Turkey Reservoir Transparency

For the COVERED subset (~120 large and medium dams in the DSİ baraj doluluk database), DSİ publishes daily fill percentages and storage volumes. Daily granularity for >50% of covered places this in the 80-99 band. The DSİ portal showed a nationwide average fill of 69.7% as of May 2026 and 50 billion m³ active storage as of March 2026, demonstrating current, actionable per-reservoir data. All major hydropower reservoirs (Atatürk 48,700 Mm³, Keban 30,600 Mm³, Karakaya 9,580 Mm³, Ilısu ~10,400 Mm³, Altınkaya, Hirfanlı, Seyhan, Kıralkızı) are individually included.

For the COVERED subset, DSİ's primary delivery mechanism is an HTML web portal with no documented public REST API. Data is presented as rendered tables or embedded JavaScript widgets, making programmatic scraping difficult and unsupported. Historical aggregate data is available as Excel downloads (provincial fill rates 2010-2017). EPİAŞ operates a documented REST Transparency Platform API but covers hydroelectric generation volumes — not per-reservoir storage or fill percentage. Two open-source Python packages (eptr2, transparencyEpias) wrap the EPİAŞ API but for energy-side data. Dominant per-reservoir channel is therefore narrative HTML / scrapable widgets, placing this in the 20-39 band.

Methodology v1.3.0 (capacity-weighted), conservative denominator. Reported Turkish reservoir storage in the DSİ inventory is approximately 190,000 hm³ across ~400 reservoirs >10 hm³, dominated by the GAP cascade (Atatürk ~48,700 hm³, Keban ~30,600 hm³, Karakaya ~9,580 hm³, Ilısu ~10,400 hm³ — together ~99,000 hm³) plus the Anatolia multipurpose reservoirs (Altınkaya, Hirfanlı, Seyhan, Kıralkızı) and several dozen mid-sized hydroelectric and water-supply reservoirs. Applying a +13% conservative uplift to account for the long tail of smaller DSİ irrigation reservoirs and göletler-grade structures that sit above the 10 hm³ threshold but never enter the daily baraj doluluk panel, private and BOT/BOO hydropower scheme compensation reservoirs added during the 2010s build-out, plus municipal supply reservoirs of secondary cities (Bursa, Konya, Kayseri, Adana) not consolidated in the national portal, the realistic denominator is approximately 215,000 hm³. COVERED capacity ≈ 150,000 hm³ via DSİ baraj doluluk daily database (~120 large and medium dams) + İSKİ Istanbul + TEİAŞ Daily Water Status Reports. coverage = round(100 × 150,000 / 215,000) = 70. The 120 covered dams include every strategically dominant reservoir; the remaining ~280 reservoirs >10 hm³ are smaller hydroelectric and irrigation reservoirs not individually exposed in the national daily portal.

Median historical depth across the ~120 covered reservoirs is approximately 10-15 years online, placing this in the 10-20 year band (80-99). DSİ provides annual statistical reports with historical series; Excel files covering provincial fill rates from 2010-2017 are directly downloadable. A 2024 official statistics edition confirms ongoing publication. Underlying operational records extend much longer — Atatürk Reservoir water level data from 2002-2020 is cited in peer-reviewed literature sourced from DSİ records, and cumulative energy generation records since dam inauguration (1970s-1990s) are documented — but the median publicly accessible online series is roughly 10-15 years for the typical covered dam.

DSİ publishes baraj doluluk data daily for the COVERED subset; the turkiyebarajlar.com aggregator (sourced directly from DSİ) confirms daily automated refreshes with the portal showing a last-update timestamp of May 4, 2026 at time of evaluation. İSKİ (Istanbul) and other municipal water administrations also update their subset daily. TEİAŞ issues Daily Water Status Reports for hydroelectric plants. Daily cadence for >50% of covered places this in the 80-99 band; not 100 because instantaneous telemetry (sub-daily) is not publicly exposed.

DSİ publishes basic metadata for each monitored dam (total capacity, active storage, dam height, primary purpose) within its statistical yearbooks and regional pages, and reservoir safety assessment guidelines reference standardized capacity classification methods. However, there is no single publicly accessible, English-language methodology document explaining how daily fill percentages are measured, how sedimentation adjustments to capacity are handled, or how data quality is assured. Academic literature references DSİ measurement data but notes methodology details are obtained through official cooperation, not public documentation. The EPİAŞ platform documents its API endpoints clearly for energy-side data.

The DSİ portal and all regional DSİ office websites are exclusively in Turkish. As of 2025-2026, the English-language version of dsi.gov.tr (dsi.gov.tr/english) returns an error page. Annual statistics documents are published in Turkish only. The EPİAŞ Transparency Platform API has partial English documentation and an English-language web interface — but this covers energy market data, not reservoir storage. Turkey does not submit reservoir level data to ENTSO-E (observer member only), so no English-language data flows through the ENTSO-E Transparency Platform.