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Instituto de Investigação
em Vulcanologia e Avaliação de Riscos
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Referência Bibliográfica

CABRAL, J.A., GOMES, A.M., FERREIRA, T. (2010) - Salt Water Intrusion at Tarrafal Municipality. Salt Water Intrusion Meeting, Azores 2010. (Poster)


​Cape Verde archipelago is located in the Central Atlantic and not very far from the African coast. It is formed by ten islands of volcanic origin. The climate of the archipelago is characterized by two distinct seasons: “time of breezes” that runs from December to June and corresponds to the dry season, and “time of waters” the rainy season that lasts from August to October. July and November are considered transition months. Occasionally heavy rainfall in a torrential regime may occur accumulating in one day or few days as much as the annual rainfall of some islands.
Tarrafal Municipality is located on the northern region of Santiago Island, where temperatures are quite high all year round with long periods without any rainfall. It possesses a highly vulnerable agro-ecossystem where water and soil management are important keys to ensure its economical development and environmental balance. The qualification of strategic water resources requires a sustainable management model. The contents of the plan that is presented constitute a contribution to the definition of measures to be taken aiming the fulfilment of environment as well as economical goals.
The deficient water management within the municipality, with marked overexploitation of resources, is contributing to a clear degradation of the water quality due to an increasing contamination with sea water. The high demographic growth recorded in recent years together with low educational levels have been the main causes for misguided water exploitation with no respect for imposed daily pumping limits. On the other hand no big advantage is taken from surface water due to the use of traditional irrigation techniques. Besides, the farmers low educational levels, do not favour a correct use of water sources.
Excessive sand mining in Tarrafal has caused negative impacts, not only at the beach level but also within the aquifer. As a matter of fact, sand mining leads to the reduction of beach quality with the consequent decrease in tourism and economical loss for local populations. As a result people tend to divert their activities towards agriculture and even more sand mining. The degradation of alluvium causes more damage to the coastal aquifers with increasing salinity.
The above mentioned problems lead us to perform a detailed study of the situation, including aquifer characterization, measurements of water depth and water body distances to the shoreline, physical and chemical analysis and continuous monitoring of conductivity. The aims of this work are to take preventive measures in order to avoid a higher degradation of water resources.