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has been cited by the following article:

• TITLE: Rainfall and Runoff Observations in the Subtropical Forest of Okinawa Island, Japan

  AUTHORS: Naoki Kabeya, Akira Shimizu, Takanori Shimizu, Hitoshi Ikuzawa, Takuya Arakaki, Hiroshi Furugen, Yashuhiro Ohnuki, Shiho Asano

  KEYWORDS: Direct Runoff, Forested Watershed, Okinawa Island, Rainfall-Runoff Observation, Sub-Tropical Forest, Water Balance

  JOURNAL NAME: Journal of Water Resource and Protection, Vol.6 No.6, April 29, 2014

  ABSTRACT: We set up two experimental catchments to provide an improved understanding of hydrological processes in a subtropical forested area in the northern part of Okinawa Island, Japan. We calculated runoff using water level data (recorded by a pressure-type water level gauge installed in a box culvert) and a discharge rating curve (derived from in situ observations). Water balance calculations for 2010 showed that the rainfall, runoff and evapotranspiration losses (= rainfall – runoff) were 3403.6 mm, 2285.7 mm and 1117.4 mm, respectively. This result was in agreement with previous results from other forested experimental catchments in this region. Direct runoff, as a proportion of event total rainfall, can be expressed by the empirical equation (Qdirect = 0.0048, Pevent 1.7971, R2 = 0.9599). When Pevent was 100 mm or less, the ratios of Qdirect to Pevent were less than 15% in general. When Pevent exceeded 100 mm, the ratios were 20% - 30%.