Argentina Reservoir Transparency

For the COVERED subset (~70 reservoirs: ~50 hydropower in CAMMESA's dispatch system + ~20 irrigation/multipurpose dams in AIC, EBY, CTM and Mendoza Aquabook), publication is consistent but fragmented across agencies. CAMMESA's weekly PDF bulletin reports cota, inflows, outflows and storage for dispatch-relevant plants. AIC publishes monthly PDFs with daily cota tables for the five major Neuquén/Limay/Negro reservoirs. Yacyretá (EBY) and Salto Grande (CTM) publish daily operational cotas. Mendoza's SIH issues daily hydromet bulletins with reservoir volumes via Aquabook. INA's SIyAH provides near-real-time flow/level for the Plata Basin gauges. The typical covered reservoir has cota and inflow reported at least weekly; volumetric storage and fill % are less consistently published.

For the COVERED subset, the dominant access mechanism is PDF (CAMMESA weekly, AIC monthly) or HTML scraping (EBY, CTM, Aquabook). INA SIyAH offers a documented RESTful API (alerta.ina.gob.ar/a5/apiUI) returning JSON/CSV/XML/GeoJSON, but it covers Plata Basin river gauging — not the national reservoir storage population. SNIH is a web query interface, not a true API. The datos.gob.ar 'Disponibilidad de agua' dataset holds static metadata only. Extracting reservoir storage data programmatically for the covered subset requires scraping multiple PDFs and HTML pages from at least seven distinct agencies.

Conservative capacity-weighted estimate applied 2026-05-29. Numerator/denominator: n_covered ≈ 70,000 / n_total ≈ 120,000 hm³ including Yacyretá (binational with Paraguay, ~21,000 hm³), Salto Grande (binational with Uruguay, ~5,500 hm³), El Chocón (~20,200 hm³), Piedra del Águila (~12,000 hm³), Alicurá (~3,200 hm³), Cabra Corral (~2,880 hm³), Río Tercero/Ministro Pistarini, Los Molinos, Cruz del Eje, Escaba, Ullum, La Florida and ~100 reservoirs above 10 hm³ per ORSEP. CAMMESA covers the strategic hydropower in dispatch + AIC (Comahue 5) + EBY (Yacyretá) + CTM (Salto Grande) + Mendoza Aquabook (~15 irrigation). Applying conservative downward adjustment (~-9 points) to recognise that (1) provincial multipurpose dams in Córdoba, Salta, Tucumán, San Juan and Catamarca have intermittent-to-absent public data even when appearing in the ORSEP fiscalised registry, (2) the long tail of irrigation reservoirs outside Mendoza is unpublished, and (3) data fragmentation across 7+ agencies means de facto coverage is lower than nominal reservoir count would suggest. coverage = round(100 × 70,000 / 120,000) = 58.

MEDIAN history for the COVERED subset is approximately 7–10 years of online-accessible series. CAMMESA's hydraulic database back to 1992 (30+ years) is the MAX, applying only to the dispatch-relevant aggregate context, not the typical covered reservoir's downloadable daily series. AIC monthly PDFs are routinely available online from ~2016–2017 onward. EBY and CTM publish operational pages with rolling archives of 5–8 years. Mendoza Aquabook bulletins are searchable back ~5 years. INA SIyAH has multi-decade gauge series for the Plata Basin but these are river stations, not reservoir storage. Pre-2000 operational reservoir sequences require formal information requests. Median accessible series for the typical covered reservoir: ~7–10 years.

For the COVERED subset, the typical cadence is WEEKLY (driven by CAMMESA's Boletín Semanal, which is the only source covering all dispatch-relevant hydropower reservoirs simultaneously). A subset publishes daily (EBY, CTM, Mendoza SIH), while AIC publishes monthly PDFs with daily tables for the preceding month. There is no unified national daily reservoir dashboard comparable to Spain's embalses.net. The median covered reservoir is therefore weekly-updated.

For the COVERED subset, ORSEP publishes standardized technical metadata for each fiscalised dam (height, crest length, total reservoir capacity hm³, spillway capacity, installed power, year of commissioning). The Secretaría de Energía 'Catálogo de Recursos Hídricos' compiles technical specifications for major hydroelectric reservoirs. INA's national reservoir sedimentation evaluation provides georeferenced reservoir sheets. However, operational measurement methodology — stage-storage curves, gauge-to-volume conversion, sedimentation correction factors, uncertainty bounds, bathymetric resurvey schedules — is not routinely disclosed in machine-readable form for individual covered reservoirs.

All primary operational data sources — INA SIyAH portal and API, CAMMESA weekly bulletins, AIC monthly reports, SNIH, ORSEP registry, EBY operational reports, Mendoza Aquabook — are exclusively in Spanish with no English-language interface, documentation or translated data exports. The INA RESTful API documentation is Spanish-only. The CTM Salto Grande site is available only in Spanish and Portuguese. The only English-language access to Argentine reservoir data comes from third-party international datasets (World Bank, EIA, GRanD, GloHydroRes) — none of which provide operational time series. An international user needs working Spanish to access any current operational data.