Effects of Clearcutting on Rain‐on‐Snow Runoff in Western Oregon: A New Look at Old Studies

Abstract

Results of updating and reanalyzing streamflow data from studies in two experimental watersheds in western Oregon suggest that clearcut logging has altered snow accumulation and melt enough to have increased the size of peak flows caused by snowmelt during rainfall. In a 96‐ha clearcut watershed in the transient snow zone, peak flows with return periods of roughly 3–8 years were higher than predicted by prelogging data. In a similarly clearcut 10‐ha watershed, sizes of peak flows caused by melting of relatively deep snowpacks during rainfall were also higher after logging. Higher peak flows indicate a higher rate of water delivery to soils, which, in turn, suggests increased potential for both hillslope and channel erosion.