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Water Campaign™ case study

MORNINGTON PENINSULA SHIRE, VICTORIA

Stormwater Reuse Project – David MacFarlane Reserve, Sorrento

: Community action

: Corporate action

: Partnerships

: Water conservation

: Water quality

The Mornington Peninsula Shire is a large municipality located 50 kilometres south of Melbourne. Its population of 142,659 people increases to over 200,000 during the summer peak period. Council is an ICLEI member and joined the Water Campaign™ in 2003.

Synopsis

: The David MacFarlane Reserve in 1925

David MacFarlane Reserve was known as an area prone to flooding.

Through community consultation a decision was made to redevelop the reserve using Water Sensitive Urban Design (WSUD) principles to reduce the risk of flooding, while improving stormwater quality and making large amounts of water available for reuse.

Motivation

Historically David MacFarlane Reserve was used for market gardens and livestock paddocks and its low-lying point has always been prone to flooding.

Prior to the upgrade, stormwater would collect in a natural sump and then be pumped out to the bay.

In large rain events the area would flood and damage surrounding infrastructure, including the Sorrento community centre, tennis club, tennis courts, scout hall and CFA training track.

: Flooding in 2005

: Flooding in 2005

Now stormwater is collected from three areas – Hotham Rd, Morce Ave and Melbourne Rd – and goes through Gross Pollutant Traps (GPTs) to collect the large litter and debris.

Two of the drainage lines are then diverted to a reuse basin, where the water is pumped to a 30-megalitre storage dam on the neighbouring Sorrento Golf Club for reuse in irrigation.

The third drainage line is diverted to a wetland that is situated below the reuse basin in order to maintain natural flows. During larger storms excess water also flows over the weir wall of the reuse basin and into the wetland, which treats the water using biological processes.

: Construction at the David MacFarlane Reserve

When water in the wetland reaches predetermined levels it is pumped to the bay by Melbourne Water.

In 1999 the David MacFarlane Reserve Master Plan called for the implementation of a wetland or an ornamental lake within the reserve.

This plan, written in consultation with the community, was developed to find an integrated approach to the Reserve that accommodated the needs of all stakeholders.

Capital works funding approved the construction of a wetland rather than an ornamental lake due to its ability to remove pollutants from the water.

The Sorrento Golf Club entered into a legal agreement with the Council to connect a second rising main to the pump station to recycle some of the stormwater for irrigating the golf course.

While previously using a combination of potable water and groundwater, with continued drought conditions making potable water a scarce resource and rising salinity in the groundwater bores, the club was looking for alternative sources.

Council saw the potential for the golf club to irrigate with stormwater as a big saving to the community and its potable water supply.

: Construction at the David MacFarlane Reserve

: Construction at the David MacFarlane Reserve

Funding and partners

The Stormwater Reuse Project had three funding partners: Mornington Peninsula Shire, the State Government of Victoria and the Sorrento Golf Club.

Council applied for and received a State Government of Victoria Stormwater and Urban Water Conservation Grant of $246,767 to construct the wetland, a GPT and stormwater reuse basin.

The wetland and GPT contributions were matched by Council, and the funding for the reuse project was matched by the Sorrento Golf Club, which contributed $90,000.

The two additional GPTs were funded using Council’s drainage upgrades budget.

Process

As the wetland was already in the design phase when the grant was awarded, Council decided to break the project into three parts:

Part 1 – the wetland
Part 2 – the stormwater reuse basin
Part 3 – the three GPTs.

The pump station at the bottom of the wetland is the last component, to be completed by Melbourne Water within 2008.

: Diagram of the new wetlands

The wetland was completed by October 2005, with ongoing landscaping being carried out up until May 2007.

It contains two sedimentation ponds, an interconnecting ephemeral zone with varying bench heights and a rock filter wall (see diagram).

In conjunction with landscape planting the wetland was designed to mimic a natural waterway.

The stormwater reuse basin was designed by GHD Pty Ltd, constructed by Maw Civil Pty Ltd, and completed in March 2007.

Due to the natural salinity levels in the ‘Sorrento Sump’ the basin was constructed with a plastic liner beneath the surface to separate the salty groundwater from the stormwater.

Stormwater captured within the reuse basin is pumped directly to the 30-megalitre storage dam on the golf course.

During larger storms excess water flows over a weir wall and into the wetland.

The GPTs were installed and completed by May 2007, two funded by Council’s drainage upgrades budget and the third co-funded by Council and the State Government of Victoria grant.

As the new Regional Drainage Authority, Melbourne Water was responsible for the construction of the new pump station at the downstream end of the wetland.

: Reuse basin

The station was completed in early 2008, after being delayed from its original schedule due to the need for an assessment on Aboriginal heritage impacts.

The GPTs and side entry pits are maintained by Council through its service provider, Nepean Waste, and the wetland is maintained by the Regional Drainage Authority, Melbourne Water.

The quality of the water that is used to irrigate the golf course is monitored by the Sorrento Golf Club.

Savings and benefits

Water conservation benefits

The project saves 70 to 120 megalitres of potable and ground water each year, which was previously used by the Sorrento Golf Club for irrigation.

Water quality benefits

The wetland treats the stormwater of phosphates, oils and silts before it enters the bay. The project also reduces the volume of water extracted from an aquifer that is considered at risk from over use.

Additional benefits

Council engaged with the community through the development of the David MacFarlane Reserve Plan and with the Sorrento Golf Club to develop a win-win project.

The project has been so successful that the Sorrento Golf Club has decided to fund the construction of a second dam on its premises in order to capture the large quantities of water that enter the reuse basin in intense rain events.

: The David MacFarlane Reserve in 2005

: The newly completed wetland

Costs

The whole project cost $615,000, including:

Design – $80,000
Wetland Construction – $200,000
Reuse Basin Construction – $200,000
Landscaping – $60,000
2 Gross Pollutant Traps and Litter Baskets – $75,000

Further information

Alison Leighton
Team Leader, Water and Waste Services
Mornington Peninsula Shire
Ph: +61 (0)3 5950 1297

Mornington Peninsula Shire Council website

See the Community Water Grants website for lists of previous grant recipients.

Contact details

For further information about the ICLEI Water Campaign™ in Australia please contact:

ICLEI Oceania
4/267 Collins St
Melbourne Vic 3000
Ph:   +61 3 9639 8688
Fax:   +61 3 9639 8677
Email:   oceania@iclei.org
Website:   www.iclei.org/oceania/water

Acknowledgements

Thanks to Alison Leighton for her assistance in producing this case study.

Photographs supplied by Council.

Quoted population figures are taken from the Australian Bureau of Statistics Report 3218.0, Regional Population Growth, Australia 2006-07, March 2008.

Call for future case studies

Does your council have an initiative that could be promoted by the Water Campaign™ as a future case study?

We’d like to hear if your council has implemented an innovative water saving initiative or project to improve water quality. Contact your Water Campaign State Manager with details.

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