EFFECT OF SCALE OF CATCHMENT ELEMENT ON RUNOFF RESPONSE OF THE DISTRIBUTED MODEL

Abstract

Distributed runoff models have been becoming powerful for describing the naturalrunoff processes. Such kind of model should reflect topographical features of a catchment. Then, it is necessary to examine about the possibility of aggregationas the catchment model. The purpose of this study is to investigate the effect of catchment scale of the element on runoff response characteristics. Runoff simulations in the conditions of the overland flow and the interflow by using two kinds of different mesh sizes of digital elevation model in the Hayakawa River, central Japan, were carried out. Then the concentration times of these runoffs were discussed. The result is as follows; 1) the concentration time depends on the mesh scale, 2) the influence of aggregation caused a difference in case of computation, and 3) the problem is solved by using a model parameter that gets equivalent average concentration time.