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 (651Kb)
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19,964,000 Yen (FY1995 5,268,000 Yen)
Some hydrological observations were conducted at Bukit Tarek Experimental Watershed in tropical rainforest. Soil physical properties, soil depth and water flow patterns in soil were investigated. The detail obtained information are useful in order to analyze water flow and slope stability in tropical rainforest. In addition, rainfall characteristics, runoff characteristics, role of soil moisture variations in rainfall-runoff responses and evapotranspiration from a basin were analyzed using hydrological data.
There is a distinct diurnal cycle in precipitation at BT, in which about 60% of the rainfall occurred between 13:00 hr and 19:00 hr. The rainfall at BT was characterized by short duration and high intensity. The stormflow generation depended strongly on the antecedent wetness which represented by initial runoff rate. For storms with initial runoff rate ≧0.1mm h-1, rain water excess over the initial loss, that is about 30mm in this case, seems to become stormflow. Confined and unconfined recession constants are 0.02290-0.05315(mean: 0.04265) and 0.01095-0.01962(mean: 0.01590), respectively. Though heavy rain normally occurred every month at BT, there were occasional short dry spells during dry months and the soil moisture decreased for the periods. The streamflow hydrograph responded quickly to rain event but declined rapidly during dry conditions. The streamflow hydrograph responded quickly to rain event and declined gently during wet conditions. The daily mean evapotranspiration was calculated by the short-term period water-budget method considered water storage. The values varied from 2.74 to 4.86mm day-1. There isn't distinct seasonal variation.
Tropical Rainforest, Rainfall Characteristics, Runoff Characteristics, Hydrological Responses, Evapotranspiration