Citation

Tabler RD. Transp. Res. Rec. 1974; 506: 65-78.

Copyright

(Copyright © 1974, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

New engineering criteria for snow fences have been used to design a snow control system that is unusually effective in preventing drifts, improving visibility, and reducing the formation of road ice. This paper describes these criteria and the research results on which they are based. The amount of blowing snow arriving at each site was estimated from an equation relating the snow transfer coefficient, the transport distance, and the precipitation received over the contributing distance. Measurements in southeast Wyoming show the "equivalent transport distance" to range from about 500 to 1200 m. The height and number of rows of fencing at each site were selected to provide the required capacity. An equation for computing the cross-sectional area of the saturated lee drift behind the new Wyoming Highway Department standard-plan fence is given. Tall (3.8-m) fences have been used in perference to shorter ones because experience has shown taller structures to be more efficient in trapping snow and to have a much lower construction cost per unit of storage. Because studies have shown the average trapping efficiency of a fence from onset of accumulation to time of saturation to be about 85 percent, storage capacity is made about 20 percent greater than the estimated amount of blowing snow. Terrain can be used to greatly increase the capacity of snow fences; for example, capacity is increased 15-20 percent for each 0.017 rad of downslope behind a fence and about 15 percent for each 0.017 rad of upslope in the approach zone. Because wind sweeping around fence ends reduces storage times the height, length of fences should be at least 30 times their height and staggered barreirs should be overlapped at least 8 times their height.