Brazil19 states · ONS official data

Reservoir Watch

Real-time fill levels for 102 Brazilian hydroelectric reservoirs across 19 states. Data updated 3× daily.

Average fill

64.0%

Total volume

204 km³

Reservoirs

102

Critical

Low level

By ONS subsystem

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Status:Critical (<20%)Low (20–40%)Normal / High (>40%)

Brazil at a glance

National average fill

64.0%

204,366 of 319,365 hm³ usable storage

Reservoirs

102

States

Usable capacity

319 km³

Volume stored

204 km³

Critical

Low level

National fill — multi-year

ONS subsystems

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SUDESTE/CENTRO-OESTE

68 reservoirs

1 critical

Average fill

62.3%

131,336 hm³ storedView →

NORTE

7 reservoirs

Average fill

66.5%

35,501 hm³ storedView →

NORDESTE

8 reservoirs

1 low

Average fill

62.8%

22,364 hm³ storedView →

SUL

19 reservoirs

1 critical

Average fill

77.0%

15,165 hm³ storedView →

By state

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Sorted by capacity

São Paulo

19 reservoirs

2 low

Average fill

71.4%

28,656 hm³ storedView →

Minas Gerais

19 reservoirs

2 low

Average fill

62.6%

51,317 hm³ storedView →

Goiás

13 reservoirs

3 low

Average fill

45.8%

25,884 hm³ storedView →

Pará

4 reservoirs

Average fill

66.4%

26,946 hm³ storedView →

Paraná

11 reservoirs

1 low

Average fill

91.4%

26,859 hm³ storedView →

Bahia

4 reservoirs

1 low

Average fill

64.7%

19,344 hm³ storedView →

Amazonas

1 reservoirs

Average fill

59.8%

6,106 hm³ storedView →

Tocantins

4 reservoirs

Average fill

80.8%

2,794 hm³ storedView →

Mato Grosso

5 reservoirs

Average fill

69.8%

3,654 hm³ storedView →

Rio Grande do Sul

6 reservoirs

1 critical

Average fill

63.6%

3,724 hm³ storedView →

Santa Catarina

5 reservoirs

Average fill

87.9%

3,430 hm³ storedView →

Pernambuco

1 reservoirs

Average fill

55.5%

1,970 hm³ storedView →

Rondônia

4 reservoirs

1 critical

Average fill

21.9%

1,057 hm³ storedView →

Piauí

1 reservoirs

Average fill

45.1%

862 hm³ storedView →

Sergipe

1 reservoirs

Average fill

73.2%

30 hm³ storedView →

Mato Grosso do Sul

1 reservoirs

Average fill

94.9%

858 hm³ storedView →

Alagoas

1 reservoirs

Average fill

75.6%

158 hm³ storedView →

Rio de Janeiro

1 reservoirs

Average fill

78.5%

475 hm³ storedView →

Amapá

1 reservoirs

Average fill

105.0%

243 hm³ storedView →

All reservoirs

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Dataset coverage

80%of national storage capacity has public data

Tracked

102

reservoirs

With data

102

reservoirs

Tracked capacity

571,021

hm³

Source: ONS — Operador Nacional do Sistema Elétrico · ANA — Agência Nacional de Águas

Covers major reservoirs in the ONS hydrology monitoring system. Brazil has thousands more smaller reservoirs not yet tracked.

About reservoirs in Brazil

As of October 7, 2026, the reservoirs we track across Brazil that report live levels hold roughly 204,366 hm³ of water — about 35.8% of their combined capacity. Taken together, Brazil's reservoirs are low.

Across the region, 2 reservoirs are at critically low levels and 10 are low. SAO ROQUE is the fullest at 105.0%, while JIRAU is the lowest at 0.9%.

Over the most recent week on record, 23 reservoirs rose and 34 reservoirs fell across Brazil.

Storage figures for Brazil come from ONS; the most recent reading is from October 7, 2026. Each reservoir below links to its own page with full history and seasonal context.

Brazil at a glance

Reservoirs tracked: 102
Average fill: 35.8%
Water stored: 204,366 hm³
Combined capacity: 571,021 hm³
At critically low levels: 2
Fullest: SAO ROQUE (105.0%)
Lowest: JIRAU (0.9%)
Last updated: October 7, 2026