Environment Matters Spring - Summer 2023

Reclaiming our waterways naturally A major stabilisation project in one of Ipswich’s priority creeks showcases the importance of natural materials in rehabilitating damaged and eroded waterways.

Woogaroo Creek bank stabilisation

Woogaroo Creek bank during flow

Two sites along Woogaroo Creek in Goodna have been transformed following a waterway recovery project completed in May 2023. In both sites logs, large tree rootballs, rocks, jute matting and about 3,000 native plants have been installed to stabilise the banks, increase resilience to future flood events, and provide habitat for native species. Typically projects such as this can use hundreds of logs each time, so wherever possible salvaged materials are used. Logs might come from sources such as land cleared for a road widening project, or trees felled due to safety issues, or flood debris that is causing a hazard such as logs trapped under a bridge. Using salvaged materials minimises the environmental impact of the project and provides a positive use for trees that would otherwise be turned to woodchip.

PILE FIELDS Upright logs installed in the creekbank are called pile fields. These are designed to slow the velocity of flood water as it rises and inundates the bank, and provide protection to the bank and plants. In 15–20 years these pile fields will rot away, by which time the native trees will have grown and will provide bank protection instead.

ROOT BALLS Rootballs from large trees placed in the creek are an important element of the

project. Scour will form around the rootballs, creating pools that are ideal habitat for species such as fish, turtles, crustaceans and even platypus.

Salvaging mature lomandra

Council uses thousands of plants each year in revegetation projects – usually small tubestock. When an opportunity to salvage 60 mature lomandra from a transport project site came up, council officers were quick to act. The plants were dug out with a machine to minimise rootball interference, and transported to an existing Habitat Connections site on Bundamba Creek. A trench with deep watering and slow-release native fertiliser was prepared for the lomandra to provide the best opportunity for establishment.

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