PREVIOUSConstruction Stormwater BMPs—The Text Version
Slide 1
Construction Stormwater BMPs—The Good, The Bad, and The Ugly
Presented by: Andrew Craig, Washington
State Department of Ecology
Kurt Baumgarten, Whatcom County, Planning
Division
The purpose of this presentation
is to give citizens more concrete information
about judging construction sites. Cities, counties, and the state receive many
complaints with questionable credibility, and must determine which deserve a
response. Educating citizens is one way to ensure that mostly credible
complaints are made.
Slide 2: Goals
of the Presentation
** Protect water quality!**
Provide clear criteria for evaluating construction site BMPs
Provide clear criteria about accessing private property
Ensure complaint referrals (from you) address real, not perceived
construction
site problems
Sometimes
complaints are made only because the citizen does not approve of the
development taking place. This is irrelevant unless it involves water quality
problems.
Slide 3:
Goals, continued
Level the playing field—identify
construction sites doing a good job, and those
doing a poor job, protecting water
quality.
Ensure construction site operators who are doing the
“right thing” are not
penalized:
- With time/work delays from inspectors
- For implementing and maintaining effective
BMPs on site
Inspectors want to focus compliance work only on
those who are doing a poor job
The county and the state DOE are jointly responsible
for overseeing construction
sites for compliance with state
and/or local laws
Slide 4:
Today’s Stormwater BMP Talk
“BMP” means Best Management Practice
Washington State and local (Whatcom County or city) regulations require owners
and operators of construction sites to implement erosion
and sediment
control BMPs to keep sediment on site and to protect
water quality
If sediment gets off site, it goes to a water body, which can cause problems
Slide 5:
Today’s SW BMP Talk, continued
BMPs consist of Source Control and Treatment measures
The preventative approach: Source control BMPs prevent sediment from leaving the
site
and are very effective when implemented and maintained.
Treatment BMPs reduce, but do not eliminate, the amount of sediment leaving the
site.
They are not as effective, when implemented, as source control BMPs.
Many construction companies focus only on treatment BMPs, even though they are
less effective.
Slide 6:
Today’s SW BMP Talk, continued
Typically, a combination of Source Control and Treatment BMPs is written
into stormwater
plans for construction sites.
“Site Inspections” include a review the site’s stormwater plan and the site’s
conditions
(BMP implementation)
Assessing BMP implementation is the focus of this presentation
A stormwater plan is what is written on paper; site conditions are what is
actually
occurring on the ground
Slide 7:
Today’s SW BMP Talk, continued
What do inspectors look for?
What common problems to inspectors see?
Slide 8: What
does an inspector look for?
“Discharges of pollutants leaving a site and entering water courses
OR ditches and
storm drains that discharge to water courses.”
*Pollutants = primarily muddy water and sediment; can also be
petroleum (oil,
grease, fuels), fertilizers, and pesticides. If water contains sediment, there
is a good
chance that it contains other pollutants as well.
*Water courses = streams and their tributaries, lakes, wetlands, marine
waters
(bays, harbors, estuaries)
Slide 9: Storm
Drains and Ditches
Contrary to popular belief, storm drains and ditches DO NOT discharge to
sewer
treatment plants.
Most stormwater discharges are INTENTIONALLY separated from your sewer treatment
plant to keep it from overflowing or preventing proper sewage
treatment.
Slide 10: Why
is dirt a pollutant? Why is it bad?
Dirt clogs fish gills, preventing them from breathing
Dirt covers spawning gravels (and fish eggs) used by anadromous or resident fish
(Note:
anadromous fish are those that spend part of their life in
fresh water and part in salt
water. A well-known example: salmon)
Dirt contains nutrients, such as phosphorous and nitrogen, which can lower the
amount of
dissolved oxygen in a stream, lake, river, or estuary. This
can harm aquatic life.
Phosphorous
and nitrogen are chemicals found in plant fertilizers, and they fertilize the
plants and algae in the water, causing the plants to grow and multiply. When
these
plants die, bacteria use oxygen to break down the plants. Dissolved oxygen,
which
fish breathe, is reduced.
Slide 11: What
does an inspector look for?
“The substantial potential for pollutants to
leave a site and enter water courses, or
ditches and storm drains that discharge to water
courses.”
*Substantial potential = imminent, about to happen when certain conditions
occur.
*Certain conditions
= typically rainfall events, which cause soil erosion Predicting
rainfall can be difficult, and varies from day to day.
Slide 12: What
does an inspector look for?
Is there a stormwater plan on site?
Is the stormwater plan (and its listed BMPs) implemented and adequate to prevent
pollution?
Is the written stormwater plan (BMPs) implemented on site?
Slide 13: What
common problems do Ecology Inspectors see?
No stormwater plan
No implementation of the existing stormwater plan (BMPs)
Use of only one BMP where a combination of many is necessary for effective
erosion
control.
No monitoring of the site and BMPs by the operator/owner
No adaptive management of existing BMPs to prevent discharges off site. In
other words,
the site morphology changes, but the BMPs don’t
Discharges of sediment leaving the site
Citizens can help with these problems by monitoring sites over a period of
time. The
Department of Ecology tries to educate contractors about the
importance of BMPs
Slide 14: BMP
Examples—Good, Bad, and Ugly
Slide 15: Good
BMPs—Source Control, Source Control, Source Control
Stop the erosion before it starts!
Source control is the cheapest and most cost-effective means of preventing
pollution.
Clearing as little vegetation as possible is the best source control.
Slide 16:
Source Control, Photo 1
This photo shows a soil pile covered in anchored plastic, and an exposed
hillside covered
in mulch. Plastic prevents rain from reaching the soil; only
clean water runs off.
Slide 17:
Source Control, Photo 2
Most hillsides can be managed effectively using different kinds of mulch,
such as straw or
bark. Proper mulch depth is critical. Mulch is properly
applied when no soil is visible
beneath it.
The mulch diffuses the impact of individual raindrops so that soil particles
aren’t
dislodged
Slide 18:
Source Control, Photo 3
A filter cloth that traps sand and silt (though not clay—the particles
are too small) and
allows water to pass through is called a silt fence.
Silt fences are either source control or treatment BMPs, when used and
maintained
properly
A properly-installed silt fence has a flap that is dug into a trench in the
ground so that
nothing can get underneath it. The most effective silt
fences are reinforced with wire
fencing and anchored properly in the soil.
Slide 19:
Source Control, Photo 4
This picture shows hillsides surrounding a waterway in a depression.
A thick layer of mulch and bark covers the hillsides. Straw fills the
depression around the
waterway. Silt fences are dug in at the foot of the hills
where mulch meets straw.
Slide 20:
Source Control, Photo 5
The same area as in slide 19, this photo shows grass that was planted by
the
construction company. Any vegetation, such as grass, can be
a source control.
Slide 21:
Source Control, Photo 6
Steep hillsides can effectively be covered with Visquine plastic that is
anchored with
sandbags
Slide 22:
Source Control, Photo 7
On areas where mulch and plastic are unfeasible, such as an on-site road,
gravel over
packed dirt can be used as an alternative. It diffuses
raindrops, resists erosion, and is
drivable.
Plastic on the hillside and silt fences are other source controls in this photo
Slide 23:
Source Control, Photo 8
There are many excellent BMPs shown here.
The steep hillside is covered in a thick layer of bark and mulch, which slows
down the
water coming off the hill
A grass-lined swale (shallow ditch) at the base of the hill slows and captures
more water
Silt fences help in areas that are difficult to mulch
Slide 24:
Source Control, Photo 9
This photo shows a BMP workshop for construction workers. Several BMPs
are anchored to
the hillside, and a water truck sprays each to test for
erosion.
Slide 25:
Source Control, Photo 10
At the workshop, costs per acre of various materials were provided
A few examples for perspective:
- Hydroseed (sprayed-on grass seed), $700-$1000 / acre
- Blown straw, $1000 / acre
- Hand-placed straw, $4000 / acre
- Coir (coarse fiber made from coconut husks), $15,000 / acre
*Note: Prices listed may be subject to change (depending on supply/demand and
other factors).
Slide 26:
Source Control, Photo 11
Still at the workshop, Excelsior netting is tested
Excelsior consists of a fish net-like material with hay woven into the netting
Cost per acre, $4500
Slide 27:
Source Control, Photo 12
Anchored plastic is very effective at preventing erosion underneath it,
but where does the
runoff water go once it reaches the bottom of the hill?
Cost per acre, $3800
Slide 28:
Source Control, Photo 13
A combination of straw and jute matting is very effective, and relatively
inexpensive
(Jute is a coarse fiber made from bark)
Cost per acre of jute, $4000
Slide 29: Good
BMPs—Treatment
Infiltration and Pollution Prevention
Most effective when used in combination with other source control BMPs.
Slide 30:
Treatment, Photo 1
Treatment bioswale, designed for post-construction conditions to capture
what comes
off of roofs and streets; not designed to treat high
volumes/concentrations of
muddy water
This bioswale consists of a grass-lined channel, with many twists and turns and
rock
check dams to slow water flow from light to moderate
rainfall; sand and soil
underneath; plus an underdrain.
Slide 31:
Treatment, Photo 2
Silt dams in a ditch, made from sandbags, are at best a temporary “fix.”
They slow the
water and allow larger particles to fall out.
The dams stop water from cutting further into the soil, and must be maintained
after the
water drains away. Most effective in light to moderate
rainfall conditions.
Straw bales should NOT be used as dams. They cannot conform to ditch contours,
and
allow water to pass through too easily. These also degrade
and can actually put
pollutants into the water.
Slide 32:
Treatment, Photo 3
An example of how sandbags conform to ditch contours
Slide 33:
Treatment, Photo 4
In addition to on-site treatment and filtration, muddy water may be
collected in a pond,
then pumped to treatment tanks.
Sand filters reduce the water’s turbidity (muddiness), but professional
inspectors must
ask, where does the water go once it’s cleaned?
Slide 34:
Treatment, Photo 5
Once again, preserving native vegetation is excellent source control. It
also offers an
option for on-site treatment of muddy stormwater
contained/collected at
construction sites.
Water can be pumped into the natural vegetation, where percolating pipes allow
the
water to come out slowly and filter into the soil.
These must be checked daily by the builder to ensure they are working properly
Slide 35:
Treatment, Photo 6
Sand inside of a plastic tarp creates a dam in front of this storm drain
(which also has silt
fence-like filter cloth surrounding it).
Water is pumped out from behind the dam (before it reaches the storm drain) and
into a
gravel parking lot for infiltration into the soil.
Slide 36:
Treatment, Photo 7
Muddy water may be pumped to holding ponds as a temporary BMP
This can become expensive, due to few source controls being implemented on site.
Clean water must be prevented from getting in and causing the pond to overflow
Slide 37:
Questions?
Slide 38: Bad
BMPs
No source control, inadequate source control, discharges, or substantial
potential for
discharges from the site
Slide 39:
Construction Site Risk Criteria
Are there exposed soils on site?
How steep is the exposed area?
How close is the exposed area to a watercourse, or a ditch or storm drain that
enters a
watercourse?
Where will storm water, or surface water flowing through the site, go? Is there
an
obvious outlet?
If it rains, will muddy stormwater leave the site?
Slide 40:
Construction Site Risk Criteria, continued
What is the source of muddy water on site? (Does it come from off site?)
Do muddy water and sediment stay on site or leave the site (and enter a
watercourse)?
Is there a clear plume of muddy water and sediment leaving the site and entering
a waterway?
How much muddy water is leaving the site (e.g. kitchen faucet trickle, garden
hose at full
pressure, more than a 55 gallon drum = >50 gallons/minute)?
Slide 41: Bad
BMPs, Photo 1
A silt fence that has not been dug into the ground is letting water leak
underneath
Exposed soil with no source control shows signs of erosion—rills and channels
Where is the water going?
Slide 42: Bad
BMPs, Photo 2
The water is going into a ditch
Where does the ditch lead? Follow it. Does it lead to a watercourse or storm
drain?
Slide 43: Bad
BMPs, Photo 3
This is a big, steep dirt pile with no covering and no silt fence
If it rains, the water will drain to the road, and then to a ditch or storm
drain
However, this picture was taken in the middle of summer, when the forecast
predicted
sun for at least 2 weeks. This lessens the risk but does not
eliminate it.
This site needs source control BMPs, and to be monitored more once wet weather
approaches
Slide 44: Bad
BMPs, Photo 4
Another uncovered dirt pile, this time with straw bales surrounding it
A large gap between bales lets water through, and sediment surrounds the
adjacent
storm drain
Once again, this is a summertime picture, so there is less risk
Straw bales can be effective for sheet flow when used properly, but this is not
an
appropriate place for hay bales
Slide 45: Bad
BMPs, Photo 5
No source control, water is running off site
The dirt surface has been packed down, and though this technique can prevent
some
erosion in a very light rain over short periods of time, it
is ineffective here.
Where is the water going? Follow it, if you can
Slide 46: Bad
BMPs, Photo 6
Another exposed area with runoff and channeling.
Slide 47: Bad
BMPs, Photo 7
This swale is an attempt at treatment, but a rock dam is ineffective if
water can flow
around it
The grass on the sides of the swale stabilizes soil and helps somewhat to
control
erosion.
Slide 48: Bad
BMPs, Photo 8
This photo shows an area with a lot of grass (good), but a lot of exposed
soil (bad).
Slide 49: Bad
BMPs, Photo 9
Some source control measures were taken, but it rained heavily enough to
cause erosion
Erosion should be a red flag to developers. This site was not monitored
The water from this site drains directly to a salmon stream
Slide 50: Bad
BMPs, Photo 10
A steep slope was sprayed haphazardly with Hydroseed
Straw bales have not been spread as mulch over exposed soils, and a temporary
retention
pond is nearly full
This site has substantial potential for erosion, with rainfall.
Slide 51: Bad
BMPs, Photo 11
Mulch was added to a few places at this site, but not enough, leaving
exposed soil
Where would the water go if it rained here?
Slide 52: Bad
BMPs, Photo 12
The water would run down a steep slope to the road
Across the road is a lake
Slide 53: Bad
BMPs, Photo 13
A large, uncovered dirt pile is eroding, and the water runs downhill
Treatment measures are supposed to be used as soon as soil is exposed, unless a
section is being worked or used within the next day
Slide 54: Bad
BMPs, Photo 14
More uncovered soil with erosion channels
Muddy water is about to overflow the ditch into the storm drain
Slide 55: Bad
BMPs, Photo 15
A large expanse of exposed soil with a lot of erosion
A leaky silt fence here does nothing to prevent pollution
Slide 56: Bad
BMPs, Photo 16
Part of the area is covered, but not all
The muddy water goes directly into a stream
Slide 57: Bad
BMPs, Photo 17
Source control is not finished or monitored
Erosion and discharge to a stream
Slide 58: Bad
BMPs, Photo 18
A completely exposed construction site
(These people were willing to implement BMPs after informed of their violation;
the site
was shown earlier with BMPs in place)
Slide 59: Bad
BMPs, Photo 19
Same location: water ran down a swale to a stream
Source control materials were on site, but not used
Slide 60: Bad
BMPs, Photo 20
Same location: this shows the outlet of the swale
Grass was supposed to be planted here, but was not
Slide 61: Bad
BMPs, Photo 21
Same location: an ineffective silt fence allows muddy water into a
stream
Slide 62: Bad
BMPs, Photo 22
Same location: another view of the silt fence and stream
Slide 63: Bad
BMPs, Photo 23
Muddy water coming off a construction site is entering a storm drain
Once asked, the construction company was able to stop the discharge within 5
minutes,
as shown earlier with a temporary dam and pumping water to a
gravel parking lot for
infiltration.
Slide 64: Bad
BMPs, Photo 24
Erosion channeling water directly to a stream
Slide 65: Bad
BMPs, Photo 25
Same location, different view
Slide 66: Bad
BMPs, Photo 26
An uncovered soil pile is discharging muddy water onto the roadway
Where is it going?
Slide 67: Bad
BMPs, Photo 27
The water is flowing directly into a storm drain
This is one
example of why photos are so important. The next day, the dirt pile could be
gone, along with all evidence of pollution. But photos (with a time/date
stamp!) can
prove otherwise.
Slide 68: Bad
BMPs, Photo 28
Water is flowing down a dirt construction road
Where is it going?
Slide 69: Bad
BMPs, Photo 29
Some of the water is going to a stormwater pond, designed for
post-construction
conditions
If a pond overflows, like this one, there is a big problem
Where is this water going?
Slide 70: Bad
BMPs, Photo 30
A pipe drains water from the pond into a creek
These people can’t claim to be unaware of where the pond drains to—they have
placed
hay bales in the ditch: the bales are useless to prevent
muddy water from entering the
stream; muddy water just flows around/under the hay.
Slide 71: Bad
BMPs, Photo 31
Close-up of the previous slide, clearly showing muddy water leaving the
pipe
Ponds can be okay, for example during the summer, if they do not discharge.
They
should be pumped dry before the rainy season. The
water can be used for irrigation or
dust control.
Slide 72: Bad
BMPs, Photo 32
This photo shows a large expanse of uncovered, packed soil with a large
dirt pile. Water
can drain to a ditch in the distance.
This site poses less of a risk because it is so flat, and far from any water
body. Also, it is
the middle of summer.
The dirt pile is being used, so it is okay for it to be uncovered at this time.
The time of year is an important factor to consider.
Slide 73: Bad
BMPs, Photo 33
This is a large, muddy stormwater pond, with an outlet to a ditch over
the berm in the
background
This pond is okay for now since it is seven feet below overflow stage
It should be pumped before the rainy season
Slide 74: Bad
BMPs, Photo 34
These sandbags form a pseudo-pond that has overflowed
Some water was pumped out, but not enough, and rain merely refilled the “pond”
A clear plume of sediment is visible
Slide 75:
Questions?
Slide 76: Ugly
If it is UGLY, it is not a BMP. It’s called a mistake, and immediate
corrective action is
necessary
Examples: - High volume, direct discharges from the site to waterways
- Evidence of ineffective or no source control BMPs in place
- Soils are eroding and entering waterways
- There is no debate that more source control and treatment BMPs
are
necessary
(Some of the “Bad” BMPs can also be considered “Ugly”)
Slide 77: Ugly
BMPs, Photo 1
Cutting concrete results in alkaline water
A filter over the storm drain catches only large particles, not small. It does
nothing to
reduce chemical concentrations, either.
Options for the workers: stop working in the rain; get permission from the local
government to pump to sewers
Slide 78: Ugly
BMPs, Photo 2
This photo was taken before any BMPs were put in place, except for a silt
fence
The silt fence was not dug in, and has been knocked down
There are many exposed soil areas
Slide 79: Ugly
BMPs, Photo 3
Same location: Erosion had to continue for a long time to get to this
point
Sediment flows directly into a stream
Slide 80: Ugly
BMPs, Photo 4
This silt fence has been knocked down, and pollution is clearly visible
Slide 81: Ugly
BMPs, Photo 5
Another ineffective, improperly installed silt fence with many exposed
soil areas.
Slide 82: Ugly
BMPs, Photo 6
A large plume of muddy sediment is leaving this pond at the rate of
thousands of gallons
per minute. Water is flowing over exposed soil, directly
into a salmon spawning area.
If you see a situation like this—call immediately!
Slide 83: Ugly
BMPs, Photo 7
This is a clear violation, with sediment leaving the site
Slide 84: Ugly
BMPs, Photo 8
Three hours of heavy rain caused extensive erosion on this packed,
exposed soil
Where does the water go?
Slide 85: Ugly
BMPs, Photo 9
In this case, the water is not going anywhere
A stormwater retention pond is in the background
This is a bad situation, and the site is in violation, but it could be worse if
the muddy
water went to a creek.
Slide 86:
Questions?
Slide 87:
Private Property—Do’s and Don’ts
Remember the golden rule: Treat another person’s property the way you
would want your
own property to be treated—with recognition and respect
Otherwise, you could be prosecuted and go to jail
Slide 88: DO
NOT
- Enter property marked “No Trespassing”—no exceptions
- Walk onto private roads leading into the site (whether they are paved or not)
- Argue with a property owner/contractor about where their property boundary is
located
- Stay on private property after you are asked to leave
Slide 89: DO
- Stay on public rights-of-way (e.g. streets, sidewalks, street
shoulders). Private roads
(paved or unpaved) leading into the site do not count. This
is a safety issue.
- Identify yourself, what you are doing, and for whom you are volunteering
- Offer to share the information you are collecting
- Stick to the facts about the site, if asked
Slide 90:
Private Property and Your Safety
- Trespassing is a criminal offense
- Whenever in doubt about whether property is private or public, assume it is
private and
do not enter
- Construction sites contain heavy equipment, unstable terrain, and
unpredictable
conditions. Stay alert when close to them, and don’t enter
- Be safe, rather than sorry. Your safety is priority one.
Slide 91:
Questions?
Email questions to Baykeeper Wendy Steffensen:
waters@re-sources.org
