Evaluating the effectiveness of macro-level water-saving policies based on water footprint sustainability indicators

Sustainable water resources management is a main objective of government macro-level documents. Assessments of such documents should be performed before their implementation because they may be ineffective or even result in negative consequences. The current study quantitatively determined the capacity of four important Iranian macro-level documents and their policies to achieve sustainability for water resources. Commonly considered measures include: a) expansion of modern irrigation systems, b) change in the cropping pattern, c) change in the cropping date and d) deficit irrigation. A comprehensive approach was developed by linking the SWAT optimization model and water footprint sustainability indices for the assessments. The two management scenarios examined were: (1) improving the status of water resources and; (2) improving the economic situation or minimizing income loss. The Tashk-Bakhtegan (TB) Basin was selected as a pilot study to explore the effec-tiveness of the methodology and assessment of the documents. The results showed that, under scenario 1, the policies from the documents had the capacity to improve the blue sustainability indices of the basin, but they were unable to meet the environmental water demand. The policy for scenario 2 was associated with a decrease in the level of income in the agricultural sector and a decrease in the area cultivated. It was found that a 20-28% reduction in the cultivated area was required for the sustainability of the TB Basin environment. It was shown that the approaches in the documents had the potential for improving the sustainability of water resources. However, their capacity was insufficient and their success depended on issues such as the ability for effective water allocation and control of rebound effects as well as compensation for economic loss. This was crucial for consideration of future macro-level documents. The proposed modeling framework can be strongly recom-mended for wider applications.