Reservoir · Tasmania · Australia · BOM Water Data Online
Lake Trevallyn
62.3% full
Capacity
12.3 hm³
Volume stored
8 hm³
River
South Esk River
Year completed
1955
Coordinates
41.445°S, 147.081°E
Last updated
2026-09-07
Current fill
62.3%vs 7 days ago
+3.5%gaining
vs 1 year ago
+11.4%year-over-year
7-day trend
↑rising
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: 2026-09-07.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. -41.445, 147.081 · Open in Google Maps
About Lake Trevallyn
As of September 7, 2026, Lake Trevallyn is filled to 62.3% of its total capacity, holding roughly 8 hm³ of water out of a maximum 12 hm³. At this level the reservoir is within its normal operating range.
Over the most recent week on record the fill level has risen by 3.5 percentage points, and it is 11.4 points above its level on the same date a year earlier.
Across the readings we hold for Lake Trevallyn — 1094 data points between September 10, 2023 and September 7, 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
- 62.3%
- Water stored
- 8 hm³
- Total capacity
- 12 hm³
- 7-day change
- ▲ 3.5 pts
- Year-on-year
- ▲ 11.4 pts
- 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
- September 7, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 7 Sep 2026 | 62.3% | 8 |
| 6 Sep 2026 | 63.9% | 8 |
| 5 Sep 2026 | 60.8% | 8 |
| 4 Sep 2026 | 54.5% | 7 |
| 3 Sep 2026 | 61.0% | 8 |
| 2 Sep 2026 | 59.1% | 7 |
| 1 Sep 2026 | 57.5% | 7 |
| 31 Aug 2026 | 58.8% | 7 |
| 30 Aug 2026 | 61.2% | 8 |
| 29 Aug 2026 | 61.3% | 8 |
| 28 Aug 2026 | 59.3% | 7 |
| 27 Aug 2026 | 56.7% | 7 |