The Inhabitants' Life in the Lowland of the Kiso, Nagara and Ibi Rivers

Abstract

(1) In the lowland of the Kiso, Nagara and Ibi rivers, the people constructed embankments around the villages and arable land for the flood control to protect the villages from the flood. The flood control community is called Waju in Japanese.
(2) People have long dwelled in the Waju region and a part of the dike was already built in the ancient time. But it is only in the early 17th century when the main parts of the Waju embankment were established for the first time. The construction of Waju increased since then.
(3) When a Waju was established, the earth and sand were accumulated in the river bed. As a result, the river bed became so higher that the embankments were frequently broken in the feudal time. To cope with this situation, they raised the ground level of the building land and there built the mizuya in Japanese for an emergency evacuation. They used mizuya as a temporary house and a store-place of flood. Moreover, they raised the ground level with the earth produced by the digging of a moat in a part of the paddy. Through this procedure, the reduction of the rice production was prevented (horita in Japanese).
(4) Since the Meiji era, the extensive river improvements by the government decreased the flood damage. And Waju, which was an unofficial organization in the feudal period, was controlled by a lower branch of the government's river administration.
(5) In the Waju region, wet rice fields changed into dry ones in the Showa era. With increasing urbanization and industrialization, it became difficult to maintain the organization of the flood control. On the other hand, a new type of flood has also appeared.