What is dredging? 

Dredging is an essential process aimed at maintaining navigable waterways. It involves the removal and relocation of built-up sediment from channels to ensure that water routes remain safe and accessible for residential, commercial and recreational users. The program is expected to move 10-15,000 cubic meters of sand and sediment. 

Benefits of dredging

Dredging keeps channels safe for movement, allowing our community to explore our waterways. It also supports the flow of sand towards our northern beaches. 

What to expect during dredging

When dredging is taking place, you may see dredging vessels and machinery along the waterways and foreshore areas. A cutter suction dredge moves across the bottom of the channel, sucking up sediment and pumping it through a pipeline to the disposal site.

Some low-level noise from boat engines and minor disruptions to boat traffic may occur during this time. Should air get in, the pipeline may float to the surface. For safety, boat users should follow navigational lights and signage and keep an eye on the water to avoid any collisions. 

A dark-coloured plume is often present in the water during the dredging process. This is floating fine sediment removed from the channel floor.  Once the work is complete, the plume normally disappears within 24 hours. Sediment pumped to the disposal site will return to a light colour after a few days of sun exposure. 

Continuous monitoring is conducted throughout the dredging period to ensure no detrimental effects on water quality 

Sand bypassing

The Department of Transport conducts the sand bypassing program each year at the Dawesville Cut and Mandurah Ocean Entrance channels. This sand bypassing allows safe navigation around these entrance channels while also allowing the natural flow of sediment to continue along the coast. 

More information on dredging and sand bypassing

The City is committed to protecting Mandurah’s beautiful waterways. 

It is important that the foreshores near these waterways are developed and managed effectively. Managing our foreshores; 

  • Ensures the protection of natural values that help to filter pollutants from our urban development and activities
  • Provides habitats for our local and visiting international waterbirds
  • Provides a range of recreational activities for our community
  • Enables ongoing asset management and monitoring. 

Mandurah boasts numerous waterways and wetlands, some of which are internationally recognised and protected, through the Ramsar Convention on Wetlands, Japan Australia (JAMBA) and the China Australia Migratory Bird Agreements (CAMBA).

Benefit of wetlands

Although these wetlands, depending on their location may not have water covering the entire soil all year,  are very important to our natural environment, providing benefits such as:

  • The control flooding that help protect our coastal areas by slowing down the movement of waters
  • Filtering waste and pollutants and improving the quality of water
  • Conservation of biological diversity
  • Providing habitat for a great diversity of plant and animal species
  • Provision of  economic and recreation value from recreational fishing to tourism
  • Hold important social and cultural values to members of our community.

Wetlands in Mandurah

  • Peel-Yalgorup System (Peel Inlet and Harvey Estuary)
  • Lake Clifton
  • Lake Goergrup
  • Creery Wetlands
  • Hexam Close
  • Samphire Cove
  • Lower Serpentine
  • Murray River

With an estimated 80 percent of wetlands on the Swan Coastal Plain having been cleared, filled, drained or otherwise destroyed since European settlement, the City’ Foreshore Rehabilitation Project will help minimise our impact, and enable the protection and rehabilitation of these valuable waterways.

Visit the Peel Harvey Catchment Council's website for more information

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