Reservoir · Tasmania · Australia · BOM Water Data Online
Lake Cethana
13.0% full
Capacity
112.2 hm³
Volume stored
15 hm³
River
Forth River
Year completed
1971
Coordinates
41.509°S, 146.133°E
Last updated
2026-07-28
Current fill
13.0%vs 7 days ago
+1.6%gaining
vs 1 year ago
+6.3%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: 2026-07-28.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. -41.509, 146.133 · Open in Google Maps
About Lake Cethana
As of July 28, 2026, Lake Cethana is filled to 13.0% of its total capacity, holding roughly 15 hm³ of water out of a maximum 112 hm³. At this level the reservoir is critically low. Of that total, about 48 hm³ is usable (live) storage.
Over the most recent week on record the fill level has risen by 1.6 percentage points, and it is 6.3 points above its level on the same date a year earlier.
Across the readings we hold for Lake Cethana — 1095 data points between July 30, 2023 and July 28, 2026 — the level has ranged from a low of 0.4% (July 23, 2026) to a high of 29.7% (September 2, 2024). On average the reservoir is fullest around September and at its lowest around June.
The dam at Lake Cethana was completed in 1971. It is operated by BOM primarily for water supply. It lies within the Forth River Basin basin at 41.509°S, 146.133°E.
Key facts
- Current fill level
- 13.0%
- Water stored
- 15 hm³
- Total capacity
- 112 hm³
- Usable capacity
- 48 hm³
- 7-day change
- ▲ 1.6 pts
- Year-on-year
- ▲ 6.3 pts
- Primary use
- Water supply
- River
- Forth River
- River basin
- Forth River Basin
- Year completed
- 1971
- Operator
- BOM
- Coordinates
- 41.509°S, 146.133°E
- Last updated
- July 28, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 28 Jul 2026 | 13.0% | 15 |
| 27 Jul 2026 | 11.4% | 13 |
| 26 Jul 2026 | 13.0% | 15 |
| 25 Jul 2026 | 9.4% | 11 |
| 24 Jul 2026 | 0.9% | 1 |
| 23 Jul 2026 | 0.4% | 0 |
| 22 Jul 2026 | 0.7% | 1 |
| 21 Jul 2026 | 3.3% | 4 |
| 20 Jul 2026 | 7.2% | 8 |
| 19 Jul 2026 | 10.4% | 12 |
| 18 Jul 2026 | 13.2% | 15 |
| 17 Jul 2026 | 14.8% | 17 |
Frequently asked questions
What is the current water level of Lake Cethana?
As of July 28, 2026, Lake Cethana is at 13.0% of its capacity, holding approximately 15 hm³ of water, according to BOM data.
Is Lake Cethana reservoir full?
No. As of July 28, 2026, Lake Cethana is critically low at 13.0% of its capacity, so it is not full.
Is the water level at Lake Cethana rising or falling?
The level at Lake Cethana is rising — it gained 1.6 percentage points over the latest week on record.
How much water can Lake Cethana hold?
Lake Cethana has a total capacity of 112 hm³, of which about 48 hm³ is usable storage.
Where is Lake Cethana reservoir located?
Lake Cethana is located in Tasmania, Australia, within the Forth River Basin basin (coordinates 41.509°S, 146.133°E).
When was Lake Cethana dam built?
The dam at Lake Cethana was completed in 1971.
What is Lake Cethana used for?
Lake Cethana is used primarily for water supply, and is managed by BOM.