Month: May 2025

At EnviroStraw, we’re always innovating to help land managers, engineers and environmental professionals combat erosion – especially in areas where soils are highly dispersive and water flow is unpredictable.

One of the most powerful tools in our erosion control range is GeoSpray: a premium-grade surface stabiliser specifically engineered to protect bare earth from the damaging effects of concentrated water flow. But don’t just take our word for it. We recently commissioned respected soil scientists Landloch Pty Ltd to put GeoSpray through rigorous, independent testing. The goal? To assess its ability to prevent erosion in challenging soil types under channel flow conditions. The results were compelling— confirming that GeoSpray offers significant soil stabilisation benefits, even under extreme hydraulic stress.

The problem – fragile soils and fast-flowing water

Bare, exposed soil is one of the greatest risk factors for erosion. When left unprotected, even short-duration water flow – such as storm runoff or overland flow in newly constructed drains – can cause serious damage. The removal of topsoil, sedimentation of waterways and costly remediation work are all common consequences.

To test GeoSpray’s performance, the team at Landloch recreated real-world channel flow conditions in a specialised soil flume. The test soil was deliberately chosen to be dispersive, moderately sodic and light clay in texture – typical of the subsoils exposed during drainage construction in Australian landscapes. These soils are notorious for poor cohesion and rapid erosion under flow.

The test – bare soil vs GeoSpray

Two treatments were tested under increasing flow rates and gradients:

• Control: untreated soil (baseline)
• GeoSpray: applied at a rate of 4 kg/m² (dry matter equivalent), mixed with 900 mL of water per kg of product

Flow rates were increased in increments, with water depths and erosion effects monitored and recorded over several days. The flume system was calibrated to simulate gradients of 3.7% and 9.1% and flow rates up to 21.5 L/s were applied—equating to shear stresses up to 32.7 Pascals.

The results – clear water, stable soil

The difference in performance between the control soil and GeoSpray-treated plots was dramatic.

• The control plots began to erode at shear stresses as low as 5.5 Pa, with severe erosion observed at just 15 Pa. Suspended sediment was visible in the flow from the earliest stages.
• By contrast, GeoSpray-treated plots showed no erosion even at the maximum flow velocity tested. The water remained clear with no visible sediment movement or incision into the soil surface.
• Critical shear stress for GeoSpray-treated surfaces exceeded 30 Pa, representing a >200% improvement over untreated soil.
• Maximum permissible flow velocities were estimated between 2.6–3.2 m/s—comparable to values recommended for erosion control blankets, turf-reinforced mats and rock armouring.

Why it works – strength from the surface

GeoSpray acts like a protective skin over the soil. Once applied it increases cohesion at the surface layer, effectively holding soil particles in place – even under aggressive water flow. By reducing the detachment of particles and resisting incision, it provides both surface stability and clear runoff, which is critical for water quality management.

The report also noted that while slight “bulging” of the surface was observed at peak flow rates (due to pooling beneath the product), no failure or detachment occurred. This speaks to the resilience and durability of GeoSpray under challenging conditions.

Real-world applications

The findings from this study reinforce GeoSpray’s value in practical field conditions. It’s particularly suited for:

• Drainage channels and swales
• Roadside batter stabilisation
• Construction site runoff management
• Any exposed dispersive or sodic soils

Because it creates an immediate surface seal, GeoSpray is ideal for use in areas where vegetation establishment is slow or unreliable.

A smarter solution for soil stability

The science is in – GeoSpray not only works, it excels. Whether you’re engineering erosion solutions for infrastructure projects or rehabilitating disturbed landscapes, GeoSpray offers a reliable, tested method to protect soil and preserve the environment.

Want to learn more about how GeoSpray can work on your site? Contact our team today to explore your options.

Preventing erosion on commercial and industrial sites has become increasingly complex across Australia, as challenging soil conditions, unpredictable weather patterns and the push for sustainable outcomes, particularly with native vegetation, are making traditional methods less effective.

Thankfully, EnviroStraw’s BioGrowth program provides a science-backed, environmentally friendly alternative that delivers immediate protection while restoring long-term soil health, even amidst ongoing natural disasters.

Tackling erosion in tough environments

Many commercial projects, particularly mine site rehabilitations and steep slope developments, face major hurdles when it comes to erosion control. These areas often have soils that are low in carbon and sodic, and are chemically imbalanced with little or no topsoil. Establishing vegetation in these conditions, especially native grasses and trees, is not just difficult – it’s critical for long-term site stability.

The situation is made worse by Australia’s increasingly extreme weather. Torrential rainfall causes rapid overland water flow while extended dry spells and strong winds make it difficult to maintain hydration on newly treated areas. In these environments, erosion control products like EnviroMatrix and EnviroBond are essential to keep soils intact and seeds in place.

The BioGrowth difference

Unlike conventional methods that rely on heavy applications of compost, lime or gypsum, BioGrowth is built on advanced soil technology and microbial science. It targets the root cause of poor soil health rather than simply masking it. With its specially designed suite of microbes and non-leaching fertilisers, BioGrowth helps improve soil balance, increases plant-available nutrients and supports rapid plant establishment both below ground and above ground. And it does all this without the need for topsoil.

This is particularly valuable on remote or difficult-to-access sites where watering programmes are limited or impossible. BioGrowth is native-plant friendly and is designed with Australia’s harsh climate in mind.

Another key feature of BioGrowth is its ability to provide instant erosion control from the moment it’s applied. The hydromulch layer includes hydrocolloid binders that adhere to the soil surface and also bind the top layer of soil particles together. On highly dispersive soils or extreme slopes, adding EnviroBond to the mix further enhances the stability of the hydromulch and protects against heavy rain or long dry spells. This ensures that the applied seed and fertiliser remain in place, giving plants the best possible start.

If conditions are favourable, results can be seen in as little as 7 to 14 days. However, water availability and correct seed selection remain vital. Without moisture, no treatment will succeed. And choosing the right plant species for the local climate and soil type is just as important to ensure long-term success.

A new way to think about soil health

Soil is more than just a medium for growing plants – it’s a living system, much like the human gut, where microbes and nutrients interact to sustain life. The BioGrowth program takes a holistic view of soil health, identifying the underlying chemical imbalances and working with natural microbial processes to correct them.

Healthy soil supports healthy plants, and healthy plants are the foundation of effective erosion control. Once vegetation takes hold, it offers a self-sustaining solution that not only prevents erosion but also improves biodiversity and ecosystem function. BioGrowth is more than an erosion control solution – it’s a smarter, more sustainable way to restore damaged land.

By rebuilding soil health and working with nature, EnviroStraw is helping industries move toward a future where revegetation is not just possible, but successful from day one.