The calassification of rainfall runoff patterns in Hokkaido

Research Project

Project/Area Number	04660243
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	農業土木
Research Institution	HOKKAIDO University
Principal Investigator	SAKURADA Junji Faculty of Agriculture, Hokkaido University Lectur I, 農学部, 講師 (80001460)
Project Period (FY)	1992 – 1994
Project Status	Completed (Fiscal Year 1994)
Budget Amount *help	¥1,900,000 (Direct Cost: ¥1,900,000) Fiscal Year 1994: ¥400,000 (Direct Cost: ¥400,000) Fiscal Year 1993: ¥400,000 (Direct Cost: ¥400,000) Fiscal Year 1992: ¥1,100,000 (Direct Cost: ¥1,100,000)
Keywords	Rainfall / Intensity of rainfall / Pattern of runoff / Tankmodel / Soils
Research Abstract	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.