This paper describes the performance of a small undershot water wheel for power generation in a snow drainageway. The drainageway is utilized to remove snow surrounding houses and on roads in winter. The small hydroelectric power generation is expected the power source for a heater for the snow melting. The eifects of the height and number of blades on the performance of the water wheel were investigated by the field test at Shiramine, Hakusan-city, which is one of a heavy snowfall area in Japan. The water wheel had a diameter of D = 600 mm and a width of W = 410 mm. The water velocity was approximately 2.5 m/s. The power coefficient for a water wheel decreases with an increase in the height of blade. The power coefficient for a water wheel increases with an increase in the submerged height of blade h_c. The maximum power output of the water wheel is 84W at h_c/D = 0.20. The power coefficient for a water wheel with 8 blades and 100mm height has a maximum at C_<pmax> = 0.24. For a water wheel with 12 blades, the high power coefficient has a wide range to tip speed ratio.