Because our business involves disturbing land, we are very aware of the need to keep soil in its place. I was reminded of this recently by a walk in my neighborhood. I live a few streets away from the Etowah River in Lumpkin County. While on my walk, I looked through the woods and noticed that the river was an ugly yellowish color.
Why are our local rivers brown/yellow?
Local historian and artist John Kollock used to talk about the orange Soque River in which he and his friends swam in Habersham County. It was orange from the red clay that ran off of the corn fields and probably from logging and other earth disturbing activities. These days, our rivers run orange and yellow because of the large amount of land clearing done to build houses, roads and buildings. The creamy, versus clear, water flowing by is our land, our topsoil and subsoils. Once it is gone to the river, the storm sewers, the lakes and ultimately the ocean, it is gone.
When you see a heavily silted creek, river or lake, you know that there are problems upstream.
What is a silt fence?
A silt fence is a temporary sediment barrier that is set up to control the flow of dirt as it washes. Fences are made from fabric held in place by posts. You see them, black and orange, hopefully, at construction sites of all kinds. We use them while we work to install a project. Because the porous fabric clogs quickly, the posts and the installation of the fence are the key to their effectiveness.
Why should silt fences be used?
Silt fences need to be used to protect our natural and built waterways. During the course of construction, soil is disturbed and often moved around. When rain falls, the disturbed soil moves; it runs off with the water. It washes down streets, into storm drains, off hillsides and into our waterways. From a Georgia Forest Watch (http://gafw.org) email, “Stream sedimentation occurs when poorly designed or maintained gravel/dirt roads wash into nearby streams and rivers, profoundly negatively affecting fish and other wildlife.” Environmentally, silt fencing should be used so that aquatic habitats will be protected. Economically, silt fences should be used to save governments, and thereby taxpayers, money. The less silt and sediment that has to be cleared from drinking water, the fewer resources have to be expended.
Sediment is considered nonpoint source pollution. The Illinois Environmental Protection Agency says, “The name “nonpoint source pollution” is derived from the concept that there is no single point from which the pollution comes; it comes from everyone and everywhere. Nonpoint source pollution is the nation’s and the state’s number one threat to water quality.” (https://www2.illinois.gov/epa/topics/water-quality/watershed-management/nonpoint-sources/Pages/what-is-nonpoint-source-pollution.aspx)
How does improper use affect our rivers?
While silt fences are simple in concept, they require attention, repair and replacement to maintain their usefulness. As mentioned above, proper installation and materials are the key. Improper placement and poor materials can make the fence(s) a complete waste of money.
DuluthStreems.org explains ways nonpoint source pollution impacts our waters. “Although sediment is a part of the natural environment, human activities sometimes increase the amount that ends up in our streams. These sediments are usually fine grained sands, silts and clays that can cover up coarser sediments and the spaces between rocks and cobbles that provide habitat for aquatic life.”
These are just some of the specific ways that sediment impacts our waters.
- Suspended sediment decreases the penetration of light into the water. This affects fish feeding and schooling practices and can lead to reduced survival.
- Sediment reduces the amount of light penetrating the water, depriving plants of light needed for photosynthesis.
- Suspended sediment in high concentrations irritates the gills of fish, and can cause death.
- Visit http://www.lakesuperiorstreams.org/understanding/impact_erosion.html for an extensive list.
Lessons in silt fencing
When you see any of these things in a silt fence, it is not working.
- It has been run-over by water or silt. See Image 4
- It has water or silt running under it
- Water or silt is running around the sides of it
Image 3: The silt fence in the lower left of this photo has obviously been destroyed. Here’s my story: A second contractor delivered rip rap (grey stone) to ameliorate the erosion occurring in the ditch and just dumped it on top of the existing silt fence.
Image 4: This image tells us two things. One, the silt fence is obviously failing because water and dirt are spilling over it. Two, the installation or plan for silt fencing was not correct to begin with. Either stronger posts were needed, and/or an additional fence should’ve been installed above it.
Image 5: While hard to see, there is one long, and half buried, silt fence in this picture. The failing fence can be seen on the right, then there is tremendous over-wash, and the fence reappears in the woods on the far left. Note, also, the clay that has washed into the woods, which will eventually wash into the creek or branch at the bottom of this hill.
What can we do about it?
- If you are going to be involved in earth disturbing activities, be sure to work with firms that use best practices.
- Talk with the contractor before work begins to ensure that your project will not contribute to sedimentation pollution.
- Report non-functioning silt fences to organizations and agencies that can help.
- The Georgia Environmental Protection Division (https://epd.georgia.gov/watershed-protection-branch/nonpoint-source-program)
- Chattahoochee Riverkeeper (chattahoochee.org)
- Soque River Watershed Association (www.soque.org)
- Your county’s code enforcement office
- Your homeowners association
The protection of the environment, be it flora, fauna, or our water sources, is of great importance to Art of Stone Gardening. Look around your property. Is there exposed soil? Are you in the middle of or planning to disturb the soil in some way? Are silt fences in your future? Below is a good primer from the Environmental Protection Agency. Better yet, give Art of Stone Gardening a call. We care about our shared environment, and we thank you for your interest in keeping the soil in place.