Analysis of hydrologic characteristics applying to the filter separation AR method and the hourly rainfall components are inversely estimated from the ARX model from runoff data.

The purpose of this paper is to separate the total severe rainfall runoff into runoff components of overland flow, interflow and groundwater flow. The cut-off frequency to separate the total runoff time series into component runoff was determined by the slope of the semi-logarithmic plots of the recession curve. Time series of hourly runoffs are separated into components of surface flow, inter-flow and groundwater flow by numerical filters whose cut-off infrequencies are determined from the order of magnityde comparison of AR (autoregressive) coefficients of runoff data. Coefficients of the autoregressive moving average model applied to each of the subsystems were determined by the least-squares criterion from the recession period data. Time series of hourly rainfalls can be inversely estimated from hourly runoff by this method and it is consistant well with the observed effective precipotation time series. The estimated time series of rainfalls agree relatively well with the real rainfall data. It is clear that the filter separation AR method constitutes a flood system with higher accuracy than other methods.

autoregressive method

filter separation

hydrograph

inversely method

runoff