The calassification of rainfall runoff patterns in Hokkaido

通过对北海道石狩川流域几个小流域的水槽模型径流分析，结果表明：当降雨量较大时，第一水槽的低径流孔系数较大，火山灰土壤流域的低径流孔系数较大，结果表明，泥炭狗流域的土壤肥力系数与其它土壤类型的土壤肥力系数有较大的差异，降雨历时、总降雨量、降雨强度、峰值降雨量等变量对第一池和第四池低渗孔系数的影响主要受降雨特性的影响，火山灰土壤集水区的决定系数对径流孔的各项系数影响较大，集水区的土壤是最大的影响因素，火山灰土壤集水区的决定系数受火山灰土壤集水区的影响最大结果表明，在降雨量峰值时，粘性土流域的影响较大，草地土壤的孔隙度、渗透率和入渗量均小于森林土壤，草地的降雨量峰值系数在0.4-0.6之间，大于森林土壤。

The resalts that the runoff anarysis by Tankmodel were examined at several watersheds in Ishikari River basin in Hokkaido were followed.When the rainfall is large, the coefficient of the low runoff hole at the first tank was large.the coefficients was larger at the watershed of the volcanic ashes soil, loam soil and clay soil.The coefficients at the peat dog watersheds were differed tenndensy from other soil watersheds.By regression anarysis with expanatory variable of rainfall duration, of total rainfall, of rainfall intencity and of peak rainfall, the coefficients of the low runof hole at the first tank and the 4th tank were influenced by rainfall charactristics.Specially, the coefficient of determination of the volcanic ashes soil watersheds was large influenced for all the coeficients of the runoff hole.Soils of watershed is a largest element.the volcanic ashes watershed was influenced by the total rainfall.Clay soil watershed was large facter at peak rainfall.The values of pores, permiability and infiltrations of soils at the pastuter was smaller than that of the forest.The coefficient of the peak discharge at the pastuer was the value of 0.4-0.6 for the center or back peak of rainfall.This was larger than that of the forest.