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Rill erosion in natural and disturbed forests: 1. Measurements
Robichaud, P.R.; Wagenbrenner, J.W.; Brown, R.E. 2010.
Rill erosion in natural and disturbed forests: 1. Measurements.
Water Resources Research 46, W10506, doi:10.1029/2009WR008314. 14 p.
Keywords: rill erosion
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Abstract:
Rill erosion can be a large portion of the total erosion in disturbed forests, but
measurements of the runoff and erosion at the rill scale are uncommon. Simulated rill
erosion experiments were conducted in two forested areas in the northwestern United
States on slopes ranging from 18 to 79%. We compared runoff rates, runoff velocities, and
sediment flux rates from natural (undisturbed) forests and in forests either burned at low
soil burn severity (10 months or 2 weeks post-fire), high soil burn severity, or subject to
skidding of felled logs. The runoff rates and velocities in the natural sites
(2.7 L min-1 and 0.016 m s-1, respectively) were lower than those in all the disturbed sites
(12 to 21 L min-1 and 0.19 to 0.31 m s-1, respectively), except for the 10-month old low
soil burn severity site where the velocity (0.073 m s-1) was indistinguishable from the
natural sites. The mean sediment flux rate in the natural sites also was very small
(1.3 × 10.5 kg s-1) as compared to the rates in the disturbed areas (2.5 × 10.4 to
0.011 kg s-1). The hillslope gradient did not affect the runoff or sediment responses. The
sediment flux rates generally were greater in the initial stage of each inflow period than in the
steady state condition, but there was no corresponding transient effect in runoff rates. Rill
erosion modeling implications based on these data are presented in part 2 of this study.
Moscow FSL publication no. 2010g
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