19 March 2018
At Edithvale and Bonbeach, the level crossings will be removed by lowering the rail line into a trench.
Because of the projects’ proximity to the Edithvale-Seaford wetlands, the Level Crossing Removal Authority prepared an Environment Effects Statements (EES) to understand and manage any potential environmental impacts from the projects.
Extensive modelling and testing
We had a team of ecologists, planners, heritage experts, engineers and hydro-geologists working to understand the local environment.
Our studies were extensive. We drilled nearly 150 geotechnical bores in the area and installed groundwater monitoring bores in over 120 of these holes.
We also installed 5 water gauges to monitor surface water levels.
The bores installed for this investigation remain in place and can be used to monitor local groundwater at Edithvale-Seaford Wetlands, enhancing knowledge of this important ecosystem into the future.
We used the data to create a model, based on 20 years of historical climate records, to predict changes. We ran the model nearly 200 times to test a range of scenarios up to 100 years into the future.
Methodology undertaken for modelling the water environment
| Task | Stage 1 | Stage 2 | Stage 3 |
|---|---|---|---|
| Task 1: Preliminary assessments | Preliminary groundwater impact assessment based on regional datasets | - | - |
| Task 2: Site investigations | Regional site investigation programs | Wetland specific site investigations | Conceptual hydrogeological modelling |
| Task 3: Numerical groundwater model | Build and calibrate a numerical groundwater model |
Predict impacts from the numerical groundwater model | Build and calibrate a saltwater intrusion model |
| Task 4:Water balance model | Adopt and calibrate a water balance model | Predict impacts from the water balance model | - |
|
Task 5: Risk and impact assessment |
Assess risks and impacts to wetlands, groundwater quality and use | - | - |
Our investigations found that the level crossing works would not impact the Edithvale-Seaford Wetlands.
This is because groundwater changes resulting from the project are highly unlikely to occur closer than one kilometre from the wetlands.
This means that the vegetation, birds and animals in the wetlands would be not be impacted by the project. In addition, and for extra confidence in our mitigation measures, we will implement a monitoring and management plan to make sure no impacts arise as a result of the trench.