In 2016, Council undertook City-wide floodplain mapping which identified locations which are at risk from flooding and considered a range of future scenarios, including infill development and the ongoing impacts of climate change.

Council has developed and endorsed a Stormwater Drainage Program to address the findings of this report that will be delivered over a 15-year period. The next stage of works will focus on the upgrade of the Trinity Valley stormwater management network.

The ‘Trinity Valley’ (comprising the suburbs of St Morris, Trinity Gardens, Maylands, and Stepney) Drainage Upgrade will be delivered in four stages, between 2021-2025. The upgrade works will involve the installation of a new underground stormwater management network to increase capacity and provide improved flood mitigation during significant rainfall events.

Stages and 3 will be undertaken in the suburb of Trinity Gardens, with work to include the installation of new stormwater infrastructure, including culverts, pipes, and stormwater pits.

In some areas, the work will also include the reconstruction of existing roads with new asphalt as part of Council’s annual asset renewal program.

To accommodate the new, often larger stormwater infrastructure some alterations to existing SA Water connections also needs to be undertaken. It is expected that these works can be completed with minimal disruption to service supply.

Council has engaged with local stakeholders to develop a program for the work that limits the impact of construction activities on local business and community.

The upgrade will be undertaken over two stages, as follows:

STAGE 2 Stormwater Upgrade works will be undertaken along Albermarle Avenue and Ashbrook Avenue in the suburb of Trinity Gardens. These works are expected to commence in October 2023 and be completed May 2024.

STAGE 3 Stormwater Upgrade works will be undertaken along Jones Avenue, Amherst Avenue and Aberdare Avenue. These works are programmed to be undertaken during school holidays (16 December 2023 to 26 January 2024) to avoid disruption to the school community.

The construction work to install large culverts and pits requires sizeable trenches to be excavated in the road corridor. Most roads impacted by the Upgrade will require a reduction to one-way traffic, and some intersecting roads will experience up to two-day closures. Some short-term closures will also be required to property access (driveways) to enable the construction works.

For the Stage 3 works, to complete the construction works over the December/January 2023-2024 school holidays, Jones Avenue will be temporarily closed from Portrush Road to Amherst Avenue for the period of construction whilst the drainage and road reconstruction occurs. The full road closure will allow construction to be undertaken expediently, and without disruption.

More information regarding traffic arrangements during construction can be found on this website.

At times during construction, driveway access to your property may be impacted for a short period. In the event that property access is impacted, we will contact you ahead of these works occurring.

Property owners will not be required to modify their existing stormwater arrangements.

You can learn more about the Trinity Valley Drainage Upgrade by visiting this page or call our Citizens Service Team on 08 8366 4555.

If you would like to be kept up to date as works progress, please email trinityvalley@npsp.sa.gov.au