Project kick-off: Along the Lower Caboolture riverbanks, the ball is rolling towards flood resilience and more!
Here is a great chance to get a behind-the-scenes look at how nature-based technology is building disaster resilience, and reducing erosion and nutrient discharge into waterways, all while conserving cultural heritage.
On-ground works have progressed at five of nine designated sites as part of the Lower Caboolture Resilience and Nutrients Offset Program, and our project team has given us the low-down on some great insights from the works so far.
One of our largest-scale projects is well underway, making headway in the proactive restoration journey being undertaken along the Lower Caboolture River.
Our team has been busy rolling out the works for this Unitywater-backed initiative, where nature-based solutions are being implemented to restore the riverbanks and reduce sediment and nutrient pollution to waterways. These works aim to improve water quality, increase biodiversity, enhance fish habitat, and build flood resilience.
The area is also a protected cultural Heritage site. Kabi Kabi First Nations peoples lived in the area and cared for Country for many thousands of years.
After European settlement, it was transformed into the Morayfield Plantation where cotton was grown from 1861 and then sugarcane from 1866. Remnants of the original homestead can still be visited by the public today.
To ensure the ongoing protection of cultural heritage at the site, all earthmoving works are being inspected by Kabi Kabi representatives and archeologists who will assist in identifying any culturally significant artifacts, such as middens, tools, bones, and housing structures.
Threads of the past unhearted
As the project has unfolded, a treasure trove of cultural heritage items linked to the Morayfield Plantation has been brought to the surface by our earthworks. A thoughtful management plan has been put into place to respond to findings as they emerge.
Our earthmovers diligently conducted initial investigations of soil treatment areas with support from the project archaeologist to identify important artifacts and features.
As we are working in a protected area, we adjusted our work plan, while a team of experts determines the best course of action to preserve the finds.
To ensure that, in addition to finds related to the history of the Morayfield Plantation, the monitoring and safe handling of any First Nations' cultural heritage finds can be guaranteed, we have been working in collaboration with Kabi Kabi, archaeologists, and the Department of Environment and Science who have offered expert knowledge and advice during the earthworks.
These collective monitoring efforts highlight a commitment to ensure that the restoration efforts uphold the values and history of the area.
What the project has achieved so far: A transformation at site B1
On nearby sections of the river, thick lines of mangroves stand as guardians of the riverbank, protecting it from boatwash and erosion. By contrast, the challenge at site B1 (shown above), was that mangroves had been lost, leaving the bank vulnerable, and making it difficult for new mangrove saplings to establish.
At the beginning of July, major earthworks commenced at this site, as the dedicated team broke ground for the restoration mission. The works began in earnest, reshaping the vertical eroding riverbank and creating a flat battered bench, where it is hoped newly planted mangroves will thrive.
Fast forward to September and in a few short months, the riverbank has undergone an amazing transformation.
Log structures have been installed on the bench to break up the waves from passing boats, protecting young mangrove saplings, and creating fish habitat.
Check out the results in the photos below.
The last piece of the puzzle is being added this month.
Mangrove propagules will return to the riverbank, a mix of careful planting and nature’s whims. Some will be planted on the bench, and others will wash in with the tide and establish naturally. As they grow and mature, they will permanently protect the bank against erosion and eventually link up with the mangroves upstream and downstream to create a continuous habitat along the river’s edge.
Beyond the reach of the tides, the land above will undergo a transformation of its own through revegetation with native trees and shrubs, further fortifying the riverbanks and creating new habitats.
Mangroves propagules to the rescue at sites B3 and B9
In areas that are only accessible by boat, the project has implemented a different style of nature-based solution to protect the riverbanks from erosion and boat wash.
Here the mangroves are encouraged to recolonise through the use of BESE-Elements, an incredible cutting-edge, sustainable technology that provides structural support for new propagules to grow and establish.
Sometimes nature has other plans Only when they've soared to freedom will this last section of the reshaping go ahead. |
Mangroves are coastal and riverbank protection powerhouses, helping to slow down powerful water surges, protecting the riverbanks from erosion, trapping sediment and nutrients that would otherwise be discharged into waterways, and acting as restorers of aquatic ecosystems.
Two of the sites have been set up for successful mangrove revegetation with this technology. Coming from the Netherlands, BESE-Elements® are not new to Healthy Land & Water, having been successfully put to use in other restoration projects including our Lungfish habitat restoration and Pumicestone Passage shellfish habitat restoration projects.
This technology (as you can see in the photo above) is a 3D matrix. The grids are made entirely out of a waste product, potato starch, which fully biodegrades within 5–10 years.
This acts as a temporary structure to kickstart ecosystem restoration. It is an ideal way to help retain plant seeds (propagules), support the colonisation and growth of saltmarsh plants and mangroves, restore marine ecosystems like shellfish reefs, and trap sediment that otherwise would have flowed into the waterways. We often call mangroves the kidneys of the coast, given the work they naturally perform in purifying the water.
As shown in the photo below, the structures are first secured on the riverbank with wooden stakes and ropes to prevent them from being washed away by tides and boat wash.
Then precious propagules are collected and installed into the structure to achieve the best outcomes for our restoration. The structures also act as traps and retain propagules that are washed off by the water, allowing those seeds to germinate.
We can’t wait to give you more updates as the works progress at all nine sites!
A little about the project background and its purpose
Earlier this year, we sat down with our Land Restoration Assistant Team Leader Samille Loch-Wilkinson to talk about the ambitious project aimed at building resilience along the Lower Caboolture River. By building resilience, the works are also preparing the area to accommodate the predicted population growth for South East Queensland.
This project, funded by long-standing partner Unitywater, involves extensive riverbank restoration and revegetation works covering 2.4 km of the Lower Caboolture River, with works to be carried out at nine sites.
The program features innovative green engineering solutions to prevent riverbank erosion and the consequent sediment and nutrient loads entering the waterways. At the same time, through revegetation, the project is helping restore riparian habitat, protecting biodiversity along the waterways, and providing natural resilience to future floods and erosion.
The works have many benefits including improving water quality, biodiversity, and aquatic ecosystem health, as well as enhancing terrestrial habitat for native wildlife.
You can read the full more about the overarching project here.
Acknowledgments
Kabi Kabi Aboriginal Corporation.
Bunya Bunya Aboriginal Corporation.
City of Moreton Bay.
BESE Ecosystem Restoration Products.
Barung Landcare.
Various local private landholders/leaseholders.
Works engineering was designed by Alluvium Consulting.
This project is delivered by Healthy Land & Water with funding from Unitywater.