In order to describe and map the Brazilian Southeast groundwater, the IBGE makes available today (04/28/2016) the Hydrogeological Map of he Southeast Region. The information aims at enhancing knowledge on the behavior of aquifers in the Region, giving support to the planning, management and rational and sustainable use of regional water resources. Technical data and information produced for the drawing of this map are available on the portal of the IBGE for research and download, in PDF and shapefile (file format containing geospatial data in a vector form. It is used by Geographic Information Systems, also known as GIS). Click here to download the pdf file and here to access the shape format.

Map reveals production capacity of Southeast aquifers

The hydrogeological units set in this map were defined based on the geological characteristics (type of rock) and on the productivity of the tubular wells, which was established based on the flow rate (which is the quantity of liters that can be extracted, by hour, of a certain point of groundwater capture). The total number of 27,535 perforated tubular wells in the region served as basis for this survey. Four major sets of aquifers or hydrogeological domains were identified: porous (made of sedimentary rocks; the water flows through small empty spaces, the pores), fissured (made of fissures where water is accumulated, fissured-porous and Karstic (which form subterranean rivers).

Some wells perforated in porous aquifers (the most productive ones in the Region) reach up to 500 thousand liters/hour. A well with such characteristics, in a pumping regime of 12 hours/day, will produce 6 millions liters/day. Considering a per capita consumption of 250 liters/person/day, this capture alone could be enough to supply a population of 24 thousand persons.

Designed at a scale 1:1,800,000 (1 cm = 18 km), the map uses as a digital platform the software GeoMedia. This tool, in whose environment the graphic elements are structured by information level and associated to a databank, allows the user to identify the geological and hydrogeological elements that comprise each one of the geospatialized units, as well as to execute geoprocessing tasks (thematic surveys and compositions).

The map results from a dynamic process, which can be frequently updated, as a significant amount of data is added up to the database.

Water crisis reveals importance of other ways of capturing water

The four states that integrate the Southeast Region (São Paulo, Minas Gerais, Rio de Janeiro and Espírito Santo) amounts to an area of around 924.510 km², where 85.3 million people lived in 2014 (42.0% of the Brazilian population). Between 2014 and 2015, the relative scarcity of rainfall in this Region (which usually presents no serious problem of water supply) triggered a severe water crisis, mostly in São Paulo, where there were significant consequences to several socioeconomic segments, mainly in the municipalities of the Metropolitan Area of the capital.

As a result, the aquifers (geological formations capable of storing and producing groundwater) become even more important, for the water issue in the Southeast Region opens room for the discussion about the use of other models for the regional water matrix.