Many big builders are all too familiar with the erosion-control
plans required by the feds, while many small builders have never
heard of these requirements. Site controls to prevent sediment from
washing away into nearby waterways are mandatory for every building
site larger than an acre, and as the availability of buildable
coastal lots tightens, it's becoming increasingly harder to pass
under the radar.
Even for those familiar with the regs, implementing an effective
erosion-control plan is no slam dunk. Common elements of the plans,
such as putting up silt fences intended to capture and trap
waterborne soil, can be expensive and time consuming. And many
builders complain that the measures and accompanying paperwork
often don't seem effective. One critic put it this way: "Muddy
water in, muddy water out, and a lot of money in between."
Regulators and advocates, on the other hand, insist erosion and
sediment control is effective when done right. And they have no
shortage of cheerleaders. Muddy roads and cloudy streams tied to a
decade-long nationwide building boom have left many residents eager
for a clampdown, especially in coastal areas where water quality is
a crucial issue. For contractors, the upshot is steadily increasing
pressure to do a better job, alongside stricter and stricter
An effective erosion-control plan includes maintenance to
adjust and strengthen measures as work progresses.
Helping to bridge the disconnect between the builder's
understanding of what works and the regulator's compliance
standards is an increasing body of research on how to wring the
best performance from common erosion-control plans and measures.
This is key, since incorrect or slipshod installation and
maintenance are by far the most prevalent reasons why erosion- and
sediment-control plans fail, experts say.
The goal of an effective erosion-control plan is to retain soil
on site and prevent it from washing down storm drains and ditches
into local waterways. Silt fences are a common technique, but these
are vulnerable to damage from wind, and they must be maintained
(above). A good silt fence should be staked every 4 to 6 feet with
the geofabric buried at least 4 inches into the soil below. Straw
bales will help to reinforce the fence line (top right). Even
better is to build a "super silt fence" using woven wire
reinforcing (bottom right).
A Shock to Waterways
Few dispute that construction-site erosion poses a significant
problem. Stormwater runoff from residential, commercial, and
industrial areas, including construction sites, is responsible for
21% of impaired lakes and 45% of impaired estuaries, according to
the U.S. Environmental Protection Agency (EPA). While agriculture
is a common source of erosion in rural areas, erosion from
construction sites contributes by far the largest amount of
sediment in urban waterways, the EPA reports.
Anne Kitchell is program manager of implementation for the Center
for Watershed Protection, a nonprofit education and advocacy group.
She says eroding soils sop up nutrients, pesticides, and other
chemicals, then shuttle them into waterways. There, sediments cloud
streams and rivers, preventing sunlight from reaching aquatic
plants and making it hard for fish and other aquatic wildlife to
breathe and forage.
Because rain sets the process in motion, storms can have a dramatic
and rapid impact, Kitchell notes. "It's sort of like the shock to
the system from a tropical storm," she explains. "The most damage
can happen in a short time during the construction phase." Coastal
regions are often flat, which leads some to conclude that coastal
erosion is not an issue, Kitchell says. To the contrary,
sediment-filled water buries plants and shellfish in sensitive
estuaries, she notes.
To address the threat, the EPA developed the National Pollutant
Discharge Elimination System, or NPDES, issuing its first phase of
stormwater regulations in 1990. Initially, the agency required
"Best Management Practices" (BMPs) and so-called "Storm Water
Pollution Prevention Plans" (SWPPPs) only for construction sites of
five acres or more. But that figure was reduced to one acre in
2003, effectively putting all but the smallest construction jobs
under federal regulatory oversight.
Many states have followed the federal government's lead.
Nationally, East Coast states and cities tend to have the toughest
rules and enforcement, though others may be catching up, says John
Peterson, chairman of the governmental relations committee for the
International Erosion Control Association (IECA).
Meanwhile, under pressure from residents who want to clean up local
waterways, more and more municipalities have either already adopted
or are considering their own more-stringent guidelines. "As
communities are finding themselves accountable and on the hook for
improving their water quality, they are looking to see how they can
prevent problems from happening in the first place," Kitchell
As a result, municipalities often clamp down hardest. North
Carolina's Charlotte, which the IECA cites as a national model, is
a good example. Going beyond federal regulations, the Queen City's
erosion-control rules, adopted in 2002, impose immediate fines for
grading without a permit and causing off-site sedimentation, with
no grace period to correct the situation. Charlotte also has eight
full-time erosion-control inspectors who visit sites every two
weeks, leading to more frequent enforcement than elsewhere. And the
city holds contractors, not just property owners or managers,
accountable for failures of erosion control.
The ability to fine contractors has had a huge impact, says Steve
Gucciardi, Charlotte's senior erosion-control coordinator. "Once we
wrote contractor accountability into the ordinance, things became
very different," he notes. "We've assessed a lot of civil
penalties. It's had a tremendous effect."
He adds that numerous cities and counties in North Carolina,
Tennessee, and elsewhere in the Southeast routinely seek his
assistance in strengthening their own erosion-control
Faced with tough rules bound to get tougher, what's the best
strategy for contractors? Learn the rules, learn and practice
proper installation and maintenance techniques, and tap new and
more advanced technologies when available and appropriate.
Best-management practices for protecting curbside inlets
include the use of products such as absorbent inserts and straw
wattle (top left). It's critical to anchor these protections.
Gravel bags alone (top right) might help keep large construction
debris out of drains, but they won't be very effective at keeping
sediment out, and the bags are subject to damage in storms
None of this is cheap, however. Today, erosion and sediment control
represents between 3% and 6% of total development costs, according
to the Center for Watershed Protection. Stormwater regulations of
all sorts add from $1,400 to $4,500 to the cost of every lot, the
National Association of Home Builders says.
But failing to "do it right" can be even more expensive for
contractors who face fines. Gucciardi, the Charlotte inspector,
says that the city "routinely, almost on a daily basis," levies its
maximum fine of $5,000 per day for infractions.
In his experience, major home builders are less at risk of
violations than small builders.
"It all comes down to dollars. The major home builder is going to
have the money to hire the grading company that has a tremendous
amount of resources and equipment to install and maintain
erosion-control measures," he says. "The smaller guy, he's really
got to pay attention to his budget more closely, and the smaller
guys are the ones I have the hardest time getting to come into
At Coastal Contractor's request, Gucciardi provided a list of the
five biggest mistakes made by small builders and contractors:
1. Not understanding erosion-control rules.
2. Not understanding that mud in the street is considered off-site
sedimentation. Muddy roads trigger the most citizen complaints,
3. Not realizing a storm drainage system usually ties into a stream
or water body.
4. Allowing post-construction drainage into adjacent properties.
(It's not a construction-site erosion issue per se, but rather a
stormwater management issue.)
5. Having the misperception that sites under an acre are exempt
from the erosion-control ordinance.
To be sure, contractors of all sizes have their own problems with
regulators. An extremely common one is inconsistent enforcement.
"One of the things I guess I am most rabid about is getting some
consistency in terms of inspection and enforcement," says the
IECA's Peterson, adding that it's not uncommon for contractors to
receive vastly different treatments even within the same
Storm sewer catch basins and yard drains must be protected on
all sides. Straw bales (above right) are commonly used, but they
provide limited filtering effect and are seldom buried, so water
simply passes through them. Best practice calls for a staked-in box
inlet surrounded by reinforced silt fencing
In 2006, Congress considered a bill, the Stormwater Enforcement and
Permitting Act, that proponents — including the National
Association of Home Builders — said would help streamline the
process. But the bill did not pass, and its future prospects are
Though installation and maintenance remain major problems, changes
are also needed at the community planning level, according to
"Muddy Water In - Muddy Water Out?," a report published by the
Center for Watershed Protection.
Detention vs. Retention: Detention measures
aimed at slowing the rate of discharge include sediment traps
(above). Retention measures, such as a sediment basin (right) are
meant to reduce the quantity of stormwater by creating a pond for
sediment to settle out, allowing some of the water to evaporate
Erosion- and sediment-control plans fail for two general reasons,
the report states. Too often, they're not integrated with a
community's other stream-protection guidelines, such as stream
buffers and wetlands conservation. And they are often based on
"cookie-cutter" manuals that may be outdated or lacking detailed
Traditional and New Techniques
Contractors can choose from literally dozens of different
erosion-control techniques and products for varying terrains and
circumstances. But the general, two-pronged strategy boils down to
this: prevent soil from eroding in the first place, then contain
whatever soil does wash free.
On the prevention side, smart planning is one of the first and most
effective steps, Kitchell says. Contractors can keep the
possibility of erosion to an absolute minimum through planning
"phased clearing," or clearing only land they plan to build on
right away. With developments — even small developments
containing a small number of houses — developers and builders
can also forestall headaches through planning clustered housing and
leaving most natural space undisturbed, she says.
An ineffective construction entrance spreads mud into the
public roadway — a common occurrence that allows sediment to
wash down storm sewers and raises the ire of neighbors.
Beyond that, both traditional and new techniques can be effective.
Once soil is exposed, the most common traditional method is
temporary stabilization through planting grass or other plants.
Recent or emerging technologies, meanwhile, include spray-on
"tackifiers" that grip loose soil, and environmentally friendly
turf reinforcement mats that both hold soil in place and provide
substrate for plants.
On the containment side, there are several common techniques, all
of which are problematic in Kitchell's eyes:
Silt fences. Contractors often fail to
bury them deep enough, causing waterborne sediment to flow under or
over them. They also incorrectly install them parallel to water
flows, which has little or no impact. For better results, says
Kitchell, bury silt fences deep and use them only in areas of light
flow. Contractors might also turn to relatively new tubular socks
filled with water-filtering compounds touted by manufacturers as
Construction pad entrances. Contractors
often fail to install filter fabric beneath gravel entrances to
construction sites intended to help remove dirt and mud from
exiting trucks, Kitchell says. As a result, the trucks tamp the
gravel into the mud, rendering the pad useless and spreading mud
onto the roads, Kitchell says.
Straw bales. Contractors use straw bales
to divert water away from a drain but often fail to bury the bales
to ensure they have the desired effect. More typically, water flows
under or directly through the bales. Better to use more
sophisticated techniques like absorbent sacks and filter inserts
for drains, Kitchell says, adding that many communities are
outlawing straw bales.
Ideally, contractors who successfully control erosion will keep
inspectors at bay while preserving the waterways that contribute to
the value of their neighborhoods and subdivisions. But they may
also see a financial benefit. Gucciardi, the Charlotte inspector,
says one developer told him that he noticed an uptick in home sales
after he began consistently keeping streets clean and free of dirt
in his new developments. ~
Aaron Hoover writes about science and the environment from his
home in Gainesville, Fla. He is a regular contributor to Coastal