Economic evaluation of different snow-removal systems is important for optimizing measures against heavy snowfall in an urban area. In the present paper, a new method for the estimation is proposed and applied to two existing snow-removal systems on the roads of the commercial area of Nagaoka city. The annual costs and benefits of snow-melting pipes and snowremoval vehicles are calculated by using previous data of snow removal.
The calculated benefit-cost ratios in that area are 10.9 and 16.1 for the snowmelting pipes in the years of average and abundant snowfall, respectively. The same ratios for the snow-removal vehicles are 10.7 and 7.6. This means that both systems are economically effective. The dependence of the costs and the benefits on the amountsof snowfall is also examined. It is concluded that the snow-removal vehicles have higher benefit-cost ratio than the snow-melting pipes in years of total snowfall less than 600cm. However, in years of snowfall greater than this, the snow-melting pipes are shown to have higher cost-benefit ratio.

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A new measuring system for snow-dumping channel systems is developed in this study. The fraction and the transport rate of the snow in the snow-water mixture flowing in a channel can be measured in real time by this new system. The depth of the mixture and the traveling speed of snow clusters can also be measured continuously. This paper describes the application of the conductometric method to this new system and experimental results obtained in an indoor testing channel. The experimental results show that this new system is sufficiently practical.

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Snow cover environments in Japan are classified into four categories using the mesh climatic data. They are wet snow region, dry snow region, intermediate region and depth hoar region. The wet snow region is the region in which every layer of the deposited snow is wet due to percolation of snow melt water throughout the winter season. In this region snow cover is governed by the melt metamorphism even in the coldest period of winter season. The regions which are climatically colder than the wet region are divided into two snow-type regions, namely the depth hoar region where development of depth hoar is expected and the dry snow region.
Areas where the monthly maximum snow cover depth in any month between December and March is greater than 10cm are examined using the mesh climatic data. Critical values of the monthly mean temperature dividing the wet snow region and dry snow region were determined from snow surveys. The regions that have a monthly mean temperature in January higher than 0.3°C in the mesh climatic data belong to the wet snow region and the region, in which the monthly mean temperature in January is lower than -1.1°C belong to the dry snow region. The regions with intermediate monthly mean temperature in January are classified as intermediate regions.
The depth hoar region are decided from the empirical formula obtained by Akitaya and Endo (1982), substituting variables for the mesh climatic data.

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[in Japanese]

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[in Japanese]

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