BOA ESPERANÇA
Piauí · PARNAIBA
Useful capacity
1,912 hm³
Coordinates
6.751°S, 43.568°W
Operator
ONS
33.7% of useful capacity
Current fill
33.7%of useful capacity
vs 7 days ago
-3.2 pplosing
vs 1 year ago
-3.7 ppyear-over-year
7-day trend
↓falling
Drought context
Storage vs October average
89%of normal
33.7% full on 2026-10-26, against an average of 37.9% for October across 2 years of readings (-4.2 points).
Rain over the last three months · 11 October 2026
Near normal
In the three months to 11 October 2026 the area around BOA ESPERANÇA had rain close to normal for the season. Rainfall compared with the long-run record for the same season at this point (Copernicus Global Drought Observatory, SPI-3 index −0.70). Rain, not storage. Brazil drought figures →
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Technical specifications
| Total capacity | 5,085 hm³ |
| Usable capacity | 1,912 hm³ |
| Primary use | Hydroelectric |
| Operator | ONS |
| River | PARNAÍBA |
| Province | Piauí |
| River basin | PARNAIBA |
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 6.751°S, 43.568°W · Open in Google Maps
About BOA ESPERANÇA
As of October 26, 2026, BOA ESPERANÇA is at 33.7% of useful capacity, holding 644.9 hm³ of 1,912 hm³. Of the 5,085 hm³ total capacity, that is 12.7%. At this level the reservoir is low.
Over the most recent week on record the fill level has fallen by 3.2 percentage points, and it is 3.7 points below its level on the same date a year earlier.
Across the readings we hold for BOA ESPERANÇA — 65 data points between October 26, 2025 and October 26, 2026 — the level has ranged from a low of 22.7% (December 5, 2025) to a high of 100.0% (May 1, 2026). On average the reservoir is fullest around May and at its lowest around November.
It is operated by ONS primarily for hydroelectric power. It lies within the PARNAIBA basin at 6.751°S, 43.568°W.
Key facts
- Current fill level
- 33.7% of useful capacity
- Water stored
- 644.9 hm³
- Total capacity
- 5,085 hm³
- Usable capacity
- 1,912 hm³
- 7-day change
- ▼ 3.2 pp
- Year-on-year
- ▼ 3.7 pp
- Primary use
- Hydroelectric power
- River
- PARNAÍBA
- River basin
- PARNAIBA
- Operator
- ONS
- Coordinates
- 6.751°S, 43.568°W
- Last updated
- October 26, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 26 Oct 2026 | 33.7% | 644.9 |
| 25 Oct 2026 | 34.4% | 657.9 |
| 24 Oct 2026 | 34.9% | 666.9 |
| 23 Oct 2026 | 35.0% | 670 |
| 22 Oct 2026 | 35.4% | 676.1 |
| 21 Oct 2026 | 35.8% | 685.1 |
| 20 Oct 2026 | 36.3% | 694.1 |
| 19 Oct 2026 | 37.0% | 707.1 |
| 18 Oct 2026 | 37.5% | 716 |
| 17 Oct 2026 | 38.1% | 728.1 |
| 16 Oct 2026 | 39.1% | 747 |
| 15 Oct 2026 | 39.7% | 759.1 |