Project goal:

Install and monitor Evaporation Covers in the Great Southern to investigate their effectiveness as a water saving initiative and secure future water supplies.


Installed. Monitoring Trial Underway.

Delivery Date:


What’s happening?

The Water Corporation has installed evaporation covers, as part of a trial, at three of our sites across the Great Southern Region. The sites include the Ravensthorpe Dam 4, Salmon Gums Quarry Dam and Lake King Reservoir. 

The installation of the covers occurred progressively during Q4 2023.

As part of the trial, additional monitoring will continue for an extended period after the installation.

Why Use Evaporation Covers?

The Great Southern Region is a drying climate and in recent years some locations have required water carting during the summer period.

We will be installing the evaporation covers across a number of water sources in the Great Southern Region, as a water saving initiative and to secure future water supplies.

The covers being used in this trial are a Hexa-Cover® system, where many individual floating plastic modules join to form an evaporation blanket. The modules self-adapt to the shape and level of water in storage.



The Hexa-Cover® system has reported over 50% reduction in evaporation during use and is approved for use on drinking water sources in line with AS4020.

This Evaporation Cover Trial is jointly funded by the Australian and Western Australian governments. Australian Government funding is provided by the National Water Grid Fund.



The covers will be installed on dams in Ravensthorpe, Lake King and Salmon Gums, in the Great Southern Region.

How Will This Impact Me?

All work will be undertaken on Water Corporation property Monday - Saturday between the hours of 7am and 6pm.

Nearby residents may notice additional trucks and workers approaching and leaving our sites while the covers are being installed.

There should be no impact to your water service from this work.

Interested in knowing more?

If you’d like to register for updates or have any general questions contact Water Corporation’s Community Engagement Advisor, Emma Halligan on 9420 2198, or Project Manager, Josh D’Souza on 9420 2128 or

For any faults, outages or security issues please call 13 13 75.

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