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CE 513. Erosion in the Fall Creek Watershed. Rick Faber. Erosion in the Fall Creek Watershed following the Clark Fire: Implications for the Hehe Timbersale. Clark Fire destroyed 5000 acres of undisturbed forest land in late 2003
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Erosion in the Fall Creek Watershed Rick Faber
Erosion in the Fall Creek Watershed following the Clark Fire:Implications for the Hehe Timbersale • Clark Fire destroyed 5000 acres of undisturbed forest land in late 2003 • Fall Creek is home to genetically diverse population of anadromous fish • Current proposals are for a 2500 acre timber sale in the neighboring Hehe Creek basin.
A is soil loss (tons/acre/year) R is the rainfall/runoff erosivity factor K is the soil erodibility factor (tons/acre/year) L is the slope length factor S is the slope steepness factor C is the cover management factor P is the support practice factor The universal soil loss equation is:A = R • K • L • S • C • P
Isoerodent Map of Oregon R = 50
L & S: Length & Steepness Now combined and expressed as a single factor. (Moore and Burch 1986) ArcHydro Spatial Analyst
C-Factor LARSE DATA
Mean Soil Loss for Fall Creek Watershed The loss of one inch of soil due to erosion is equivalent to 150 tons of soil per acre.
Limitations • Sedimentation vs erosion • Truncate the Flow accumulation grid for LS factor • Land cover & time • Systematic error?