Puelches Aquifer

Puelches Aquifer
Name	Puelches Aquifer
Location	La Pampa Province; Buenos Aires Province; Río Negro Province; Neuquén Province
Country	Argentina
Type	Alluvial and fluvial plain aquifer
Area	~170000 km2
Depth	variable
Recharge	Precipitation, river infiltration

Puelches Aquifer The Puelches Aquifer is a major regional groundwater system underlying parts of central and eastern Argentina, spanning provinces such as La Pampa Province, Buenos Aires Province, Río Negro Province, and Neuquén Province. It provides critical water resources for urban centers like Bahía Blanca, Bahía Blanca (city), and Mar del Plata as well as for agricultural and industrial activities associated with regions around General Roca, Viedma, and Santa Rosa. The aquifer interacts with surface waters of the Río Colorado (Argentina), Río Negro (Argentina), and the Colorado River (Argentina), and has been the subject of hydrological assessments by institutions including the Facultad de Ingeniería, Universidad Nacional de La Plata, Servicio Geológico Minero Argentino, and international partners like the United Nations technical agencies.

Overview

The hydrostratigraphic unit identified in provincial and national water inventories underpins extensive plains formed during Cenozoic sedimentation events tied to the broader Pampean and Patagonian basins. Management bodies and research centers such as the Consejo Nacional de Investigaciones Científicas y Técnicas, INTA, and regional water authorities have characterized its role in supplying municipal systems for municipalities comparable to Bahía Blanca (city), Mar del Plata, and agricultural districts near General Pico and Santa Rosa. Historical development of groundwater extraction links to expansion of irrigated agriculture promoted by policies associated with provincial administrations and infrastructure projects like irrigation schemes linked to the Río Negro (Argentina) basin. The aquifer's behavior is also referenced in comparative studies of South American plains aquifers, including analyses involving the Guaraní Aquifer and Pampa Plain groundwater systems.

Geology and Hydrogeology

Sedimentary sequences within the Puelches unit reflect deposition of Quaternary loess, fluvial gravels, and sandy conglomerates over older tertiary formations related to tectonic phases that affected the Andes Mountains and the Patagonian Andes. Aquifer hydraulic properties include heterogeneous transmissivity and storativity influenced by facies changes described in stratigraphic work by teams from the Universidad Nacional de La Plata, Universidad Nacional del Sur, and the Servicio Geológico Minero Argentino. Groundwater flow is modulated by recharge from precipitation events associated with climate patterns documented by the Instituto Nacional de Tecnología Agropecuaria and by evapotranspiration regimes examined in studies referencing the El Niño–Southern Oscillation and regional climatology from the Instituto Nacional de Meteorología y Hidrología.

Extent and Basin Boundaries

The spatial outline extends across provincial administrative boundaries into physiographic units adjacent to the Pampa Húmeda, Patagonian steppe, and the coastal plain bordering the Atlantic Ocean (South Atlantic). Hydrogeological divides link to paleochannels of the Río Colorado (Argentina) and the Río Negro (Argentina), with demarcation considered in basin planning by provincial water commissions, municipal planning authorities in Bahía Blanca (city), and basin studies coordinated with the Secretaría de Recursos Hídricos. Mapping projects have involved cartographic work from the Instituto Geográfico Nacional (Argentina) and comparative frameworks referencing South American hydrographic basins such as the La Plata Basin.

Water Quality and Chemical Characteristics

Chemical signatures show variable salinity gradients influenced by evapoconcentration, marine incursions along the Atlantic margin, and anthropogenic inputs from agriculture and urban areas. Analyses by laboratories at the Universidad Nacional del Sur and CONICET detail major ion chemistry with sodium, chloride, sulfate, and bicarbonate distributions, and trace elements assessed against standards similar to those promulgated by public health agencies in Argentina. Nitrate and pesticide residues have been monitored in contexts involving irrigation districts and crop systems promoted by the Instituto Nacional de Tecnología Agropecuaria, while salinization episodes are compared with cases in the Colorado River (Argentina) delta and coastal aquifers adjacent to Viedma.

Usage and Water Supply

Extraction for municipal supply, irrigation pivots near centers like General Pico and Santa Rosa, and industrial uses associated with agroindustry and port facilities in Bahía Blanca (city) drive demand. Supply planning integrates source substitution and conjunctive use strategies evaluated by water planners at the Ministerio del Interior, Obras Públicas y Vivienda, provincial water directors, and academics from Universidad Nacional del Comahue. Historical pumping trends correlate with population growth in urban nodes such as Bahía Blanca (city) and with expansion of irrigated agriculture supported by programs linked to INTA extension services.

Environmental Impacts and Management

Concerns include aquifer drawdown, progressive salinization, land subsidence in localized sectors, and ecological impacts on wetland remnants tied to the Laguna Mar Chiquita system and coastal marshes near Bahía Blanca (city). Management responses feature regulatory frameworks at provincial levels, monitoring networks by the Servicio Geológico Minero Argentino, and integrated water resource initiatives drawing on expertise from FAO-linked projects and bilateral cooperation with neighboring basin authorities. Conservation strategies reference best practices from international cases involving the Guaraní Aquifer System and basin management approaches advocated by multilateral organizations like the World Bank.

Monitoring and Research Studies

Ongoing hydrogeological research involves isotopic fingerprinting, numerical groundwater modeling, and long-term piezometric monitoring conducted by teams at Universidad Nacional del Sur, Universidad Nacional de La Plata, and the Consejo Nacional de Investigaciones Científicas y Técnicas. Collaborative studies have been published in venues associated with the International Association of Hydrogeologists and presented at scientific meetings involving stakeholders from provincial governments, municipal utilities of Bahía Blanca (city) and Mar del Plata, and technical agencies such as the Servicio Meteorológico Nacional. Data repositories and mapping efforts engage institutions including the Instituto Geográfico Nacional (Argentina) and provincial water information systems.

Category:Aquifers of Argentina