IENE 2016

Hokkaido, the 2^nd largest island of Japan, is quite snowy with annual snowfall of approx. 700 cm and the max. 200 cm cumulative snow. The tremendous snow accumulation due to such heavy snowfall causes in winter the function deterioration or loss of deer-vehicle collision prevention facilities including deer-proof fences, jump-outs, one-way gates, underpasses, overpasses, and warning signs. Especially, deer-proof fences are sometimes even broken by deep snow accumulation. This study outlines how snow accumulation hinders the function of deer-vehicle collision prevention facilities and seeks measures to minimize the snow troubles.

The types of the facility function deterioration or loss caused by snow accumulation are broadly classified into two: one is the trouble without physical break and another is the one caused by physical facility damage. The facility function deterioration or loss without physical damage of facilities include cases such as: deer fences whose heights are lowered by snow accumulation cannot prevent deer from entering the roadway, or deer cannot use an underpass because its entrance is blocked with snow. The facility function deterioration or loss due to physical damage of facilities may occur because of a part of or complete damage on fence posts, mesh fences, one-way gates’ bars and warning sign poles.

This study focuses on troubles caused by snow on deer fences. In winter, the deer fence height is lowered due to snow accumulation, which enables deer to overleap the fence to enter the roadway. This problem becomes serious when deer fences are located in the area that is within or close to a deer wintering place. In such an area, in the thawing season, the repetition of thawing and freezing of snow hardens accumulated snow, which facilitates deer to overleap deer fences so as to enter the roadway. As a countermeasure against such problems, the height of the fences is increased to prevent deer from entering the roadway in the snowy season.

The state of the facility function deterioration or loss due to physical damage of facilities including fence posts and mesh fences may vary depending on the level of snow accumulation, topography, cut slope structures, weight pressures of removed snow and the location where they exist. To minimize the problems caused by broken deer fences by snow, facility maintenance or repair works are conducted to strengthen or replace damaged parts.

More information on the function deterioration or loss of deer accident prevention facilities caused by snow need to be collected to keep the facilities to function properly in winter in snowy areas, seeking for solutions to minimize the snow troubles.