1. Professor of Hydraulics and Hydrology Units, Kanazawa Inst. of Technology, 3-1, Yatsukaho, Hakusan-shi, Ishikawa Prefecture 924-0838, Japan (corresponding author).
2. Graduate Student, Civil Engineering Dept., Kanazawa Inst. of Technology, 7-1, Ogigaoka, Nonoichimachi, Ishikawa Prefecture, 921-8501, Japan