In the United States, we have the most abundant, fertile soil of anywhere else in the world. Alabama’s soil profile contributes significantly to the fertility of our country’s soil.
However, there is a very real threat to the sustainability of our nation’s and more particularly our state’s soil.
Wind and water erosion are two of the most harmful causes of soil degradation in our country and state.
According to the USDA Natural Resources Conservation Service 2012 report, the United States loses an average of 4.6 tons per acre per year. Though this number is down significantly than where it was a few decades ago, it is still a staggering amount of erosion.
As residents of Alabama continue to move to growing cities like Auburn and Opelika, development and construction are on the rise. These are some of the greatest mediums by which erosion occurs.
So, how do we curb the rate of erosion and preserve our soils?
One of the best ways to do this is by using silt fences at development and construction sites.
What Is a Silt Fence?
A silt fence is a temporary barrier made from interwoven wire and geotextile cloth that acts as a filter for sediment rich runoff. The barrier is usually supported by wooden stakes hammered into the ground.
Silt fences are employed in areas where the soil is disturbed. This can be in the areas surrounding construction sites, areas affected by fires, earthquakes, floods, and other natural disasters, or areas that have experienced significant loss of vegetation in a relatively short period of time.
These areas are unable to contain the native soil profile because they have lost the physical structures that usually hold the soil in place.
Silt Fences should be maintained until the disturbed land has reached a level of regeneration and soil stabilization that is sufficient to maintain a healthy local soil profile.
How Does a Silt Fence Work?
Erosion control by silt fences is a simple concept.
At the most basic level, silt fences act like coffee filters for your morning cup of coffee.
When you turn on your coffee pot to brew coffee, it pours water over loosely held together grounds. The filter that you place in the pot then keeps the grounds themselves in the coffee maker while the water passes through to your pot.
When water picks up disturbed soil it carries it away until the soil loses velocity and settles.
Silt fences filter out the sediment carried in this water and allow the water to move on without the soil, thus preserving the soil integrity of the work site and safeguarding the water quality of that area and areas downstream from it.
In order for Silt Fences to be effective, they must be regularly maintained and checked after every runoff event.
This is because if there is one point in the silt fence that gives way, then a large amount of the sediment that would normally be preserved will flow through that breach and continue the harmful erosion process.