SAMUEL
Rondônia · AMAZONAS
Capacity
3,493.44 hm³
Coordinates
-8.752°N, 63.454°W
Operator
ONS
66.1% full
Current fill
66.1%vs 7 days ago
-3.8%losing
vs 1 year ago
+16.2%year-over-year
7-day trend
↓falling
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Technical specifications
| Total capacity | 3,493.44 hm³ |
| Usable capacity | 2,550.2 hm³ |
| Primary use | Hydroelectric |
| Operator | ONS |
| River | JAMARI |
| Province | Rondônia |
| River basin | AMAZONAS |
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. -8.752, -63.454 · Open in Google Maps
About SAMUEL
As of July 28, 2026, SAMUEL is filled to 66.1% of its total capacity, holding roughly 1,686 hm³ of water out of a maximum 3,493 hm³. At this level the reservoir is within its normal operating range. Of that total, about 2,550 hm³ is usable (live) storage.
Over the most recent week on record the fill level has fallen by 3.8 percentage points, and it is 16.2 points above its level on the same date a year earlier.
Across the readings we hold for SAMUEL — 52 data points between August 15, 2025 and July 28, 2026 — the level has ranged from a low of 0.0% (November 14, 2025) to a high of 96.7% (May 1, 2026). On average the reservoir is fullest around April and at its lowest around November.
It is operated by ONS primarily for hydroelectric power. It lies within the AMAZONAS basin at 8.752°S, 63.454°W.
Key facts
- Current fill level
- 66.1%
- Water stored
- 1,686 hm³
- Total capacity
- 3,493 hm³
- Usable capacity
- 2,550 hm³
- 7-day change
- ▼ 3.8 pts
- Year-on-year
- ▲ 16.2 pts
- Primary use
- Hydroelectric power
- River
- JAMARI
- River basin
- AMAZONAS
- Operator
- ONS
- Coordinates
- 8.752°S, 63.454°W
- Last updated
- July 28, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 28 Jul 2026 | 66.1% | 1,686 |
| 24 Jul 2026 | 69.9% | 1,783 |
| 17 Jul 2026 | 74.6% | 1,903 |
| 10 Jul 2026 | 77.9% | 1,988 |
| 3 Jul 2026 | 83.3% | 2,124 |
| 26 Jun 2026 | 86.3% | 2,200 |
| 19 Jun 2026 | 90.0% | 2,295 |
| 12 Jun 2026 | 92.8% | 2,367 |
| 5 Jun 2026 | 94.0% | 2,398 |
| 29 May 2026 | 95.0% | 2,422 |
| 22 May 2026 | 94.3% | 2,404 |
| 15 May 2026 | 95.2% | 2,428 |
Frequently asked questions
What is the current water level of SAMUEL?
As of July 28, 2026, SAMUEL is at 66.1% of its capacity, holding approximately 1,686 hm³ of water, according to ONS – Operador Nacional do Sistema Elétrico data.
Is SAMUEL reservoir full?
No. As of July 28, 2026, SAMUEL is within its normal operating range at 66.1% of its capacity, so it is not full.
Is the water level at SAMUEL rising or falling?
The level at SAMUEL is falling — it dropped 3.8 percentage points over the latest week on record.
How much water can SAMUEL hold?
SAMUEL has a total capacity of 3,493 hm³, of which about 2,550 hm³ is usable storage.
Where is SAMUEL reservoir located?
SAMUEL is located in Rondônia, Brazil, within the AMAZONAS basin (coordinates 8.752°S, 63.454°W).
What is SAMUEL used for?
SAMUEL is used primarily for hydroelectric power, and is managed by ONS.