At the same time in this study, it was determined that the existing regulations and practices regarding water usage patterns and water pollution are not sufficient. For this reason, the WEAP model was applied to the basin to determine the optimum GZR planning system and the optimum operating policy of the plan. The main issue of this planning is how the GZR system will meet future water needs. For this reason, the optimal monthly water distribution policies were simulated with the WEAP model using the past 33 years’ debts, and the performance of the GZRB was re-evaluated. Optimum simulation diagram for different scenarios such as domestic, irrigation water and ecological water needs have been established and implemented