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Trinity Valley Drainage Upgrade Stages 2 & 3

Trinity Valley Drainage Upgrade Stages 2 & 3

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Category: Stormwater drainage network

Project management

Managed by City of Norwood Payneham & St Peters

Design: Stantec Australia

Contractor to be confirmed.

Project details

The Trinity Valley Drainage Upgrade will reduce the risk of flooding in the suburbs of St Morris, Trinity Gardens, Maylands & Stepney – which is known as the Trinity Valley.

The new stormwater drainage infrastructure will reduce surface flood waters during storm events by capturing stormwater and temporarily storing it in a detention basin at St Morris Reserve, as well as underground detention tanks within the road network.

The works are designed to:

  • increase capacity of stormwater infrastructure
  • alleviate future flooding where possible
  • protect dwellings from future one in-100-year stormwater events
  • utilise Council reserves to act as detention areas
  • address upstream flooding to reduce pressure on downstream system.

Project funding

The Federal Government is contributing $9.9 million as part of its Preparing Australia Program, which targets projects that improve resilience against natural disasters.

The investment is being matched dollar by dollar by the Council, resulting in a near $20 million investment to reduce the risk of flooding.


The upgrade works will be completed over three years in the following order:

  • Stage 2 & 3: September 2023 – March 2024
  • Stage 4: November 2023 – April 2024
  • Stage 1: August 2024 – January 2025

Project background

The upgrades to stormwater drainage infrastructure stems from the City-wide floodplain mapping project which identified locations which are at risk from flooding and considers a range of future scenarios, including infill development and the ongoing impacts of climate change.

Site Address

St Morris, Trinity Gardens, Maylands & Stepney


Estimated $20,000,000

Project Contact

Contact Paul Mercorella

Contact role Manager, City Assets

Phone 08 83664517


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