ASSESSING THE EFFICIENCY OF IRRIGATION WATER USERS' ASSOCIATIONS AND ITS DETERMINANTS: EVIDENCE FROM TUNISIA

This article analyses the efficiency of water users' associations (WUAs) in the Cap Bon region of Tunisia and studies its main determinants. The analysis is performed in two stages. First, the efficiency is measured via the non-parametric "data envelopment analysis" (DEA) technique. The DEA models are constructed not only to assess the overall WUA efficiency but also to evaluate the management and engineering sub-vector efficiencies separately through a mathematical modification in the initial DEA model. In a second stage critical technical and organizational determinants of efficiencies are assessed using a Tobit model. Results show that on average, 18.7% of the used inputs could be saved if the WUAs operated on the frontier. The inefficiencies found can furthermore be mainly attributed to the number of years of experience in operating a WUA, in addition to the number of water pipes managed and the irrigation ratio. The average scale efficiency, which can be calculated as the ratio between constant and variable returns to scale efficiencies, was around 71%, indicating that many WUAs are not operating at an efficient scale. The scale inefficiencies result mainly from administrative and organizational variables. Sub-vector efficiencies show that on average, the inefficiency of WUAs is more linked with inefficiency in expenditures related to their internal management and functioning, than to engineering inefficiencies. Copyright (C) 2008 John Wiley & Sons, Ltd.