Evaluation of Equity in Distribution Water by Hydromodule Index: in Ordibehesht Channel in Dorudzan Dam

The Ordibehesht canal is one of the main canals of Doroodzan Dam, covering 7000ha. In this canal water distribution has been by the volumetric method since 2002. The hydromodule index has been commonly used to evaluate water distribution equity in irrigation networks, and is based on water allocation. In order to evaluate equity in water distribution, among the tertiary canals the hydromodule index was computed as the ratio of delivered water by the doroodzan water district divided by the area covered by each tertiary canal. Following computation of this index, water distributions among the tertiary canals were evaluated. It was assumed that each farming area covered by a tertiary canal would remain constant during all seasons of the year. But in reality winter and summer season crops different cultivation areas, and thus require different quantities of delivered water. As results computed values are higher for summer crops. Application of this index for winter crops showed that equity in water distribution among the tertiary canals was not considered during winter season, to the extent that the index values for the T15, T17, T21 and T24 canals were quite low. But high values were obtained for the T16 and T20 canals. The results indicated about average index value for theT18, T19, T22, and T23 canals.