Unlike
wastewater, which flows to a treatment plant, stormwater in many areas flows to
waterways without any additional treatment. Discharges often include pathogens,
nutrients, surfactants, and various toxic pollutants. Since the National
Pollutant Discharge Elimination System (NPDES) Phase II went into effect in
2003, smaller municipalities and private concerns have been required to have
greater control of stormwater runoff. The response to the regulation has meant a
burgeoning and highly competitive trade in products designed to capture and
treat pollutants, improve the ease of installation, and allow for cost-effective
maintenance. The best management practices (BMPs) used for the purpose include
filter protection devices and catch basin inserts.
Paying
Attention After BMPs Are Installed
Flooding,
which occurs when an excessive volume of runoff is generated, causes more damage
to property and infrastructure than any other weather hazard. Annual property
damage estimates range in the billions of dollars. Reducing flooding is an
ongoing challenge for many municipalities. In addition to flooding, some areas
face additional issues posed by cold weather.
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Photo: Blocksom |
| Some filters can be cleaned just by sweeping or rinsing. |
Jennifer
Gadzala is the MS4 [municipal separate storm sewer system] operator for the town
of Chesterton, IN, in the northwest section of the state. Cold-weather areas
face a different set of challenges, according to Gadzala. “No product works best
at every time of year. They are all site-dependent. In January, we had over 12
inches of snowfall in a single day. Then it melted in one day and we had an inch
of rain. Every BMP was overwhelmed with flooding and runoff. Even structural
BMPs suffer.”
Maintenance
needs also vary from area to area, according to Gadzala, who describes a site in
Chesterton that had highly erodible soil. “Sediment-laden water was jumping
curbs and heading toward inlets. The developer first tried laying filter fabric
under the inlet grates, but they became clogged with sediment, resulting in
ponding and flooding roads.”
Blocksom
filters were installed in October 2007, but by March they had not been
maintained. “They were never cleaned, and they were clogged with mud,” Gadzala
says. Blocksom suggests removing the grate with the attached filter, then
cleaning it before putting it back on.
“Maintenance
needs depend on the site,” Gadzala says. “You have to look at the filters to see
how overburdened they are. If there is sediment around the sides, a shovel will
work; if they’re smothered in mud, you have to take them off and clean them.
These particular filters went through a winter of numerous snowfall events and
were hit several times by snowplows.”
Maintenance
falls on an owner or developer, Gadzala says, emphasizing that no filter is
dependable during the winter months without continued maintenance. “The
cold-weather states are a different world from the warm states when it comes to
certain sediment control products.”
Steve
Ovsak is project superintendent on a stormwater relief project being completed
by Ruby-Collins Inc. of Atlanta. The project, in the historic district of
Savannah, GA, involves replacing the old storm drainage system with
larger-capacity pipes to relieve flooding in the adjacent areas of Alice and
Tattanall Streets. Installation includes 6,100 feet of reinforced concrete pipe,
36 storm manholes, 56 curb inlets, more than 1,100 feet of sanitary sewer pipe,
and seven sanitary sewer manholes. The reinforced concrete pipe mainline starts
at 54 inches downstream on Montgomery Street and proceeds to 18 feet upstream at
the Chatham Square area. The project, begun in January 2008, is estimated to
take just over a year.
According
to Ovsak, flooding has been a problem in the district for at least 150 years.
The first two phases of this project involved building a microtunnel, or trunk
line, to carry water from the street to the Springfield Canal and then into the
Savannah River. “The old system was undersized, old, and decrepit,” he
says.
Ovsak,
who has been in the construction business for 15 years, says this is the first
time he has used Silt-Saver products to protect an inlet. The reusable
Silt-Saver devices have HDPE frames that fit over the inlets and are covered
with filter fabric. “The normal coconut [coir-fiber] sock, you threw away, but
this one can be washed and reused. The rock bags get run over and aren’t used
anymore.”
Monitoring
is an ongoing process for Ovsak. “I take a sample after every major rainfall.
The results are that good: water quality is maintained at or below the original
sampling.”
Decreasing
the incidence of flooding has many positive benefits, including reducing auto
accidents and traffic congestion and improving insurance rates in areas likely
to experience street and property damage. And protecting inlets from pollution
results in cleaner and healthier water sources for
everyone.
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Photo: Silt-Saver |
| A Curb Inlet Filter protects an existing inlet. |
As
superintendent of a yearlong project to replace 16 blocks of street in Rawlins,
WY, Kenny Bartels has had to worry about keeping polluted water from entering
drains in an area that on June 14, 2008, experienced what he calls a “40-minute
blizzard.”
“One
advantage to the cold is that there is less water flow when temperatures are
freezing,” Bartels says. He has found Blocksom filters effective for this
project. “You just take them off and rinse them. They can take tremendous
amounts before plugging.”
Bartels
says that he has used silt fences on projects in South Dakota and has found them
much less effective than Blocksom’s mats. “They plugged up so bad; these are
easy to use. You just lay them over where the water is going. They’re small, a
5- by 6-foot mat, and one man can easily lift one for
cleaning.”
In
this case, a state highway running through a city, local area crews will be
responsible for maintenance.
Bartels
says that the state EPA monitors the effluent. “They take what they see coming
out at face value. As long as they see an honest effort.”
Ocean
Views Bring Tourists—and Trash
Cities
located near an ocean face particular challenges when managing stormwater
runoff. Beachfronts and harbors face continual traffic, both maritime and human,
and all of these elements lead to pollution of the waterways. Frequent cleanout
of inlet filters and catch basins becomes a matter of time and
money.
Eric
Sanford of DDC Engineers Inc. is director of municipal services in Myrtle Beach,
SC. Since adopting a single Snout—an oil-water-debris separator—at a stormwater
convention from T. J. Mullins of Best Management Products several years ago, he
has installed between 80 and 100 of the little beasts in the downtown area
alone. “I just loaded one into my truck and took it home.”
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Photo: Best Management Products |
| A Snout is used in a catch basin to filter gross pollutants. |
The
Snouts serve as the first line of defense in a beach area where people come to
play hard and don’t spend much time picking up after
themselves.
“We
use Snouts at a point source to filter gross pollutants such as cigarette butts
and trash,” Sanford says. “We get up to a million tourists a day along the Grand
Strand coast here in the summer, and people are pigs.”
He
has used the snout in tandem with other BMPs such as catch basin inserts and oil
booms. “Most of this area was developed in the ’50s, and everything would
discharge directly to the beach,” Sanford says. “The discharge pipes stopped at
the dune and then washed into sand gullies to the water’s
edge.”
The
Snouts are inserted into existing catch basins, where they filter sediment,
leaves, and other debris. “For the money, they’re a cheap BMP,” Sanford says.
“For their dollar value, they are one of the better BMPs. They stand the test of
time and are easy to install as a retrofit.”
Sanford
says that the Snouts catch 75 to 80% of the pollutants. “We use these when size
dictates; they’re a source treatment BMP.”
Since
NPDES Phase II went into effect, storm drains have become a more prominent
concern. “For the last 100 years, people in the United States have worried about
water and sewer, not storm drains,” Sanford says. “The storm drainage industry
and mentality have come a long way in the last five to 10
years.”
Sanford
says that dealing with stormwater runoff has become a major priority for the
50-mile Grand Strand area that comprises the oceanfront, and right now the
biggest effort is in storm drainage. “Once we lose the beach, we lose
everything.”
While
acknowledging that the Snout is not the answer to every problem, Sanford retains
his loyalty to the adoptee. “There is no magic bullet, but [this solution] is
stupid-simple.”
Easy
maintenance resulting in lower labor costs becomes a high priority in any
project requiring multiple applications. Chris Bellucci is the project engineer
for the Department of Environmental Protection at Lemon Creek on Staten Island
in New York.
“We’re
making all new stormwater collection areas in order to send the water to
retention basins instead of releasing it directly into creeks, rivers, and the
ocean,” Bellucci says. One of the tools he’s using is a Blocksom inlet filter.
“They work great; they are easy to change. You just cut off the old wires like
zip ties and reattach new pieces. Previously, New York had to have the old
standard filter fabric with stone on top. Those were hard to clean, because you
had to remove the top and take it apart, then put on new
material.”
Bellucci
says maintenance is easy with the new filters. “I can just send a guy to sweep
off the dirt and debris or scoop it with a shovel. If the filter rips or tears,
we can just put in a new piece.”
Installation
is quick and efficient. “It’s just a woven fiber zip-tied to the top of a catch
basin grate.”
Jose
Casio, a stormwater engineer for the city of North Miami Beach, says that the
BMP Snout baffle is the required baffle for the city’s public works projects.
Currently working on the Hanford Boulevard (Downtown) Projects, a roadway and
drainage improvement project, the City of North Miami Beach Public Stormwater
Division is a big fan of the BMP Snout baffle. “It is durable and long-lasting,
much stronger than other baffles currently in the market.”
Casio
says that the BMP Snout baffle may cost a little bit more than some of its
competitors, but it is worth the cost in the long run. “If a regular baffle is
damaged, it can involve cutting roadway pavement, excavation, and restoration,
which makes it expensive to replace.”
For
Casio, the Snout’s other advantage is its clean-out port. “For maintenance, you
just take it out and access the French drain pipe for cleaning. Just open,
insert the hose, and flush.”
Long
Beach, CA, a city with a population of over 461,500, is the fifth largest city
in California. The Port of Long Beach handles the most cargo tonnage of any port
on the West Coast. And every year, approximately 5 million people bask in Long
Beach’s 345 days of sunshine.
The
city’s commitment to balancing environmental quality with the obvious economic
benefits of port activity is reflected in Healthy Harbor Long Beach, an
initiative aimed at enhancing air quality, water quality, and wildlife
habitats.
According
to the city’s Web site, the Harbor Department has dug up contaminated sediment
from the harbor bottom and buried it in land created for new port terminals.
This innovative reuse earned the port the Environmental Hero Award from the EPA.
In addition, the Harbor Department has launched a stormwater pollution
prevention initiative. Tenants are trained in pollution-fighting practices such
as using drip pans to catch engine oil, sweeping sites frequently, and sampling
and analyzing stormwater runoff. The California EPA has honored the Harbor
Department for this program.
Tom
Leary is a stormwater program officer for the Long Beach Department of Public
Works’ Stormwater Management Division. He says that the city is using a variety
of methods to treat stormwater runoff. Some of these are pollution prevention
and education, enforcement, source reduction, control devices (clarifiers),
street sweeping, standard urban stormwater mitigation plans (SUSMPs), and the
California Environmental Quality Act compliance.
Long
Beach is using AbTech’s Smart Sponge technology in catch basins whose tributary
drainage is recreational waters. “In addition to successfully addressing the
targeted pollutant—bacteria—the units also capture grease, sediment, and trash
with no compromise to the flood control system,” Leary says. “The great thing
about the AbTech inserts is they sit inside the catch basins and are easily
accessible from the street, making maintenance quick and
easy.”
Maintenance
Takes Center Stage on Construction Sites
Any
construction area poses constant challenges for stormwater maintenance. George
Sholy, president of S & S Landscaping in Fargo, ND, describes a recent job
for General Contractors Master Construction on 52nd Avenue in Fargo that
involved placing inlet protection devices at various phases of road
reconstruction. “This is an expanding part of town where they are changing the
road from two to four lanes and adding new underground sewer and water lines,”
Sholy explains.
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Photo: AbTech |
| Smart Sponge units capture bacteria, grease, sediment, and trash with no compromise to the flood control system. |
The
initial phase of the project involved placing straw wattles around existing
inlets and in ditch bottoms. Once the roadway was removed and new pipes were
installed, the inlets were switched to another type and Dandy Sacks, from Dandy
Products of Westerville, OH, were added to filter debris. “The Dandy Sack fits
the inlet and hangs below the grate to filter sediment,” Sholy says. “After each
event, we check to see if it is plugged, then we clean it or replace it. It’s
reusable, and, usually, we can use it a few times.”
In
2008, it rained in Fargo every other day for the first two weeks of June,
according to Sholy. “The rain held up the project for a while, and we had to
change the filters more often. We were called out several times to unplug them
and get rid of the debris.”
After
the paving process, the crew seeded and sodded along the roadways, using
hydromulch and adding straw wattles where needed. “Once the roadway was graded,
we installed new inlet protection until the turf was established,” Sholy
says.
Any
runoff eventually goes into the nearby Red River, so the motivation is high to
keep the effluent free of debris. Sholy has been pleased with the Dandy product.
“It is easy to install, easy to maintain, and easy to clean. The Sack is also
reusable. That’s why we like it.”
Steve
Kesler, project superintendent for Shannon Strobel & Weaver of Auburn, AL,
last year directed construction on a Super Wal-Mart in Covington, GA. While the
actual building was finished ahead of schedule in 10 months, Kesler says he
stayed around for another three months until the store was up and running in
September 2007. One of Kesler’s concerns was to monitor the efficiency of inlet
protection devices from Silt-Saver.
The
stormwater pollution prevention plan (SWPPP) prepared by Wal-Mart engineers did
not specify a particular product, only that some type of filters be placed in
the inlets. Kesler says he opted instead for Silt-Saver’s silt fabric-wrapped
unit that comes in one solid piece “shaped like an L” and fits over the inlet.
“It doesn’t break down like the blocks do. It is easier to clean and handle and
fits over the curve of the inlet itself.”
The
project also utilized Silt-Saver’s plastic domes to cover manhole inlets.
“Wal-Mart’s minimum requirement was a silt fence using two by fours.
Silt-Saver’s filter fabric goes over a plastic dome that sits down over the
hole. When rainwater runs to the hole, it filters the sediment. You just take
the cover off the dome, clean it, and return it. It’s easier to work with than
the two-by-four fence and it’s more efficient cost-wise.”
Big
things are underway in Idaho Falls, ID. In June 2007, developer Ball Ventures
began work on a 400-acre planned community along the banks of the Snake River.
The project includes housing, offices, shops, restaurants, and
parks.
John
Gregory, manager of Specialty Construction Supply, which sells, installs, and
maintains erosion control materials, says the 3-mile-long area is a high-profile
job for his company. “It’s right on the Snake River, and HK Contractors are very
vigilant in their applications to prevent silt and sediment from entering the
river.”
To
protect the river during the long construction phase of this project, Gregory’s
company has been hired to install products that will keep out debris and filter
the sediment that gets into the stormwater system. “We started in 2007 with silt
fence installation; we use different products for every phase,” he
says.
The
company uses Dandy products such as Curb Sacks and Bags. If the inlets don’t
have grates, the company uses straw wattles. Silt fences with straw wattles
behind them are used to keep the dirt back along the length of the
river.
Charles
Fraga works for Gregory as water pollution control manager. “I’m the weekly
inspector. I drive over after every rain to see if the devices are
working.”
Apparently
Dandy is living up to its name. “The Snake River is sensitive,” Gregory says,
“and the products are doing a great job.”
Tripp
Bishop is general manager for the construction division of ACF Environmental in
Richmond, VA. He uses a variety of products, including the GutterGator, patented
and distributed by ACF and used exclusively for curb inlet protection by Centex
Homes, a Washington, DC–area builder of new homes.
“The
GutterGator increases the flow of water, it’s easy to maintain, and you can take
it out and power-wash it. You can reuse them until they break apart, allowing
you to do maintenance at the road level rather than sucking the debris out of
the storm sewer.”
The
GutterGator, Bishop says, is lightweight and lets the water flow through a green
mat, which is attached with Velcro to a stiff, high-density plastic backbone.
“If the backbone breaks, say from a tractor tire, you can just remove the mat
and reuse it. It’s a high-flow turf that won’t biodegrade or
photodegrade.”
While
the Gator seems ideal for curbs in a construction area, Bishop also gives high
praise to the Erosion Eel from Friendly Environment, which he says is ideal for
high-flow ditch lines and swaths. “I’ve used it as a check dam to slow water
velocity. It will check the flow and slow erosion on the downstream side, so it
both purifies and checks. It does a good job of segregating chemicals such as
phosphorous and leaving impurities behind. Studies have shown that it gets out
up to 95% of the impurities.”
But
the best part of the Eel, according to Bishop, is its reusability. The
10-foot-long geotextile tube, about 10 to 11 inches in diameter and filled with
recycled tire rubber, can simply be put down on the ground where needed and
picked up and moved when a project is finished. “It’s costly,” Bishop says, “but
it pays for itself on the first job, and you can use it
again.”
Fabco
Industries of Jericho, NY, supplies two models of drain inlet filtering inserts
that are targeted towards erosion or sediment control. The StormSack and the
StormSok each consist of a mounting system together with a replaceable woven
geotextile filtering bag. They feature lifting tabs for easy cleanout, plastic
mesh bag liners to protect the geotextile material during cleanout, and a can
fitted with an optional absorbent boom to capture oils and grease. “This boom is
a popular option here on Long Island where the bags are used as pre-filters to
larger BMPs,” says Fabco’s John Markee.
Markee
says that the bags are used in Nassau County, NY, in large land-based
infiltration areas. He says the majority of customers use catch basin inserts in
areas that have really no other protection, such as urban areas where property
is scarce and expensive. He says the customers using filtering insert units are
purchasing StormBasin and StormPod; and while these are effective on sediments,
if that is to be the primary use, he suggests StormSack or StormSok
instead.
“Speaking
from our own experience, which is focused here on Long Island, NY, and the
surrounding states of New Jersey and Connecticut, these agencies select
filtering cartridges that treat for pathogens and nutrients. This is because of
the high number of bathing beaches located in villages like Great Neck,
Smithtown, and Freeport. They have installed these near affected water bodies.
The town of Huntington is trying them at two beaches.”
Markee
recommends cleaning catch basins about three times a year. “In most cases they
can be cleaned out in 10 minutes or less. Modern sweepers can be equipped with
catch basin cleaning wands, and the sweeping itself reduces materials than can
collect. When the basins do need cleaning, the same crew and piece of equipment
can handle the job.”
End
users generally agree that “there is no magic bullet” when it comes to
purchasing stormwater protection. The consensus seems to be that most of these
products are easy to install, cost effective, and a whole lot more efficient
than the piece of chicken wire topped with a brick that was often used in the
old days.