Busy in Boise
A homeowner in Boise, ID, had recently purchased his house and wanted an entirely new look for his property.
“The site was very sloped, sitting on top of a hill. So there was a lot of steep terrain involved. It was a complete remodel,” says Aaron Lowe, owner of Boden Haus Landscape in Boise. “The existing landscape that had been there for 10 or more years was completely stripped off and removed.
“In doing so, we had to set up a perimeter of erosion control, not only at the bottom of the slope, but also intermittently up the slope about halfway.”
Lowe opted to use the Gator Guard sediment control wattles for this project. The material is composed of a UV-resistant geotextile packed with photodegradable closed-cell recycled foam.
“The reason we went with them was because of their durability. With the requirements that were put in front of us in order to work in the city and county regarding their erosion and sediment control demands, we went with these wattles because of their longevity.
“Using a straw wattle with harsh weather can be difficult to use. They break down and may not be able to be reused. But the Gator Guard product offers good longevity. We looked at it, knowing that if we invested in them, we’d be able to reuse them. We can store them and use them again on another project and probably get multiple years of use out of them instead of just one or two jobs. From a cost standpoint, they’re almost the same as a straw wattle, but they last much longer.
“We also used what is referred to as a witch’s hat at any drop inlets in the street. In addition, we used gravel bags along the slope to slow down anything that would potentially get to the street.”
Lowe says he used about 1,200–1,500 linear feet of the Gator Guard wattles. “Maybe a little more. We used them around the whole perimeter of the property. They worked very well for us, not just for sediment control, but also to keep a nice, clean work site for the extended amount of time that we were there.”
City inspections occurred fairly regularly, but not according to a precise schedule.
“I think it depended on how busy the city was,” says Lowe. “I don’t think they gave us an exact date when they were going to be out. It depends on the size of the project as well. But it seemed like they came out at least every couple weeks. They would check to see if it was still an open project and look at the erosion and sediment control items.
“We didn’t hear anything negative from anyone and didn’t have any issues from the owner. I think everyone was happy that we kept a clean site. Regarding the city, we were always approved when they did site inspections.”
Although a number of rainstorms and thunderstorms dropped a significant amount of rain on the site, they didn’t impede the work in progress.
“Over the time period we were there, there were good-sized storms. If we weren’t already there working through the storm, we ran out there to make sure the erosion control stuff was still in place and that it was working. We didn’t have any bad problems.
“In the spring here we get a lot of moisture, and thunderstorms in the summertime. But we were constantly walking up and down the site, working on it and doing whatever needed to be done and always assessing soil movement. We were very happy with the product.”
Lowe notes that he had little or no maintenance to perform with the wattles, other than cleaning up any excess sediment.
“At times, we may have needed to nail something down or move something for a piece of equipment and put it back down. The gravel bags occasionally were an issue. When they’re in the street people may not see them and run over them, causing them to split apart. Those were replaced a few times. Otherwise, we didn’t need much maintenance.”
He also comments that to achieve better erosion and sediment control, the site grading wasn’t done all at once.
“It was an ongoing process,” he says. “It was a process that we had to go through, to do things in the right sequencing. We did a lot of hardscape, a lot of retaining wall, a lot of patio work, so there were different times we had to deal with slopes during different stages of the project.”
Staged Release Silt Fence Demonstrates Its Effectiveness
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.
Staged Release Silt Fence
Keeping Huntington Beach Beautiful
One of the “hot buttons” for construction site inspectors is trackout of dirt, rock, and sediment from a work site. This matter was of special concern in Huntington Beach, CA, where a six-story apartment complex was being built on a highly visible 5-acre site in the city.
“They were having a bit of a trackout issue on the street, because the whole site was originally just a dirt pad,” explains Tony Decker, project manager with BMP Solutions, based in southern California. “We kept spreading rocks, and trucks were driving over the rocks, but this was getting maybe 50% of the mud and dirt that were on the tires.
“So we laid down nine trackout plates at the construction entrance, forcing trucks to drive over each set of plates before they went on out into the street. It was helping significantly. Then every couple days we had a worker who, at the end of the day, would sweep off the accumulated silt and debris on the plates. So there would regularly be clean, fresh trackout plates to drive over.”
Trackout plates on a southern California site
Instead of debris entering the city streets and sewer systems, it remained onsite. The trackout plates were supplied by Contractors Services of Lakewood, CA. Some were rented by Decker’s BMP Solutions, while others were purchased outright.
“We’ve tried a couple different companies while we’ve been in business, but we prefer Contractors Services’ plates because they use thicker steel, they weigh more, and they’re just a heavier-duty, better quality product, in our opinion,” says Decker. “Some other plates use thinner steel or they’re lighter, and they tend to bend over time. They can crack and chip, and they’re not as good a product over time.
“We’ve had some plates on job sites for over a year. We have three plates of our own that we bought from Contractors Services. On one of our projects they’ve been in place for over a year and they haven’t bent or given us any problems. They’re still in great shape. All we do is use a laborer onsite every week or two to sweep them off, and they’re good as new.”
In addition to the trackout plates, other BMPs have also been employed on this project.
Trackout plates on a southern California site
“Around the entire site, we put gravel bags as an erosion control device, so that when it rained, the water would run to the gravel bags. These gravel bags were then essentially filtering the water and allowing cleaner water to pass through, which would go into the street and enter the storm drain. We had protection on the storm drains as well, as a secondary erosion control device.”
Decker notes that at this point in the project, nasty weather isn’t of great concern. “It’s in a bowl. They’re below grade now. Everything has been maintained onsite. We have had some problems at another job site where they are building on a dirt pad. Two- and three-inch rain storms came, and they had quite a few inches of water on the site. It was almost like a giant lake. But here it hasn’t been an issue.”
Nor have there been environmental or habitat issues to speak of. Decker mentions, however, that on some other work sites that sit adjacent to a conservation area, the city and public works agencies have insisted on the use of trackout plates so that any potential runoff into the street doesn’t get thrown into the inlets and into the sensitive area.
The city inspectors that Decker has worked with frequently want to see trackout plates in place, and they visit sites regularly.
“I don’t know their exact schedule, but on most of the jobs we’re on, the city inspectors are out there about once a week or once every two weeks, and then also after each rainstorm. Pretty much all of the city inspectors require the use of trackout plates. They’re pretty happy when they see them out there. I’ve had a couple jobs just in the last couple months where a plan doesn’t show any plates but the city or the public parks inspector will require plates to be out there, because it’s an added erosion control measure.”
Gator Guard was used partway down the slope as well as for perimeter control.
Typically, Decker says, “Once a site is paved, and there’s much less chance of any sediment leaving the site—that’s when they’ll remove the trackout plates. On this site, the dirt pad has now been replaced with pavement.
“Nevertheless, on this Huntington Beach job, which is a high profile project, they wanted to leave the trackout plates on the asphalt just as an added measure, to make sure no sediment was going into the street. This project is on the main city street, so there is a lot of exposure, a lot of eyes watching the job site.”
He adds that he doesn’t recall a job site where trackout plates damaged newly laid asphalt. “They sit flat, and as long as they’re sitting flat when you’re driving over them, it doesn’t damage it at all. I’ve never had a complaint about the plates on asphalt.”
Sometimes Decker will spray a soil binder to help seal vulnerable areas, minimizing the risk of erosion while work is in progress. This soil binder will typically remain on slopes until landscaping takes place, but it wasn’t necessary on this Huntington Beach project.
Once the city saw that the trackout plates were in place, inspectors’ concerns about sediment tracking out into the street were eased. “They realized the trackout plates were making a big difference,” says Decker. “We were initially having a sweeper out there once a week, but now the sweeper is out there maybe once a month.”
Walmart Construction Both Large and Small
Tim George, senior project manager with Shames Construction, describes two Walmart construction projects, one in northern California and one in southern California.
“We were working on a Walmart project in South Sacramento,” he says, “and they require us to implement a SWPPP [stormwater pollution prevention plan], even if it’s not required by the state inspectors. This particular project had a staging area for an existing building and an existing parking lot.
“The project was pretty small. It was basically a tenant improvement. It was an existing building, but there were some parking lot repairs. Walmart requires that if you have staging anywhere, you protect the perimeter of your staging area.”
The Walmart engineer originally had designated a specific product for sediment control, but it turned out that it wasn’t readily available. “There was going to be a two-week lead time to get it, and the DuraWattle from WTB Inc. was available,” says George. “We asked the engineer about it, and that’s what he recommended. We’ve kept it in place and it works well.
“It was used in the staging area. There was fencing for the perimeter of a 200- by 200-foot area, and we lined the perimeter with the DuraWattle product, about 800 linear feet in all.”
George notes that this was his first experience with the DuraWattle. “I like it. It’s a good product.”
The only other BMP employed on the project was drain inlet protection. According to George, however, there has only been one storm for the duration of the project, and that wasn’t enough to cause any problems, either with drain inlets or with sediment runoff.
The wattle allows water to filter through the material while keeping sediment on the other side. So cleaning up the sediment periodically is required, but otherwise, no other maintenance is necessary.
The other Walmart project that George is working on is in Perris, CA, located about 70 miles southeast of Los Angeles. This project is much larger, taking place on some 38 acres and involving detention basins, over a mile of silt fence, drain inlet filters, a couple of check dams, hay wattles, and gravel bags.
“We’re building a Walmart from the ground up there,” explains Dennis Chatham, superintendent for Shames Construction. “It’s about a quarter-mile from an existing city street.”
In addition to the various BMPs, Chatham says crews have a little drywall around the perimeter, replacing silt fence for a short distance. They have also done some hydroseeding on some sloped areas on the site.
“In addition,” says Chatham, “construction access consists of 100 feet of a paved area, about 100 feet of crushed rock, and then shaker plates in addition to that. These are also commonly referred to as rock plates. When vehicles run over them, they knock the rocks off the vehicle.”
He says, “We have two stormwater detention basins that hold stormwater onsite, until the sediment settles out. We don’t have the discharge finished yet, so we’ve been collecting and storing the stormwater, with no way for it to get offsite. We skim the surface after a rain to let it dry out. It’s a long, slow process, and labor intensive.
“The basins drain into the ground. When it is finished, it will have a crushed rock bottom, but right now, it’s just dirt with hydroseeded embankments. I don’t believe they’ll have any lining, just crushed rock to let the water percolate into the ground.”
He notes that between Christmas and New Years’ Day the area received about 2.5 inches of rain, but he is quick to point out that it didn’t come all at once. “They were small, intermittent rains,” he says, and there were no failures on any of the BMPs on the job. But it was a bit of a nuisance for other workers at the site.
“When it was rainy and muddy, we had to weather-proof the area for the people working in the building. We made everyone park out of the way, parallel to our construction exit. The rain shut down some of our outside activity, but it didn’t shut down work inside the building. It was just a little inconvenient for those workers. They had to walk about 600 to 800 feet, carrying their tools.”
Wind was actually an impediment at times, he reports, knocking over some temporary structures. But the BMPs themselves held in place. Even with all of the BMPs employed on the site, Chatham also has a street sweeper cleaning the streets when there is heavy truck traffic.
“It’s easier to be proactive,” he notes.
