Bryn Estyn Water Treatment Plant flood study

Client: TasWater
Location: Tasmania / Australia
Date: 2020 - 2021  

Providing flood level information for upgrading a critical water supply plant 

Background

The Bryn Estyn Water Treatment Plant (WTP) is a critical infrastructure component for the delivery of secure water supply to Hobart. It is located on the right bank of the River Derwent, approximately 3.5 km upstream of New Norfolk.

As an input to an upgrade for the water treatment plant, TasWater required flood level information for the site to facilitate the preliminary upgrade design.

Solution

Prior to undertaking any analysis, Entura reviewed the proposed project with TasWater and provided guidance regarding flood risk, suitable site flood immunity, and the level of hydrologic and hydraulic analysis required to provide suitable design inputs.

We leveraged our considerable experience of modelling the Derwent catchment and used existing hydrological and hydraulic models of the area to estimate flood levels at the site for existing and future climate conditions. The TUFLOW hydraulic model of the River Derwent was updated to include proposed changes to the water treatment site associated with the preliminary upgrade design.

Services provided

• Hydrological and hydraulic modelling

Outcome

Entura presented the hydrological modelling outcomes in a way that clearly articulated the uncertainty of the analysis, to ensure this would be considered by the upgrade design team.

The hydraulic modelling results were presented at key locations around the site for the upgrade design team to check whether the site infrastructure would be protected from flooding for a range of flood events.

Flood maps were also prepared by Entura to show peak modelling flood depth, water surface elevations and flow velocities around the water treatment plant site.

The Bryn Estyn Water Treatment Plant upgrade was TasWater’s largest ever capital works project and was completed in September 2023, on time and under budget. It now stands ready to deliver 160 million litres of drinking water to Greater Hobart per day, futureproofing water quality, availability and reliability for generations to come.

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