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<br />Terry, J.P., and Shakesby, R.A., 1993, Soil hydrophobicity effects on rainsplash- <br />simulated rainfall and photographic evidence: Earth Surface Processes and <br />Landforms, v. 18, p. 519-525. <br />Video cameras and still photography were used in conjunction with rainfall simulation <br />experiments to investigate the erosional effects of rainsplash on water-repellent soils. The <br />experiments used sandy loam soil samples from the Agueda Basin in north central Portugal. <br />Although not explicitly stated, the water repellency appeared to be fire-related. Splash <br />ejection droplets from water-repellent soils were larger, slower, and carried more sediment <br />than drops from wettable soils. The mechanism of detachment (illustrated with carroons) <br />also differed, in that rainfall on water-repellent samples exposed the underlying dry soil to <br />splash detachment by subsequent drops, whereas wettable samples developed a "cohesive <br />surface layer" that reduced soil loss. As a result, splash losses were consistently greater on <br />water-repellent samples. The implications of these results are discussed with respect to <br />erosion of water-repellent soils (particularly in burned areas). <br /> <br />Topalidis, S., and Crockford, R.H., in press, Water Repellency in a dry schlerophyll <br />eucalypt forest - runoff generation: Hydrologic Processes. <br />Rainfall-induced runoff characteristics were investigated in a small, eucalypt catchment near <br />Canberra Australia. The study combined information from tensiometers and piezometers <br />with measurements of surface hydraulic conductivities to help explain the occurrence of <br />anomalously low runoff values for precipitation events. Despite the presence of intensely <br />water-repellent soils and observations of overland flow, instruments recorded very little <br />surface runoff in the catchment. Researchers concluded that runoff was negligible because <br />macropores enabled water to bypass the water-repellent soils at the surface and infiltrate to <br />lower layers. Most of the water moved through macropores less than lmm in diameter, <br />although larger macropores resulting from burrows and channels adjacent to tree roots, also <br />provided conduits for infiltration. This was another case in which the water-repellent soils <br />had an unusually high clay content (20-40%). <br /> <br />Van Dam, J.C., Hendrickx, J.M.H., Van Ommen, H.C., Bannink, M.H., Van <br />Genuchten, M.Th., and Dekker, L.W., 1990, Water and solute movement in a <br />coarse textured water-repellent field soil: Journal of Hydrology, v. 120, p. 359- <br />379. <br />This paper provides a method for simulating unstable water flow in naturally water-repellent <br />soils. A numerical model based on Richards' equation for unsaturated flow and Fickian- <br />based convection-dispersion equation for solute transport is presented. Water repellency is <br />accounted for by defIning a factor equal to the volumetric fraction of the soil occupied by <br />preferential flow paths. <br /> <br />37 <br />