In order to help preserve and manage water resources in the Northeastern part of Brazil, IBGE makes available today, December 16, 2013, Hydrochemical Map of Groundwater in the Northeast Region of Brazil, the Hydrochemical Map of Surface Water in the Northeast Region of Brazil and the Hydrogeological Map of the Northeast Region of Brazil. 

The three maps, in a 1:2:500,000 scale (1cm=25km) will be available as PDF files accessible at ftp://geoftp.ibge.gov.br/mapas_tematicos/recursos_hidricos/regionais.The release of shape files on the IBGE web site is expected to occur in the first semester of 2014. The same applies to INDE (National Infrastructure of Spatial Data) geoservices. 

The nine states which form the Northeast Region take up an area of 1,554,257 km², about 970,000 km² of which corresponds to the Polygon of Drought. In this area  there is a predominance of semi-arid climate conditions, sometimes catastrophic, which cause repeated damage to agriculture and to fishing and lead to serious social and economic problems. 

The three maps present details about the aquifiers and the chemical quality of ground and surface waters in the Northeast Region - the poorest in terms of water resources in Brazil - providing subsidies for the planning of actions and, above all, for the rational use of water resources. Being the result of a dynamic process, the maps can be regularly subject to updates, as new data are included in the IBGE database.

Hydrochemical Map of Groundwater in the Northeast Region of Brazil

The Hydrochemical Map of Groundwater in the Northeast Region of Brazil  was designed according to information obtained from 10,478 physicochemical tests – all of tube wells – and  defines chemically homogeneous areas with reference to potability, chemical facies and adequacy of waters for use in irrigation.  

In South America, groundwater run-off represents about 36% of the total flow of water.  In most of the Brazilian territory there are aquifers with positive water balance and a great level of recharge.

The low groundwater generation capacity of the Northeast, especially in the semiarid region results from the lack of rain, the high evapotranspiration potential and the low storage capacity of the crystalline substrate, often present in that area subsoil. 

Hydrogeological Map of the Northeast Region of Brazil

The Hydrogeological Map of the Northeast Region of Brazil presents cartographic representations of a group of geological units with similar hydrogeological characteristics. This selection is mainly based on lithology (the analysis of rocks which form the soil), but factors of structural, tectonic, physiographic, stratigraphic nature, recharge and circulation of squifiers, physico-chemical characteristics of groundwater and other conditions were also considered. 

The provinces and archaeological domains are defined according to flow (m³/h) and specific flow (l/s/m) figures, extracted from constructive data of more than 54 thousand tube wells formed in this region, and employed as the bases for this study. 

Hydrochemical Map of Survace Water in the Northeast Region of Brazil

The Hydrochemical Map of Surface Water of the Northeast Region of Brazil gathers a group of 843 physicochemical tests of rivers, creeks and weirs, and produces cartographic images river basin districts with chemical affinity.  All this material has been assorted in a database which classifies waters according to the following criteria: level of potability, chemical type and use in irrigation. 

The combination of topics in individual maps becomes possible due to the use of colors (chemical types), hatch (potability levels) and symbols (irrigation classes), which allow the user to have a global view of the features of ground and surface waters in this Major Region.