Northeastern Brazil Groundwater Project

Groundwater Modeling
Applied to the Açu Aquifer in
Rio Grande do Norte

About 1 million km² of northeastern Brazil is a semi-arid, drought prone region, and one of the poorest in Latin America.  Most of the region’s economic and social problems can be linked directly or indirectly to a shortage of water.  About 85% of the area is underlain by massive, impervious granitic rocks in which groundwater exists only in fractures and is generally brackish.   A few sedimentary basins hold large volumes of good quality groundwater, but for the majority, their hydrology and vulnerability are poorly understood, and there is real danger that they will be unable to sustain the growing demand for their water resources which, in turn, could result in irreversible damage to the aquifers.

One of the most important sedimentary aquifers in the northeast of Brazil is the Açu aquifer which lies at the base of the oil producing Potiguar basin in the state of Rio Grande do Norte. The Açu is fast becoming the main source of domestic and industrial water, not only for the  communities within its boundaries, but also for communities outside the basin that would otherwise have to depend strictly on poor quality brackish groundwater from fractures in the granitic bedrock. 

The government of Rio Grande do Norte has plans to service a much larger number of communities with water from the Açu aquifer than it currently does, despite the fact that it does not know how much water can sustainably be drawn from  the aquifer.  There is growing concern amongst experts that the uncontrolled exploitation of the Açu aquifer will eventually lead to disaster as more and more people come to depend on it for their livelihood.  Already, excessive pumpage is thought to be responsible for parts of the aquifer becoming saline due, presumably, to the inflow of brackish groundwater derived from the crystalline basement rocks to the south of the basin.  

Project Objective

The objective of this project is to evaluate the groundwater potential of a portion of the Açu aquifer by building a model based on data from existing wells and other information assembled by PROASNE's Brazilian partners in this project, CAERN, SRHID and UFRN.  This will help these organizations to better manage the aquifer and provide an important benchmark for making decision in regards to future expansion in the usage of the resource.

In the process of carrying out this objective, there will be continuous capacity building of the institutions involved in managing the Açu aquifer by training their personnel and carrying out all project activities jointly with them.   There will also be training of Federal and state institution personnel involved in  similar activities in the other two states in which PROASNE operates (Ceará and Pernambuco).  The Canadian partner in this project, Waterloo Hydrogeologic Inc. will perform all the required technology transfer tasks.  For additional information on project objectives, methodology, etc., please see Project Proposal from WHI.

Update: May 2003

The project came to a  successful conclusion in April 2003 with a detailed presentation of the results during a workshop organized for this purpose in Natal/RN.  A well illustrated and very impressive final report - in Portuguese only - was presented by the Canadian partner Waterloo Hydrogeologic Inc., and is available on line from this site.  Earlier, in November 2002, a 6-day short course on groundwater modeling, using preliminary data from the present study of the Açu aquifer, was given to some 22 professionals representing several of PROASNE's partner organization in the three states.