Vulnerabilidades socioambiental na zona de proteção ambiental 9, Natal/RN

This work aims to analyze socio-environmental vulnerability in the Zone of Environmental Preservation -9, located in the northern of the city of Natal / RN. This objective was outlined when we noted a large number of households (about 2000) located in an area considered relevant in terms of environmental and social conditions, notably because of the existence of lakes, sand dunes and rivers that contribute to groundwater recharge Dunas/Barreiras Furthermore, this area is widely used for agricultural activities. The methodology used during this research is accorded to the literature review about the concept of vulnerability, consultations in public agencies for data acquisition, field research and questionnaires. Data collected from each category of vulnerability (social and environmental) were tabulated, analyzed and presented as tables, maps and texts. According to theoretical concepts and methodology of Alves (2006), Cutter (1996), Torres (2000), Acselrad (2006) e Hogan e Marandola Junior (2005; 2006; 2007), the research is structured in the preparation of an environmental diagnosis of the neighborhoods of Blue Lagoon and Pajuçara and subsequent analysis of socio-environmental vulnerability in the Zone of Environmental Preservation -9, especially Area 1, 2 and 3.There was a variation in results between the social vulnerability and environmental vulnerability categories for each area of the Zone of Environmental Preservation -9. However, the crossing between the two categories above showed that Area 3 had the highest level of environmental vulnerability, followed by Area 1. On the other hand, the Area 2 was considered of minor environmental vulnerability. In this sense, this work presents relevant subsidies to the planning of public policies, to identify and characterize the critical areas with high socio-environmental vulnerability

Desempenho de uma lagoa de infiltração na absorção de cheias e na recarga de aquífero

A type of macro drainage solution widely used in urban areas with predomi-nance of closed catchments (basins without outlet) is the implementation of detention and infiltration reservoirs (DIR). This type of solution has the main function of storing surface runoff and to promote soil infiltration and, consequently, aquifer recharge. The practice is to avoid floods in the drainage basin low-lying areas. The catchment waterproofing reduces the distributed groundwater recharge in urban areas, as is the case of Natal city, RN. However, the advantage of DIR is to concentrate the runoff and to promote aquifer recharge to an amount that can surpass the distributed natu-ral recharge. In this paper, we proposed studying a small urban drainage catchment, named Experimental Mirassol Watershed (EMW) in Natal, RN, whose outlet is a DIR. The rainfall-runoff transformation processes, water accumulation in DIR and the pro-cess of infiltration and percolation in the soil profile until the free aquifer were mod-eled and, from rainfall event observations, water levels in DIR and free aquifer water level measurements, and also, parameter values determination, it is was enabled to calibrate and modeling these combined processes. The mathematical modeling was carried out from two numerical models. We used the rainfall-runoff model developed by RIGHETTO (2014), and besides, we developed a one-dimensional model to simu-late the soil infiltration, percolation, redistribution soil water and groundwater in a combined system to the reservoir water balance. Continuous simulation was run over a period of eighteen months in time intervals of one minute. The drainage basin was discretized in blocks units as well as street reaches and the soil profile in vertical cells of 2 cm deep to a total depth of 30 m. The generated hydrographs were transformed into inlet volumes to the DIR and then, it was carried out water balance in these time intervals, considering infiltration and percolation of water in the soil profile. As a re-sult, we get to evaluate the storage water process in DIR as well as the infiltration of water, redistribution into the soil and the groundwater aquifer recharge, in continuous temporal simulation. We found that the DIR has good performance to storage excess water drainage and to contribute to the local aquifer recharge process (Aquifer Dunas / Barreiras).