Outdoor scale modeling of shrub barriers in drifting snow

Abstract

Model shrub barriers one-twentieth the average height of corresponding mature plants were exposed to snow drifting on a frozen lake, to test the effects of barrier porosity and row spacing on snow accumulation. Single rows with porosities of 8, 15, and 23% produced drifts with average cross-sectional areas of 9 H 2, where H is model height, The area of the average deposition downwind of a 36% porosity model was 12 H 2. Total deposition behind two model shrub rows spaced 8, 10 and 14 H apart, perpendicular to the wind, was greatest for the largest spacing. At this spacing, the minimum snow depth between rows was 0.5 H. The experiments demonstrate the importance of maintaining porous barriers. Gaps, simulating shrub mortality, greatly reduced snow storage, especially during high winds. Results from this investigation indicate that a porous shrub in rows spaced at least 14 times the average barrier height, would provide good snow distribution for forage production between rows.