Launceston Tamar Estuary River Health Action Plan - Margaret Street Sewer Diversion Project

Our River. Our Future

Revitalising kanamaluka/Tamar estuary

The kanamaluka/Tamar estuary is a special landscape that connects our community. We appreciate its importance to Launceston and the wider community, which is why we are making investments today to ensure its health for future generations.

As part of the Tamar Estuary River Health Action Plan (TERHAP), we are delivering new sewerage infrastructure for the city to improve the health of kanamaluka/Tamar estuary and the environment that surrounds it.


What's this project all about?

We’ve constructed a new underground diversion chamber at our Margaret Street Sewage Pump Station, using a construction method known as a Caisson, to help divert sewage and stormwater flows from Old Margaret Street Pump Station to New Margaret Street Pump Station.

This construction method involved sinking a new concrete structure (Caisson) deep into the ground. The Caisson was formed from large precast concrete rings which were sunk into the ground as material was excavated from within the rings. The structure was made watertight with a bottom plug and a roof structure.

This was the ideal construction method for a site such as this where there is very limited space for open excavation. Using this method also meant we minimised the impacts of our construction on nearby neighbours and the surrounding parkland. It will be used to direct all sewer flow into the New Margaret Street Pump Station. This enables our upcoming project to upgrade the pumping capacity at Margaret Street allowing transfer of larger amounts of sewage and stormwater to Ti Tree Bend Sewage Treatment Plant for treatment.

The video below demonstrates a similar Caisson construction method that will be using.



This project is one of many we’ll be delivering to improve the operation of Launceston's combined system which manages the flow of both sewage and stormwater.

The projects we are delivering as part of the Tamar Estuary River Health Action Plan (TERHAP) will help divert sewage and stormwater flows away from kanamaluka/Tamar estuary, reducing the frequency and volume of overflow events, helping to keep our waterways cleaner.

For more information about our TERHAP projects visit Tamar Estuary River Health Action Plan (TERHAP) Project.


This underground chamber will improve the way we manage these combined sewage and stormwater flows by improving the pumping capacity and the performance of our infrastructure during significant rain events.

Together with the Tamar Estuary Management Taskforce and through the Launceston City Deal, we’re improving the health our waterways.

Project update

During September 2023 we completed the final phase of major construction by lifting the large concrete lid into place for this new underground diversion chamber at our Margaret Street Pump Station.

Local contractors, Bridge Pro Engineering used a specialised construction method to sink large, prefabricated concrete segments deep underground. This method of construction is often used when site conditions do not allow for open excavation.

Lid lift photo

The Tamar Estuary River Health Action Plan (TERHAP or the Plan) is an initiative of the Tamar Estuary Management Taskforce (TEMT) and the Launceston City Deal, to improve the health of kanamaluka/Tamar Estuary.

TERHAP is jointly funded by the Australian and Tasmanian governments, the City of Launceston and TasWater.

TERHAP - Funding Partner logos



City of Launceston engineers visit the Margaret Street Pump Station

Early in July we hosted a site visit for council engineers.

This was a great opportunity for their engineers to visit the project to hear and see first-hand from our project team about the construction methodology being used.


Project timeline

Construction commenced October 2022

Construction completed September 2023.

TERHAP Projects

We will be delivering a number of projects to improve the efficiency of our combined sewage and stormwater network.  For further information on TERHAP related projects please click on the links below.

Tamar Estuary River Health Action Plan Project

TERHAP - St John Street Pump Station Upgrade

TERHAP - New Sewer Pipelines Projects

Have a question?

For the latest information about TasWater projects and news please visit our website regularly and follow us on social media:

Instagram @ TasWater (@tas_water)

Youtube @TasWater - YouTube

X @ TasWater (@Tas_Water)

If you would like to connect with one of our Community & Stakeholder Engagement team members about a project happening near you, please email [email protected] or call 13 6992.

Join our mailing list to keep up to date with the TERHAP project

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