Over roughly an eight-month period, the Tennessee Department of Transportation (TDOT) conducted tests on the new Staged Release Silt Fence (SRSF) by Silt-Saver Inc. The demonstration test site was located in Franklin, TN, along Interstate 65.
Approximately 2,000 linear feet of the SRSF material was tested. Despite being subjected to a number of major storms, the silt fence held up well. The one exception was a massive downpour of 5 inches of rain within a three-hour period.
“This one failure was not the product’s fault,” explains Mark Reed of Reed Landscaping. “The water came through a box culvert, and it took down everything. It took down trees, it took down 120 feet of a 6-foot chain-link fence, and it took out two 4-foot rock check dams we had built. It took down everything. There was no erosion control measure that would handle that.”
The civil engineering inspector at the site concurred. “To my knowledge, there is no erosion control method that would have sufficed under the circumstances,” he writes.
Testing was completed in the summer of 2014. “But the product is still out there, even though the test is done and completed. TDOT’s consultant that was on the job has written a report on it and was very happy with it. I wrote a report to Silt-Saver, and we had zero issues with the product,” states Reed. “It definitely worked equal or superior to what TDOT currently has in their qualified list of products.”
Reed especially appreciated the ease with which the product is installed, particularly compared with traditional silt fence.
“You just dig a four-inch by six-inch trench, put in your post, and you go. On the other hand, if you’re doing it as per current TDOT standards, which is a wire-backed fence, you dig a trench, then drive your steel T-posts, then put the wire in. You have to bend the bottom of the wire flat to the trench. Then you have to attach that to the post. Then the fabric is put up, where you have to attach the fabric to the wire, then both products to the post, and then you have to backfill.
“You can imagine how cumbersome that is. But when you put Silt-Saver’s product in, you just dig a trench and drop it in. It’s got a green line on it, embedded into the fabric, that lets you know how deep you have to be, so that your 90-degree bend to put your material down flat at the bottom of the trench works out just right, and then you backfill. This saves loads and loads of time. And that translates into major money savings.”
Reed notes that although the product is well designed, it is important that contractors understand how to properly install the system.
“I decided to visit another project, by another contractor, in a nearby area,” he says. “He was also using the SRSF, but was having some difficulties. From what I could tell, this contractor was using an opening of 12 inches to install the silt fence. In my experience, that will cause it to fail. Improper installation such as overexcavating the width and depth, and not compacting properly, will cause the product to fail.
“The opening should be 4 to 6 inches, with well-compacted soil used for backfill. Making the opening bigger may make installation easier, but will likely make the silt fence fail.”
On the other hand, if the work is done correctly, there should be no problems at all, according to Reed.
“If installed per TDOT specifications and Silt-Saver specifications, it will not fail,” he wrote in a report to Silt-Saver. He urged TDOT to add the SRSF to its approved list, noting, “In the long run this product will benefit TDOT because the cost impact is less, labor is less to install, and removal will be less costly. This product will benefit TDOT when installed correctly.”
Indeed, Reed has used the SRSF on a number of his projects recently. He says that damage from ultraviolet exposure has not occurred to date. “It still has not deteriorated, even after sitting in place on a couple different projects for over a year now.”
He also notes with surprise how some contractors are trying to take advantage of the unusual strength of the product. “The posts are still standing up after more than a year. They’re rigid; they haven’t begun to break down yet. We even have some contractors who use them as retaining walls. That is ridiculous, since it’s not meant to be a retaining wall for grading operations, but they do it anyway.
“I think it’s a phenomenal product,” he adds. “It’s a time-saver, which of course adds to the bottom line for whoever is installing it. It’s equal to or better than what is on the market.”
Especially when there’s not a 5-inch monsoon coming down.