Über Nero
An open-source dashboard monitoring water reservoir levels across Europe.
Unsere Mission
Nero exists to make water data accessible, understandable, and useful. We monitor reservoir levels across 13 European countries. Raw data from government water agencies is often published in formats that are difficult for ordinary citizens to interpret. We transform this data into a clear, visual dashboard that anyone can use — whether you are a farmer planning irrigation, a journalist covering a drought, a policymaker evaluating supply risk, or a resident wondering about water availability.
Water scarcity is a growing challenge across Europe. Countries from the Mediterranean to Scandinavia are grappling with increasingly severe droughts, irregular precipitation, and pressure on freshwater reserves. We believe that transparent, timely access to water data is a prerequisite for informed public discourse and effective policy-making. Nero is our contribution to that transparency.
Länder, die wir überwachen
Zypern
17 major dams with data from the Water Development Department. Historical records from 2009 to the present, updated every six hours. Data published under CC BY 2.0.
Griechenland
Major reservoirs serving the Athens metropolitan area, with data from EYDAP (Athens Water Supply and Sewerage Company). Updated every six hours.
Spain
Spain's 20 largest reservoirs by capacity, with data scraped from embalses.net. Covers major basins including Guadiana, Tajo, Duero, Ebro, and Guadalquivir. Updated weekly.
Portugal
Portugal's 20 largest reservoirs, with data from APA/SNIRH (Portuguese Environment Agency). Covers major basins including Guadiana, Tejo, Douro, and Mondego. Updated monthly.
Czech Republic
15 major Czech reservoirs, with data from CHMI (Czech Hydrometeorological Institute). Covers the Vltava, Ohře, and Moravice river basins. Updated every six hours.
Austria
15 major Austrian Alpine reservoirs. Primarily hydroelectric storage in the Alps. (Data integration pending — no public per-dam API available.)
Italy (Sicily)
13 Sicilian reservoirs, with data from OpenData Sicilia, sourced from the Sicilian Basin Authority. Covers reservoirs critical to the island's water supply and agricultural irrigation. Updated daily.
Finland
15 major regulated lakes and reservoirs, with data from SYKE (Finnish Environment Institute). Covers Finland's largest regulated water bodies from Lapland to the Lake District. Updated daily.
Norway
5 electricity price zones, with data from NVE Magasinstatistikk (Norwegian Water Resources and Energy Directorate). Tracks aggregate hydroelectric reservoir filling across NO1–NO5 regions. Updated weekly.
Switzerland
4 Alpine reservoir regions, with data from BFE/SFOE (Swiss Federal Office of Energy). Covers hydroelectric storage across Switzerland's major Alpine catchments. Updated weekly.
Bulgaria
20 major reservoirs, with data from the MOEW daily bulletin (Bulgarian Ministry of Environment and Water). Data integration pending.
Germany
15 major reservoirs sourced from regional water authorities across German federal states. Data integration pending.
Poland
15 major reservoirs, with data from IMGW (Institute of Meteorology and Water Management). Data integration pending.
Methodik
Nero fetches data from official government water agencies via their public APIs. Nero checks for new data every six hours automatically. However, the actual freshness depends on how often each country's agency publishes updates — some update daily, others weekly or monthly. On first launch, Nero performs an initial seed that downloads available historical data. From then on, incremental syncs fetch only new readings.
All data is stored locally and served directly to users — there is no intermediary processing that alters the raw values. Percentage figures represent the ratio of current storage volume to the dam's maximum design capacity as reported by the respective water authority.
Schwellenwerte der Schweregrade
Nero uses a three-tier colour system to communicate the urgency of each reservoir's fill level at a glance:
- Kritisch — unter 20% Kapazität. Verdunstungs- verluste nehmen zu, die Wasserqualität verschlechtert sich und Stauseen können den Totspeicher erreichen. Landwirtschaftliche Zuteilungen werden typischerweise gekürzt und kommunale Rationierung kann eingeführt werden.
- Warnung — 20 bis 40% Kapazität. Die Reserven sind reduziert und Sparmaßnahmen werden empfohlen. Die Meerwasserentsalzung kann zur Kompensation erhöht werden.
- Normal — über 40% Kapazität. Normaler Betriebsstand mit vollen Zuteilungen und ausreichenden Reserven.
Häufig gestellte Fragen
Wie oft werden die Daten aktualisiert?
Nero checks for new data every six hours automatically. However, the actual freshness depends on each country's upstream data source — Cyprus and Greece update daily, Norway and Switzerland weekly, and some countries monthly. The "Last Updated" timestamp on each page shows when the displayed data was last refreshed.
How accurate is the data?
Nero displays data exactly as published by each country's national water agency — we do not alter or model the raw values. However, Nero is an independent project and does not guarantee the accuracy or timeliness of third-party data. If an upstream source is temporarily unavailable, the most recent available data continues to be displayed. Always refer to the official national portal for authoritative figures.
Warum zeigen manche Staudämme 0% oder sehr niedrige Füllstände?
Small dams can empty entirely during extended dry periods. This is a physical reality, not a data error. These dams respond dramatically to even modest rainfall and can swing from empty to full within days.
Was ist MCM?
MCM stands for Million Cubic Metres, the standard unit for measuring reservoir volumes. One MCM equals one billion litres — enough to fill roughly 400 Olympic swimming pools.
Ist diese Website mit einer Regierung verbunden?
No. Nero is an independent open-source project that reuses publicly available data from government water agencies.
Kann ich diese Daten für Forschung oder Journalismus verwenden?
Yes. The underlying data is published by government agencies under open data licences. You are free to cite, reproduce, or build upon it with appropriate attribution.
Über das Projekt
The name "Nero" comes from the Greek word for water (νερό), reflecting the project's focus and its Mediterranean roots. The project is maintained by an independent developer and has no affiliation with any government — it is a civic technology initiative that reuses publicly available open data to promote water transparency.