Peter Hopper Lake, situated within Redleap Recreation Reserve in Mill Park, is one of City of Whittlesea's largest waterbodies and attracts visitors from the local 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 have 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. Check out the concept plan.

What are the main problems with the lake, and how does the planned work address these?

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.

Peter Hopper Lake has accumulated large quantities of silt from stormwater runoff that feeds into the lake. Silts bind all sorts of contaminants as they wash off the catchment, including Phosphorous which impacts the lake 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 zone to capture finer silts before they enter the lake. These will protect the lake from ongoing natural contamination in the future.

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.

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, such as nitrogen and phosphorus, occur naturally, but much of the nutrients in our waterways come from human activities such as fertilizers 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.