There’s an old advertising saying: “You never see a piano ad unless you’re in the market to buy a piano.” And this might also be true of stormwater inlets. The ubiquitous receptacles are such a routine feature of streets and parking lots that they’re virtually invisible. But, if you are a contractor breaking ground, a municipal stormwater manager, or a business owner with parking lots, these inlets that need protecting seem to be everywhere. And they all need protecting from trash, sediment, and chemical pollutants.
In an era of ever-increasing stormwater permitting requirements, simply fencing off debris is no longer good enough. Fortunately, technologies have come a long way from rudimentary steel grate protectors that at best hold large trash back, and at worst dam up and cause flooding.
Cleaner City Buses and Cleaner Water
Stormwater management is a key component to Hendersonville, TN-based Jen-Hill Construction Materials’ product line. Jen-Hill’s stormwater focus leads it to take projects involving both old and new infrastructure, says Jason Painter, Jen-Hill’s East Tennessee sales manager.
“Suntree Technologies has a number of stormwater management products, and my company Jen-Hill has been working with them for at least 15 years, installing a variety of products that treat stormwater at the individual inlet with the Grate Inlet Skimmer Box, in concrete flumes with Flume Filters, and at the end of pipe systems with the Nutrient Separating Baffle Box,” says Painter.
Painter describes a recent project in which the Knoxville area transit maintenance facility, located in an older part of the city’s downtown area, was brought in line with updated stormwater requirements.
“This facility was built originally in 1989. Planned upgrades in 2013 meant that the facility would have to comply with newer, stricter stormwater regulations, so Jen-Hill was contracted to retrofit the catch basins on the property with treatment devices.”
The facility is where city buses are maintained, stored, and washed, and the catch basins required a system that would remove solids and hydrocarbons washing into the inlets. The transit facility is located off First Creek, which Painter says feeds right into the Tennessee River.
Many of the inlets at the facility had obstructions down inside the catch basins. With detailed measurements and good communication, he says, Suntree can accommodate these obstructions during the manufacturing process. “The nice thing about working with Suntree is that their product line can adapt to old infrastructure without the need for much work on the concrete inlet or pipe system. Not only does this cut down on costs, but it’s a custom fit that does a great job.”
The Grate Inlet Skimmer Box (GISB) is made from a marine-grade fiberglass and uses a series of stainless steel screens to capture debris. “Inside the box, there is a deflection shield that holds debris inside even when peak storm events occur. The GISB also has a hydrocarbon storm boom installed around the tray at the top of the box,” he notes.
He adds the storm boom can be tailored to attack the type of pollutants the customer is most concerned with. The transit maintenance facility not only used the wrap-around boom that sits on the top tray of the GISB, but also, he says, “Additional booms were installed down in the center of the box to add more treatment capacity of the hydrocarbons.”
Painter recommends that these inlet devices be inspected every three months during the first year to get a sense of how much debris is being collected.
“During the first year, we recommend people check the boxes quarterly, and pay attention to seasonal changes that might affect the amount of foliage and debris that accumulate in the unit. Obviously, if you are at a site like a gas station or a site with a lot of public traffic, you would want to service these more often to remove debris and replace the booms.”
From a maintenance perspective, the cleaning is fairly straightforward, as the boxes are resting under the grate.
“You can service the Skimmer Boxes with a vacuum truck, or onsite personnel can remove them by hand for maintenance. You do not have to worry about damaging the units with maintenance equipment because they are durable and built to last. You can use a vacuum truck for cleanout, or pull them out like a trash can.”
In his experience, Painter says, “The Suntree Grate Inlet Skimmer Box is preferred by municipalities because of its ability to treat runoff and because of its durability. Suntree Technologies is a valuable partner, and we are committed to providing a diverse product line that meets today’s challenging stormwater management needs.”
Orange is a “Dandy” Color for Safety
“You see orange all over Denver’s streets,” says Ken Kinnard of Denver, CO’s Bowman Construction Supply Co. “Anywhere there is road construction in Denver, and throughout much of Colorado, you’ll see the bright orange Dandy Bags.” Bowman’s company is a distributor of Dandy Products’ erosion control and inlet protection products.
“Sediment is the big reason we use the bags. Whether it’s roads or bridgework, or any other kind of construction project where water is draining, these temporary protection devices do the job.” The products include the Dandy Bag, which can be used with flat grates; the Dandy Curb, an inlet filter for curb and median inlets without grates; the Dandy Curb Bag, a curb inlet filter; and the Dandy Sack, which hangs beneath a storm grate.
Kinnard says the bags, purposefully introduced in bright orange for visibility and to convey the concept of safety, are made of a high-filtration geotextile that allows high flowthrough of water while containing debris and sediment. As it slows the water, it decants the sediment. Because the inlet protection devices are about half the height of typical urban drain inlets, they do their job without causing water damming.
“The size of the tube is paramount to prevent downstream flooding, which is critical as we have a lot of snow in Colorado, and tremendous runoff. During the huge Interstate I-25 expansion, these curb bags were used by the hundreds, but because they are so tough, tractor rigs can drive right over them. Even after six months of rugged abuse, they held up. The top layers wear out, but the rest of it still performs as it’s supposed to.” Kinnard estimates the life of a Dandy Bag under these circumstances to be about six to seven months.
Dandy Curb Bag
Connecting People, Protecting the Water
During the decade-long Denver light rail expansion, most recently connecting the city’s Union Train Station to the Denver airport, Donald Crouse, erosion control manager of Eagle P3 FasTracks, had a decision to make.
“We look for all the places on our construction route where stormwater can escape our perimeter; it’s inlets predominately, and I selected the Dandy Products. I felt they were the most unique and also the best product that can attack this problem, plus make it simple to install and maintain. We looked at all the graded and curb inlets and installed different Dandy products based on use and applications for each respective inlet.
“We’ll take, for example, a curb inlet that has a grate, we’ll pull the grate and put the bag in there, or if there is an area inlet we’ll use a Dandy Curb Bag around that. The nice thing is we’ll throw 10 or 15 of these in the truck and spend the rest of the day putting them on curbs, and if they’ve been compromised we’ll put a new one in.”
He says the bags act as a microfilter, trapping sediment and allowing it to settle while the water both passes through and, at times, up and over the bag.
“This is important, because with some products the water will simply pond up in front of a bag at the curbline, and this becomes a safety hazard to traffic as vehicles can lose control.”
At about half the height of the curb inlet, the device filters water without causing flooding.
With the 33 miles of light rail expansion nearing completion, Crouse says the project protected about 450 inlets with Dandy devices on one line, and another 150–200 on a different segment.
“I’ve had to put these Dandy Bags in the middle of streets, and one reason I chose them was because of the orange color and bright visibility. They’re incredibly long lasting—and even with heavy trucks constantly rolling over them they hold up.”
Everything in the front range of Denver drains to the Platt River, and Kinnard reflects on the role of these inlet protection barriers protecting the watershed.
“Urban sediment is a big problem, but within the last 15 years these new geotextiles that comply with stormwater mitigation do a great job with filtration and high flow.”
As a result, he says, the world-class fly fishing in Colorado is better than ever, and the rivers are cleaner now than in the 1960s. “My kids are seeing cleaner rivers, less sediment, and almost zero chemical discharge than when I was their age, thanks to these sediment collecting and erosion protection devices.”
Making Boating Season Environmentally Friendly
Jim High is the owner of Maryland’s Baltimore Boating Center, a certified Clean Marina. This certification includes “having a stormwater plan, an emergency handbook and safety data sheet, monitoring of volatile organic compounds, and a recycling program,” says High.
High says he got involved with the Maryland Clean Marina initiative when he assumed ownership of the facility in the 1980s. With 70 slips and 125 high-and-dry storage racks, full mechanical service, and full discount marine store, High says his facility is “a busy place for families and boat owners accessing the recreation and fishing opportunities of the Chesapeake Bay,” which is a 10-minute boat ride away.
About 100 marinas in Maryland are certified through the state’s Department of Natural Resources (DNR). Having served as an advisor on the Clear Creeks program of a local watershed area, High is committed to good stewardship of water resources.
The Baltimore Boating Center uses the Snout inlet protection device from Best Management Products Inc. Since 1999, more than 65,000 installations of the Snout have been protecting surface waters across the US, the UK, and the US Pacific territories, says T. J. Mullen, founder of the company and inventor of the Snout.
The company, with offices in Lyme, CT, and Baltimore, MD, had a background in both the stormwater and sanitary sewer business. Mullen says, “We saw the need for the quality of stormwater runoff to be improved, but most structure-oriented devices were expensive. We wanted to provide simple and affordable solutions that municipal engineers and regulators would actually use.”
He the quirky name came about because the product “kind of looked like a nose, in profile, and we wanted the name to be memorable—and everybody remembers the Snout.”
The device is made of marine-grade fiberglass and marine-grade hardware, and, like a boat, it is made in an open mold creating a strong, lightweight, and resilient product. While it is “flexible enough to withstand intense dynamic stresses,” says Mullen, it weighs only 15 pounds and is easy to handle, compared to something that could weigh 200 pounds if it were made of cast iron or steel.
The design premise is also quite simple. “It relies on the fact that many pieces of trash and most oils are floatable, and heavier particles will sink; it’s just basic gravity.”
Further enhancing the Snout’s capacity is the Bioskirt, which, Mullen says, “targets oils and greases through its adsorption design. The Bioskirt is a really thick fabric and mildly hydrophobic—in other words, repelling water—but it does attract hydrocarbons.”
He says a typical Bioskirt can absorb a gallon of oil, “which if you think of a gallon of oil floating on water, that’s a lot of oil.”
High has been using the Snout for more than a decade.
“We powerwash boats here, and the water from that has to be filtered and collected. I have four bays here that powerwash, and I have Snouts and Bioskirts on them. We collect the water from the cleaning; after it passes through this filtration system it is considered clean, and it’s then pumped into the sanitary sewer system.”
Although the effort is voluntary, High says, “Everyone has a stake in keeping our resources clean. This is the final place where stormwater enters the Chesapeake Bay. When regulators come out, you can show them you’re working hard for a small family facility that is doing their best to help the local environment.”
A Wing-Gate inlet protection device installed on Bourbon Street in New Orleans
Too Much of a Good Thing
Everybody loves a party, and nobody loves a good time more than New Orleans, particularly during Mardi Gras when nearly one and a half million visitors flood the city, more than tripling its usual population. But after any good time, there is a lot to clean up from the festivities, and street trash is an overwhelming burden. This year the city had help, thanks to the Wing-Gate automatic retractable screen (ARS) stormwater inlet protection devices from California-based United Storm Water Inc. and United Pumping Services.
Company stormwater sales manager Terry Flury explains how the specialized protection devices help municipalities cope with the everyday headache of trapping trash and protecting stormwater. “Although we originated in southern California, compliance with increasingly stringent policies of municipal separate stormwater sewer systems [MS4s] across the country is helping drive our popularity. Our full-capture devices are all stainless steel and have a five-millimeter perforated screen that prevents items as small as a cigarette butt from entering storm drains.
“We also have stormwater filter DrainPacs that filter out hydrocarbons, and we can customize the filter media to address whatever the customer needs. For example, if you’re concerned about heavy metals, oils, or fertilizer, the filter media could be Perlite, activated carbon, or whatever you might need to address the problem.”
And customizing the product is all in a day’s work, even when it’s a rush to meet the deadline for arguably the country’s biggest, or at least most enthusiastic, outdoor party.
“We recently did a Wing-Gate screen install on Bourbon Street in New Orleans,” explains Flury, “and we had to come up with a special design. Our standard ARS screens are configured completely different and could not accommodate the New Orleans street grate models, which are very unusual and strange looking, made around 1900, and all cast iron with multi-phased support legs.”
Flury says the city wanted something in place by Mardi Gras 2016, so the design team was challenged to come up with a new configuration.
“We did a pilot test of 30 basins and came up with a Wing-Gate design that was completely different. This went through [the city’s] approval process and we had the screens in place well before Mardi Gras.”
City officials were pleased, he says. “We’re now working on a plan to eventually do the whole city.”
The Wing-Gate devices, he explains, are automatic retractable screens that respond to the incoming water, both retaining trash and allowing water to flow. The ARS fits right into the curb openings; in dry months the screen prevents trash from entering the catch basins, and during rain events it opens after water reaches about 40% of curb height. Connector screens then act as a second line of defense for debris, protecting the outlet pipes.
Sometimes meeting client needs has to address more than making a new size or configuration. Flury describes how the bright stainless steel of the ARS was virtually a magnet for scrap collectors in some urban areas. “So for customers who need it, what we’ve done is simply finish the stainless in flat black paint with a powder coating, which replicates plastic and draws far less attention and protects their investment.”
Since the company actually comprises two entities—United Stormwater and United Pumping—Flury says they can manage not only client stormwater needs, but also hazardous waste.
“If we run into a hazardous waste issue, we can act in a remedial capacity. For example, if we run into an oil spill, oil in storm drains, our crews will come and dam up the area and either broom off or vacuum the oil. We really have the best of both worlds when it comes to managing and protecting our water.”
Aerial view of the spillway
Maintaining the Historic Legacy
The US Naval Academy, the undergraduate college for the country’s naval service in Annapolis, MD, was originally founded in 1845 by then-Secretary of the Navy George Bancroft. Located on 10 acres of old Fort Severn, the academy campus is sited where the Severn River flows into the Chesapeake Bay. Across the Severn River is the Naval Support Activity Annapolis, the site of a recent remediation project.
Mark Friar, site construction manager with Agviq LLC, a subsidiary of Point Hope Alaska’s parent company Tikigaq, explains that the Severn River is a major tributary to the bay.
“After years of collecting facility runoff, the academy’s 4-acre lagoon filled with sediment conveyed by the runoff. A makeshift berm surrounding this area had originally been installed to try and contain sediment, which allows it to settle before the waters flow down a 27-foot slope toward the Severn River through a deteriorated 12-inch corrugated metal pipe, but this area needed an entire overhaul.”
Under the Navy’s Environmental Restoration Program, the lagoon berm was rebuilt and principal and emergency spillways constructed to contain sediment and prevent erosion from the facility’s stormwater runoff.
Next to the lagoon is a wetland called Woolchurch Cove, which acts as a collecting site for lagoon spillover during heavy storms. The cove holds sediment as well and allows the collected overflow to simply settle and percolate. “The catchment lagoon receives quite a bit of stormwater from parking lots up above, coming through conveyance pipes and making its way down to the ravine,” he says. “That water flows into the lagoon; adequate protection from sediments reaching the Severn River is of primary concern.”
With the approval of the Maryland Department of the Environment (MDE), the effort was tied in with a landfill cap remediation project. Agviq worked on both efforts at the same time.
“When we moved to the site, the existing berm was extremely deteriorated, and we had to be very careful of our construction methods to ensure the berm was stable during construction.”
The Snout and the Best Management Products trash screen were installed during the project.
“We got hooked up with T. J. Mullen and his company, BMP, through our project engineers, CH2M Hill, and the site quality-control manager,” says Friar. “As we were procuring the principal spillway concrete structure, now in the lagoon, they suggested we include the Snout and trash screen from BMP to achieve design requirements in providing protection of the principal spillway inlet from debris. The Snout and trash screen specifications were provided to NAVFAC for review and subsequently approved for use on the principal spillway structure.”
Today the berm has been successfully rehabilitated with erosion mats, riprap, tons of gravel, topsoil, grass, and a road realignment. These improvements have made a big difference controlling erosion and ensuring the berm is protected from major storms. The BMP products play a key role, located at the critical point of the principal spillway where lagoon waters are making their final way towards the Severn River. The trash screen keeps large branches and debris from clogging the system, and the Snout funnels clean water through the spillway toward the river.
Friar says, “It’s great to have clients and suppliers who definitely want to be good neighbors to their land and its legacies.”
