The new version of the GAWA -2019 model using Java Script andASPis developed. The study area located atthe lower Chao Phraya Basin between the Chao Phraya River and Tha Chin River, with a total of 131 nodes in this system. The schematic diagram has been set up, includingcanal flows 175 reaches. The appropriate GAs parameters included as follows: the number of 100 alternative sets of Probability of Crossover (Pc) was 0.088, Probability of Mutation (Pm) was 0.00787, and the penalty factorsof water balance R1, R2and R3 were equal to 1, 1 and 4, respectively. All Supply = 692.600 m3/s and All Supply calculation by GAWA -2019 = 692.591 m3/s. The result shows equitablemanners of the systems answers the desired objectivesallocation and provide opportunities to access water resources in all sectors appropriately. I could help optimize the water allocationin the irrigation system andreduce in equitable at real timeconflicts.