Indonesia Reservoir Transparency

Real-time water surface elevations (TMA, in meters above sea level) for the three Citarum cascade reservoirs — Jatiluhur (Ir. H. Djuanda), Cirata, and Saguling — are publicly visible on the PJT II website, timestamped multiple times daily. However, these are elevation readings, not storage volumes. SINBAD (sinbad.sda.pu.go.id), the national dam and reservoir information system maintained by the Ministry of PUPR (Kementerian PUPR), reportedly displays TMA and volume for a broader set of dams, but actual data retrieval requires submitting a formal request through the Dam Monitoring Centre (Pusat Monitoring Bendungan), making it operationally non-public. The WRDC portal (pdsda.sda.pu.go.id) requires authenticated login. For the vast majority of Indonesia's 292 registered dams — particularly on Sumatra, Sulawesi, Kalimantan, and eastern islands — no publicly accessible operational storage data exists. Current storage volume as a quantitative metric is not published for any reservoir.

No REST API or structured open-format data feed is available for Indonesian reservoir data from any official source. The PJT II hidrologi page renders readings as HTML with no download functionality, no CSV export, and no API endpoint. SINBAD data is accessible only via a formal request workflow (contact form → Dam Monitoring Centre review → email/WhatsApp delivery). The WRDC portal requires username and password registration with no documented public API. PUPR's Open Data portal (data.pu.go.id) offers annual static metadata tables for dams in CSV/XLSX format (editions for 2019, 2021, 2023) but these contain infrastructure attributes — dam name, height, province, purpose — not operational time-series storage data. The national Satu Data Indonesia portal (data.go.id) likewise holds only structural catalogue entries, not time-series records. The SIHKA/PUSAIR system (gis.pusair-pu.go.id) aggregates 836 manual and 1,327 telemetry stations but provides no documented API and no download for processed reservoir-level data.

PJT II publishes real-time TMA (water surface elevation, not volume) for the three Citarum cascade reservoirs (Jatiluhur + Cirata + Saguling ≈ 4,420 Mm³ out of ~25,000 Mm³ national total) — strategic facilities only. Approximately 150 additional dams across Sumatran, Kalimantan, Sulawesi, Papuan and outer-island estates lack any public operational data. Score lowered from 20 to 15 to apply a conservative discount: PJT II's coverage is limited to its strategic Citarum cascade and reports elevation only (not volume/fill %), and the ~150 dams outside the strategic Java cascade are individually absent from any public reporting. Prior justification (preserved for context): v1.3.0 capacity-weighted: coverage = round(100 × covered_capacity_hm³ / total_national_capacity_hm³). Indonesia's total reservoir capacity above 10 hm³ is approximately 25,000 Mm³ across ~150-200 qualifying reservoirs spread between Java (87 reservoirs, ~5,800 Mm³), Sumatra, Kalimantan, Sulawesi and the eastern islands. PJT II's hidrologi page publishes real-time TMA for the three Citarum cascade reservoirs; PJT I's Brantas cascade and occasional news appearances bring partially-covered capacity to ~5,000 Mm³ on a generous capacity-weighted basis. Coverage = round(100 × 5,000 / 25,000) = 20.

The PJT II hidrologi page shows only the current day's readings with no publicly accessible historical time-series. PJT II's public information portal (jasatirta2.co.id/layanan_informasi) publishes annual reports and sustainability reports (2020–2024) and a 'Realisasi Pemberian Air' (water delivery realization) document for 2023, but these are PDF narrative documents, not machine-readable time-series datasets. PUPR's annual static dam datasets span 2019–2023 but contain infrastructure attributes only. Academic studies and internal operational models (e.g., the stochastic cascade model for Saguling-Cirata-Jatiluhur presented at ICSBE 2025) use decades of historical data held internally by operators. No public portal provides a machine-readable multi-year time-series of reservoir storage or water levels with consistent formatting.

The PJT II hidrologi page is the sole publicly refreshed source and updates multiple times per day — readings carry timestamps such as '28 Mei, 17:00 WIB', indicating intra-day refresh cadence. However, this partial real-time coverage is limited to water surface elevation for only three reservoirs, and no volume or fill-percentage figure is published. For all other official channels (SINBAD, WRDC, data.pu.go.id), data is either gated behind login or updated only annually as static tables. The BBWS Citarum telemetry portal (opbbwscitarum.higertech.com) also appears to update in real-time but is oriented toward river gauge stations, not reservoir volumes, and requires login for full access.

Indonesia has an established regulatory and standards framework for dam monitoring. Ministerial Regulation PUPR No. 27/PRT/M/2015 mandates a national water resources information system (SISDA). The national standardisation body BSN has published SNI standards covering dam management and design flood methodology (including SNI 3432:2020 for spillway capacity). PUPR regulations require Automatic Water Level Recorder (AWLR) and Automatic Rainfall Recorder (ARR) equipment at managed dams. However, none of the public-facing portals provide explicit documentation of sensor placement methodology, calibration procedures, volume calculation curves (bathymetric surveys), data quality control protocols, or derivation of storage from elevation. The relationship between the TMA elevation readings published by PJT II and actual storage volumes is not explained to users. Bathymetric survey schedules and uncertainty ranges are not published.

Every official Indonesian reservoir data portal operates exclusively in Bahasa Indonesia: jasatirta2.co.id, sinbad.sda.pu.go.id, pdsda.sda.pu.go.id, data.pu.go.id, gis.pusair-pu.go.id, and all BBWS regional sites. No English-language interface, toggle, or documentation is provided. The Indonesia Water Portal (indonesiawaterportal.com), an independent sector gateway, carries news in English but does not publish reservoir storage data. The ADB's Citarum project documentation (in English) provides historical context but is not an operational data source. For international users, all primary data channels are effectively inaccessible without Indonesian language fluency.