2008 Volume 14 Pages 205-210
In order to deal with recent change of runoff characteristics by urbanization of a river basin, construction of facilities for rainwater storage and infiltration has been planed as a flood control measure in the basin. However, the construction plan has not been in progress due to high costs and limited sites for the facilities. In this paper, we propose a new utilization method of paddy fields remained in the basin as an alternative measure. This research aims to evaluate rainwater storage function of paddy fields and to verify a new procedure to improve the function, through on-site observations and simulation analyses. A water-balance model on storage-drainage process in each paddy field is identified based on observed data, and by using a runoff analysis model based on the kinematic wave theory, the runoff processes from a drainage area consists of many paddy fields are simulated for a probabilistic design rainfall. From results of the runoff simulation, it is found out that paddy fields have applicability as the runoff control facilities.
