Transboundary Waters Atlas

The story of the visible and water we share.

0shared river basins 0shared aquifers 0water treaties since 1820
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Explore the data

One world. Two water maps.

The same planet, mapped two ways — the rivers and lakes we see on the surface, and the aquifers hidden beneath. Switch between the two views, recolour by theme, and click any shape for its full story.

Surface: basin polygons from the TFDD Basin–Country dataset (Oregon State University). Underground: IGRAC/UNESCO Transboundary Aquifers of the World, 2025 edition. Pinch or ⌘-scroll to zoom.

Stories

Every shared water has a story.

Long-form visual journeys through the world's great shared basins and hidden aquifers — their legends, their history, their treaties, and what comes next.

← drag to browse · five stories at launch, more to come

The country lens

The waters you share.

Pick a country and see every river basin it shares and every aquifer beneath its borders — straight from the TFDD register and the IGRAC 2025 map.

Cooperation, and its shadow

882 treaties — and 2,758 conflicts

The same water that produces the world's densest record of cooperation produces a rising tally of conflict. Both are shown by decade: the diplomacy above, the disputes below.

Treaties signed · TFDD, 1820–2023

All water treaties Substantive groundwater provisions

Water-conflict events · Pacific Institute, from 1900

1900194019802020

The cooperation indicator

How well is each water shared?

Every story in this atlas carries a cooperation status — a five-step composite built from three published, citable sources. It is a summary, not a verdict: conflict and cooperation often coexist on the same river.

01 · Event history

What has happened

Water-related interactions between the countries, scored on the BAR intensity scale from the TFDD International Water Events Database.

02 · Institutional depth

What has been agreed

Treaties, their scope, and river basin organizations — computed directly from the TFDD International Freshwater Treaties Database, 1820 to today. This leg also colours the map above.

03 · Operational arrangements

What works today

Coverage by operational cooperation arrangements as reported under UN SDG indicator 6.5.2 — the only measure that also covers aquifers.

For most of the 426 shared aquifers, no cooperation assessment exists at all. That emptiness is one of this atlas's most important findings. Recent water-conflict incidents come from the Pacific Institute's Water Conflict Chronology — a running record of events where water was a trigger, weapon or casualty — shown inside stories as a separate "shadow record", a history rather than a verdict. Full method & data lineage →