an assessment model for the virtual water of irrigation networks

the main objective of this study was to develop an assessment model for the virtual water of irrigation networks using analytical hierarchy process. for this purpose, 14 modern irrigation networks of iran were selected. also, 14 effective factors on the virtual water of these systems were considered as decision criteria. expert choice software was used for ranking the virtual water values of the proposed irrigation networks. the average virtual water of irrigation networks with regard to the 5-year data, 2002-2006, was determined. the results showed that the actual virtual water of the nekooabad irrigation network was the highest (17.04 m3 kg-1) and the sefidrood irrigation network had the lowest amount (2.17 m3 kg-1). the results of the ahp model indicated that the saveh and dez irrigation networks with a relative weight of 0.112 and 0.045 had the most and the least virtual water content, respectively. the sensitivity analysis of the proposed model demonstrated that the cultivated area and crop water demand had a significant effect and water quality and water price had a low effect on this index. comparisons showed that the results of ahp model were in good agreement with actual virtual water results. the findings revealed that ahp model is an efficient approach to assess the virtual water of irrigation networks. hence, the proposed model, as a user-friendly model, can be also applied to assess the global water productivity of irrigation networks.