01 · The problem
What is happening
Amazonian communities depend on rivers for transport, food and water. In recent severe droughts, river levels at Manaus and across the basin fell far enough to strand vessels, isolate communities, interrupt supply chains and cause fish and river dolphin mortality. Brazilian hydrological services publish river level records for Manaus that span more than a century, allowing individual events to be placed in historical context.
High severity. Serious, widespread effects requiring sustained action. Severity is descriptive editorial metadata summarising documented effects. It is not a measured index or a score.
02 · Causes
Why it is happening
- 01
Rainfall deficit in the basin
Extended periods of below-normal rainfall reduce river discharge across the catchment.
- 02
Ocean temperature patterns
El Nino conditions and unusually warm tropical Atlantic surface temperatures shift rainfall away from parts of the basin.
- 03
Forest loss and moisture recycling
Reduced forest cover weakens the evapotranspiration that recycles moisture and sustains regional rainfall.
03 · Impacts
Who and what it affects
- 01
Isolated communities
When rivers are the only roads, low water cuts off access to food, fuel, medicine and markets.
- 02
Fish and wildlife mortality
Shallow, unusually warm water has caused large fish die-offs and deaths of river dolphins.
- 03
Disrupted transport and energy
Cargo and passenger vessels are stranded, and hydropower and supply chains are affected.
- 04
Increased fire risk
Dry conditions make both cleared land and standing forest far more flammable.
04 · Solutions
Documented approaches
River level monitoring and early warning
Hydrological monitoring that allows communities and logistics operators to prepare for low water.
Expected effectReduces the impact of isolation by enabling pre-positioning of supplies.
Emergency supply logistics
Pre-planned delivery of water, food, fuel and medicine to river communities during low-water periods.
Expected effectLimits humanitarian impact during severe events.
Forest protection as drought mitigation
Maintaining forest cover to sustain the moisture recycling that supports regional rainfall.
Expected effectAddresses one contributing factor over the long term.
05 · Key indicators
What can be measured
- Manaus river level record
- Recorded since 1902
The Rio Negro gauge at Manaus provides one of the longest continuous river level records in the tropics, maintained by Brazilian hydrological services.
06 · Sources
Where this comes from
- [1]Hydrological monitoring of the Rio Negro at ManausServiço Geológico do Brasil (CPRM/SGB)sgb.gov.br(opens in a new tab)
- [2]Drought monitoring and civil protection reportingCentro Nacional de Monitoramento e Alertas de Desastres Naturais (Cemaden), Brazilgov.br(opens in a new tab)
Links open the publishing organisation's site. Some point to the publisher's main page, where the named report or dataset can be found.