The Impacts of Forest Type on Peak Flows in Long-term Hydrological Data at Three Small Forested Catchments

摘要

This study was conducted to clarify the forest function of floods modulation through the relationship between rainfall and peak flows in the three kinds of forest type. The experiment sites in Gwangneung include the natural mature deciduous and plante d young coniferous forests. Also the rehabilitated mixed forest locates in Yangju, Gyeonggi-do, Hydrologic data including rainfall, discharges have been measured in the gauging weirs from 1982 to 1999, About 110 storm hydrographs for each site were selec ted for the purpose of analyzing the amount of rainfall to peak flows and peak flow rates Peak flows in the planted young coniferous forest increased suddenly as the amount of rainfall to peak increased over 100 mm as a threshold value. On the other hand the rehabilitated mixed forest showed the threshold value of 50 mm. Difference of threshold values in two forests resulted from conditions of forest structure and soil. Peak flow rates of the natural mature forest deciduous increased very gradually to 2 00 mm rainfall owing to good conditions of forest structure and soil. In case of the planted young coniferous forest, the slope of relation line between peak flow rates and rainfall is gentler after 10-year. The mixed forest showed no difference between the slopes before and after 10-year. Difference of peak flows between three forest types decreased considerably in July 1993 compared in July 1983. The result above reflects the fact that forest development improves the forest function of peak-flows modu lation.