2009/hess-13-935-2009.html The full text article is available as a PDF file from https://hess.copernicus.org/articles/13/935/2009/hess-13-935-2009.pdf

Preferential flow paths have been found to be important for runoff generation, solute transport, and slope stability in many areas around the world. Although many studies have identified the particular characteristics of individual features and measured the runoff generation and solute transport within hillslopes, very few studies have determined how individual features are hydraulically connected at a hillslope scale. In this study, we used dye staining and excavation to determine the morphology and spatial pattern of a preferential flow network over a large scale (30 m). We explore the feasibility of extending small-scale dye staining techniques to the hillslope scale. We determine the lateral preferential flow paths that are active during the steady-state flow conditions and their interaction with the surrounding soil matrix. We also calculate the velocities of the flow through each cross-section of the hillslope and compare them to hillslope scale applied tracer measurements. Finally, we investigate the relationship between the contributing area and the characteristics of the preferential flow paths. The experiment revealed that larger contributing areas coincided with highly developed and hydraulically connected preferential flow paths that had flow with little interaction with the surrounding soil matrix. We found evidence of subsurface erosion and deposition of soil and organic material laterally and vertically within the soil. These results are important because they add to the understanding of the runoff generation, solute transport, and slope stability of preferential flow-dominated hillslopes.

 References Anderson, A. E., Weiler, M., Alila, Y., and Hudson, R. O.: Subsurface flow velocities in a hillslope with lateral preferential flow, Water Resour. Res., in review, 2009. Bouma, J., Jongerius, A., Boersma, O., Jager, A., and Schoonderbeek, D.: Function of Different Types of Macropores During Saturated Flow through 4 Swelling Soil Horizons, Soil Sci. Soc. Am. J., 41(5), 945–950, 1977. Brand, E. W., Dale, M. J., and Nash, J. M.: Technical Note: Soil pipes and slope stability in Hong Kong, Q. J. Eng. Geol., 19, 301–303, 1986. Fannin, R. J. and Jaakkola, J.: Hydrological response of hillslope soils above a debris-slide headscarp, Can. Geotech. J., 36(6), 1111–1122, 1999. Fannin, R. J., Jaakkola, J., Wilkinson, J. M. T., and Hetherington, E. D.: Hydrologic response of soils to precipitation at Carnation Creek, British Columbia, Canada, Water Resour. Res., 36(6), 1481–1494, 2000. Fannin, R. J. and Wise, M. P.: An empirical-statistical model for debris flow travel distance, Can. Geotech. J., 38(5), 982–994, 2001. Freer, J., McDonnell, J. J., Beven, K., Peters, N. E., Burns, D. A., Hooper, R. P., Aulenbach, B., and Kendall, C.: The role of bedrock topography on subsurface storm flow, Water Resour. Res., 38(12), 1269, https://doi.org/101029/2001WR000872, 2002. Flury, M. and Fluhler, H.: Tracer Characteristics of Brilliant Blue Fcf, Soil Sci. Soc. Am. J., 59(1), 22–27, 1995. German-Heins, J. and Flury, M.: Sorption of Brilliant Blue FCF in soils as affected by pH and ionic strength, Geoderma, 97(1–2), 87–101, 2000. Ghodrati, M. and Jury, W. A.: A Field-Study Using Dyes to Characterize Preferential Flow of Water, Soil Sci. Soc. Am. J., 54(6), 1558–1563, 1990. Holden, J., Burt, T. P., and Vilas, M.: Application of ground-penetrating radar to the identification of subsurface piping in blanket peat, Earth Surf. Proc. Land., 27(3), 235–249, 2002. Hutchinson, D. G. and Moore, R. D.: Throughflow variability on a forested hillslope underlain by compacted glacial till, Hydrol. Process., 14(10), 1751–1766, 2000. Jones, J. A. A., Richardson J. M. and Jacob, H. J.: Factors controlling the distribution of piping in Britain: a reconnaissance, Geomorphology, 20, 289–306, 1997. Kitahara, H.: Characteristics of pipe flow in forested slopes, IAHS-AISH P., 212, 235–242, 1993. McDonnell, J. J.: A Rationale for Old Water Discharge through Macropores in a Steep, Humid Catchment, Water Resour. Res., 26(11), 2821–2832, 1990. Montgomery, D. R. and Dietrich, W. E.: A physically based model for the topographic control on shallow landsliding, Water Resour. Res., 30(4), 1153–1171, 1994. Montgomery, D. R., and Dietrich, W. E.: Hydrologic processes in a low-gradient source area, Water Resour. Res., 31(1), 1–10, 1995. Mosley, M. P.: Streamflow Generation in a Forested Watershed, New-Zealand, Water Resour. Res., 15(4), 795–806, 1979. Nistor, C. J. and Church, M.: Suspended sediment transport regime in a debris-flow gully on Vancouver Island, British Columbia, Hydrol. Process., 19(4), 861–885, 2005. Noguchi, S., Tsuboyama, Y., Sidle, R. C. and Hosoda, I.: Morphological characteristics of macropores and the distribution of preferential flow pathways in a forested slope segment, Soil Sci. Soc. Am. J., 63(5), 1413–1423, 1999. Onda, Y.: Seepage Erosion and Its Implication to the Formation of Amphitheater Valley Heads – a Case-Study at Obara, Japan. Earth Surf. Proc. Land., 19(7), 627–640, 1994. Peters, D. L., Buttle, J. M., Taylor, C. H. and Lazerte, B. D.: Runoff Production in a Forested, Shallow Soil, Canadian Shield Basin, Water Resour. Res., 31(5), 1291–1304, 1995. Pierson, T. C.: Soil pipes and slope stability, Q. J. Eng. Geol., 16, 1–11, 1983. Roberge, J. and Plamondon, A. P.: Snowmelt runoff pathways in a boreal forest hillslope, the role of pipe throughflow, J. Hydrol., 95, 39–54, 1987. Sherlock, M. D. and McDonnell, J. J.: A new tool for hillslope hydrologists: spatially distributed groundwater level soilwater content measured using electromagnetic induction, Hydrol. Process., 17(10), 1965–1977, 2003. Sidle, R. C.: Shallow groundwater fluctuations in unstable hillslopes coastal Alaska, Zeitschrift für Gletscherkunde und Glazialgeologie, 20, 79–95, 1984. Sidle, R.C.: Groundwater accretion in unstable hillslopes of coastal Alaska, IAHS-AISH P., 156, 335–343, 1986. Sidle, R. C., Noguchi, S., Tsuboyama, Y., and Laursen, K.: A conceptual model of preferential flow systems in forested hillslopes: evidence of self-organization, Hydrol. Process., 15(10), 1675–1692, 2001. Sidle, R. C., Tsuboyama, Y., Noguchi, S., Hosoda, I., Fujidea, M., and Shimizu, T.: Seasonal Hydrologic Response at Various Spatial Scales in a Small Forested Catchment, Hitachi-Ohta, Japan, J. Hydrol., 168(1–4), 227–250, 1995. Sidle, R. C., Tsuboyama, Y., Noguchi, S., Hosoda, I., Fujidea, M., and Shimizu, T.: Stormflow generation in steep forested headwaters: a linked hydrogeomorphic paradigm. Hydrol. Process., 14(3), 369–385, 2000. Tani, M.: Runoff generation processes estimated from hydrological observations on a steep forested hillslope with a thin soil layer, J. Hydrol., 200(1–4), 84–109, 1997 Terajima, T., Sakamoto, T., Nakai, Y., and Kitamura, K.: Suspended sediment discharge in subsurface flow from the head hollow of a small forested watershed, northern Japan, Earth Surf. Proc. Land., 22(11), 987–1000, 1997. Terajima, T., Sakamoto, T. and Shirai, T.: Morphology, structure and flow phases in soil pipes developing in forested hillslopes underlain by a Quaternary sand-gravel formation, Hokkaido, northern main island in Japan, Hydrol. Process., 14(4), 713–726, 2000. Tromp-van Meerveld, H. J. and McDonnell, J. J.: Threshold relations in subsurface stormflow: 1. A 147-storm analysis of the Panola hillslope, Water Resour. Res., 42(2), W02410, https://doi.org/10.1029/2004WR003778, 2006a. Tromp-van Meerveld, H. J. and McDonnell, J. J.: Threshold relations in subsurface stormflow: 2. The fill and spill hypothesis, Water Resour. Res., 42(2), W02411, https://doi.org/10.1029/2004WR003800, 2006b. Tsuboyama, Y., Sidle, R. C., Noguchi, S. and Hosoda, I.: Flow and Solute Transport through the Soil Matrix and Macropores of a Hillslope Segment, Water Resour. Res., 30(4), 879–890, 1994. Tsukamoto, Y. and Ohta, T.: Runoff Process on a Steep Forested Slope, J. Hydrol., 102(1–4), 165–178, 1988. Uchida, T., Kosugi, K., and Mizuyama, T.: Effects of pipeflow on hydrological process and its relation to landslide: a review of pipeflow studies in forested headwater catchments, Hydrol. Process. 15, 2151–2174, 2001. Uchida, T.: Clarifying the role of pipe flow on shallow landslide initiation, Hydrol. Process., 18(2), 375–378, 2004. Uchida, T., Kosugi, K., and Mizuyama, T.: Runoff characteristics of pipeflow and effects of pipeflow on rainfall-runoff phenomena in a mountainous watershed, J. Hydrol., 222(1–4), 18–36, 1999. Uchida, T., Kosugi, K., and Mizuyama, T.: Effects of pipeflow on hydrological process and its relation to landslide: a review of pipeflow studies in forested headwater catchments, Hydrol. Process., 15(11), 2151–2174, 2001. Uchida, T., Meerveld, I. T., and McDonnell, J. J.: The role of lateral pipe flow in hillslope runoff response: an intercomparison of non-linear hillslope response, J. Hydrol., 311(1–4), 117–133, 2005. Weiler, M. and Fluhler, H.: Inferring flow types from dye patterns in macroporous soils, Geoderma, 120(1–2), 137–153, 2004. Wu, W. and Sidle, R. C.: A distributed slope stability model for steep forested basins, Water Resour. Res., 31(8), 2097–2110, 1995.