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<br />Poff, R.J., 1989, Distribution and persistence of hydrophobic soil layers on the Indian
<br />burn, in Berg, N.H., ed., Symposium on Fire and Watershed Management:
<br />Pacific Southwest Forest and Range Experiment Station, Sacramento, Calif.,
<br />October 26-28,1988, Proceedings, General Technical Report PSW-l09, p. 153.
<br />This report describes the occurrence of water-repellent soils in the Tahoe National Forest,
<br />following the Indian fire in September, 1987. Approximately 250 ha contained severely
<br />water-repellent layers up to 38 centimeters thick, but 5- to 10- centimeter thicknesses were
<br />more common. The deepest and most intense layers were found beneath stands of white fIr.
<br />Areas without duff, however, did not exhibit water repellency, suggesting that the amount
<br />and type of litter present before the burn contributed to the development of fire-induced
<br />water repellency. The thickness of the A horizon and fire intensity also appeared to affect
<br />the nature of repellency. Mechanical disturbance of thick water-repellent layers proved
<br />ineffective in mitigating hydrophobic conditions, but did appear to improve conditions
<br />where thinner layers existed.
<br />
<br />Richardson, J.L., and Hole, F.D., 1978, Influence of vegetation on water repellency in
<br />selected western Wisconsin soils: Soil Science Society of America Journal, v.
<br />42, p. 465-467.
<br />Soil wettability was assessed with respect to various soil types and plant communities in
<br />western Wisconsin. Three criteria were used to characterize the water repellency, including
<br />wetting angle, water drop penetration time (WDPT), and 900 surface tension. Researchers
<br />found that water repellency appeared to be linked to fungi under plant communities with red
<br />pine (Pinus resinosa) or hemlock (Tsuga candensis). They also found that burning prairie grass
<br />resulted in increased soil-water repellency.
<br />
<br />Ritsema, C.J., and Dekker, L.W., 1994, How water moves in a water repellent sandy
<br />soil- 2. Dynamics of fingered flow: Water Resources Research, v. 30, no. 9, p.
<br />2519-2531.
<br />The companion paper to Dekker and Ritsema (1994), this one focuses on the dynamics of
<br />finger flow. Researchers found that the width of the "fingers" in the fIeld would expand or
<br />shrink in diameter, depending on weather conditions. They also found that water contents
<br />in the fingers were higher in the top soil, and became drier with depth. Finger flow was
<br />found to be an important process in grass-covered, water- repellent, sandy soils.
<br />
<br />Ritsema, C.J., and Dekker, L.W., 1995, Distribution flow- a general process in the top
<br />layer of water repellent soils: Water Resources Research, v. 31, no. 5, p. 1187-
<br />1200.
<br />This investigation attempts to quantify the effects of "distribution flow", a term introduced
<br />in the 1993 paper by Ritsema, et al. The authors describe several soil factors that facilitate
<br />the formation of distribution flow, including the presence of a water-repellent layer. They
<br />conclude that modeling of distribution flow must be done in two or three dimensions.
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