TRÊS MARIAS
Minas Gerais · SAO FRANCISCO
Capacity
19,528 hm³
Coordinates
-18.218°N, 45.262°W
Operator
ONS
92.3% full
Current fill
92.3%vs 7 days ago
-0.7%losing
vs 1 year ago
+20.0%year-over-year
7-day trend
→stable
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Technical specifications
| Total capacity | 19,528 hm³ |
| Usable capacity | 15,278 hm³ |
| Primary use | Hydroelectric |
| Operator | ONS |
| River | SÃO FRANCISCO |
| Province | Minas Gerais |
| River basin | SAO FRANCISCO |
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. -18.218, -45.262 · Open in Google Maps
About TRÊS MARIAS
As of July 28, 2026, TRÊS MARIAS is filled to 92.3% of its total capacity, holding roughly 14,097 hm³ of water out of a maximum 19,528 hm³. At this level the reservoir is high. Of that total, about 15,278 hm³ is usable (live) storage.
Over the most recent week on record the fill level has held broadly steady (-0.7 pts), and it is 20.0 points above its level on the same date a year earlier.
Across the readings we hold for TRÊS MARIAS — 52 data points between August 15, 2025 and July 28, 2026 — the level has ranged from a low of 51.8% (December 12, 2025) to a high of 102.3% (April 17, 2026). On average the reservoir is fullest around April and at its lowest around December.
It is operated by ONS primarily for hydroelectric power. It lies within the SAO FRANCISCO basin at 18.218°S, 45.262°W.
Key facts
- Current fill level
- 92.3%
- Water stored
- 14,097 hm³
- Total capacity
- 19,528 hm³
- Usable capacity
- 15,278 hm³
- 7-day change
- ▼ 0.7 pts
- Year-on-year
- ▲ 20.0 pts
- Primary use
- Hydroelectric power
- River
- SÃO FRANCISCO
- River basin
- SAO FRANCISCO
- Operator
- ONS
- Coordinates
- 18.218°S, 45.262°W
- Last updated
- July 28, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 28 Jul 2026 | 92.3% | 14,097 |
| 24 Jul 2026 | 93.0% | 14,209 |
| 17 Jul 2026 | 93.8% | 14,334 |
| 10 Jul 2026 | 94.7% | 14,470 |
| 3 Jul 2026 | 95.3% | 14,555 |
| 26 Jun 2026 | 95.8% | 14,635 |
| 19 Jun 2026 | 96.4% | 14,734 |
| 12 Jun 2026 | 97.3% | 14,864 |
| 5 Jun 2026 | 97.9% | 14,951 |
| 29 May 2026 | 98.5% | 15,046 |
| 22 May 2026 | 99.1% | 15,144 |
| 15 May 2026 | 99.7% | 15,237 |
Frequently asked questions
What is the current water level of TRÊS MARIAS?
As of July 28, 2026, TRÊS MARIAS is at 92.3% of its capacity, holding approximately 14,097 hm³ of water, according to ONS – Operador Nacional do Sistema Elétrico data.
Is TRÊS MARIAS reservoir full?
No. As of July 28, 2026, TRÊS MARIAS is high at 92.3% of its capacity, so it is not full.
Is the water level at TRÊS MARIAS rising or falling?
The level at TRÊS MARIAS has been broadly stable over the latest week on record (-0.7 points).
How much water can TRÊS MARIAS hold?
TRÊS MARIAS has a total capacity of 19,528 hm³, of which about 15,278 hm³ is usable storage.
Where is TRÊS MARIAS reservoir located?
TRÊS MARIAS is located in Minas Gerais, Brazil, within the SAO FRANCISCO basin (coordinates 18.218°S, 45.262°W).
What is TRÊS MARIAS used for?
TRÊS MARIAS is used primarily for hydroelectric power, and is managed by ONS.