河川流出と融雪流出過程の調査法

Abstract

Streamflow can be only measured as a spatially integrated value among the basin-wide water balance components. As the measurement of high-water flow is important for the river planning and the flood control measures in large rivers in Japan, new studies are proceeding with the improving the accuracy of streamflow measurement such as ADCP and PIV techniques. Meanwhile, during the low-flow period or in the small river, conventional gauging methods are used, including the current meter method and the weir. Dilution gauging method is effective particularly in the mountainous gravel-bed streams. However, reported examples are not so much. Understanding to the role of snow within the snowmelt runoff process is essential in the snowy cold region. Snow lysimeter and snow pillow are useful in these studies. Preferential flow through the snowpack and the dependence of percolation speed on the snow properties are studied using those equipments. Most difficult problem is how to estimate the basin averaged snowmelt amount. Additional researches are needed which combines conventional snow melting factor method and satellite imagery data.