Abstracts for the 5th International GAME Conf.
3-5 October 2001
Aichi Trade Center
Nagoya Japan
Runoff characteristics of a small stream in the Siberian tundra and their seasonal changes
Yoshiyuki Ishii (1), Mutsumi Nomura (2), Yuji Kodama (1), Norifumi Sato (1), Hironori Yabuki (5)
(1) Institute of Low Temperature Science, Hokkaido University
(2) Hokkaido University Forest
(5) Frontier Observational Research System for Global Changes
Rainfall-runoff characteristics of a small stream (5.5 km2) were examined in the Siberian tundra during the three summer seasons from 1997 to 1999. Storm hydrographs showed steep rising limb and slow recession, and the runoff ratios were high ranging from 0.6 to 0.9. These characteristics were similar in the North American tundra stream. However, the average time from initial rise to peak in 32 storm hydrographs was three times faster than that in North America. As the stream channel network is well developed in this basin, flow pass of the water on the slopes covered with tundra vegetation is short. In addition, the streambed gradient is steep ranging from 0.02 to 0.06. These hydraulic features in topography could cause the fast response time in the rainfall-runoff relationship. Thawing depth of the active layer increased from 10 cm in early June to 50 cm in late August. However, the seasonal changes in runoff characteristics due to mainly the increase of soil water storage capacity was not recognized clearly. The time lags between the hyetograph and hydrograph centroids and runoff ratios were remarkably changed from event to event.
Submittal Information
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Institute of Low Temperature Science, Hokkaido University | |
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Kita 19, Nishi 8, Kita-ku, Sapporo 060-0819, Japan | |
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ishiiy@pop.lowtem.hokudai.ac.jp | |