Kitaaizu

Kitaaizu occupies the river plain of the Aizu basin, where cultivation depended on keeping water in channels that frequently changed course. During the sixteenth century, works such as the Tomikawa, Ushizawa and Kurimura weirs supplied fields. Farmers cut artificial channels when the river abandoned an old bed, and settlements bearing names meaning new fields or new villages spread by the end of the Sengoku period.

The Aizu earthquake of 1611 blocked drainage near Yamazaki and left extensive land under water. Successive domain governments struggled to restore it. In 1645 the Hoshina administration undertook drainage works at Yamazaki; records place the opening of new rice fields there fourteen years later. River engineering also reached Kitaaizu's own bank: a seventeenth-century account describes diverting the stretch between Sano and Mawata, now Mamiya, for about three months. Irrigation and flood control required coordinated labour, tying the basin's villages to the domain's officials and construction levies.