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[MIS23-03] The Characteristic Water Level Changes Mechanism of Kinugasanoike Pond on the Northern Japanese Alps
Keywords:Kinugasanoike, alpine ponds, water level, water balance, Northern Japanese Alps
Kinugasanoike (36.262°N, 137.615°E, 2215 m a.s.l.) is a small pond in a linear depression on the main ridge of the Northern Japanese Alps, caused by gravitational deformation of the mountain’s bedrock. The Kinugasanoike is thought to form in relation to evolution of the linear depression on the main ridge, however the recharge mechanism of the pond is not clear. The authors aim to clarify the characteristic water level changes mechanism of the Kinugasanoike due to observation of hydrostatic water level, water temperature, chemical characteristics of water (EC, pH, main ion concentration), and precipitation, in addition, analysis of the picture images of interval camera.
Kinugasanoike is completely iced and covered with 4m of snowpack in winter. The pond surface appears in mid-June every year when the snow melt is completed. The area of the catchment of the Kinugasanoike is 26724 m2, of which the area of the lake surface at steady water level is 258 m2. The snow-melting water is supplied from the surroundings to the Kinugasanoike, but snow-malting water accumulates on the ice because surface of the pond is still iced when early snow-melt season. On rainfall events, the pond level is sensitive to rainfall exceeding 2 mm per hour. This suggests that hourly precipitation exceeding 2 mm will cause surface runoff and raise the lake level even if there is no preceding rainfall. The Baiu and typhoon season brings a large amount of precipitation. The hourly rainfall of 20mm continues for 3 hours causes the water level of the pond rapidly rise more than 1m, but it take rapidly decreese return to the steady water level after the rainfall.
Kinugasanoike is completely iced and covered with 4m of snowpack in winter. The pond surface appears in mid-June every year when the snow melt is completed. The area of the catchment of the Kinugasanoike is 26724 m2, of which the area of the lake surface at steady water level is 258 m2. The snow-melting water is supplied from the surroundings to the Kinugasanoike, but snow-malting water accumulates on the ice because surface of the pond is still iced when early snow-melt season. On rainfall events, the pond level is sensitive to rainfall exceeding 2 mm per hour. This suggests that hourly precipitation exceeding 2 mm will cause surface runoff and raise the lake level even if there is no preceding rainfall. The Baiu and typhoon season brings a large amount of precipitation. The hourly rainfall of 20mm continues for 3 hours causes the water level of the pond rapidly rise more than 1m, but it take rapidly decreese return to the steady water level after the rainfall.