Water Resources Allocation Management in the Hablehroud Basin Using a Combination of the SWAT and WEAP Models

In this study, a combination of the SWAT and WEAP models were utilized for planning and integrated water resources allocation management in the Hablehroud Basin. The SWAT model was calibrated and validated using the monthly discharge at the basin outlet in the period of 1998-2012. The coefficient of determination, the Nash–Sutcliffe efficiency coefficient, root mean square error, and model efficiency, in validation phase were calculated 0.80, 0.71, 1.81 and 0.89, respectively. These values suggest that the model performance can be classified as “good”. To simulate the supply and demand in the basin and to assess different management scenarios, the estimated flows produced by SWAT for each subbasin were considered as the input for the WEAP model and the percentage of met demand in the present situation (Reference scenario) for each demand node was obtained. The results showed that the agricultural lands of Firoozkouh and Garmsar irrigation and drainage network are facing a shortage of water, especially in the warm months of the year. Therefore, scenarios such as changing cropping pattern, reducing crop area, reducing water per capita in urban and rural demand nodes, increasing irrigation efficiency and combined scenarios were considered to balance the supply and demand of water. The results showed that water consumption reduction and striking a balance between the supply and demand in the basin can be better achieved if simultaneous use of different water management strategies (increasing irrigation efficiency, per capita reduction, and crop pattern change) are to be considered in the basin.