Transboundary: Groundwater management issues for Guarani aquifer (# 368)

The quality of groundwater recharging the Guarani aquifer is threatened in some areas by rapid land-use changes, and locally by rapid urbanisation. Action was taken by the World Bank through a GEF-funded project on the ‘Sustainable Development & Environmental Protection of the Guarani Aquifer’, which included scientific studies, institutional provisions and transboundary groundwater management. This case study reinforces the lesson to ‘think globally but act locally’. 


The Guarani Aquifer is a huge system of Triassic-Jurassic sandstones (mainly of Aeolian origin) underlying more than 1 million km2 of Brasil (62% of area), Paraguay Uruguay & Argentina – with around 30,000 km3 of fresh groundwater in storage, a current rate of exploitation of just over 1 km3/a (94% in Brasil) and major potential for municipal and industrial water-supply, supplementary irrigation and hydrogeothermal resources (reaching 40-60 C in its more deeply-confined sections).

The quality of groundwater recharging the aquifer is threatened in some areas by rapid land-use changes (from natural forest to arable soya-bean cultivation), and locally by rapid urbanisation – but only very locally are there indications of excessive groundwater abstraction (eg. Ribeirao Preto-Brasil) or transboundary groundwater resource or quality dimensions (eg. Rivera-Uruguay/Santana do Livramento-Brasil, Ponta Pora-Brasil/Pedro-Juan Caballero (Paraguay), Concordia (Argentina)-Salto (Uruguay).

Action Taken

During 2003-08 the World Bank mobilised and executed a GEF-funded international project on the ‘Sustainable Development & Environmental Protection of the Guarani Aquifer’, implemented by the OAS and the respective governments, with the support of the IAEA and BGR-Germany.

In addition to extensive collaborative scientific studies of aquifer characteristics and behaviour, and a systematic and critical review of the national/state level institutional and legal provisions for groundwater management (both in a local and transboundary context), the project featured a number of international transboundary groundwater management pilot projects which through ‘local champions’ addressed the issue of stakeholder mobilization on integrated water and land use management.

Lessons Learned

In very large groundwater systems like the Guarani Aquifer, it is essential to ‘think globally but act locally’ (and redefine institutional responsibilities and legal powers as necessary) if progress on practical groundwater resource management and quality protection is to be achieved.

While this has in part been achieved by GEF-funded Project, the interface between groundwater interests and land-use planning (both urban in terms of establishing protected wellfields and rural in the sense of influencing the drivers on agricultural cropping) still requires considerable further work.  

Importance of Case for IWRM

Good example of mobilising interest and then action on ‘preventative groundwater resource management and quality protection’ at different scales from international to national and local.

The case also illustrates the challenge of institutional sustainability of such an initiative.