• Journal of the Korean Geographical Society
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• v.41 no.4 s.115
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• pp.404-417
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• 2006

In order to clarify some characteristics of hydrological cycle in the subalpine zone of Mt. Halla, water balance has been analysed using hydrological data of a first-order drainage basin around Mansedongsan and meterological data of Odeung AWS. The experimental basin extends from 1,595 m to 1,645 m in altitude and has an catchment area of 1.34 ha. It is largely underlain by trachybasalt and covered with sasa bamboo and sedges. Hydrological observations were carried out every 20 minutes from April 15 to September 19, 2004. The basin shows the total precipitation of 3,074 m that is 1.6 to 3 times of those in coastal and intermontane regions. Surface runoff amounts to 850 mm that is equivalent to 27.6% of the precipitation. By contrast, evapotranspiration only accounts for 14.2% of the precipitation, and the remnant of 1,790 m penetrates underground through a basement. The basin is located in the subalpine zone and then it has a high rainfall intensity as well as a large rainfall due to frequent orographic precipitation. But surface runoff usually dose not exceed 30% of the rainfall while Percolation demonstrates about 2 times of the runoff. Compared with granite or gneiss basins in Korea Peninsula, the experimental basin is characterized by a higher portion of percolation in water balance. And it is probably related to the highly permeable basaltic lavas in Jeju Island which are also overlain by porous volcanic soils.