RESOLVE EROSION ISSUES ON FARMS

Months after installation the vegetation has grown through the mat. In time this will help to anchor the mat and also assist to capture and filter valuable sediment and topsoils from washing away in heavy rain.

A native sub-tropical forest tree, ‘bush nuts’ or Macadamia trees grow in typically high rainfall and rich volcanic soil conditions. Current harvesting techniques and orchard maintenance require machinery that can form tracks and ruts on the soft soils between the rows of trees. Couple that with orchards that have no grass growing between the rows and it results in soil erosion and orchard degradation.

The heavy rainfall also contributes to slippery soils and boggy patches. This not only impacts the quality of the orchard and production of the trees, but also impacts the costs and expenses lost during production and harvesting. It also leads to orchard maintenance issues in regard to mowing and keeping out vermin.

The Macadamia Orchard before concrete erosion mats installed, showing soil erosion and orchard degradation from machinery tracks and ruts formed on ground without grass growing between trees.

Australian Concrete Mats (ACM) recently provided a client with the innovative concrete erosion mat. After recognising the impact of his soil degradation and the loss of his topsoil washing down the creek from his Macadamia nut orchard, Len H. from Alstonvale NSW, knew that mats from ACM was the perfect solution for orchard’s erosion issues.

The concrete mat is supplied in a roll, so it can be easily placed into position then unrolled quickly and easily using farm machinery.

The mat helped to prevent and minimise the following issues:

• Tracks becoming slippery and boggy around and between trees
• Farm gravel roads being washed out at overflows and spillways
• Orchard drains being filled and blocked with excess debris
• Machinery getting bogged during harvesting, spraying or maintenance works
• Unsafe access to soft edges of dams and drains, preventing regular mowing and clearing
• Drains not able to be mowed without getting bogged or cut deeper trenches into the drains
• Drains rendered ineffective due to lack of clearing and maintenance
• Hard armour scour protection for dam spilways and overflows
• Valuable top soils and nuts washing away
• Tree roots exposed leaving them vulnerable to disease and damage

Made with concrete and geogrid, the textured concrete shapes of the mats create a hard-armoured protective surface for the soil. The space between the concrete shapes makes the mats flexible and permeable, which helps to prevent water from pooling on top of the ground that creates accumulative boggy conditions. The flexible mat protects the soils from washing away and prevents deep rills and gullies advancing into the orchards.

The concrete mat unrolls into position. It is supplied with biodegradable nutrition mat that will help to encourage growth of grasses underneath and through the mat.

Len engaged a local excavator company to shape a water spoon drain, which he could then direct the excess water coming out of his orchard to. This drain consisted of a 2400mm-wide concrete mat being placed end to end to create a drain that is 150m long.

Installation was easy and quick, and could also be installed using machinery already in the shed. Once the eroded orchard drain was prepared, scraped, reshaped and seeded, the rolls were placed alongside the drains and simply unrolled into position. Each side was anchored using steel Ubars Anchors. The mats were immediately able to be driven over, and began working right away!

Showing how a vegetated drain helps capture and filter the sediment from entering the waterway.

The rolls of concrete mat come pre-rolled with an underlay geotextile. The bio-degradable nutrition underlay helps to promote the growth of vegetation through the mat, this vegetation also helps to anchor the mat, long term. Helping to filter the sediment as it flows over the mats, the vegetation in turn helps minimise valuable sediment and top soils from washing away into waterways.

Within only a few days the grass begun to shoot through the mat. Proof of the mats success and worth was tested only a week after installation. During a heavy sub-tropical rain event, (typical of the north coast region), the skies opened up, water was flowing at volumes through the orchards. Utes were able to be driven across where the mats were laid on the farm tracks to inspect the storm damage, preventing any unsafe slippage on the tracks and leaving no track marks on the wet soils underneath.

The concrete mat creates a hard and safe drivable surface on the ground that can be driven on with both mowers and tractors.

Within weeks, the hard and stable driving surface the mats enabled the first orchard mowing to be completed. The mowing was completed safely and quickly, with no vehicles getting bogged as they drove across the drains and on the drain edges.

A long-term and cost-effective investment to protect orchards and farms from soil erosion and sediment control, Australian Concrete Mats are a proven solution that delivers low-maintenance and peace of mind.

Nine months after installation, and following storm season, the mat has protected the drains from scouring, allowed vegetation to grow and made drains safe to drive across and protected from erosion – resulting in less orchard degradation and loss of topsoils.

Flexible Australian concrete mats are an easy-to-use, efficient and cost-effective alternative solution, which provides ongoing benefits for both land and catchment managers as well as for the environment.

Find out how Australian Concrete Mats can help you with your next project via the links below.