Agricultural irrigation of vine crops from desalinated and brackish groundwater under an economic perspective. A case study in Siġġiewi, Malta

Maltese agriculture faces great challenges due to the severe scarcity ofwater. Sufficientwater resources, in quantity and quality, are necessary to cover the demand in the production of wine grape, one of the most important crops in Maltese agriculture. But also, economic efficiency is essential in the grape cultivation. A Cost-Benefit Analysis (CBA) is defined for Maltese vineyards in the Siġġiewi region, considering two irrigation scenarios, irrigation with groundwater or “do-nothing”, comparedwith the “use non-conventional waters” from mixing water from a small desalination plant and groundwater. For the alternative ‘mixing desalinatedwater with groundwater’ it is possible to improve water availability and quality for vine crops, while increasing economic benefits for farmer. The results indicate a profitable project fromaminimumarea of 1 ha, but final benefit is highly dependent on the irrigated surface extension according to water price. Desalination, compared with other type of nonconventional water is considered the best option in this assessment with a small reverse osmosis (RO) desalination plant (120 m3 /day) for covering the irrigation needs