CGRG Bibliography of Canadian Geomorphology
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Author : Beaudry, P.G.; and Golding, D.I.
Date : 1985.
Title : Snowmelt and runoff during rain-on-snow in forest and adjacent clearcut
Publication : Presented at Snow Property Measurements Workshop, Lake Louise, Alberta, April 1-3, 1985. Technical Memorandum
Issue : 140.
Page(s) :
Abstract
Abundant precipitation during late fall and winter is a predominant characteristic of the Coastal mountains of British Columbia. At high elevations snowfall is the dominant process, while at low elevations precipitation may fall almost exclusively as rain. The zone referred to as the transient snow zone, located between the high and low elevation, receives a mixture of snow and rain, with many successive snow-accumulating and melting periods throughout the season. For southwestern British Columbia this transient snow zone extends form about 400 to 1000 meters above sea level. The heavy winter rainfall that coincides with the presence of snow in this transient snow zone is often the source of peak flows for many coastal watersheds. The combination of large amounts of rainfall and rapid snowmelt has the potential for initiating debris torrents, floods and headwater erosion. Harr (1981) documented the potential hazards naturally occurring from thjis type of event and indicated that 85% of landslides studied in western Oregon were associated with snowmelt during rainfall. Many of the present forest harvesting activities are located in this transient snow zone. Recently the question has been raised by forestry and fisheries managers, forest companies, and the public as to how does forest harvesting affect snowmelt and subsequent runoff during rain-on-snow events. Of concern is the possibility of much higher runoff generated from large clearcut areas, compared to uncut forests, resulting in higher peak flows. The U.S. Army Corps of Engineers (USACE) 1956 snowmelt equation suggest that clearcut harvesting could increase runoff during rain-on-snow, largely due to the higher snowmelt rates caused by increased transfer of sensible and latent heat to the snow surface. However, some authors suggest that clearcut logging has little or no effect, or even decreases runoff (Harr et al. 1975, Harr and McCorrison 1979, Rothacher 1973, Anderson 1970). This study was initiated with two main objectives: 1. To compare the energy and water balances of a melting snowpack during rain-on-snow for the forest and for a recent clearcut, and 2. To determine the applicability of the USACE snowmelt equations for coastal rain-on-snow situations in both forest and open sites.
Bibliography of Canadian Geomorphology