In which regions in Paraguay is Gurrani aquafier located?
Executive summary
The Guaraní (Guaraní/Guarani) Aquifer underlies portions of Paraguay primarily in its eastern and southeastern provinces — notably the Alto Paraná/ Ciudad del Este corridor, Itapúa/Encarnación, and adjacent departments such as Caaguazú — with pilot and study areas documented in those zones [1] [2] [3]. Reporting and hydrogeological syntheses also show the Paraguayan share as a distinct sub-area of the larger Paraná Basin footprint of the Guaraní System, but precise lateral limits inside Paraguay remain incompletely mapped and contested in parts of the literature [4] [5].
1. What the question is asking and how sources treat it
The user seeks a geographic answer: which regions inside Paraguay sit above the Guaraní Aquifer; scientific and policy sources address this at two levels — administrative/place names (departments and cities) and geological/ basin descriptors — and both must be reconciled to avoid overstating precision where hydrogeological mapping is still partial [3] [6] [4].
2. Direct geographic answer: eastern and southeastern Paraguay, with named localities
Multiple technical and outreach sources identify southeastern and eastern Paraguay as the parts of the country most clearly overlying the Guaraní Aquifer, with explicit mentions of the Alto Paraná area (Ciudad del Este), Itapúa (Encarnación), and the Caaguazú region as belonging to the aquifer’s outcrop or vulnerable non‑confined areas [1] [2] [3]. Project documentation for Guaraní pilot sites and regional studies describes a “rearing area in the extreme south‑east of Paraguay” including small towns such as Hohenau and Trinidad and cites the aquifer outcrop covering a substantial fraction of local pilot areas [3]. The World Bank and project summaries quantify Paraguay’s portion of the aquifer at roughly 71,700 km2, reinforcing that the national exposure is concentrated in the eastern half of the country rather than the arid western Chaco [7].
3. The geological frame: Paraná Basin, sandstone formations, and local expression
The Guaraní Aquifer System is a sandstone reservoir principally within the Paraná Sedimentary Basin; in Paraguay its occurrence is the product of Triassic–Jurassic sandstones overlain by Cretaceous basalts in places, meaning the aquifer appears as outcrops or semi‑confined units where basalts thin or erode — conditions that correspond to eastern Paraguayan terrain and river basins that feed recharge zones [6] [4]. Hydrogeological syntheses repeatedly place the Paraguayan portion inside the larger Paraná/Chaco‑Paraná basin complex that defines the transboundary footprint shared with Brazil, Argentina and Uruguay [6] [3].
4. Where mapping and reporting diverge — uncertainty and alternative claims
Not all sources agree on neat departmental lists: while many outreach and project documents emphasize southeastern/eastern Paraguay, some syntheses describe the aquifer’s Paraguayan expression as “central” or even extending into northern sectors in maps that reflect different basemap thresholds or incomplete subsurface data [4] [8]. Scientific authors and regional maps caution that precise lateral boundaries inside Paraguay remain partially unresolved because of limited borehole coverage and complex subsurface transitions, so statements about exact departmental limits must be understood as best‑available interpretations rather than immutable borders [5] [4].
5. Practical implications and governance notes
From a policy perspective Paraguay holds a modest but meaningful share of the Guaraní System (approximately 71,700 km2 in several accounts) and has been a partner in multilateral Guaraní programs and inventories that show Paraguay accounts for a small percent of current reported extraction — around 2% in some inventories — but the country’s eastern aquifer zones are highlighted as vulnerable where urban and agricultural expansion pressures are growing [7] [9] [2]. Those facts underline why regional studies and the Guaraní Aquifer Agreement emphasize cooperative mapping, monitoring and conservative use across the transboundary basin even as detailed Paraguayan boundary delineation continues to be refined [10] [3].