Runoff characteristics in a tropical rain forest catchment

Abstract

Knowledge of runoff characteristics plays an important role in managing the function of water conservation in the forests. Hydrological observation was conducted at Bukit Tarek Experimental Watershed (BTEW) of a tropical rain forest in Peninsular Malaysia. Stormflow, groundwater recession and stream regimen characteristics were analyzed based on 3-y (1992-1994) of record. Small storm events (< 30 mm) produced less than 10% of rainfall as stormflow, which may have been determined in the stream channel and riparian areas. The stormflow depended strongly on the antecedent wetness as represented by the antecedent flow rate during large storm events (≥ 30 mm). The depth and physical properties of soils could be important factors to determine production of stormflow. The discharge-duration curves were different among 1992, 1993 and 1994 because of the differences of variation in rainfall (e.g. monthly distribution) and annual rainfall. The relationship between ratio of plentiful runoff to scanty runoff and recession coefficient at BTEW was similar to the results from watershed underlain by the same geology in Japan. These results imply that soil, variation in rainfall, as well as annual rainfall and geology are important factors to understand runoff characteristics.