A simple deterministic model, that needs little input-data, is derived. It is based on an analysis of the recession curve, where new considerations are introduced. Input data consist of time-series of precipitation, initial values of storage in upper and lower soil-storages and in interception storage, and initial runoff. Output data are time-series of evapotranspiration, interception, upper and lower soil-storages and runoff, all given as 2-hour mean values.