DEVELOPMENT OF LUMPED RUNOFF MODEL BASED ON SATURATED SUBSURFACE FLOW IN MOUNTAINOUS RIVER BASINS

Abstract

A lumped runoff model in mountainous river basins is developed. This model consists of three runoff components, i.e. river flow and two types of subsurface flows in saturated zone. These water movements are represented by the basic differential equations derived from the hydraulic principles, such as the equations of unsteady flow and the Darcy’s law based on Dupuit-Forchheimer assumption. The identification procedure of the model parameters is presented and the estimation method of runoff hydrograph from the calibrated model is given. The model is applied in the Miwa experimental area (1.36 km²) and the Miwa dam catchment area (311.1 km²) of the Mibu River, Chubu area, Japan. The results show the good agreement between estimated and observed flood flow hydrographs.