Abstract
The groundwater level rise in the Ishikari Bay coastal area during the snowmelt period was analyzed using precipitation and snow depth data from a neighboring meteorological station, AMeDAS (AutomatedMeteorological Data Acquisition System). From a comparison of the variations in groundwater levels and snow depth, it was confirmed that snow cover played an important role in increasing the groundwater levels during the snowmelt period. The amount of precipitation that occurred before the snowmelt period was derived from determining the first day of snow cover and the first day of snowmelt. The amount of snow water equivalent that was present before the snowmelt period was calculated by subtracting the melting amount at the bottom of the snow cover from the calculated precipitation amount. A linear relationship was recognized between the amount of snow water equivalent and the rise in the groundwater level during the snowmelt period. The prediction of the groundwater level rise was made possible by using the amount of snow water equivalent. The total amount of snowmelt water was calculated by adding the precipitation amount during the snowmelt period to the amount of snow water equivalent, and this was also compared with the amount of groundwater level rise. A proportional relationship was recognized between these two amounts. The accumulated precipitation during the snow period was compared with the degree of groundwater level rise. It was considered that two-thirds of the accumulated precipitation during the snow period contributed to the groundwater level rise during the snowmelt period.
