2008 Volume 2 Pages 14-17
This study examines rainfall-runoff characteristics of catchments underlain by granitic and sedimentary rock. Differences in bedrock geology and forest age for sedimentary rock catchments were considered. In granite catchment, the quick flow ratio was small and baseflow was sufficient even during dry conditions because of large water storage within the soil and the relatively homogeneous weathered bedrock. In sedimentary rock catchments, water that infiltrated to the soil and fractured bedrock drained quickly, causing large quick flow over short, rainstorm timescales. The peak flow was lower in sedimentary rock catchments with older forest where the soils were more developed over longer periods of forest growth. The differences among sedimentary rock catchments by forest age were smaller than the differences between granitic and sedimentary rock catchments. Bedrock geology is of primary importance for categorizing and identifying universal rainfall-runoff characteristics.