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

66.4%

Total volume

212 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

66.4%

212,157 of 319,365 hm³ usable storage

Reservoirs

102

States

Usable capacity

319 km³

Volume stored

212 km³

Critical

Low level

National fill — multi-year

ONS subsystems

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SUDESTE/CENTRO-OESTE

68 reservoirs

1 critical

Average fill

62.8%

132,356 hm³ storedView →

NORTE

7 reservoirs

Average fill

74.4%

39,750 hm³ storedView →

NORDESTE

8 reservoirs

1 low

Average fill

69.5%

24,724 hm³ storedView →

SUL

19 reservoirs

2 low

Average fill

77.8%

15,327 hm³ storedView →

By state

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Sorted by capacity

São Paulo

19 reservoirs

3 low

Average fill

62.4%

25,014 hm³ storedView →

Minas Gerais

19 reservoirs

1 low

Average fill

65.6%

53,713 hm³ storedView →

Goiás

13 reservoirs

2 low

Average fill

51.4%

29,049 hm³ storedView →

Pará

4 reservoirs

Average fill

73.8%

29,919 hm³ storedView →

Paraná

11 reservoirs

2 low

Average fill

87.4%

25,679 hm³ storedView →

Bahia

4 reservoirs

1 low

Average fill

70.4%

21,042 hm³ storedView →

Amazonas

1 reservoirs

Average fill

72.3%

7,385 hm³ storedView →

Tocantins

4 reservoirs

1 low

Average fill

82.0%

2,835 hm³ storedView →

Mato Grosso

5 reservoirs

Average fill

73.1%

3,827 hm³ storedView →

Rio Grande do Sul

6 reservoirs

Average fill

65.3%

3,826 hm³ storedView →

Santa Catarina

5 reservoirs

Average fill

89.0%

3,473 hm³ storedView →

Pernambuco

1 reservoirs

Average fill

66.3%

2,354 hm³ storedView →

Rondônia

4 reservoirs

1 critical

Average fill

31.6%

1,530 hm³ storedView →

Piauí

1 reservoirs

Average fill

60.2%

1,150 hm³ storedView →

Sergipe

1 reservoirs

Average fill

70.7%

29 hm³ storedView →

Mato Grosso do Sul

1 reservoirs

Average fill

80.6%

728 hm³ storedView →

Alagoas

1 reservoirs

Average fill

71.3%

149 hm³ storedView →

Rio de Janeiro

1 reservoirs

1 low

Average fill

38.4%

233 hm³ storedView →

Amapá

1 reservoirs

Average fill

96.7%

224 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 September 9, 2026, the reservoirs we track across Brazil that report live levels hold roughly 212,157 hm³ of water — about 37.2% of their combined capacity. Taken together, Brazil's reservoirs are low.

Across the region, 1 reservoir is at critically low levels and 12 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, 25 reservoirs rose and 32 reservoirs fell across Brazil.

Storage figures for Brazil come from ONS; the most recent reading is from September 9, 2026. Each reservoir below links to its own page with full history and seasonal context.

Brazil at a glance

Reservoirs tracked: 102
Average fill: 37.2%
Water stored: 212,157 hm³
Combined capacity: 571,021 hm³
At critically low levels: 1
Fullest: SAO ROQUE (105.0%)
Lowest: JIRAU (0.9%)
Last updated: September 9, 2026