Short Virtual Presentation & Digital Poster 10th Australian Stream Management Conference 2021

Building stable and resilient foreshores using a natural approach (#31)

Marjolein Oram 1 , Andrew Attewell 1
  1. City of Gold Coast, GCMC, QUEENSLAND, Australia

Why did we do it?

In 2015 the Damian Leeding Memorial Park, adjacent the upper estuary of the Coomera River, was undergoing significant bank scour and bed erosion causing a risk to infrastructure and people’s safety. There was also a long-term threat that the river could break into the recreational lake within the park. The naturalised stabilisation works keeps the park safe while allowing mangrove seedlings to re-establish and sediment to build up behind the logs. 

What did we do?

City of Gold Coast engaged a geomorphic engineer to undertake an erosion assessment and develop an innovative design using hardwood trees. The Damian Leeding Foreshore Stabilisation Project was successful in stabilising 450 meters of foreshore. Hardwood instream structures were placed on the riverbed together with systematic revegetation of the bank. The logs are tethered to 106 marine hardwood piles. The structures are designed to reduce velocities on the foreshore by manipulating the hydraulic forces. The re vegetation phase consisted of 7100 native riparian plants which tie the whole project together.

What have we learned?

We are monitoring the project’s success. Outcomes include:

  • The bank is adjusting to a natural profile
  • Sediment is building behind the logs
  • High success rate of mangrove seedlings growth
  • Fauna using the habitat 

Why does it matter?

This type of stabilisation works maintains estuarine processes and improves water quality, fisheries habitat and aquatic ecological values.

  1. Coomera River estuary processes study and foreshore management plan, Riparian Engineering 2012
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