Reservoir · Western Australia · Australia · BOM Water Data Online
Glen Mervyn
51.2% full
Capacity
2.1 hm³
Volume stored
1 hm³
River
McCallum Creek
Year completed
1969
Coordinates
33.498°S, 116.100°E
Last updated
2026-07-26
Current fill
51.2%vs 7 days ago
0.0%stable
vs 1 year ago
+14.9%year-over-year
7-day trend
→stable
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: 2026-07-26.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. -33.498, 116.100 · Open in Google Maps
About Glen Mervyn
As of July 26, 2026, Glen Mervyn is filled to 51.2% of its total capacity, holding roughly 1 hm³ of water out of a maximum 2 hm³. At this level the reservoir is within its normal operating range.
Over the most recent week on record the fill level has held broadly steady (+0.0 pts), and it is 14.9 points above its level on the same date a year earlier.
Across the readings we hold for Glen Mervyn — 1051 data points between July 30, 2023 and July 26, 2026 — the level has ranged from a low of 2.0% (April 27, 2024) to a high of 77.5% (October 17, 2025). On average the reservoir is fullest around October and at its lowest around May.
The dam at Glen Mervyn was completed in 1969. It is operated by BOM primarily for water supply. It lies within the McCallum Creek Basin basin at 33.498°S, 116.100°E.
Key facts
- Current fill level
- 51.2%
- Water stored
- 1 hm³
- Total capacity
- 2 hm³
- 7-day change
- No change
- Year-on-year
- ▲ 14.9 pts
- Primary use
- Water supply
- River
- McCallum Creek
- River basin
- McCallum Creek Basin
- Year completed
- 1969
- Operator
- BOM
- Coordinates
- 33.498°S, 116.100°E
- Last updated
- July 26, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 26 Jul 2026 | 51.2% | 1 |
| 25 Jul 2026 | 51.2% | 1 |
| 24 Jul 2026 | 51.2% | 1 |
| 23 Jul 2026 | 50.7% | 1 |
| 22 Jul 2026 | 50.2% | 1 |
| 21 Jul 2026 | 50.1% | 1 |
| 20 Jul 2026 | 49.8% | 1 |
| 19 Jul 2026 | 49.0% | 1 |
| 18 Jul 2026 | 48.1% | 1 |
| 17 Jul 2026 | 47.3% | 1 |
| 16 Jul 2026 | 46.7% | 1 |
| 15 Jul 2026 | 46.3% | 1 |
Frequently asked questions
What is the current water level of Glen Mervyn?
As of July 26, 2026, Glen Mervyn is at 51.2% of its capacity, holding approximately 1 hm³ of water, according to BOM data.
Is Glen Mervyn reservoir full?
No. As of July 26, 2026, Glen Mervyn is within its normal operating range at 51.2% of its capacity, so it is not full.
Is the water level at Glen Mervyn rising or falling?
The level at Glen Mervyn has been broadly stable over the latest week on record (0.0 points).
How much water can Glen Mervyn hold?
Glen Mervyn has a total capacity of 2 hm³.
Where is Glen Mervyn reservoir located?
Glen Mervyn is located in Western Australia, Australia, within the McCallum Creek Basin basin (coordinates 33.498°S, 116.100°E).
When was Glen Mervyn dam built?
The dam at Glen Mervyn was completed in 1969.
What is Glen Mervyn used for?
Glen Mervyn is used primarily for water supply, and is managed by BOM.