Evaluation of Water Utilization of Farm Pond in Paddy and Upland Irrigation Area

Abstract

The objectives of this study are clarifying the water utilization of farm pond and evaluating the farm pond capacity. The field observation is conducted in a farm pond command area located in Uwaba area, Saga prefecture, south-west Japan. In this area, the water utilization is complicated because the land use condition is various. The inflow rate, outflow rate, and water level of farm pond are measured to clarify the water utilization. In addition, the inflow rate to paddy field block and upland field block from the farm pond is observed. The observation results indicate that the water utilization in the paddy field affect the farm pond water balance and shortage of irrigation water is brought because the water demand for puddling and paddy planting, and successive no-rain days is increase. To avoid the shortage of the irrigation water, the irrigation water should be supplied from not only farm pond, but also the reservoirs, inflow rate and outflow rate of farm pond should be controlled, and the rotational irrigation should be introduced in the paddy field.