Análise de aspectos climatológicos, agroeconômicos, ambientais e de seus efeitos sobre a bacia hidrográfica do rio Mundaú (AL e PE).

Abstract

The hydrographic basin of the Mundaú River is in a fast process of environmental degradation due to the degrading anthropogenic actions. Actions to attenuate the degradation effects demand their identification and information, what makes this research very important. The climatology of the hydrographic basin was analyzed in order to show its space-time variability and the main events rainfall in the region. This study also proposes to investigate the impacts and influences of the climate in an area of social-economic and environmental importance and the causes (phenomenon), the temporal scales of the local climatic variability, its effects in the region of the hydrographic basin and as such affect aspects economic, social, agriculturist and environmental. Also, other objectives of this work was: to generate useful diagnosis and prognostic to sectors related to the water resources (water use planning, agriculturist, energy, fishery, and industrial); to propose forecast equations of rainfall anomalies using the climatic indices MEI, SOI and PDO and Atlantic SST anomalies; to quantify, with four indices, the influence of the global climate on the hydrographic basin; to generate information about the agricultural production and social-environmental aspects and to propose local handling actions, which will assist in the taking of decisions of the hydrographic basin management agencies. A “point of inversion” in the precipitation series was detected. In the Low Mundaú, the period before 1974 was more humid than after that year. In the regions of the Medium Mundaú and High Mundaú, the period after 1974 was more humid than the previous one, the opposite was noted in the coastal region. For the Low Mundaú, the index based on the Atlantic SST anomalies was used as the predictor of the precipitation anomalies of the rainy season. For the Medium Mundaú, the MEI was used as the predictor and for the High Mundaú, the MEI and the Atlantic index were the predictors. Accordingly with the agricultural production, the High Mundaú distinguished as producing of vegetal coal, beans and maize, the Medium Mundaú, of orange, milk and rice, and the Low Mundaú, of sugar cane, honey, milk and rice. It was noted that the coal-bunkers in the High Mundaú and the culture of the sugar cane in the Low Mundaú cause ecological prejudices to the hydrographic basin. It was noted that the water pollution, the rainfall distribution, and the land use, mainly for agriculture, intervene in the distribution of the decapodous macrocrustaceans of the MMELC, one of the main sources of local income. Due to the observed situation in the MMELC, as the sediment deposition which block of the lagoon, deforestation, landscape anthropogenic changes, microclimate alteration, ground waterproofing, erosion, water pollution and reduction of biodiversity, actions have been proposed to reduce and to avoid the aggravation the environmental impacts (macro-drainage, water quality monitoring, plantation of native trees, reintroduction of native fauna species, urban and tourist planning, control of real-state speculation, displacement of industries, and projects of environmental education). This work showed that generated the climatologic and meteorological information for the hydrographic basin of the river Mundaú are useful in some aspects of the agricultural sector, ambient and social-economic. At the same time, it was verified that the rainfall variability intervenes with the production of some plantations and local biodiversity. The ambient aspects had also revealed to dependents of the actions human as use, occupation of the ground and agriculture, which was proved as pollutants the local hidryc resources.