Optimal Water Allocation among the Irrigation Districts in Zayandehrud Basin with Economic Approach and Performance Assessment of Water Distribution within the District (Case Study: North-Rudasht Irrigation District)

The primary objective of this study is to develop a hydro-economic framework in Zayandehrud River Basin to optimize allocation of water released from Zayandehrud dam to downstream irrigation districts, to maximize economic benefits from agricultural activities. To achieve this goal, the existing agricultural activities in each irrigation district were simulated by applying the Positive Mathematical Programming (PMP) economic model. By coupling the developed water allocation planning model of the basin (MODSIM) with the economic model, the hydro-economic framework was then generated. Calibration and convergence of the models were performed by using the base-year (2014-2015) data. Obtained results of employing the hydro-economic framework in the management of water delivery revealed significant changes in water-allocation priorities between the irrigation districts. For instance, allocation priorities of Neko-Abad and Rudasht Irrigation Districts were first and fifth under the current conditions, respectively, which have significantly changed to fourth and second after employing the developed hydro-economic framework. As a case study, the potential of existing operating system in North Rudasht Irrigation District, as a representative of other irrigation districts in the basin, was investigated to make an infrastructure for optimum water allocation by using the hydro-economic framework. Results of modeling the existing operating system of North Rudasht Irrigation District showed a fair and inadequate performance, especially in the middle and lower sections, in optimum water allocation with an economic approach.