Track 10
Track 10 and flood water retention in Lake Reeve
The Track 10 causeway and how flood levels at Loch Sport have been calculated.
Does Track Ten affect Loch Sport's flood levels?
Track Ten has three sets of culverts that help water flow between the roadsides and keep the lake’s water levels balanced at this location. The road’s surface is about 0.8 meters above the Australian Height Datum (AHD). During major floods, like the 1% Annual Exceedance Probability (AEP) flood at 1.9 meters AHD, Track Ten gets easily overtopped, allowing water to flow westward.
Future predictions for the year 2100 indicate even higher flood levels, reaching 2.7 meters AHD. Reviews with WGCMA confirm that Track Ten does not affect Loch Sport’s flood levels.
Wellington Shire Council engaged an independent hydrologist to assess the impacts of Track Ten and flooding in Loch Sport. In summary the report found that “during significant events, including design floods, Track Ten is fully inundated so does not materially influence peak flood levels.”
A full copy of the report can be accessed here.
Things to take into account
- Flood overlays as proposed adversely impact landowners and the future of the whole town.
- Only two concerning flood events are on record: 1972 (before Loch Sport was populated) and 2007.
- The AHD71 benchmark is cited in a 2004 peer-reviewed paper (Lake Reeve excluded).
- In 2006, the first formal flood overlay AHD level was set at 1.9 metres for the Gippsland Lakes region. This suggests that a property with an AHD of 1.00m will be 0.9 metres under water (AEP 1%).
- 575 properties (20%) are currently affected in Loch Sport at 1.9m, mainly along the Lake Reeve side of town.
- The proposal is now to increase the level by 800mm to 2.7 metres. Around 2,000 properties (70%) would be affected at the proposed 2.7m AHD (AEP 1%).
- No subdivision or new building is allowed, but renovations and extensions can be made to existing structures. Why the difference across LGAs?
- DEECA, WGCMA and WSC are the three agencies with responsibility.
- WGCMA-determined flood overlays are shown in VicPlan for Loch Sport through to Seaspray, but none from the EGCMA for Paynesville, Metung or Lakes Entrance.
- Water only enters the lakes as (1) direct rainfall, (2) down the rivers from the catchments, or (3) in from Bass Strait through the entrance at Lakes Entrance (deepened in 2015 from 2.5m to 7.0m). Winds are the other factor in flooding computations.
- NASA predictions say the mean ocean level might rise by between 33cm and 5 plus metres by the year 2150. Other agencies are "all over the place" with significant low and high variances.
Flood levels
Dark blue is 1.9m and lighter blue is 2.7m. Flood mapping is available from Coastal Risk Australia.
Flood overlay at 1.9m AHD
Flood overlay at 2.7m AHD
The Track 10 causeway
Track 10 was originally a low tide causeway. A 1998 permit issued to Santos and the WSC led to its rebuilding and raising for heavy vehicle use. The impact of this alteration is visually demonstrated in images of the 2007 floods, where water is shown backing up towards Loch Sport. There is also a lack of maintenance and clear evidence of water not flowing away. A clean-up was attempted in April 2025.
Track 10 causeway
Track 10 causeway
Track 10 during the 2007 floods