Reservoir · Tasmania · Australia · BOM Water Data Online
Lake Trevallyn
32.3% full
Capacity
12.3 hm³
Volume stored
4 hm³
River
South Esk River
Year completed
1955
Coordinates
41.445°S, 147.081°E
Last updated
2026-10-26
Current fill
32.3%vs 7 days ago
-3.2 pplosing
vs 1 year ago
-32.4 ppyear-over-year
7-day trend
↓falling
Drought context
Storage vs October average
58%of normal
32.3% full on 2026-10-26, against an average of 55.4% for October across 4 years of readings (-23.1 points).
Rain over the last three months · 11 October 2026
Severely dry
In the three months to 11 October 2026 the area around Lake Trevallyn had far less rain than normal, a shortfall seen about one year in fifteen. Rainfall compared with the long-run record for the same season at this point (Copernicus Global Drought Observatory, SPI-3 index −1.89). Rain, not storage. Australia drought figures →
Data source: Bureau of Meteorology — Water Data Online (KiWIS) — daily mean storage volume, quality-controlled. Capacity from the BOM Water Storages ArcGIS layer (total design capacity in ML). Last reading: 2026-10-26.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 41.445°S, 147.081°E · Open in Google Maps
About Lake Trevallyn
As of October 26, 2026, Lake Trevallyn is filled to 32.3% of its total capacity, holding 3.99 hm³ of water out of a maximum 12.3 hm³. 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 32.4 points below its level on the same date a year earlier.
Across the readings we hold for Lake Trevallyn — 1095 data points between October 28, 2023 and October 26, 2026 — the level has ranged from a low of 6.2% (June 19, 2026) to a high of 94.5% (September 3, 2024). On average the reservoir is fullest around September and at its lowest around April.
The dam at Lake Trevallyn was completed in 1955. It is operated by BOM primarily for water supply. It lies within the South Esk River Basin basin at 41.445°S, 147.081°E.
Key facts
- Current fill level
- 32.3% of total capacity
- Water stored
- 3.99 hm³
- Total capacity
- 12.3 hm³
- 7-day change
- ▼ 3.2 pp
- Year-on-year
- ▼ 32.4 pp
- Primary use
- Water supply
- River
- South Esk River
- River basin
- South Esk River Basin
- Year completed
- 1955
- Operator
- BOM
- Coordinates
- 41.445°S, 147.081°E
- Last updated
- October 26, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 26 Oct 2026 | 32.3% | 3.99 |
| 25 Oct 2026 | 29.7% | 3.66 |
| 24 Oct 2026 | 28.4% | 3.51 |
| 23 Oct 2026 | 32.1% | 3.96 |
| 22 Oct 2026 | 33.2% | 4.1 |
| 21 Oct 2026 | 30.4% | 3.75 |
| 20 Oct 2026 | 31.5% | 3.88 |
| 19 Oct 2026 | 35.5% | 4.37 |
| 18 Oct 2026 | 38.8% | 4.79 |
| 17 Oct 2026 | 38.6% | 4.76 |
| 16 Oct 2026 | 39.5% | 4.88 |
| 15 Oct 2026 | 38.6% | 4.76 |