Modeling Irrigation Water Delivery Schedule for Rice Cultivation in East Coast Malaysia

Abstract

An irrigation water delivery-scheduling model has been developed to increase irrigation efficiency for a large-scale rice irrigation project in Malaysia. The study focused on modeling irrigation water delivery schedules during the main season and off-season of the rice-based project. The procedure used a water balance approach in which rainfall was considered as a stochastic variable. Rainfall and evapotranspiration values were used to estimate weekly irrigation water deliveries through the water balance equation. Comparison of the observed and computed irrigation delivery values for the main season and off-season showed that the observed values were higher than the computed values, indicating excess water supply in the field. With the application of this model, it was observed that a modification of the existing irrigation water delivery schedules would save a considerable amount of irrigation water during the main season and off-season. The computed irrigation schedules could save 19% and 11% of irrigation water in the main season and off-season respectively when compared with the traditional irrigation schedules.