CACU
Goiás · PARANAIBA
Capacity
227.45 hm³
Coordinates
-18.532°N, 51.149°W
Operator
ONS
92.2% full
Current fill
92.2%vs 7 days ago
+4.2%gaining
vs 1 year ago
-6.3%year-over-year
7-day trend
↑rising
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Technical specifications
| Total capacity | 227.45 hm³ |
| Usable capacity | 31.69 hm³ |
| Primary use | Hydroelectric |
| Operator | ONS |
| River | CLARO |
| Province | Goiás |
| River basin | PARANAIBA |
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. -18.532, -51.149 · Open in Google Maps
About CACU
As of July 28, 2026, CACU is filled to 92.2% of its total capacity, holding roughly 29 hm³ of water out of a maximum 227 hm³. At this level the reservoir is high. Of that total, about 32 hm³ is usable (live) storage.
Over the most recent week on record the fill level has risen by 4.2 percentage points, and it is 6.3 points below its level on the same date a year earlier.
Across the readings we hold for CACU — 52 data points between August 15, 2025 and July 28, 2026 — the level has ranged from a low of 64.4% (February 20, 2026) to a high of 100.0% (April 10, 2026). On average the reservoir is fullest around November and at its lowest around September.
It is operated by ONS primarily for hydroelectric power. It lies within the PARANAIBA basin at 18.532°S, 51.149°W.
Key facts
- Current fill level
- 92.2%
- Water stored
- 29 hm³
- Total capacity
- 227 hm³
- Usable capacity
- 32 hm³
- 7-day change
- ▲ 4.2 pts
- Year-on-year
- ▼ 6.3 pts
- Primary use
- Hydroelectric power
- River
- CLARO
- River basin
- PARANAIBA
- Operator
- ONS
- Coordinates
- 18.532°S, 51.149°W
- Last updated
- July 28, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 28 Jul 2026 | 92.2% | 29 |
| 24 Jul 2026 | 88.0% | 28 |
| 17 Jul 2026 | 90.6% | 29 |
| 10 Jul 2026 | 78.7% | 25 |
| 3 Jul 2026 | 83.3% | 26 |
| 26 Jun 2026 | 95.8% | 30 |
| 19 Jun 2026 | 89.5% | 28 |
| 12 Jun 2026 | 96.8% | 31 |
| 5 Jun 2026 | 89.5% | 28 |
| 29 May 2026 | 84.4% | 27 |
| 22 May 2026 | 88.5% | 28 |
| 15 May 2026 | 93.2% | 30 |
Frequently asked questions
What is the current water level of CACU?
As of July 28, 2026, CACU is at 92.2% of its capacity, holding approximately 29 hm³ of water, according to ONS – Operador Nacional do Sistema Elétrico data.
Is CACU reservoir full?
No. As of July 28, 2026, CACU is high at 92.2% of its capacity, so it is not full.
Is the water level at CACU rising or falling?
The level at CACU is rising — it gained 4.2 percentage points over the latest week on record.
How much water can CACU hold?
CACU has a total capacity of 227 hm³, of which about 32 hm³ is usable storage.
Where is CACU reservoir located?
CACU is located in Goiás, Brazil, within the PARANAIBA basin (coordinates 18.532°S, 51.149°W).
What is CACU used for?
CACU is used primarily for hydroelectric power, and is managed by ONS.