Evaluation of Irrigation Efficiencies in Iran

Due to specific climate conditions in Iran and impossibility of increasing new resources of water for agricultural sector, agricultural water management is essential for improving water productivity. Assessment of low irrigation efficiency in the Country and providing appropriate solutions to improve irrigation efficiency and water productivity at the national level can be a great help for modifying irrigation efficiency. For this purpose, available data on irrigation efficiencies in different irrigation systems and differnet irrigation networks (traditional and modern) were analyzed. Analysis was based on results obtained from about 200 field scale studies including 1900 measured irrigation events across Iran from 1991 to 2015. The finding showed that application irrigation efficiency (Ea) ranged between 22.5 and 85.5% having meant of 56%. The averages of Ea in the basin, border and furrow irrigation systems were 55.3, 52.9 and 52.5%, respectively. Although, Ea in sprinkler irrigation systems for example wheelmove and solid set systems were 66.9 and 52.1%, respectively. Average of Ea in pressurized and surface irrigation systems were 66.6 and 53.6%, respectively. As well as, Ea in sprinkler and drip irrigation systems were 62.1 and 71.1%, in order. Results also indicated that Ea over three decades (1992-2001, 2002-2011, and 2012-2015) were 52, 58.4, and 58.8%, respectively. However, network irrigation efficiency for three decades was in order of 67, 68.5 and 74.2%. As a result, total irrigation efficincey (Ep) was 34.8, 40 and 43.6% in these decaceds, respectively. This means that, Ep had annully increased about 1% from 1996 to 2013. An important reason for increase of irrigation efficiency over these decades are improvment of knowledge of users and beneficiars with regards to water and soil issues, improvment of new irrigation systems and extension of research findings to operators and beneficiars.