Soil Erosion – Causes, Effects & Solutions
Company operations within the mining, civil or infrastructure industries often require project removal of vegetation, this, however, exposes the bare substrate to environmental factors prone to causing soil erosion – a national issue, recognised for the detachment and movement of soil material caused by water, wind and human interface. Despite moving at a slow and often unnoticeable rate, it can take a dramatic turn and alter your project site at an alarming level by removing excess soil and impinging on the project budget.
It is vital to maintain a strong understanding of the substrate in which you operate and recognise the environmental characteristics that require active preventative measures. Planning should include temporary and long-term solutions including, topsoil management, dust suppression, revegetation and or erosion control processes to support the substrate’s mechanical structure and keep the soil in place.
The following information opens up awareness into the signs of soil erosion and the onsite effects that may impinge on worksite operations. The key to avoiding such issues is to know the problems around soil erosion, what to look out for, what control methods to put in place, and how to implement long-term solutions into your project planning.
Cause & Effect
Preparation, planning and awareness are critical factors in preventing the damaging effects of erosion on site. Water, wind and project mass movement are the main contributors to the removal of soil. The following wind and water processes highlight how quickly erosion can impinge on a worksite and underpins the importance of thorough substrate evaluations.
Water under the influence of intense gravity force can entrench wear on all substrates surfaces causing particle dislodgement, transportation and removal. The energy displaced by rain followed by water runoff, both contribute to escalated stress on the substrate resulting in detachments and transposition of soil.
These processes occur at different scales and are dependent on the depth of erosion. The longer an issue is unresolved, the bigger the solution and amendments that are required. The following erosion issues bellow provide insight into how water can affect your project site.
1. Splash erosion: The first stage of water erosion, triggered by the force of rain impacting on a bare substrate. The strength of the water breaks away aggregate, splashing soil particles as high as 60 centimetres and displacing them up to 1.5 meters away from the point of force. If this issue persists, it can prompt impacted surface crust which will reduce the infiltration properties of the substrate, causing runoff and transportation of soil.
2. Sheet erosion: stemmed from splash erosion, causing the uniform removal of substrate layers. If the process endures, it can go unnoticed for an extended period, and if the area is unattended gradual removal of nutrients and organic matter will contribute to the ill effect unproductive soil.
3. Rill erosion: the direct force of water and soil moving across a substrate, trailing an open channel. The water gradually opens up the channels and increases the detachment and transportation capacity of the substrate by disrupting the soil, plant development, and reducing landform sustainability.
4. Tunnel Erosion: a dangerous form of erosion stemmed from water permeation into soil cracks, holes or root decay, causing tunnels below the substrate. The surface structure remains intact, until the flow of water beneath increases in the width of the tunnel, causing the top layer to collapse. The process rate increases if an outlet such as an existing rill or roadside cutting intersects the tunnel providing free flow of water drainage.
Wind erosion is the action of high-velocity winds moving across a substrate triggering the removal of topsoil and rendering the remaining soil unfit for cultivation. The wind is responsible for stages of soil movement in the process of wind erosion known as surface creep, saltation and suspension.
Creeping: Stage 1
Particle Width: 2.00mm – 0.5mm
Soil Loss: 5 – 25%
Process: The velocity of wind flow creeps and drives soil fragments into a rolling motion along the substrate surface – at this stage, they are too heavy for the wind to lift.
Saltation: Stage 2
Particle Width: 0.5mm – 0.1mm
Soil Loss: 50 – 80%
Process: The transportation process of soil particles moving in an unsteady flow of air and water, resulting in a consistent ascending and descending flow. Throughout this process, other grains regularly interrupt the momentum through the means of attrition whereby other soil particles knock against each other in-flight, resulting in the development of microscopic dust fragments.
Suspension: Stage 3
Particle Diameter: Less than 0.1mm
Soil Loss: 10%
Process: Suspension is the most common type of wind movement and the most obvious to recognise – often detected as an orange cloud produced during dust storms. This process is a result of the lightweight soil particles suspended in the air for long durations and distances at a time. The suspension can be damaging, causing abrasion or sandblasting on project substrates during flight. At this stage, site management should be looking for a comprehensive Dust Suppression or revegetation solutions, to combat the potentially dangerous level of dust entering into the atmosphere.
Although rain and wind are uncontrollable environmental outcomes, you can implement a measure that will prevent the effects of soil erosion from progressing into the next stage. If you have concerns for erosion on your site, the team at SGA have a range of solutions that will suit your different environmental issues.
Control Methods & Solution
As suggested soil erosion is unpredictable and arrives in many forms, the implementation and maintenance of erosion controls such as dust suppressants are the primary defences against sediment pollution and extensive erosion control during the intermediate stage. The objective is to prevent sediment from leaving the project site and into environmentally sensitive areas. Although water erosion can be an issue, dryer climates presented across Australia, are more inclined to experience the effects of wind erosion. The following solutions will explore control measures and management activities designed to mitigate and reduce impacts associated with the onsite environmental activity.
Dependent upon a host of variables and a comprehensive site analysis conducted by our environmental consultants, either a short or long term solution can be prescribed depending on your goals and objectives for the site.
Short term solutions for soil erosion and topsoil management, often require a dust control solution designed to form a crust directly over the bare soil substrate, eliminating dust lift-off and preventing wind and rain erosion. SGA offers a range of dust suppression solutions which are proposed and tailored based on client objectives, site assessments, environmental conditions and a soil investigation – these key variable assists in the development of a proposed dust suppression solution.
Dust suppression options:
SuppressX®: a flexible interlocking coating designed for non-trafficked areas experiencing low – moderate weather events – more here.
FibreLoc®: Highly durable wood fibre coating, engineered for large exposed areas experiencing moderate-high weather events.
HydroBond®: Suitable for areas more inclined for vegetation implementation, allowing for air and water infiltration – more here.
RoadBond®: Purpose-built to provide premium protection and structural support for high trafficked areas by preventing and eliminating dust on heavy vehicle roads – more here.
Long-term soil erosion solutions are often solved through the implementation of vegetation cover or a stronghold erosion control blanket, depending on the results required.
Revegetation is the primary erosion control method chosen for environmental vulnerability areas that experience high-intensity rainfall and abrasive winds prone to weakening the soil’s resistance. Physical elements like weather and the degree of site slopes are uncontrollable; therefore, cover-crop usage becomes an invaluable investment. The plant root systems physically reinforce soil, provides erosion protection and increase the infiltration of water into the ground by forming physical pathways.
For areas that require a set and forget solution, our EcoArmour® erosion control blanket can offer extensive coverage and guaranteed longevity.
Given the number of products available, SGA’s environmental consultant can chat to you further about the following solutions on offer:
Erosion Control Options:
EnviroLoc® – Hydromulching Bonded fibre matrix (BFM): a hydraulic erosion control product utilising a high-performance matrix combined with water and nutrient properties for optimal retention and an enhanced growth environment – more here.
EnvrioPro – Hydromulching Hydraulic Growth Medium: a one-stage process utilising a mixture of water, seed fertiliser, binders and marking dyes combined with hygroscopic fibres designed for either flat or sloped terrain – more here.
EnviroSprout™ – Hydroseeding: containing tailored seed blends and beneficial microbes for optimal seed strike rates, added protection and enhance vegetation results – more here.
EcoArmour® – Erosion Control Blanket: A blend interlocking fibres and unique binders form a non-flammable crust that incorporates into the substrate forming a sturdy, resilient cover flexible enough to move with the ground without cracking. Suitable for areas requiring minimal maintenance and resist cover for up to 20 years – more here.
Large projects require extensive planning and thorough consideration of the project soil on site, to avoid environmental issues further down the track, SGA, consultants, can provide guidance and appropriate erosion control methods and solutions.
Contact the team today for more information.