No.51 pp.3558, 2015 Komazawa Journal of Geography Rivers and Hydrological-Environment of Musashino-Upland in Tokyo Metro. SUMIDA Kiyomi Keywords: Musashino-uplandShakujiigawa-riverNogawa-riverunconfined groundwater confined groundwaterinundation inside the leveenomizumizumichi 846 km 2 47 km m m210m 15m 20m 35
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47 1972 1982 1.3 km 4 8 1 2,700t 2.5 km 21km 21km 21km 3 3km 2km JR 1928 1977 19811988 100m75m 1,000 26 710m 12m 38
1969 2 2 1. 95m57m1,000 2 70m 2. 2m 1m 3. 72m 4. 70m 70m 70m m 39
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2006 2007 10m 8 10m 3.5 5m 1316m 12m 12m 4 4km 67m 13 24m 42
図4 国分寺崖線付近の地形発達史 模様が描かれていない場所は 流路周辺の湿地帯 砂模様は砂礫が分布している多摩川の河原 43
1996 cm NEC JR 5 30 3 30 1 1 19931979 9AMeDAS 94 20 1mm2136 mm22 22 mm23 9mm24 1mm69 mm AMeDAS19 mm 4mm 7mm 50 cm100 cm 1993 846 km 2 1 1,700mm 144m 3 44
1978 58m 5 14m 1,000 34 6 6 1.2.3.4.5.6.7. 8.9.10.11. 12 8 45
m 12 8 4m 1m 1999 1967a, b 1966 8 7 7 56 300 mm 46
1966 8 112 3 30 mm 1967 28 8 2 8 2 8 10 47
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Rivers and Hydrological-Environment of Musashino-Upland in Tokyo Metro. SUMIDA Kiyomi The area for the research was Musashino-Upland, where many rivers exist. The rivers have been grouped into three categories based on the location of the head of the river (Fig. 1). 1) Those in Sayama Pediment 2) Those under terrace cliff 3) The others The longest river streaming on the upland is Syakujii-river, whose river head islocated in the eastern side of Kodaira city, and it merges into Sumida-river 20 km ahead. Fig. 2 and 3 show the geological history of Syakujii-river. Nogawa-river has its head under Kokubunji-terrace cliff. The river was formed 50 thousand years ago. As erosion of the river started 40 thousand years ago, it now runs alongside Kokubunji-terrace cliff. Some of the rivers appear after heavy rain and these are called Mizumichi. The occurrence is often followed by flooding like in Kunitachi city. Akishima city used to have an abundance of springs but most of them have disappeared as underground water is drawn and used to support living activities in the area. Fig. 8 10 show Free ground water level and spring points. In Musashino-Upland, as the cities have developed, flood occurs near rivers when the region experiences significant rainfall. It s important to correctly understand the nature of the land and its rivers, in order to minimize the disaster of flood. Keywords: Musashino-upland, Shakujiigawa-river, Nogawa-river, unconfined groundwater, confined groundwater, inundation inside the levee, nomizu, mizumichi Part-time Lecturer, Department of Geography, Komazawa University 58