Inlet Protection During Construction and After

Feb. 3, 2015

Water-a simple molecule of one oxygen and two hydrogens, with such a simple design. It’s the very structure of water that makes it strong enough to force boulders loose on a hillside. By water’s polarity, water molecules attract more water molecules and soon the long branched “polymers” are strong enough to make marvelous memories for honeymooners at Niagara Falls, or disastrous ones for families in Japan.

Still, water is not alone. It doesn’t create all this havoc without having an accomplice. Through very specific chemical bonds water has an affinity for soil particles. Like two best friends, water and soil are almost always found journeying together. Whether Mother Nature encourages their journey or humans help them along, their journey would not take them far without the force of gravity. Whether it’s rushing furiously to get past boulders and homes-or diving deep to wiggle into crevices-gravity is the accelerator in the process.

Rain or snowmelt dislodges soil particles, which are carried along in the stormwater runoff. Rushing across surfaces-cleared land, driveways, yards, parking lots, and rooftops-it picks up pollutants on its way to nearby surface waters. Everything hitches a ride with stormwater including water solutes, minerals, petroleum hydrocarbons, nitrogen and phosphorus, pesticides, and heavy metals. Most have the potential to attach to that simple water design. Pollutants that do not chemically bond with water become suspended in the water column and ride their way down to rivers, lakes, or coastal beaches.

It shouldn’t come as any surprise that when construction sites break ground, the very nature of these activities increase the soil’s vulnerability to erosion, resulting in stormwater runoff. As soil is stripped of vegetative protection, the one thing sure to get it up and moving is its best friend-water. Stormwater is considered to be the number one cause of stream deterioration and impairment of urban rivers.

Susceptibility to erosion makes it critical to reduce sediment in runoff from the beginning and continue until long-term restabilization of the site is achieved. And in many locations restabilization has become a part of the process in itself and on a more permanent basis.

A vast assortment of active- and post-construction products are manufactured to either stop sediment from entering surface water or to clean up pollutants prior to final discharge. Sedimentation and stormwater discharge controls include check dams, silt fences, sedimentation basins, wattles, sand or gravel barriers, velocity dissipation devices, drainage swales, and many others. While they have the same main objective, they run the gamut from simple and easy, to those that are the more complex in design and maintenance. For drainage inlets, there is a drain inlet protection BMP for every site variable (soil type, topography, rainfall, or history).

Stormwater seeps into soil, and is trapped by an erosion control technique, or it may leave the construction site as runoff through stormwater sewer systems. Storm sewer systems are often installed early in a project, when the area is most prone to erosion. During early work on a construction site, storm drain and inlet protection is critical.

Curb Updates
In Yellow Medicine County, MN, the Department of Transportation (MNDOT) has a site with the challenge of keeping sediment out of the storm drains while construction workers chop and remove concrete curbs to install improvements mandated by the Americans With Disabilities Act (ADA). Additionally, crews will resurface sections of highway that runs through Clarksfield, says Timothy Burgess, ADA inspector with MNDOT.

Vicky Dosdall, president and owner of Lawn & Driveway Services Inc. in Morris, MN, was hired to perform inlet protection and site restoration. “The MNDOT project is bituminous surfacing and ADA improvements,” she explains. “What they do is remove the curb and sidewalk at the corners and put a ramp in that is friendly to wheelchairs, walkers, and anyone with physical difficulties to get onto the sidewalk without having to step up.”

Dosdall uses ERTEC Top Guard drain inlet protection products, which come in a variety of configurations. As a business owner, she likes their low cost and high performance. ERTEC is an Alameda, CA, company that produces sediment control products.

“ERTEC Top Guard is easy to install,” says Dosdall. “You don’t need to lift or remove the grates. From an employer’s perspective, if I have an employee out there lifting grates, there’s a chance of a back injury. With Top Guard there are big labor savings because one person can install these within 5 minutes. But, because it’s intended to be used multiple times, it saves all around. Plus, they can go right into the recycle bins.”

On the MNDOT highway project, Dosdall’s company installed 28 ERTEC Combo Guards and two Drop Guards. She says the only thing she had to do prior to installation was go out to the job site to measure the grates.

“Drop Guard is used for field inlets, as opposed to inlets on developed property-that is, on asphalt or other hard surfaces,” explains Vince Morris, president of ERTEC. “Drop Guards are sold in 7-foot panels that wrap around the inlets. They trench it-using a trenching shovel or a pick if soil is hard-down 4 inches and wrap the panels around the inlet until the inlet is protected. Drop Guard is held up with wood stakes and screws.”

Drop Guard is designed to allow water to flow through, reducing its velocity and filtering out particles. This filter is designed for concentrated flow and is self-cleaning once post-storm sediment is removed.

“They fasten down with zip ties, and a rock log or a sand bag could be used when the inlet protection is being used for a job that lasts only a few days,” says Dosdall.

“If traffic is too close to the curb and you can’t use gravel bags, you can use wire ties to secure the Combo Guard units in place,” Morris adds. “Common rebar tie wire is ubiquitous and acceptable to use to tie down the Combo Guards to the underlying grates.”

Once construction of ADA ramps and highway repairs is complete, Dosdall will do the important task of restabilizing the site with turf. At the end of the project the construction crew can remove all of the ERTEC products and store them or move them to another jobsite.

The Transitional Care Facility
Most large cities in Oregon drain to the Columbia, Willamette, or McKenzie rivers or their tributaries. In many areas of the state, stormwater systems use large stormwater cartridge vaults, bioswales, rain gardens, sedimentation manholes, and double or single catch basins with inserts to help remove pollutants from runoff.

Doug Paul has worked with catch basin inserts and related products for over a decade. Currently a distributor for Oldcastle Stormwater Solutions, he sold the KriStar line of catch basin inserts for about twelve years. In January 2014, Oldcastle Precast Inc., a leading manufacturer of precast concrete, polymer concrete, and plastic products in the United States, acquired the assets of KriStar Enterprises Inc. The purchase added three manufacturing locations in California, intellectual properties, and the maintenance division, Drainage Protection Systems (DPS), to Oldcastle, now called Oldcastle Stormwater Solutions. KriStar was the developer of the FloGard system including FloGard+Plus catch basins and inserts.

Paul is active in Oregon with the Department of Water Quality (DWQ) and Department of Environmental Quality (DEQ) and stays abreast of new guidelines. On active construction sites, Oregon allows a fairly wide assortment of BMPs, while remaining steadfast to stormwater management guidelines, “as long as they do the job for which they were intended.”

The Oldcastle/KriStar catch basin inserts (post-construction) are used for retrofitting existing sites or in new construction, Paul explains. The inserts are designed to capture hydrocarbons, sediment, and heavy metals that might be attached to soil particles. “Most projects in Oregon are using the FloGard or FloGard+Plus products for both steel and concrete basins,” he says.

In a recent project, Paul installed eight of the FloGard+Plus inserts in parking lot catch basins at the new Salem Transitional Care (STC), a branch of Avamere Family of Companies care facility. Avamere, located in Wilsonville, OR, provides post-acute care and adult living. Salem Transitional Care will provide 72 new patient rooms and will assist patients transitioning from surgical procedures.

Ground was broken on the 5-acre site for the STC in November 2013. The new facility is a 53,000-square-foot building designed by the Salem firm CB|Two Architects. Construction was done by LCG Pence Salem, a LEED-accredited construction company in Oregon, and provided between 80 and 120 new jobs in the area.

A combination of stormwater management BMPs was used for the project. Two asphalt parking lots accommodate 50 to 100 vehicles; each has catch basins frequently placed to encourage water flow toward the stormwater system. French drains serve to direct water away from building foundations and retaining walls in the front areas.

“This all drains into the swales,” says Paul. “A large rock sign also drains into the swale. Then from the larger swale, stormwater flows through the ditch inlet and into the stormwater system.”

The FloGard+Plus multipurpose catch basin inserts are designed to trap sediment, debris, and trash as well as hydrocarbons (grease and oil) from first-flush low flows. Additionally, a high-flow bypass allows for flows to circumvent the device while retaining sediment and larger floatables such as debris and trash, still allowing sustained maximum design flows under extreme weather conditions.

The FloGard+Plus catch basin line provides for filtration of solids through a screen or a liner. Inside the liner, a pouch with a non-leaching absorbent material captures oil and grease.

In recent years the Oregon DEQ mandated that cities develop a program for catch basin maintenance. The Portland metro area services basins within its jurisdiction, while in twelve surrounding cities maintenance is contracted to private companies.

“Some Oregon cities are changing their codes, allowing them to inspect private stormwater systems for compliance with maintenance requirements,” says Paul. “They will allow a short time frame for owners to comply before fines will be assessed for noncompliance. Most engineering groups are requiring maintenance programs as part of the permit process.”

Oldcastle DPS recommends its filters be serviced on a regular basis, but it leaves the schedule to the customer, depending upon the amount of runoff in the area, the pollutant loading, and the amount of debris (leaves, paper, and trash) present. At minimum, DPS recommends servicing the FloGard+Plus catch basins three times a year and changing the filter medium once a year. As part of the maintenance contract, DPS disposes of all trash and waste at an approved disposal site and provides the disposal records to property owners.

Paul says that maintenance of catch basins should be part of the overall installation agreement with the property owners. “After I install them, I go back and follow up with the owners of the property and put them in contact with Oldcastle DPS for maintenance.”

Sag Harbor Village
EPA estimates that between 1988 and 1994, there were over 12,000 instances where people could not swim safely in US coastal beaches because of high pollution and bacteria levels. Population increases and development along coastal areas will put additional pressures on water quality in these regions, forcing communities to develop more stringent water quality management plans.

Sag Harbor is an incorporated village on Long Island in Suffolk County, NY. The 2010 census put the population of the village at a little over 2,000. Sag Harbor has historical roots that date back to the American Revolution and the War of 1812. Even further back, it was declared an international port by 1789 and soon became a major whaling port. The whaling industry peaked around the 1840s but collapsed in 1847 with the discovery of kerosene and coal oils.

About 100 years later, in 1947, a giant drainage “ditch” was cut through Havens Beach in Sag Harbor. The ditch was 900 feet long and 25 feet wide, and 137 acres drained into it, explains Dee Yardley, superintendent of public works for Sag Harbor Village. “It had to have some way to go out. And back then, that’s just the way it was done.

“It was a trench that went all the way out to the beach,” he continues. “All the water just flowed to the lowest area. It was stormwater runoff and in some areas, the water just sat there.”

As the Suffolk County Department of Health monitored beach water quality in recent years, it found that the bacteria counts increased in the ditch. Stormwater runoff from the village was accumulating in the old ditch area, Yardley says. And while the situation had been under study for a number of years, in 2012 it got a welcome supporter. The mayor of Sag Harbor, Brian Gilbride, was very active in his support stormwater improvements at Havens Beach. Upon his re-election as mayor, he took on the project, commenting that he was looking forward to “tackling the stormwater runoff pollution at Havens Beach, as well as erosion at the West Water Street.”

Nancy Pierson, senior public health sanitarian with the Suffolk County Department of Health Services’ Office of Ecology, explains, “In an effort to protect public health, the Suffolk County Department of Health Services’ Office of Ecology conducts a comprehensive bathing beach water-quality-monitoring program from mid-May through mid-September at approximately 191 beaches. The frequency of sampling is determined using a tiered, risk-based approach, with more testing conducted at beaches that have historically demonstrated periods of poor water quality or are potentially at risk because of their proximity to pollution sources. Sampling at these beaches is typically performed at least twice per week.”

To evaluate beach water quality, levels of indicator organisms are used as an estimate of fecal contamination. Although the organisms are usually considered to be harmless, they may indicate that fecal contamination is present, along with other disease-causing organisms. Per recommendations from EPA under the BEACH (Beaches Environmental Assessment and Coastal Health) Act and the requirements of the New York State Sanitary Code for Bathing Beaches, Suffolk County uses Enterococci as the indicator organism for its marine beaches.

Pierson says that obtaining grant funding through the BEACH Act has allowed Suffolk County to expand its beach monitoring program significantly in recent years. Where it collected approximately 520 samples in 2002-03, it increased its collections to more than 4,000 in 2013. In 2003 only the beach was being sampled. But in 2008 resident complaints and concerns about possible bacterial contamination led Suffolk County to start sampling the end point of the long trench.

“Decisions regarding beach closures are based on sample results as well as various beach-specific factors, including knowledge of potential sources of contamination in the beach watershed, historic water quality data, past criteria exceedances, weather, and area flushing characteristics,” she notes. “Under certain conditions, such as during or in anticipation of unusually heavy rainfall, or other events or situations that can pose a risk to public health, advisories recommending against bathing are issued. Precautionary advisories are typically issued for a 24-hour period to allow for sufficient tidal exchange to dilute any contamination that may be present. And although beaches may close in response to these advisories, they are not an indication that unacceptable bacterial levels exist, but rather are a precaution against potential contamination.”

However, while the bacteria counts at the Havens Beach outfall continued to rise, potentially threatening beach water quality, officials searched for a source or sources and for alternatives to solve the problem. The Village of Sag Harbor, together with Inter-Science Research Associates Inc. as its environmental and planning consultant, approached the Suffolk County Department of Health Services’ Office of Ecology to get input, data, and expertise in this area. Richard Warren, AICP, president of Inter-Science Research Associates, and Mike Schiano, environmental planner with the company, became involved with Havens Beach as site designers, planners, and coordinators, together with S.L. Maresca Associates, a local consulting engineering firm.

“On Long Island, most septic systems are subsurface systems and could potentially be a problem,” explains Schiano. “All the testing came up inconclusive.” He says the Suffolk County Department of Health Services conducted dye testing of some nearby septic systems to see if any of them were contributing to the ditch’s bacteria levels, but they came back negative. But, because the bacteria levels were high, officials wanted a solution: “Fix the problem!”

“At marine and coastal beaches in Suffolk County, stormwater runoff is the predominant source of bacteria-laden water,” says Pierson. “The effects of the runoff on water quality are site specific, and are influenced by a number of factors, including the type of land use, area topography, and the degree of tidal flushing. Both Enterococci and Escherichia coli bacteria can be introduced to recreational waters from a variety of sources, including stormwater runoff, resident waterfowl populations, failing or poorly operating septic systems, sewage spills, boats and marinas, floatable debris, and from bathers themselves.”

“We knew we would need more than just one technique to ensure the highest removal efficiency,” says Schiano. “The ditch area needed to be dredged to remove the material that had been building up in it since it was created in 1947. Once the ditch was dredged, it was filled with clean sand to provide a stable bottom for planting material. We also included a settling basin that extended about 200 feet from the inlet pipe, a check dam at the end of the basin, and an area about 700 feet by 20 feet for a wetland with aquatic plants that helped to remove nitrogen and other typical stormwater pollutants.”

In planting the bioswale, Schiano explains, all of the plants were planted in clean sand with no soil amendments. The mix of native plants included duck potato (Sagitaria latifolia), pickerelweed (Pontederia cordata), soft rush (Juncus effusus), tussock sedge (Carex stricta) and narrow-leaved cattail (Typha angustifolia). All plant plugs were planted 1-foot on-center. Plant populations were installed, alternating dense and open, to allow water to flow and seep.

By the time the bioremediation portion of the Havens Beach project was designed, he says, planners had already decided on AbTech Industries to supply its Smart Sponge Plus for bacteria removal on the site. AbTech Industries is a stormwater management firm located in Scottsdale, AZ. Smart Sponge Plus can be used anywhere there is a need to remove excessive bacteria. These locations vary but are often near beaches, rivers, and lakes.

The Smart Sponge Plus structure is porous and elastic, giving it excellent hydraulic properties, along with its chemical properties that make it chemically selective towards hydrocarbons. Smart Sponge is hydrophobic, so it repels water, while being oleophilic to attract oil and grease. The oil and grease are permanently bound to the Smart Sponge and will not leach back into the environment. Saturated Smart Sponge has passed EPA Toxicity Characteristic Leaching Procedure (TCLP) testing as a “non-leaching” product, and therefore can be disposed of in any nonhazardous (Class D) landfill, waste-to-energy facility, or cement kiln.

The Smart Sponge Plus contains an antimicrobial agent that is chemically bound to the polymer surface. The permanent bond allows the agent to be active without leaching out downstream, thereby avoiding toxicity issues at other locations. The organosilane derivative that is used in the Smart Sponge Plus is used in a variety of products including medical and dental products, consumables, pool equipment, and other consumer goods. Using no electricity, chlorine, or heavy metals, the mechanism works to inactivate microorganisms at the cellular level. Using flow rates and bacteria concentration, AbTech engineers the Smart Sponge Plus to meet the desired performance requirements of each individual customer.

After determining a number of factors such as flow rate, bacteria levels, sediment loading, desired bacteria reduction, and various others, AbTech recommends using a specific size Smart Sponge Plus Smart Pak bed depth. This Smart Pak bed depth will reflect the proper empty bed retention time to meet the customer’s desired bacteria reduction through the biostatic charge of the media.

Smart Sponge Plus is typically used in a vault system. Once installed, the system requires minimal routine maintenance and replacement of the antimicrobial Smart Paks to keep it operating at peak efficiency. When the Smart Paks become saturated with sediment, oil, and grease, they need to be replaced. Typically, 10-15% of the antimicrobial Smart Paks will need to be replaced each year.

Superintendent Dee Yardley described the AbTech vault installation at Havens Beach. “All the material in the ditch was dredged. There was about 5,000 to 10,000 tons dredged from there. Then they put the new sand back in. That’s the biofiltration area before it gets to the Smart Sponge Plus vault.”

He continues, “It was installed in 2013, and using a crane they literally dug a large hole to install the precast vault. It’s a giant concrete vault with stainless steel compartments for the antimicrobial Smart Sponge Plus “˜pillows,’ or Smart Paks. You can’t tell it’s even there.”

The 10-foot by 10-foot vault that houses the Smart Paks is inconspicuous to beachgoers, but there is a manhole cover on the cement top so that he, or AbTech service technicians, can go inside to service the filters.

The bacteria levels that had previously reached as high as 12,500 in October of 2009 have remained below 1,000, a greater than 92% reduction, since the Smart Sponge Plus installation in August 2013, as determined by a data chart supplied by Nancy Pierson. Also noted in the data, of 16 effluent samples taken since August 2013, 11 had bacteria levels below 300. The bioswale area is doing its part to filter the stormwater runoff as well. The data for samples taken before and after the bioswale show that 8 out of 12 samples were remarkable after passing through the bioswale.

When using the data chart supplied by Pierson, even though numbers seem erratic, there is an overall downward trend since the Smart Sponge Plus was installed.

Yardley concludes that since the Smart Sponge Plus was installed in 2013, there has been no instance of bacteria exceeding the acceptable levels at Havens Beach. 
About the Author

Linda Robinson

Linda Robinson is a journalist specializing in agriculture and land-use planning.