APPROACH TO INFILTRATION AND RUNOFF PROCESS OF RAINWATER IN SLOPE OF WATERSHED (2)

Abstract

The previous paper has proposed a mathematical model of runoff put emphasis upon theprocesses of prompt and delayed groundwater runoff. This paper deals with a practical methodfor determining constants and curves required for the model to be applied in hydrograph analy-ses.The depth of active soil layer is estimated through changes of the soil moisture content andthe river discharge. Both the inifiltration rate and soil moisture flux curves being functionsof soil moisture content cannot but be determined after trial calculations. In order to save thetrial calculations, however, those curves are given on the basis of numerical solutions under somehypothetical rain and soil conditions. Applied examples are also shown for hydrographs at theoutlet of the Minegado experimental basin.The previous paper has proposed a mathematical model of runoff put emphasis upon theprocesses of prompt and delayed groundwater runoff. This paper deals with a practical methodfor determining constants and curves required for the model to be applied in hydrograph analy-ses.The depth of active soil layer is estimated through changes of the soil moisture content andthe river discharge. Both the inifiltration rate and soil moisture flux curves being functionsof soil moisture content cannot but be determined after trial calculations. In order to save thetrial calculations, however, those curves are given on the basis of numerical solutions under somehypothetical rain and soil conditions. Applied examples are also shown for hydrographs at theoutlet of the Minegado experimental basin