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Frequently Asked Questions
Short answers to common questions about reservoirs.earth, the data and the RTI.
What is reservoirs.earth?
An open platform that tracks reservoir storage levels worldwide using official government data. We currently cover 10 countries with detailed reservoir data and rank 194 countries twice a year in the Reservoir Transparency Index (RTI).
Where does the data come from?
Exclusively from official national hydrological agencies — MITECO (Spain), USGS / BOR / USACE / CDEC (United States), APA (Portugal), ANA / ONS (Brazil), CWC (India), DWS (South Africa), WAPDA / IRSA (Pakistan), BOM (Australia), XM (Colombia), NVE (Norway). Full details in our Data Methodology.
How often is data updated?
Most reservoirs update weekly (e.g. Spain's MITECO publishes every Tuesday). Some sources provide daily or sub-daily updates (USGS, CDEC California, K-water Korea). The exact cadence for each country is documented in the methodology.
What is the Reservoir Transparency Index (RTI)?
A semi-annual 0–100 score measuring how openly each country publishes its national reservoir storage data. The RTI evaluates 194 countries across 7 weighted dimensions (data availability, technical accessibility, coverage, historical depth, update frequency, methodological transparency, language usability). See the RTI page and full RTI Methodology.
Why isn't country X tracked in detail?
We grow our country coverage organically. Adding a country requires building a country-specific data importer that handles its data source format, units, frequency and authentication. We prioritise countries where official data is open, machine-readable, and high-quality. Even when we don't track a country's reservoirs directly, it's still scored in the semi-annual RTI.
Can I use this data for research, journalism or my own project?
Yes. All reservoirs.earth original derived data and the RTI dataset are released under Creative Commons Attribution 4.0 (CC BY 4.0). The underlying official data follows each source's licence (most are public domain or open government data). Please credit reservoirs.earth and link back when you reuse data.
Is this data official?
No — reservoirs.earth is an independent project, not affiliated with any government. We aggregate and present official data faithfully, but we do not produce or certify the underlying measurements. For decision-grade use, always verify against the original source.
How accurate are the readings?
As accurate as the source. We do not modify, smooth or interpolate measurements. We do convert units (acre-feet to cubic metres, etc.) and label provisional readings where the source provides those flags. Some reservoirs lack a clean "total capacity" figure; in those cases we estimate it as the highest observed storage over a rolling window (clearly noted in the methodology).
I found an error. How do I report it?
Email info@reservoirs.earth with the specific reservoir, date, the value we show, and the correct value with a source link. For RTI score disputes, include the dimension you think is incorrect and the evidence URL.
Can I embed your data on my site?
Yes. The RTI page has an embed widget per country (/embed/rti/[country-code]) you can iframe. For reservoir-level data, the JSON and CSV downloads on the Transparency Index page are easiest to consume.
Who runs reservoirs.earth?
The project is built and maintained by Jaime Delgado as an independent open-data initiative. The RTI evaluations are produced by the same author.
Question not answered here? Email info@reservoirs.earth.