The Evolving BMP
Testing the performance of stormwater treatment devices
They’re all here, spread across the 1-acre facility
at the University of New Hampshire Stormwater Center: swales, ponds,
sand filters, treatment wetlands, hydrodynamic separators, and a host of
proprietary products all designed to keep sediment from mixing with
Every year, about 500 visitors tour this site, located in Durham, NH.
When they do, they get a firsthand look at how rapidly the world of
stormwater best management practices, or BMPs, has advanced. Today,
highway department officials, developers, contractors, and engineers
have seemingly unlimited options for preventing sediment from
contaminating the water that runs off their building sites. They have
what seem like hundreds of choices to rely on for meeting the stormwater
BMP standards set out by state and federal regulatory agencies.
This is good news. Ever since Phase II of the National Pollutant
Discharge Elimination System (NPDES) stormwater program took effect,
engineers and contractors working on smaller sites have faced the
prospect of heavy fines for violating the regulations set out by their
local environmental agencies. The vast array of stormwater products
gives these builders, planners, and engineers the best possible chance
to meet these regulations and avoid fines that could impair a project.
But all this variety brings a serious problem, too: How do engineers
and developers choose the right product for the right job? Who’s to say
what stormwater product works best at containing or treating runoff from
a 100-space parking lot surrounding a new supermarket? Who knows for
certain what product best prevents the oil and gas that drains from a
municipality’s vehicle repair shop from mixing with rainwater?
That’s where the Stormwater Center comes in. The facility tests
stormwater products side by side, determining their strengths and
weaknesses. At any time, the facility’s engineers are studying about a
dozen different stormwater systems, putting them through rigorous tests
to see exactly how effectively they prevent dirt and sediment from
mixing with runoff.
But even here, officials with the university’s Environmental Research
Group are often overwhelmed at the pace at which new stormwater
products are introduced.
“It is absolutely a challenge to keep up with the way this field
evolves,” says Robert Roseen, director of the Stormwater Center. “There
is a phenomenal amount of growth every year. From the manufacturers’
side, it seems there is about a 20% to 40% market growth every year.
There are always new products in the field. We try to act as the
Consumer Reports of the stormwater industry. But it certainly is not
easy keeping up with all the new products.”
There’s a big reason the number of stormwater products seems to grow
so quickly each year: demand. Engineers and contractors are constantly
seeking out new products that help them meet BMP requirements. And
they’re searching for products that not only meet the specifications
drawn up by their local regulatory bodies but also are easy to use,
inexpensive, and flexible.
As long as this demand remains, the companies that manufacture and develop new stormwater products are going to remain busy.
T.J. Mullen, president of Best Management Products in Middle River,
MD, says the increased regulations—and the resulting drive to produce
innovative new stormwater products—are good for everyone.
“They are certainly good for the industry,” Mullen says. “They’re
good, too, for the environment and for everybody who lives in a
community that has a discharge of stormwater that could negatively
impact them. There is more need for common-sense solutions to some of
the problems that stormwater brings.”
Mullen’s company produces the Snout, an oil, water, and debris
separator. Contractors install the products after construction is
finished to make sure that the stormwater that drains from their sites
is clean. Mullen says he’s seen a greater demand for his company’s
separator now that contractors face the reality of serious fines under
NPDES Phase II.
“For the contractors, meeting these BMPs is now a more serious
issue,” Mullen says. “They see them written into the specifications of
the projects they are working on. Today, contractors are more involved
with the onsite conditions. They are dealing more directly with
manufacturers like us, asking for advice or giving us suggestions on the
design end. That’s been a change in the last couple of years.”
Even fines, though, don’t guarantee that contractors, municipal
officials, or engineers are fully aware of all the latest advancements
in the stormwater industry. Just ask Robert Maestro.
Maestro is the owner of Occoquan, VA–based Hydrologic Solutions,
manufacturer of the StormChamber, an open-bottomed high-density
polyethylene infiltration chamber BMP. Even though his company’s product
is relatively inexpensive, is easy to install, and meets BMP
regulations, there are still several builders and engineers who don’t
know that the StormChamber exists, Maestro says.
“We are continually amazed at how many people, engineers, still don’t
know that plastic stormwater chambers exist,” he notes. “It’s amazing.
We run across it frequently. A lot of the people in the industry don’t
have time to go to the conferences. They don’t have time to read the
journals. But it is surprising. Even with municipalities, the same is
true. It becomes an educational process. That’s basically what we try to
do: educate people.”
The challenge for contractors and engineers is to discover products
like the StormChamber that allow them to adhere to the regulations
without spending a small fortune.
Does It Work?
The first question a contractor or engineer will ask about a
stormwater product is the crucial one: Will it work while at the same
time meeting local BMP regulations?
Fortunately, that’s the same question that Roseen and his peers at the Stormwater Center ask.
“Sometimes it’s hard for states to write new products into their
specifications. Some states are way ahead of their time and others are
not,” Roseen says. “There is a perception that every new stormwater
system has to be fail-proof. But that’s a hard standard to meet. New
products just don’t have that long track record yet. Many municipalities
are looking for that kind of track record. They figure that they have a
large capital investment in a project. They want a product that they
know they won’t have to worry about for the next 20 to 30 years. The
problem is, no new system can meet that standard.”
The manufacturers of stormwater products, then, rely on facilities
like Roseen’s to prove to end users and municipalities that their
products really do work as advertised.
Currently, the facility is testing all the major categories of
stormwater measures: traditional BMPs, low-impact development (LID)
techniques, and some of the more innovative proprietary BMPs. Tests are
conducted at a large commuter parking lot at the University of New
Hampshire, where researchers determine how well the products treat water
runoff on 1 acre of impervious surface during a 1-inch rainfall event.
The parking lot has a traditional stormwater management system
consisting of catch basins and piping that discharges at the head of the
facility. At this point, university researchers split the water flow
into equal streams that are sent to each of the systems the Stormwater
Center is testing.
Having each of the systems face the same storm events and contaminant
loading is key, Roseen says. It’s difficult to evaluate how different
products work if they’re not operating in the same conditions and facing
the same challenges.
“Different types of storms and contaminant loadings present different
problems,” Roseen says. “At our site, everything is normalized, the
storms, the contaminant-loading duration, all of that.”
Here’s the obvious question: Which stormwater product works best?
It’s not surprising that there’s no one right answer to that question.
Stormwater products must work well in their environment. Certain
products perform better, then, in hot, arid conditions while others
perform more effectively in colder climates. Some systems are better at
growing vegetation, a must for areas where aesthetics are important.
Others don’t grow vegetation at all. This can be fine if the stormwater
products are located in an area not seen by the public.
So those looking for Roseen and his team to provide them with a
be-all, end-all recommendation for the perfect stormwater product are
bound to be disappointed.
“Are the products getting better? That’s too big a question to
generalize,” Roseen says. “There is no one silver bullet that does
everything. There are variations of performance, suitability, and where
you might place a product. The top-performing systems, for instance, are
usually the filtration systems. But those are very large systems and
are not feasible in many locations.”
The message here? Engineers, contractors, and municipal officials
need to consider everything—the results from performance tests, the
environment in which a product will be operating, the need to grow
vegetation after construction, the cost, the ease of use—before deciding
what stormwater solution will best meet a project’s BMP requirements.
“The most positive aspect of all this is that we really are
struggling to keep up with inquiries from end users,” Roseen says. “I
think it’s a positive that there is so much interest in our results. It
does show that people are learning more about how important stormwater
Clean Runoff in Dallas
When municipal officials in Dallas asked BDS Technologies to develop
a stormwater system that would provide clean runoff from the city’s
service centers and auto pounds, the engineers at BDS researched several
BMPs. Their final decision? The StormTrooper, a stormwater interceptor
manufactured by Houston’s Park Environmental Equipment Co.
The city now relies on StormTroopers in the Dallas auto pound and in
two service centers, where city mechanics work on Dallas-owned vehicles
such as police cars and highway department equipment. It’s important
that the stormwater solutions in these facilities work as advertised,
because the vehicles stored there often leak transmission fluid and oil.
Rains could easily whisk these chemicals into the city’s sewers and
water supply, something no municipal official wants.
Freddie Guerra, vice president with BDS, says the decision to go with
the StormTrooper was one made after his firm considered all the
important elements: The product had to work well, had to be easy to
maintain, and couldn’t boast a budget-busting price tag.
“This product was just the right solution for this case,” Guerra
says. “Just looking at the maintenance and operational aspect of it,
this was the right product. It has a separate control structure so that
it’s easier to control all the debris, all the gloves, cans, and leaves.
It is easier to maintain because of that aspect.”
It’s little challenge for city officials to make sure that the
StormTrooper is working the way it’s supposed to. To make sure that the
product is working properly, engineers need only flip off the
StormTrooper’s manhole cover. This reveals a baffle between two
compartments. The first compartment should always be holding the debris
from the parking lots. The second should be clean. If this is the case,
the machine is working properly.
The product has been working at the city auto pound for more than a
year and a half, Guerra says, and at the two service centers since the
fall of 2006. Dallas is now planning to have four more StormTroopers
installed at four additional city-owned service centers.
“We’ve all in the industry expressed interest in installing
separators like this in parking lots and facilities. They just work very
well in preventing contaminants from getting in stormwater runoff,”
Guerra says. “Fortunately, more municipalities are now agreeing with
this. Here in Dallas, I think one driver of this acceptance is the
city’s outreach programs, their stormwater management program. The other
is the fact that people are so much more aware now of how runoff
impacts the environment.”
Pat Schrum, director of sales and marketing with Park Environmental,
can attest to this. His company introduced the StormTrooper in 2001.
Since then, Park has sold about 365 units, mostly in the Houston area.
Demand increased after the NPDES Phase II requirements went into
effect, Schrum says. Schrum says company officials at Park studied the
new regulations and developed a product that would meet the regulations
in Houston or Harrison County, the county in which it sits.
“People are so much more aware of products like ours now,” Schrum
says. “The engineers are spec’ing it on just about every project. It is
not easy to change BMPs once they have been turned into the City of
Houston or Harris County. But they will change them for the right
Less Expensive, Easier to Use
BaySaver Technologies Inc., based in Mount Airy, MD, began in 1996
by offering a separator product to help engineers combat stormwater
runoff. The company now also offers a cartridge filter product.
Rex Hansen, a company vice president, says he’s noticed a shift in
recent years: Contractors are more interested in finding the right
stormwater BMP than they are in throwing in any product that they can
get away with.
Of course, the reason for this may not be that contractors have
suddenly become more concerned with the environment and the impact of
their projects. They might be more worried about violating stricter BMP
This trend, though, has encouraged positive changes in the stormwater BMP industry, Hansen says.
“The regulations are getting more stringent all over the country
now,” he says. “States are asking for higher levels of performance.
Those states that had virtually no treatment requirements are now
creating tighter regulations. The combination of increasing regulations
and the increasing performance of BMPs is a good one for the environment
and for our industry.”
Companies that manufacture stormwater systems are now working to
produce value-added products that offer maximum benefits to end users,
Hansen says. Before, companies might have been content to offer
stormwater products that were effective but were very expensive to
install. Now, thanks to greater demand and improving technology,
companies are developing products that are less expensive to install and
operate but still provide the same or higher levels of treatment.
To do this, companies such as BaySaver talk not only with members of
the engineering community but also with the contractors—the end
users—themselves. This ensures that whatever new products or product
enhancements BaySaver develops will meet the needs of the people who are
going to be actually installing them.
“If we only sought feedback from the engineering community, we would
miss out on how our products truly need to work in the actual field,”
Hansen says. “It’s important to relate to the experiences that the
contractors have had. We need to make sure that we create products that
are going to be easy for our contractors to work with.”
What have Hansen and others at BaySaver learned from their
conversations? Smaller is better. Products that are flexible, that can
adapt to different situations and environments, are also much desired.
The flexibility is important. Today’s most sought-after stormwater
products are flexible enough—and do enough at a low-enough cost—to meet
the BMP requirements of as many states and jurisdictions as possible.
“Contractors have to worry about so many different sets of
regulations,” Hansen says. “The local bodies are different state by
state. Some divide their regulations by watersheds, some by counties,
some by regional water-quality boards. This means you can’t take a
broad-brush approach to solving a problem. You can’t just go with
something that meets one requirement. You need a product that works with
everyone. That could be 500 different entities or it could be 5,000.”
Some manufacturers are frustrated by the wait-and-see approach taken
by many state and local regulatory boards. Too many agencies, these
manufacturers say, are too cautious when it comes to writing new BMPs
into their regulations. This not only hurts those manufacturers willing
to develop something new but also hurts contractors who are prevented
from trying new technology that could make their jobs easier and less
Take the case of Hydroscreen, a manufacturer based in Denver. Since
1999, the company has been inventing, patenting, and selling wedge wire
screen assemblies that remove leaves, sediment, and debris that flow
over them. The screens are self-cleaning and so require little
The company’s screens have played prominent roles in some
high-profile projects. For example, Hydroscreen was called upon to
provide some emergency services to the Princess Diana Memorial Fountain
in downtown London’s Hyde Park. The fountain features water that flows
into a small pool before running down both sides of an elliptical form
and into a pool at the bottom. From there, the water flows by pipe to a
screening vault and then into a tank where it is pumped back to the top
of the fountain.
This design worked well when the fountain first opened. But then
leaves began to fall and blow into it. The leaves quickly clogged the
screen baskets, causing water to flood the vault and surrounding grass.
To solve the problem, municipal officials installed Coanda wedge wire
screens from Hydroscreen. After installation, officials turned the
fountain on and watched as the water began to circulate down the
fountain, out, over, and through the screens into the holding tank. To
test the screens, maintenance workers dumped eight large bags of wet
leaves into the fountain. The screens captured all the leaves.
But even with such success stories, Robert Weir, owner of
Hydroscreen, has found it is often a challenge to convince regulatory
bodies and contractors who haven’t tried his wedge assemblies to take a
chance on them.
“The fact that I’ve filtered drinking water through a screen—got it
to the point where it was absolutely fine to drink—doesn’t matter to
them,” Weir says. “They want to know how Pasadena uses it. Well, they
don’t use it yet, but they will. The possibilities of this product are
Weir, like others in the business of manufacturing
BMPs, says he expects both contractors and regulatory agencies to be
more willing to embrace alternate products in the future. For now,
though, Weir will continue pushing his product’s benefits, hoping to
interest as many builders and contractors as he can.
“The big frustration for me as a person who makes BMP products is
that I am usually called in, invariably, after the whole project is
built and constructed. That’s when they look to me to provide some
control over their stormwater runoff,” Weir says. “It’s up to me to
figure out how to utilize what somebody already has. I have to try to
adapt. That is the frustration in this industry.”
Author's Bio: Dan Rafter is a technical writer and frequent contributor.