Equity for an integrated water resources management of irrigation systems in the Mediterranean: the case study of South Lebanon

Abstract

To achieve sustainable management in irrigation projects, equity represents the major social challenge and the primary objective at all water management levels. However, this topic has drawn limited attention from the scientific community, and the equity concept remains ambiguous and often undefined. This paper deals with the equity among users of an irrigation system in a semi-arid Mediterranean climate. A non-linear, stochastic, static mathematical programming model has been used to maximise farmers’ utility. It takes into consideration several conditions and is subject to a specific set of constraints. Two scenarios have been selected, both of them of the on-demand water distribution: an area-based water allocation system associated with a binomial water tariff (SC1); and a farm-based water allocation system (SC2). Based on the field visits and the understanding of the case study, SC2 is believed to increase equity among farmers. Results calculated farmers’ income in both scenarios and showed that the economic cost of a socially equitable policy in the study area could be around 5% decrease in farmers’ income. Such a policy could have effects on the total volume of irrigation water between 2% and 4% less in SC2 than in SC1, while the change in the irrigated surface is insignificant. The implementation of such scenarios would improve the governance of water policies in Lebanon generating a sustainable development for the agricultural sector.