Geraldton dredging on the way

Mid West Ports Authority (MWPA) is preparing a plan to undertake maintenance dredging activities within Geraldton Port waters to remove accumulated sediments from the Commercial Harbour and Main Shipping Channel. 

This project is necessary to ensure the safe navigability and continued operations of the Port. 

Maintaining safe and efficient navigation is vital to supporting national and international trade, economic development in the mid west region and its continued connection to global markets.

During the work, over 230,000m3 of material will be removed from navigable areas, mainly the shipping channel.

“Just like rail and roads, shipping channels and other navigational areas require maintenance to keep trade flowing,” MWPA said.

“Left unmanaged, our port’s capability would be significantly reduced, with the flow on effect impacting local businesses and our community.”

The Geraldton Port maintenance dredging is set to take place in Q4 of 2021.

Maintenance dredging was last conducted in 2012. Since that time, MWPA has taken interim measures, such as sea bed levelling, to maintain channel infrastructure.

Like the 2012 maintenance dredging scheme, the 2021 campaign will use a trailing suction hopper dredger (TSHD).

“Our approach to maintenance dredging is anchored around finding the most sustainable way to manage naturally accumulated sediment. Prior to any decision to conduct maintenance dredging, we explore and evaluate how sediment material can be beneficially reused,” MWPA said.

“We utilise internationally recognised frameworks created by PIANC, the world association for waterborne transport infrastructure, to support the implementation of the London Protocol – an international treaty to protect and preserve the marine environment.”

Where possible, alternatives to off-shore at-sea disposal, known as sea dumping, are preferred.

The PIANC framework for dredge material reuse is focused on matching the supply of dredged material with beneficial use demand. It does this by considering the following factors:

• Quality of material (physical and chemical properties of dredged and required material);

• Quantity of material (volume of dredged and required material);

• Location of material (is it technically feasible to move/place material).

Their beneficial use assessment explored 24 placement options for the 2021 maintenance dredging, with 16 pre-screened and rejected due to fatal flaws and eight shortlisted for consideration.

To ensure a consistent and transparent approach, each placement option was evaluated alongside multiple criteria that considers a range of social, environmental and economic values relevant and important to the local area and region.

In developing the criteria, diverse perspectives were considered with input sought from multi-disciplinary experts. From this, three core pillars emerged:

• Protecting the environment and the future;

• Keeping the port operational;

• Financial constraints.

Environmental Impact Assessments (EIA) underpin the proposed placement options and are developed in accordance with state and commonwealth regulatory requirements and supported by detailed technical studies.

The EIA process sees environmental values specific to the port and the surrounding region mapped and the extent, severity and duration of impacts to environmental receptors assessed.

The assessment ensures that both, risks and measures to prevent or minimise impacts, are clearly identified.

Champion Bay is a healthy ecosystem driven by quality water. Marine habitats include benthic (seafloor) infauna and seagrass communities, as well as fringing high and low profile rocky reefs that support macro algae and small coral communities.

Scientific research, detailed technical studies and an independent Environmental Impact Assessment have concluded that the risk to environmental receptors from maintenance dredging at the Port of Geraldton will be predominantly low, with any possible impacts to the marine environment likely to be minor and short-term.

After completing an extensive period of stakeholder consultation with key government agencies, industry partners and local community, MWPA is planning to begin works in late 2021, between September and October.

It is estimated that the dredging program will take between 4-8 weeks, with timings dependent on shipping schedules and weather conditions.