Efficiency of Irrigation Associations in Gediz Basin, Turkey

This study concerns the determination of the technical efficiency of irrigation associations (IAs) located in the Gediz Basin in Turkey. For this purpose, 10 IAs operating in the Gediz Basin were evaluated with the use of input oriented DEA model which considers two inputs: water volume supplied (m 3 ) and total irrigated area (m 2 ), and one output: the total value of agricultural production (TL). The assurance region approach was used in DEA not only to include the decision makers’ preferences into the analysis, but also to limit the inappropriate input/output weights that may affect the efficiency scores. The IAs were evaluated during the period 2009-2011 to conclude the variation of efficiency over the study years. The results showed that, during the study period there was an increment in the number of efficient irrigation districts from 3 to 6. However, Gediz, Mesir and Salihli Right Bank IAs were not able to increase their low efficiency scores. The possible reasons of inefficiency are investigated, and the target volume of irrigation water and irrigated area ensuring the same agricultural production were determined. It is concluded that in inefficient IAs the same agricultural production revenue can be achieved with approximately 60% less water and irrigated area.