Abstract: In recent years, due to the impacts of droughts and saline intrusion, water for irrigation in the dry seasons has become an increasing problem in the Vu Gia Thu Bon Delta. Recycling irrigation return flow is a water-saving measure that helps to deal with water scarcity for irrigation. The study aims to estimate the reuse potential of irrigation return flow. The applied methods were water balance calculation, field measurement, water quality sampling and interviewing. Tu Cau and Thanh Quyt irrigation schemes were selected as the investigated sites. The results indicated that the ratio of surface return flow to the total amount of input water was 0.57 and 0.29 at Tu Cau and Thanh Quyt, respectively. The water quality analysis of collected samples argued that the return flow can be reused for irrigation. The reuse framework developed in this study can be applicable for broader water management scales.
Keywords: vu gia – thu bon basin, paddy water balance, irrigation return flow, return flow reuse, irrigation efficiency