Conjunctive Use of Water Resources Based on Drought Effects Reduction

In the recent decades, continuous droughts in Iran caused a growing withdrawal trend from groundwater resources and reduce in surface water resources, especially storage volume of dams. Therefore, exploit of water resources requires reviewing based on hydrologic conditions and especially, drought. On the other side, for the definition and characterization of drought by indices, a comprehensive survey of data existence, index applicability and goals in water resources operation is needed. In this article and towards an applicable standardized index in the conjunctive use of water resources, nonparametric functions used to achieve integration and applicability. The status of water resources is calculated via integration of climatic water balance and available hydrologic water by multivariate nonparametric function to obtain integrated drought index (IDI). In this study, the Zayandehrud River Basin is selected as the case study due to conjunctive use of surface and groundwater and occurrence of recent droughts in it. Zayandehrud Dam has a key role in streamflow regulation for downstream demands in the basin. With the index tool to determine the condition of the subbasins, dam and groundwater resources reoperation is followed by the purpose of the minimum drought intensity. This way of operation resulted in demands supply reliability of more than 90%, Lenjanat aquifer balance, storage increase of Isfahan-Borkhar and Kuhpaye-Segzi aquifers by 400 million cubic meters, supply of Gavkhooni wetland water right with reliability of 96% and mean increase of 2.7 million cubic meters per month in streamflow entering the wetland in comparison with the past.