Williamstown Dredging Study

close up of boats on the bay
October 2016

Parks Victoria has received funding from Government to undertake a dredging study for Hobsons Bay, Williamstown. The aim of the study is to prepare a dredging plan that will ensure safe navigation into Williamstown for consideration by Government. 

Background

Parks Victoria is the port and waterway manager for the local port of Port Phillip and is responsible for safe navigation. Williamstown is a significant Maritime Precinct at the mouth of the Yarra River in Port Phillip with a range of marinas, boat manufacturing and maintenance facilities, and piers and jetties along the foreshore.

Hobsons Bay receives sediment from the Yarra River which over time has accumulated to a point where it is impacting on boating access. 

Responding to concerns from Williamstown waterway users, the Minister for Ports in June 2016 announced funding to undertake “… a technical dredging study for the Williamstown Maritime Precinct.”

Purpose

The purpose of the study is to understand the size of the problem, the solution and the cost. 

Key project stages

Stage 1 - Define the problem – channel location, depth (volume) and sediment characteristics

The Williamstown Foreshore Strategic Plan 2010 provided direction regarding the location of access and transit lanes in Williamstown.  This was based on work undertaken by GHD and GeoDimensions to define the required widths of fairways in Williamstown, however there is a gap in the information regarding design vessels and depth requirements.

Stage one of this study will confirm the location and depth requirements for the Williamstown fairways in consultation with key stakeholders and sediment sampling and analysis.

At the end of stage one we will have defined the scale of the problem e.g. the volume of sediment to be removed and the nature of the sediment.

Stage 2 - Investigate the solution – disposal location in water or on land

The most appropriate form of dredging is dependent on the volume, sediment characteristic and disposal methodology.

Highly contaminated sediment may need to be disposed of to landfill. This costly process involves dredging the material and bringing it to land, dewatering and then transporting to an EPA approved landfill site.

Less contaminated sediments may be able to be disposed of to an existing Dredge Material Ground in Port Phillip, though access to these is not guaranteed.

Creating a new Dredge Material Ground may be an option, however this will require extensive environmental investigation and approvals from government Departments and Agencies.

Stage 3 - Develop dredging plan – cost estimation, statutory approvals, etc.

The dredging plan will need to document the statutory approvals required and any further investigations. All works must comply with both the National and EPA Victoria Dredging Assessment Guidelines.

The final stage is to cost the delivery of the proposed dredging works and provide this advice to Government for consideration.

What stage is the project at?

Parks Victoria has engaged a suitably qualified consultant, AW Maritime Pty Ltd, to undertake the dredging study.