This project will provide a sustainable water source for Princes Park increasing its resilience to climate change and future drought. To help conserve water, City of Melbourne has a target in its Municipal Integrated Water Management Plan for 50% of all its water to be sourced from alternative water sources (stormwater, rainwater, recycled water). This project would provide 60 million litres of water per year to Princes Park, supplying 80% of its annual water demand.

The harvesting system will only take the flows that are above the environmental flows required by the creek. The Moonee Ponds Creek experiences high flows in many rainfall events and this is the water that will be harvested. The creek will benefit from improved water quality. Each year the project will remove:

• 200kg of nitrogen and
• 20,000kg of sediments
• litter
• 60 million litres of stormwater generated by highly impervious catchment.

Part 1 – Capture and treat excess stormwater

Excess stormwater will be captured from the Moonee Ponds Creek through a stormwater pipe. This pipe will be located to make sure that all environmental flows within the creek are maintained.

The stormwater will then enter a gross pollutant trap where litter and larger pollutants are removed and then a sediment chamber to remove coarse sediments. A suction truck will be used to empty the gross pollutant trap every 3 to 6 months.

Part 2 – Storage of stormwater

The treated stormwater will then be transferred to a large underground storage tank at McPherson Field in Royal Park. This storage tank can hold 5 million litres of water so we can make the most of the larger rainfall events and have space to store water in drier times.

Part 3 – Irrigate

Stormwater will be pumped to an irrigation tank at Princes Park via a UV disinfection system. This is to make sure any pathogens are removed from the stormwater before it is used to irrigate ovals and garden beds.

Royal Park is irrigated with harvested stormwater from the Trin Warren Tam-boore wetlands. This was City of Melbourne’s first stormwater harvesting system and has been providing a sustainable water supply to Royal Park for over 15 years.

We aim to capture stormwater as close as possible to where we need to use it, however this is not always possible. For Princes Park, Moonee Ponds Creek has been identified as the most suitable source of stormwater because:

• It will provide a reliable supply of water. The creek is mostly located in urban stormwater catchments so receives extremely large volumes of excess stormwater.
• It will benefit through reduced litter and pollution if excess stormwater is harvested.

Electricity will be required to power pumps and the UV disinfection system. We will be quantifying the energy requirements of the system as we undertake the detailed design phase of the project. Our intention is for the system to be carbon neutral.

The offtake will be a pipe or weir at a level to take only excess stormwater. The pipe inlet will have a self-cleaning perforated metal screen placed in front of it to prevent large debris blocking the pipe. Once constructed, it will be an improved version of many of the other inlets that enter the creek along the concrete channel.

Fit for purpose water use matches the water quality to the end use. Drinking water is the highest quality of water. Irrigation of sport fields and open space does not need drinking quality water but does need water that is filtered and free of pathogens. This project applies the best practice approach of trapping and removing sediments and larger pollutants and including UV disinfection to kill any pathogens. Dissolved nutrients such as nitrogen and phosphorous are beneficial to the irrigated turf. The water supply will be actively monitored and if parameters such as salinity, pH and turbidity are out of the preferred range, the water will not be reused, thus protecting our soils and park users.

The City of Melbourne operates several pumped irrigation systems throughout the municipality, some close to homes. Irrigation pumps do not generate significant noise and when located within a pump shed, they are imperceptible from background city noise during operation.

To reduce the impact on existing vegetation, this project has included provision for the rising main to be directionally bored for the entire length from the Moonee Ponds Creek to McPherson Field. However, where service conflicts exist, open trench installation may be required for short sections. A temporary works plan will be developed during the detailed design phase to determine the location of boring access points to minimise the impact on the exiting flora and fauna.

The functional design has also been updated to realign the rising main along the northern edge of the wetland which will reduce impact on existing vegetation.

The rising main is proposed to run in the vicinity of a significant population of White’s Skink within Royal Park. Directional pipe boring will minimise above ground impacts and we will work closely with ecologists to ensure that we do not disrupt their burrows. Not negatively impacting the White’s Skink is a key priority of the project.

City of Melbourne operates stormwater harvesting systems at Royal Park, Lincoln Square, Fitzroy Gardens, Darling St and Birrarung Marr. Information on these systems can be found on the Urban Water website.

Your participation will influence:

• Project staging and construction – This project will mostly be underground but there will be some disruption to park users during construction. Your feedback will inform how we stage construction works so we minimise this disruption.
• Project communications – Your feedback will allow us to understand any concerns about alternative water use to ensure that all our communications materials clearly outline how these concerns have been addressed.

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