DEVELOPMENT OF A STORAGE DISCHARGE RELATIONSHIP TO REFLECT WATER RETENTION CURVE, AND ITS APPLICATION TO A DISTRIBUTED RUNOFF MODEL

Abstract

 We developed a new storage discharge relationship based on water retention curve whose parameters are determined by experiments or observations. The proposed method assumes the vertical equilibrium distribution of pressure head and uses Brooks Corey and Mualem model for estimating water retention curve and unsaturated hydraulic conductivity. The new storage discharge relationship was applied to a distribute runoff model. It was found that the model can reproduce observed discharge with realistic soil parameters. Difference in soil storage effect based on four representative soil types and initial conditions with four durations of no rain appeared clearly. Storage amounts depended on moisture situation in basins and soil porosity.