Stress hydrique et sécurité alimentaire : une vision intégrale des ressources en eau

Water stress and food safety : an integral water vision

¹ Ecole Nationale d’Ingénieurs de Tunis, BP No 37, Le Belvédère, 1002 Tunis Tunisie
² Ministère de l’Agriculture et des Ressources Hydrauliques, Direction Générale du Génie Rural et de l’Exploitation des Eaux, Rue Alain Savary Tunis Tunisie

Abstract

In a context where the water resources are limited, the traditional water vision which tries to express the water resource balance in term of supply-demand adequacy of the withdrawal water “Blue Water”, is incomplete : it doesn’t take into account the total potential of the resources and it is not based on the real evaluation of the water demand. A global water vision should consider all kind of water resources : the withdrawal water resources “Blue Water”, the Equivalent-Water of the rainfed agriculture “Green Water” and the net contribution in Equivalent-Water of the import-export foodstuffs balance “Virtual Water”. It should confront the totality of the resources to the whole of the water needs including the water involved in food production. This global water vision gives a real evaluation of the possibility of the agricultural production and allows us to express some reservations about the criteria and indicators used to characterize the water stress situations. When applied to the Tunisian water balance, this analysis indicates that, the improvement of food safety will depend, in the future, on the capacity to manage all the available water resources (improvement of the water use efficiency, valorisation of rainfed agriculture, development of alternative water resources, optimisation of the “Virtual Water” fluxes, etc).