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The Global Centre for Risk and Innovation (GCRI)
More than three hundred river basins cross national borders, and most of the world’s people live in them. A dam, a diversion or a drought upstream changes what arrives downstream. This page sets out how shared basins are observed, how the evidence is made comparable across borders, and what joint institutions need before they can decide.
Water NexusWireframe of the working environment, not a live screen. Names and values are placeholders.
Transboundary evidence and institutions. The dossier below sets out how the risk develops, what is measured, where the data come from, how it is modelled and who decides.
Storage changes timing, abstraction changes volume, and both change the sediment and nutrient loads that deltas and fisheries depend on.
Each riparian measures its own reach with its own methods. Evidence that is not comparable across the border cannot settle a dispute; it feeds one.
Treaties written for a historical flow regime meet a changed one. Allocation rules fixed in volumes fail when the volume is no longer there.
Basin commissions work when they hold a shared data platform, agreed methods and a procedure for notification. The evidence is the institution’s first product.
Where this page’s subject sits in the world: boundaries and context now, the field layers when the interactive map loads.
MapWorld map in the Equal Earth projection, land and boundaries from Natural Earth (public domain). The interactive map loads through the Nexus Foundry plugin (globe or flat view).
The systems this subject touches, the method at its core and the decisions it informs.
Each indicator carries its unit, its cadence, the kind of source behind it and the evidence label a value would carry. No values are shown: a programme supplies them under its own authority.
| Indicator | Unit | Cadence | Source type | Label |
|---|---|---|---|---|
| Border-crossing flow | cubic metres per second | daily | Gauges at agreed points | OFFICIAL |
| Reservoir storage in the basin | cubic kilometres | monthly | Operator reports, satellite altimetry and extent | ESTIMATED |
| Sediment load | tonnes per year | annual | Sampling, turbidity proxies | ESTIMATED |
| Delta salinity intrusion length | kilometres | dry season | Station salinity, models | OBSERVED |
| Basin precipitation by country | millimetres per month | monthly | Gauge and satellite rainfall | ESTIMATED |
| Environmental flow compliance | percent of months meeting the agreed flow | annual | Gauges against the agreed regime | OFFICIAL |
The topic as a computational graph: named sources feed the methods, an evidence review gates the outputs, and the decisions stay with the authorities that hold them.
Fig. 02Nodes carry their type, two metric rows and a state; connectors show what feeds what; dashed frames name the owners; the timeline is the cadence. Design of the pipeline, not a record of a run.
Named public datasets and institutional records, each with its licence class. Sources by agreement are used only under their terms and never republished.
| Source | What it gives | Licence class |
|---|---|---|
| River basin organisations | Agreed gauge records, notifications, joint assessments | Terms per organisation |
| Satellite altimetry (Copernicus, NASA) | River and reservoir levels where gauges are absent or unshared | Free and open, attribution |
| JRC Global Surface Water | Reservoir extent change over decades | Free and open, attribution |
| Transboundary Freshwater Dispute Database (Oregon State University) | Treaties and events in shared basins | Terms per database |
| CHIRPS and ERA5 | Basin rainfall independent of any single riparian | Public domain; free and open |
Water Nexus prepares evidence. The decisions below are taken by the authorities named, under their own rules, and never by the platform.
| Who decides | The question | Evidence this page serves |
|---|---|---|
| Basin commissions and riparian ministries | Whether a planned dam or diversion changes flows beyond the agreed regime | Independent storage and flow estimates, scenario sets with the regime as reference |
| Delta authorities | When dry-season intrusion threatens drinking water and crops, and what releases would relieve it | Salinity intrusion length against upstream storage and release schedules |
| Development finance institutions | Whether a project’s basin-wide effects are evidenced before financing | Basin accounts and scenarios with labels; readiness questions prepared with GRA |
Dams and reservoirs change the timing of flow, storing wet-season water for dry-season use or power generation. Irrigation withdrawals reduce flow and return water of lower quality. Sediment trapped behind dams starves downstream deltas, which can then subside and suffer salinisation.
Agreements often allocate fixed volumes or proportions based on historical records. When climate change alters the flow regime, those allocations can become impossible to meet, and disputes turn on whose data and models are right. Shared, transparent evidence does not resolve disputes, but it narrows them.
Coordinated gauging and water quality sampling with agreed methods. Data sharing may be limited by national security or commercial considerations.
Earth observation provides consistent observations of reservoirs, river width, irrigation and snow across borders, with lower precision than ground data.
Whole-basin models used to test scenarios of development and climate, with uncertainty quantification. Their credibility depends on transparent assumptions accepted by all parties.
| Method | Applied here | Canonical page |
|---|---|---|
| Hydrology and water science | Hydrology and water science in this field | STEM Commons |
| Earth observation and remote sensing | Earth observation and remote sensing in this field | STEM Commons |
| Geospatial information systems | Geospatial information systems in this field | STEM Commons |
| Forecasting and time-series analysis | Forecasting and time-series analysis in this field | STEM Commons |
| Uncertainty quantification and model validation | Uncertainty quantification and model validation in this field | STEM Commons |
Satellite estimates of storage and flow are coarser than gauges and carry stated error; they inform, they do not replace, an agreed gauge. Treaties and events are recorded unevenly across basins. Water Nexus takes no position on allocation; it prepares evidence that each riparian can examine.
| Link | Relationship | Why |
|---|---|---|
| River basin governance | Related topic | Water science informs transboundary governance; only competent authorities govern allocation. |
The current service level is R0: information and enquiries. An enquiry receives a reference and names the next step; applications, payments, compute allocations and registrations open only when their team, terms and review capacity exist.