Enviromental impact assessment of irrigation water. Pollution in the lower River Tunuyán oasis, Mendoza, Argentina

CHAMBOULEYRON, J.; SALATINO, S.; DROVANDI, A.; MEDINA DE DIAS, R.; ZIMMERMANN, M.; MARRE, M.; BUSTOS, R.; ANTONIOLLI, E.; FILIPPINI, M.; NACIF, N.; DEDIOL, C.; CAMARGO, A.; GENOVESE, D.

Mendoza, Argentina

Simposio; Simposium international irrigation and water relations in grape wines and fruit trees. National seminar sustainable water resource management in arid regions; 2001

Given the unplanned development of the upper oasis (54,000 ha) and a successful viticulture model that uses underground water only, this paper assesses the possible environmental impact on the Lower River Tunuyan oasis (81,000 ha). The hypothesis assumes that a 20,000 ha increase in cultivated area would produce a dramatic drop in groundwater levels (static and dynamic) in the local aquifer, and a reduction in the flows of brooks and springs  issuing from it -River Tunuyán tributaries used to irrigate the lower oasis. Such a reduction in water supply would increase the salt content in the available water and this would, in turn, affect sensitive peach trees and vines, in that order. Anthropic pollution, silting up of the Carrizal dam, abandonment of 30,000 ha due to soil salinization, and the disappearance of small farmers (less than 10 ha, peach orchards only) are some of the impacts assessed. Important infrastructure investments will be required to solve these problems, but this would generate an administrative and financial crisis in the River Tunuyán basin because of the progressive abandonment of cultivated lands. The proposed mitigation measures underscore the need to consolidate basin administration (nowadays subdivided and managed by two DGI subdelegations) and to allocate water on the basis of salt content, organic content and pollution load, and not only on the present proportional and equitable system.