Slide rule for snow fence design

A method for determining required height and number of rows of snow fences has been used for more than 10 years to design effective snow fence systems for controlling drifts and augmenting water supplies. Because the procedure involves complex equations that are difficult for the typical user to solve, a simple pocket-sized slide rule has been developed that allows required fence height to be quickly determined from input values for fetch (contributing distance) and precipitation. Other design criteria included on the slide rule include required spacing of fences from the area to be protected, snow storage capacity, and required number of rows of 4.5- and 9-ft fences. The paper explains the basis for all calculations and simplifying assumptions, and includes drawings of the scales needed to fabricate the slide rule.