Controlling pollution at its source should be an essential part of any stormwater protection plan. Whether you’re setting out to trap sediment or pollutants-including hydrocarbons, oil, and grease-that can attach to such particles, inlet and storm drain protection can keep waterways on your site clean and help you meet National Pollutant Discharge Elimination System (NPDES) Phase II requirements.
Meeting your goals for improving water quality can be easy as long as you undertake some quick research and pair the right treatment system with your site’s needs.
Adjacent waterways and sensitive habitats, such as wetlands, are typically considered in advance of drawing up a stormwater management plan-if only to meet permit requirements-and a combination of erosion control techniques, particularly during an ongoing construction project, may be necessary. Often, the filtration solutions are added after a project’s construction ends. In fact, the US Environmental Protection Agency recommends a combination of techniques be used with storm-drain inlet protection, such as small impoundments or sediment traps, for increased effectiveness.
In most cases, these types of devices can handle the fairly clean runoff that comes from an average rainfall. But in arid climates where the dry soil can easily wash away with a flow from a heavy rain, clogging can occur. For maximum success at your site, storm-drain protection requires maintenance. As the EPA points out, “If sediment and other debris clog the water intake, drop inlet control measures can actually cause erosion in unprotected areas.”
Whether your project’s needs entail long- or short-term solutions, a variety erosion control and stormwater specialists shared some examples detailing how protecting a site’s waterways from sediment and pollutants can be achieved efficiently.
Albuquerque Interchange
Last July, at the Interstate 25 and Interstate 40 interchange in Albuquerque, NM, a transformation began to take place.
“It’s the biggest landscape project in the state in 20 years,” says Rodger Barton of SWPPP Compliance, an Albuquerque-based company that specializes in creating and executing stormwater pollution prevention plans (SWPPPs), describing the landscaping that continues to take place along the roads around the interchange. “It’s about 70 acres. [It’s] like a facelift, just a renovation. The primary focus was to give people driving through the area something nice to look at.”
Another goal was stabilizing the site’s soil as workers basically tried “to give the area life,” he says. The tree species used included pine and cottonwood, which are native to New Mexico.
“It’s all rock, hard rockscape: just large landscape rocks bigger than your two fists,” he notes.
Construction on the highway project began during the month when rains are heaviest in the region, presenting a challenge for the workers.
“Albuquerque doesn’t get a lot of rain,” says Barton, “but when it does, it comes down hard.”
For example, following one rain event, Barton shoveled the soil that had washed into the area, collected it, and weighed it the next morning: the event washed 42 pounds of dirt onto the site.
Needless to say, proper filtration became a necessity at the site. Barton, who wrote the stormwater plan for the project, says that for safety reasons, he chose an inlet filter by Blocksom & Co., which is based in Michigan City, IN.
“If you put wattles or you put bags around a storm drain, the likelihood of somebody running into that and having an accident is very, very high. The gravel bag will easily weigh 25 to 40 pounds. If somebody hits that, they’re going to have an accident,” explains Barton. “With the filter, you can run it over and keep going. It’s not going to cause an accident.”
He describes the instillation process as easy, taking approximately five minutes to install each basin properly. The instillation time was a good match for the project because of the difficulty traffic presented to the workers, who worked using protective barrels.
“The most challenging part was being safe and not getting run over by people,” says Barton.
Barton didn’t realize how well the product suited the site until he installed it. “It’s trapped oil, tar, antifreeze, concrete. The product is by far superior to anything I’ve ever used. I’ve installed probably 250 filters on grates that are 4.5 feet by 5.5 feet. The filter works very, very well.”
Following an EPA mandate for filtration, the company also installed 30,000 feet of mulch-filled sock. Part of Barton’s role at the site was to ensure that the general contractors-Mountain West Golfscapes Inc., based in Peralta, NM, and Lee Landscapes Inc., based in Albuquerque-complied with local regulations as well as the standards set by the EPA.
“Every few weeks, I perform inspections on the site and report back to the project managers,” says Barton. “If any repairs are required, I let them know. I also provide them with a list of materials that need to be replaced.”
There are four ongoing segments to the highway-landscaping project, with each piece spending an average of about $3.5 million on erosion control. SWPPP Compliance is the only company working on the entire project, which is scheduled to be complete in early 2010.
Working Near the Railroad
Slightly farther west, a year after a Walmart store was built on a 10-acre site in Peoria, AZ, a project to connect Peoria Avenue with 79th and Grand Avenue was undertaken during the summer of 2009.
“They have to mill the asphalt,” explains Jim Anderson, manager of operations and sales at BMP Solutions based in Phoenix, a company that planned the site’s stormwater solutions. “They have to put in sidewalk curb gutter, reestablish some landscape, and put in lights and traffic signals.
“We were working with the City of Peoria, Walmart, ADOT [the Arizona Department of Transportation], and the railroad,” he says. “It made it unique.”
BMP Solutions used Gator Guard drainage and sediment control wattles constructed of woven polypropylene slit film “to stay within the requirements that the railroad had set forth. It was our best application,” says Anderson. The product, which is filled with closed-cell polyethylene foam, has a UV protective strength of 80% after 2,400 hours. It weighs about eight pounds per 25-foot single roll. Instillation pins are placed every 3 feet along the material to secure it in place at a site.
The railroad requirements included a strict boundary. “You have to stay outside of 25 feet of the tracks,” explains Anderson. “We used Gator Guard for erosion control. We’ve used it with numerous projects. It best suited the erosion control material for the application at hand other than silt fence or wattles.”
The estimated cost of erosion control at the entire site of the ongoing project, where a deer deterrent was also used for inlet protection in addition to some areas of silt fence, is difficult to determine because, as Anderson notes, “everything was a bid item.”
Inspections are conducted regularly during construction.
“One of Walmart’s requirements is that inspections are conducted until construction is completed, until the NOT [notice of termination] is filed,” says Anderson. “All corrections are made within 24 hours.”
Barring any major damage, the life expectancy of a Gator Guard wattle is approximately five years.
When one considers the Arizona climate from afar, heavy rain is typically not something that would seem a pressing concern. Yet it’s precisely because the landscape is so arid for so long that rainfall poses a challenge to stormwater planning.
“Arizona is so different because we only get 7 inches of rain a year,” says Anderson. “But when we get one of our storms, [it rains] a few inches. We need the slow rains so the soil can absorb it.”
During the three strong storms that occurred during summer construction, Anderson says, the Gator Guards used at the site functioned well and contained “any silt particles that may have been washed away during our monsoon season.”
Along the Boulevard
Eric Sanford, CPSWQ, director of municipal services for the Myrtle Beach, SC, describes the variety of debris and pollutants that can be encountered along the city’s Ocean Boulevard.
“It is tourist-generated trash, papers, cigarette butts, and plastic bottles,” he says, describing the area as a typical urban environment: “Ninety acres of 85% or greater impervious areas.”
In 2003, the SNOUT, an oil, water, and debris separator created by Best Management Products, based in Middle River, MD, was installed on sites located along Ocean Boulevard. The project’s schedule proved challenging. All work had to be completed during the off-season months, which Sanford says stretched between October and April. The goals for improving stormwater at the site were primarily the removal of “the gross pollutants and oils prior to discharging into the Atlantic Ocean,” he says, through the use of a combination of catch basin inserts with sediment boxes used for source treatment.
The city of Myrtle Beach maintains the units. Maintenance is typically required twice annually, though the frequency depends upon rain events.
The cost of erosion control wasn’t broken out for this approximately $11 million project, but economics was part of the reason Sanford says the SNOUT was selected for use at the site. Its ability to easily retrofit into existing structures and “good source treatment at each catch basin for gross pollutants and oils” were additional reasons it was chosen.
“Our business suggests that the “˜structural treatment train’ concept is becoming the predominant design methodology to improve stormwater,” says T.J. Mullen, president of Best Management Products. “While the concept has been discussed for years, it is now being practiced more readily or is required by municipalities. Rather than trying to remove all pollutants at the end of the pipe run, which was how water-quality facilities were typically deployed, designers are now incorporating water-quality controls along the drainage network-for instance, putting SNOUTs in all or most inlets to remove pollutants at the point where they enter the underground infrastructure, as is the case in Myrtle Beach.”
He describes the benefit of this treatment method as twofold. “First, the pollutants will not be as agitated or subject to as much turbulence, because they are not traveling downstream through long pipe runs were a lot of mixing occurs. Therefore, the pollution particles may remain more intact or less emulsified, and simpler controls to remove pollution can still be very effective,” says Mullen. “Second, final treatment prior to discharge at the end of a drainage run is often required or desirable to remove finer or dissolved pollutants, whether or not treatment is employed above. In this case, using a structural treatment train makes a lot of sense, as gross pollutants like trash and debris will be removed upstream, allowing a filtration or infiltration practice to perform much more efficiently and possibly requiring less maintenance because it is not overwhelmed by a large mass of material.”
More Education
Mike Dotlich, general foreman at Haselden Construction LLC in Denver, CO, and trained by the state of Colorado for stormwater management, says he’s noticed an increase in education about stormwater plans. He’s worked with a worldwide corporation in the past and he has noticed a trend that has made “everybody knowledgeable” about an area of planning that was practically nonexistent in the not-too-distant past.
“The government’s getting stricter,” he explains, noting what prompted this change. “We’re educated.” Learning more about the process and permit requirements can help contractors better select products that are best tailored to their individual sites.
Recently, Haselden constructed an addition and completed a renovation of the Auraria Science Building on a 5-acre site at the Auraria Campus in Denver, which services the University of Colorado at Denver, the Community College of Denver, and Metropolitan State College of Denver. Approximately 200,000 square feet of new space was added to the site, and the existing 142,000 square feet of space was renovated following Leadership in Energy and Environmental Design [LEED] requirements for design and construction of green buildings. These efforts, which included energy conservation, helped the project achieve LEED Gold certification.
Classrooms and laboratories in the facility are state-of-the-art facilities on a campus that is used by one-fifth of all public higher education students in the state. With such a highly visible project, aesthetics and lasting durability were concerns during construction.
“I used Combo Guard on Spear Boulevard, one of the main thoroughfares through Denver,” says Dotlich. The product, a four-layer system made of HDPE that is engineered to capture sediment while allowing stormwater to run off a street into curb and grate storm drain inlets, has an integrated filter that is 2 inches high vertically, allowing for bypass in major storm conditions. The reusable system, which weighs about 4.5 pounds, is produced by ERTEC Environmental Systems, based in Alameda, CA, and can be anchored by gravel bags or GR-8 hooks sold by the same company. The product seal controls underflow at the site. Combo Guard was selected for the project based on installation and maintenance ease.
“Combo Guard goes over the inlet. The water flows over the curbline into that,” Dotlich says, noting that the product held up to the nearby traffic and that snowplows didn’t rip it. “I used a Hard Surface Guard [also by ERTEC]. I had a silt fence up originally. The silt fence deteriorated at the site. People would run over it. If somebody did run over this, it would pop back up. You don’t put in as many man-hours as you would having silt fence around your property.
“It took three days to complete it, but if I put silt fence in there it would have taken me two weeks,” he notes. “The stakes are hard; they break, and you have to patch them. It would have taken three times the man-hours.”
The site is located “in the middle of the public eye,” explains Dotlich, noting that regulators drive up and down the street daily. Some fencing has also been used on a dirt area and a grass area on the site, and it was buried three inches into the ground with 7 inches exposed. The project, begun in 2008, is ongoing.
“We’ve had a very wet summer and a very snowy winter,” says Dotlich, who describes the monitoring involved with the Combo Guard. “We monitor it every day if we have an event of rain or snow. On a typical basis, we check it twice a week. It works wonderfully.”
California and Georgia Pipelines
The Pacific Gas & Electric Utility Co. also used Combo Guard for curb-grate combination inlets on a 6-mile pipeline site extending from Folsom to El Dorado Hills, CA, during the late summer and fall of 2006.
Because a pipeline builder needs a sediment control system that’s easily transported as the project progresses, the Combo Guard was selected over other systems that require more labor for instillation or are difficult to remove. The guards were anchored in place along the site with gravel bags placed on both sides of the grate.
“Combo Guards worked great for us on this project,” says Lyn Hudgens, safety representative for General Construction-Gas at PG&E. “They were easy to install, maintain, and reuse, and we never had to lift heavy grates. We used Combo Guard in several cities, and the inspectors liked the product.”
A gas pipeline instillation project stretching north-south approximately 200 miles through the state of Georgia began in early 2009. More than 200 streams are located throughout the construction site, and protecting their integrity became essential.
Will Roddy, CESSWI, is a staff specialist at AECOM, based in Atlanta, which provided permitting for the project and helped make sure National Pollutant Discharge Elimination System (NPDES) guidelines were being followed. “There were standard Georgia Green Book practices as far as BMPs are concerned, he says. “Pipeline work is different as far as construction goes. What we call water bars would be construction berms. We have some modified catch basins and silt fences at a diversion berm to hold sediment back.
“There are also federal permit conditions we have to follow in keeping sediment out of streams, using the silt fence at these locations where it wasn’t typically required. The goal is to keep all soil and sediment on our worksite.”
Roddy says Silt-Saver filters were selected for use at the site as an alternative to the wire-back silt fence required by the state for all wetlands.
With a large number of wetlands and streams that would have to be crossed during construction, the Silt-Saver filters, created by Conyers, GA-based Silt-Saver Inc., were also chosen for economic reasons and the fact that “it’s easier to work with, easier to install, and easier to maintain” when compared with wire-back silt fence, says Roddy. The product will remain at the site until revegetation has taken place.
“The Silt-Saver that’s installed is monitored on a daily basis with construction,” says Roddy, noting that when the site has been restored, monitoring will occur on a biweekly basis and after every half-inch rain event until the NOT is completed for the project. “It’s cut back a lot of the contractor’s expenses as far as maintenance issues. Everybody out here loves using it just for that simple reason.”
Companies affected by the recession are working with a conundrum. Mullen pointed out that at a time when tax revenues in most jurisdictions are declining, the requirements to clean up stormwater are increasing.
“The economy is taking a toll on everybody. Certainly, some projects have been put on hold while others, particularly commercial projects, have been scrapped altogether,” he says. “However, on a positive note, we have seen a steady increase in inquiries to help designers value-engineer stormwater-quality controls into projects. Cost-effective solutions are very much in vogue these days, as clients are holding engineers to tighter budgets in their stormwater and site planning.”
Finding the right short- or long-term solution for your site may seem daunting. The wide variety of choices available should be considered in addition to your project’s budget, size, scope, and climate. Reviewing those few considerations now can save your company money, time, and labor in the future.