Hydrological variations of discharge, soil loss and recession coefficient in three small forested catchments

This study aims to understand hydrological variation of discharge, soil los s and recession coefficient in three small forested catchments using the lo ngterm hydro-data from 1983 to 1992. The study catchments include the natur al matured deciduous, artificial planted coniferous and erosion-control wor ked mixed forest. The amount of discharge and soil loss varied with the rai nfall and forest type. Especially it was concerned on the variation of the recession coefficient closely related to storage capacity in three forested watersheds to clarify the effects of forest development on water resource augmentation. In erosion-control worked mixed forest, the recession coeffic ients for interflow and groundwater have gradually reduced since erosion co ntrol work finished. This can be interpreted to result from the increment o f the storage capacity caused by improvement of the soil physical propertie s in catchment after erosion control work. In artificial planted coniferous forest, the recession coefficients related to surface runoff and interflow slowly decreased as the forest grew. However all recession coefficients in natural matured deciduous forest did not show any evident trends because o f not change of the forest stand structure.