Abstract
Heavy rain fall caused the flood at the central part of Saga City in July 2, 1990. Deep flood zone was concentrated at the suburbs that are newly developped areas of Saga City.
Leveling was carried out for the water surface of flood and ground surface to clarify the influence of landsub sidence or drainage canal.
Simulations based on the tank model were carried out to reproduce the flood depth, and to check the influence of landsubsidence or drainage canal. It proved that the real drainage ability is lacked to drain the flood water, and the landsubsidence decrease the ability of drainage.
