Abstract
In this paper, two types of direct runoff which include fast or slow runoff component were separated using the observed discharge data in a terraced paddy catchment and a forest one to compare them and discuss the properties. As a result, it was found that the direct runoff in the terraced paddy field catchment was greater than that of forest catchment and direct runoff in irrigation season of the terraced paddy field was also greater than that in non-irrigation season. Then, water balance concept was applied to the period of direct runoff. It was shown that the percolation rate of the terraced paddy filed catchment was less than that of forest one and the rates were similar in non-irrigation and irrigation season of the terraced paddy filed. Furthermore, the effect of initial soil moisture deficit on direct runoff was discussed.
