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Peter Hopper Lake revitalisation


Peter Hopper Lake, situated within Redleap Recreation Reserve in Mill Park, is one of the City of Whittlesea's largest waterbodies and attracts visitors from the community, as well as beyond the municipality.

In recent years, the lake has experienced numerous algae outbreaks and water quality issues. While various treatments have had some success in restoring water quality, the effects have not been long-lasting and further work is required to improve the long-term health of the lake.

City of Whittlesea is committed to providing a long-term solution to rehabilitate Peter Hopper Lake. Council has engaged a specialist consultant to provide expert advice and develop a feasible long-term plan to improve the water quality and revive the vitality of Peter Hopper Lake.

Revitalisation works start

The Peter Hopper Lake revitalisation works started in February 2024 with the desilting of the lake. 

The desilting process, which will see the lake desilted with special dredging equipment to remove excess sediment and debris, is expected to continue until mid-2024. 

A small section of the Redleap Reserve dog park has been closed to owners and their pets while the desilting works are carried out. 

Access to the dog park’s quiet zone will be restricted until the desilting phase of the works is completed to prevent users coming into contact with the water. 

The rest of the dog park is unaffected and remains open to owners and their dogs as usual.

Improving water quality

There are several factors that have contributed to the lake's poor water quality. The upgrade will address these issues to ensure the lake will remain a place for the community and wildlife to enjoy for years to come.

Mud: Peter Hopper Lake has accumulated large quantities of silt from stormwater run-off that feeds into the lake. Silts bind all sorts of contaminants as they wash off the catchment, including phosphorus which impacts the lake's water quality through over-nutrification, leading to algae blooms and low oxygen levels in the water. Council will remove all silt from the bottom of the lake and will install a gross pollutant trap upstream of the lake to catch coarse organic debris. A sediment pond will be built at the lake's inlet to capture finer silts before they enter the lake. These will protect the lake from ongoing natural contamination in the future.

Water quantity: The lake's catchment does not currently supply enough water for the lake to refresh itself regularly. Council will be increasing the lake's inflow of water and upgrade the lake's overflow capacity in order to achieve more water turnover.

Circulation: Peter Hopper Lake is a large waterbody and movement of water is dependent on stormwater flowing in and out of the lake. This means that between rain events, water does not move around as much. To help move the water regularly and avoid it becoming stagnant, Council will be installing a pump system at the lake.

Nutrients: Nutrients, such as nitrogen and phosphorus, occur naturally but much of the nutrients in our waterways come from human activities such as fertilisers or from animal droppings. When there is an excess of nutrients in the water, it can lead to algae blooms. In order to continuously filter out excess nutrients, Council will construct a specifically designed raingarden in the northern part of Redleap Reserve. Lake water will be pumped to the raingarden and be filtered through a sandy soil and nutrient-hungry vegetation before making its way back to the lake.

Community consultation

Council received overwhelmingly positive feedback on the lake rectification proposal during the public consultation period between March and June 2023.

The feedback received through our online Engage page, as well as through our on-site pop-ups and consultation with the Friends of Peter Hopper Lake Group, can be summarised in the following themes:

Proposed infrastructure: The proposal to retrofit the lake with water-quality-improving infrastructure resonated well with the community. We have received ideas on these additional assets which the project delivery team will consider in the finalisation of the design. This includes an optimised location for the bioretention (raingarden) system to have less impact on the current park use, infrastructure features which are safe for wildlife, and perhaps the retention of the lake island infrastructure installations. A variation to the lake redesign will be published and shared with the community once available. More information on raingardens is available on Melbourne Water's website.

Site management: Given the substantial works required on the lake and the duration of the rehabilitation needing to allow for desilting, construction and re-establishment, residents have concerns about the traffic situation, noise levels and overall site accessibility during this time. Council has engaged a specialist consultant for the design of the lake's new infrastructure and is currently in the process of working through the site logistics and the impacts to visitors and local residents. Council will ensure that the impacts are communication to affected reserve users and neighbours, directly and through this website.

Wildlife: As part of the design phase, Council has engaged ecology experts who will inform the management of all species identified on-site before, during and after construction. A Wildlife Management Plan will be prepared for this purpose which will also inform about the adequate handling of pest species like the European carp and the management of the unsustainable population of white ibis on the island. We have further received a number of habitat creation ideas from the community of which a vast majority will find consideration in the final design of the works. Council will be exploring terrestrial, floating as well as underwater habitat, and their safe and successful implementation will be guided by specialist ecological advice.

Amenity: We have also received a large spectrum of ideas on how to improve and add to the aesthetics of the lake. In working through the detailed design, Council is currently exploring opportunities to utilise both existing and future infrastructure to provide for purposeful engagement with the lake that is safe for both animals and visitors. This will include viewing platforms and resting opportunities in appropriate locations, as well as small fountains that will add a playful feature while drawing in oxygen from the air which is a healthy addition to the lake. The strong landscaping expertise the design team brings to this project will ensure that the lake retains its beautiful natural look.

Safety: Safety in design, construction and future operations will be at the heart of the revitalisation of Peter Hopper Lake. Council will use the opportunity to overhaul the lake's educational signage and promote good visitor behaviour and discourage bad behaviour either through novel design or signage. With the lake acting predominantly as wildlife habitat, Council is committed to reinstating the asset to be a home for fauna and flora that visitors can engage with in a safe and respectful manner, and that all age groups will be able to enjoy.

Frequently Asked Questions

It is not uncommon to see a lake’s water quality decline from time to time, particularly during the summer months when warm temperatures, combined with low oxygen levels and high nutrient levels, lead to algae blooms. 

Pollutants such as chemicals, animal droppings and other debris can also be washed into lakes through stormwater run-off, contributing to a decline in water quality. 

Peter Hopper Lake is a large lake and requires substantial rainfall to be able to refresh itself frequently. When this doesn’t occur, the water can become stagnant.

Council has been working to address the poor water quality in the lake in a number of ways, including adding binding agents to remove excess phosphorus in the water, applying a specialised treatment to increase the oxygen levels in the water and installing four air dispersers to help oxygenate the water at its deepest and most stagnant locations. 

Unfortunately, these treatments have not had long-lasting effects and further, more substantial work is required to improve the long-term health of the lake. 

Following extensive investigations and expert recommendations, Council has a long-term plan to improve the water quality of Peter Hopper Lake. 

The first stage will see the lake desilted using special dredging equipment to remove excess sediment and debris. 

One of the advantages of dredging is that the lake’s water level can be maintained, reducing the impact of odour and having little effect on wildlife. 

The second stage of the rectification works will see the lake dewatered to enable installation of a gross pollutant trap and sediment pond to capture water and filter pollutants before they go into the lake. An offline pumped raingarden will be established to further filter and treat the water.  

A circulation pump will be installed to ensure water does not remain stagnant, which will help minimise algae forming. 

The first stage of the project is to desilt the lake, which will commence in February 2024 and continue until May 2024. 

The second stage of the works will see the dewatering of the lake and installation of new infrastructure. This is anticipated to begin shortly after the desilting works and take a further six months. 

The third stage is landscaping, which will follow the dewatering phase and continue until the end of the year. 

There will be no public access to Peter Hopper Lake once the desilting has been completed until all new infrastructure is installed and the lake can receive water again. 

During the works, the lake will need to be drained to allow for the safe construction of the sediment pond and other infrastructure. 

Once construction is complete, the lake will be progressively refilled and landscaping undertaken in and around the site. 

The precinct’s northern car park and barbecue area will be closed to the public in February 2024, with residents encouraged to use the southern car park and barbecue facilities. 

The footpath around the lake is expected to remain open to pedestrians throughout the desilting works.

Council is working closely with zoologists to manage the impacts on the various wildlife, including the White Ibis population on the central island.

A Wildlife Management Plan is being prepared to ensure that all species are cared for through safe dispersion or temporary relocation. This process is planned to take place outside of the common breeding season. 

While disturbance to wildlife is expected to be minimal during the desilting stage, a zoologist will be engaged to oversee the site and attend to any animal salvage and relocation as necessary. 

Council will be preparing a Wildlife Management Plan for the lake and specifically address the white ibis population that nests on the central island in Peter Hopper Lake. We will also work with the Department of Energy, Environment and Climate Action on developing a long-term, localised solution for the birds.

If you see any sick, distressed, abandoned or dead wildlife, please do not handle the animal yourself. 

Instead, contact the City of Whittlesea’s customer service team on 9217 2170 to have the animal removed safely. 

For non-urgent inquiries regarding the Peter Hopper Lake revitalisation project, please email 

While works are in progress, Council will continue to manage the conditions of the lake using the methods we have been using to date, which includes algaecides to suppress blue-green algae growth. 

While the lake will remain open for the most part during the desilting stage, Council asks visitors to continue to: 

  • Avoid contact with the lake water and keep dogs on a leash. No access into the lake is permitted 

  • Not handle birds or other wildlife 

  • Not feed the birds as this can attract further wildlife to the site 

  • Not fish in the lake 

  • Don’t leave rubbish behind 

More information

To discuss this matter with a member of the project team, please contact Council customer service on 9217 2170 or email

If you speak a language other than English, call 131 450.