Water and ice in Switzerland

An open, evidence-led project to understand water through its whole cycle, protect wetlands and other essential pathways, and support legal enforcement where necessary.

Live site: https://opengovclimate.ch/riverflow/

The project keeps unlike evidence unlike. A current gauge reading, a model estimate and a twenty-year-old register never share a label. Every figure states its source, date and limits.

The north star is one connected account: precipitation, snow and ice, soil, groundwater, rivers, lakes, storage, use, return flows and water crossing the border. The current release is a rigorous surface-water foundation, not the finished cycle. The work is meant to make protection enforceable: clear evidence, primary law and reproducible methods that can support legal action when needed.

What it shows

Layer	Evidence
River flow	Current BAFU discharge where a station passes the live-data rules; indicative estimates elsewhere
Relative to mean	Current discharge divided by a modelled annual mean; not a drought index
Temperature	Current BAFU station readings
Live legal screen	Fresh temperatures strictly above 25.0 °C, as review triggers under GSchV Annex 2 No. 12(4)—not findings of breach
Water quality	The current prepared NAWA TREND release, reduced to station-year summaries with exact laboratory rows on demand
Reservoirs	Federally supervised dam structures and a separate weekly regional energy-storage series
Ice	Glacier area in six inventories: 1850, 1931, 1973, 2010, 2016 and 2023
Residual flow	BAFU Q347 points and an illustrative Art. 31(1) calculation
Water use	Federal registers of hydropower, abstractions, nuclear sites and treatment plants
Wetlands	Five federal inventories of protected wetlands
Sources and groundwater	Groundwater bodies, headwaters, sub-catchments and drinking-water protection zones
Monitoring duties	Federal duties and a 26-canton public-evidence audit; evidence and freshness, not a compliance score

This is not a forecast, a finding of breach or legal advice. It is also not a complete account of Swiss water. Important omissions are listed on the Method page.

Evidence rules

• A discharge is current only when its station timestamp is valid, no more than 30 minutes old, its value is finite and non-negative, and its unit is verified. Stale or invalid observations remain inspectable but drive nothing.
• The live legal screen accepts the same 30-minute temperature window and flags only reported values strictly above 25.0 °C. The ordinance concerns human-caused temperature change after substantial mixing; the feed contains no causation, reference-state, mixing, permit or exception evidence. An alert starts review and never declares a violation.
• The station and river files contain unique identifiers. Where several valid gauges share a model reach, the newest wins, then the closest snap, then the station identifier.
• Ungauged reaches use the first connected downstream gauge, or the closest connected upstream gauge. This scaling is not a mass balance and does not model storage, diversions or travel time.
• HydroRIVERS is a coarse global model. Its source threshold is 10 km² catchment or 0.1 m³/s modelled mean flow; this map is not a complete inventory of small streams.
• The Q347 layer applies only the arithmetic in Art. 31(1) GSchG. BAFU says model values generally need local measurement, and the canton determines the adequate residual flow after applying the rest of the statutory scheme.
• A quality result below its determination limit remains censored. It is never converted to zero or used in a median. Values are not interpolated between stations and the map does not invent a composite quality score.
• GSchG Art. 58 requires the cantonal surveys needed for implementation, not one identical national station and frequency checklist. The cantonal audit records what could be verified publicly and does not pronounce legal compliance.
• Historical registers remain useful evidence of what was recorded then. They are never presented as complete current inventories.

The full methods, transformations and limits are published on the Method, Sources and Law pages.

Collaborate

This is a public collaborative project. Contributions are especially welcome from:

• hydrologists, glaciologists, limnologists and water-quality scientists;
• geospatial and open-data engineers;
• Swiss water, environmental and administrative-law researchers;
• cantonal and federal data stewards;
• translators and accessibility reviewers.

The most valuable contribution is often a precise correction: the affected place or claim, the primary source, its date, and the smallest defensible change. See CONTRIBUTING.md for scientific and legal review standards.

Please use GitHub issues for data defects, source updates and research proposals. Pull requests should keep the five language editions and the release checks in sync.

The roadmap defines the evidence needed to extend this foundation through the full water cycle and into obligation-level monitoring and enforcement.

Run locally

The publication is static and has no application backend.

cd site
python3 -m http.server 8899

Open http://127.0.0.1:8899/.

The map supports mouse, touch and keyboard. Use the wheel, pinch, or map buttons to zoom; drag or use arrow keys to pan; press Home to fit Switzerland; press Enter to inspect the feature at the centre. The country cannot be moved out of view.

Verify a release

npm ci
npm test

The release gate checks all five languages, links, metadata, accessibility, translations, JavaScript and JSON syntax, dataset identities, units, time-series order, data-derived publication facts, semantic invariants and artifact hashes.

Rebuild data

The build uses Bash, curl, unzip and Node 22. Exact JavaScript and map-processing dependencies are locked in package-lock.json.

npm ci
bash build/00-sources.sh
node build/01-stations.mjs
node build/02-network.mjs
node build/03-context.mjs
node build/04-glaciers.mjs
node build/05-users.mjs
node build/06-reservoirs.mjs
node build/07-residual.mjs
node build/09-icehistory.mjs
node build/10-names.mjs
node build/11-cantons.mjs
node build/12-wetlands.mjs
node build/13-basins.mjs
node build/17-quality.mjs
node build/18-monitoring.mjs
node build/08-vintage.mjs
python3 build/14-pages.py build
node build/15-social-card.mjs
node build/16-provenance.mjs
node scripts/verify-site.mjs

Raw source archives are downloaded outside the repository. The committed provenance manifest records the source states, build scripts, artifact sizes, counts and SHA-256 hashes. Upstream datasets retain their own licences; the Sources page lists each holder and term.

Publication

GitHub Actions verifies every pull request and every push to main. A weekly job builds federal and cantonal updates as a downloadable review patch. It never writes directly to main. A maintainer applies the patch on a branch, reviews the source and data diff, and opens a pull request. Deployment runs only for a validated main revision and binds that revision into the deployed provenance. The curated legal-evidence audit changes only after its primary records are reviewed again.

The repository is the publication record. A map URL stores its layer, centre and zoom so a view can be cited, but live observations still need their station time and underlying BAFU source.

Licence and governance

Code is available under the MIT License. Original explanatory content is available under CC BY 4.0. Upstream datasets retain their own terms and are never relicensed here. See GOVERNANCE.md for review and decision rules, SECURITY.md for private vulnerability reports, and CITATION.cff for citation metadata.