Damian Leeding Memorial ParkForeshore stabilisation projectIn 2015, the Coomera River foreshore in the upper estuary at Damian Leeding Memorial Park was experiencing severe erosion and destabilisation of the bank. This resulted in significant loss of trees and a safety risk to park users. The City of Gold Coast (City) managed an innovative and multi focused restoration treatment to stabilise the foreshore.

The City used hardwood tree logs to stabilise the river foreshore with a more natural and permanent solution.

The restoration project used a combination of hardwood logs (with root balls), hardwood marine piles and the planting of riparian revegetation.

The aim of the project is to achieve a naturalised system that will protect the river over time.

The hardwood logs have a minimum 15 to 20 year life span by which time it is expected the logs will be embedded into the river bed providing resistance to erosive forces. It is expected that no maintenance will be required as the plants will grow and the foreshore will stabilise naturally.

98 hardwood logs and 107 marine piles were used to stabilise the foreshore. The logs were placed on the river bed parallel to the foreshore and tied onto vertical piles to prevent them from dislodging during flood events. Water velocity slows down around the logs.

Existing Casuarina trees were at risk of falling down the bank so were cut back to reduce wind pressure. The remaining roots will continue to keep the bank stable while the trees resprout. The cut trees and previous fallen trees were all re-used and pinned underneath the logs to further slow waves and protect mangrove seedlings.

This organic matter may look messy but is utilised as natural habitat by estuarine flora and fauna.

The long-term benefits include:

• A safe and stable foreshore bank for park users.• Resilience in the upper estuary against potential future flood

events.• Mangrove habitat for fish, crabs, aquatic and terrestrial fauna

and birds.• Protection of the foreshore from boat wash to reduce bank

erosion.• Improved water quality • Showcase a natural alternative to bank stabilisation.

T H E P L A N

Rushcutter A

venue

Coomera River

Coomera Lake

Coomera River Island

Reserve

Damian Leeding Memorial Park

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2019

MANGROVES

A mangrove is a small

tree that GROWS IN COASTAL SALINE OR BRACKISH WATER.

The restoration project is part of a 2.5 KILOMETRE REHABILITATION PROJECT planned for REGATTA PARKLANDS and DAMIAN LEEDING MEMORIAL PARK

A FIVE YEAR MONITORING and EVALUATION PROGRAM

has commenced by

the City with assistance

from 3rd year science

students from Griffith University.

DID YOU KNOW?

2,500 people use Damian Leeding Memorial Park daily

INTERESTING FACTSDamian Leeding Memorial Park foreshore stabilisation project

BANK STABILISATION

VEGETATION RESTORATIONMangroves re-growing

Protects from BOAT WASH ISSUES

SALT TOLERANT REVEGETATION

BANK STABILISATION

The natural structure has to be strong enough to withstand

FAST FLOWS of more than 3 METRES PER SECOND

Unlike rock revetment, the instream hardwood

structures will not only stabilise the riverbank

but also IMPROVE THE ESTUARINE ECOLOGY FISH HABITAT

Hardwood tree species are denser then water and

SINK TO THE BOTTOM OF THE RIVER BED

The hardwood trees were sourced from a site

that would have otherwise been turned into wood chip

and are now RE-USED AS HABITAT

The biggest tree log used is 13 METRES LONG, has a root ball diameter of 2½ METRES and weighs 4 TONNES

The instream log structure, the mangroves

and the new riparian plants act as a NATURALISED TREATMENT THAT HAS MULTIPLE BENEFITS

13 metres

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