Types and Causes of Soil Erosion

There are a few issues that may impact many construction sites and similar areas when it comes to stormwater and pollution, and one of these is soil erosion. Soil erosion can be a precursor to several issues in this area, leading to everything from loss of topsoil to potential contamination of stormwater, and understanding how soil erosion happens and how to prevent it is very important.

At Silver Leaf SWPPP, we're proud to offer quality stormwater pollution prevention services to clients around Utah, from SWPPP development and inspections to themes like risk management and more, with erosion control serving as a top solution we provide. Across two separate blogs, let's look at everything you need to know about soil erosion and how to prevent it - here we'll look at the different types of soil erosion, plus the sorts of issues that tend to cause it. Following that, we'll go over some simple steps for preventing major erosion risks on your site.

Rain Drop Erosion

Also known as "splash" erosion, this is one of the most common types of erosion, and it occurs when raindrops fall on the soil surface, carrying away small particles. This type of erosion is most common in areas with steep slopes or that experience a lot of heavy rainfall.

This form of erosion can be especially damaging to what's known as the crumb structure of the soil, which is composed of individual particles that can be rearranged when splashed away by raindrops, leading to a much more compacted and less productive topsoil. Over time, this can lead to soil quality being drastically reduced, as well as a much increased risk for contamination in the stormwater.

Rill Erosion

An even more common type of soil erosion is known as rill erosion, and also takes place during rain events - just in a different way. In this case, especially during heavy rain, narrow channels known as "streamlets" form and begin eroding away at the soil, leading to much larger channels and gullies over time.

These streamlets can quickly cut through topsoil, and even if the water ceases (or is stopped) afterwards, these deep channels can remain for a long time, alongside an increased risk of contamination in the stormwater.

Sheet Erosion

Most common during periods of high wind, sheet erosion is when the wind carries away small particles of soil across wide areas, reducing soil quality and leading to a much higher risk of stormwater contamination. This type of erosion is especially common in areas with heavy anthropogenic activity or poor agricultural management - both of which can lead to vulnerable topsoil.

In most cases, sheet erosion only removes thin layers of topsoil, but this can be enough to drastically reduce soil quality over time if not addressed properly.

Gully Erosion

One form of erosion that's often due to human-made runoff or drainage issues is gully erosion. This is the formation of deep channels and large gullies that can cause extreme damage to the soil, removing huge amounts of soil and leading to increased contamination risks in stormwater.

Gully erosion is often caused by poor agricultural management choices, such as tilling up and down a slope instead of across it, or by human-made drainage issues, such as blocked or poorly placed gutters or drainage channels.

Stream Bank Erosion

Yet another type of erosion that can occur is stream bank erosion. This takes place whenever a river or stream changes course, leading to the soil around it becoming vulnerable and easily eroded away. Stream bank erosion is usually due to natural events such as floods or heavy rains, but can also be caused by human-made waterway alterations or land use issues.

In cases where this effect takes place on a watercourse bed, the technical term will be "scouring" - and it can take place over a large area of the bed, leading to drastic changes in the landscape.

Common Causes of Soil Erosion

We touched on several of these in our above sections, but here's a more detailed look at some of the specific effects that tend to cause these forms of soil erosion:

• Sloping: Sloping land is far more vulnerable to soil erosion, no matter the type. In most cases, even slight slopes will make your site much more likely to suffer from any form of soil erosion.
• Runoff: Whether it's runoff from a nearby waterway or runoff created by human-made drainage issues, this can be one of the biggest causes of soil erosion. Especially in areas with steep slopes, runoff can quickly cause large gullies or channels to form.
• Soil texture: Different types of soil have different levels of erosion protection, with clay soils being far less vulnerable than sand or silt-based soils. In most cases, sandy or silty soils are much more prone to any form of soil erosion.
• Poor agricultural management: This can be seen in both sheet and gully erosion, especially when water is allowed to flow downhill instead of across a slope. Poor management can also lead to other issues such as compaction, which can further worsen soil erosion problems.
• Anthropogenic activity: Whenever we build roads, install drainage systems or otherwise alter the landscape in an area, this can open it up to much higher levels of erosion from both wind and water-based sources.

As you can see, there are a few distinct causes of soil erosion that can impact construction sites and other areas alike - so it's important to be aware of these issues, take the necessary steps to prevent them and make sure your site is properly protected from any potential risks.

At Silver Leaf SWPPP, we're here to offer quality SWPPP services to clients around Utah, including erosion control. Contact us today to learn more or set up a consultation!