One of the largest river restoration projects on the Mid North Coast has just been completed on the Nambucca River, and you may not have noticed.
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Nambucca Valley Landcare, partnering with North Coast Local Land Services, recently finished the three year ‘Riparian Restoration and Water Protection of the Nambucca River’ project, also known as the North Arm Project.
Funded by Catchment Action New South Wales and the National Landcare Program, the $175,000 project was aimed at improving stream health and water quality along nearly 50 kilometres of the Nambucca River’s North Arm, upstream from Bowraville.
Improving a degrading river system
Many parts of the upper reaches of the Nambucca River system have degraded significantly over the last 150 years.
The flood size and variability in the Nambucca are higher than in other mid-north coast catchments, and when combined with geology that is naturally prone to erosion, it means our river system is sensitive to disturbance and vulnerable to change.
Clearing of native vegetation in the riparian zone and floodplain, gravel extraction, dredging, de-snagging and other human activities have resulted in channels two to three times wider, four to five times larger in capacity, and significantly straighter.
The river now carries more water, moving faster, with less vegetation holding the banks together. Together, these factors lead to erosion, loss of fertile alluvial flats, damage to infrastructure, bed level lowering and widening, decline in water quality, and changes to the water table and river flows.
For these reasons, Nambucca Valley Landcare has been focused on restoring the Nambucca for the last 20 years, working the Nambucca Shire Council, NSW Government agencies and the Federal Government.
The North Arm Project
The North Arm Project has been one of the largest and most successful river restoration programs on the Mid-North Coast in the last decade.
The first year of the North Arm project, the team developed a comprehensive survey of the North Arm river reach, recording waterway assets, erosion points, weed problems, strategic locations for engineering works, and engaging landowners to work together to target problems. These activities produced the North Arm Reach Plan and 35 individual property plans – the basis for works delivered in years two and three.
Since the publication of the North Arm Reach Plan a year and a half ago, a huge amount of work has been completed by Nambucca Valley Landcare and passionate landholders, including installing 10 new river structures, repairing 16 existing structures, over two kilometres of riparian fencing, two hectares of weed control, and planting over 1300 native trees.
Land owners working with Landcare
A large proportion of work focused on installing and repairing bed control structures, or rock girdles, to protect the river bed from further lowering. Bed controls are constructed across the river, using large quarry rock trenched across the river over a permeable fabric to lift the level of water upstream.
These structures have a number of benefits – they lift the level of water upstream, direct energy into the centre of the channel, and slow the water down to reduce the impact of flooding on vulnerable banks. Raising the water level also reinstates the deep pools the Nambucca was once known for, restoring essential habitat for fish and other native animals and plants, while also providing surface water for farmers.
A total of 21 committed landholders are working to make these outcomes possible, and contributing over $24,000 in extra cash and in-kind labour.
While there is still plenty of more work to go in restoring our waterways, the North Arm Project has been a major win for the Nambucca River.