measuring water use efficiency and productivity of tehran using data envelopment analysis

the input-oriented data envelopment analysis was used to measure the water use efficiency and productivity indices of tehran over the period 2005-13. meanwhile, the correlation between water uses and regional economic activities was examined using the gross regional domestic product index. the results indicated that the total productivity was improved 1.8% and 1.68% aspect of technical efficiency change and scale efficiency change respectively. furthermore, it was improved 12.32% aspect of technology change due to accumulation and treatment of waste water and applying water use management to increase annual water storage since 2011. the mentioned indices confirmed that a 22 million cubic meters decrease is possible in water uses without decreasing in the level of gross products related to tehran.