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SILT
FENCING - Silt fences are used as a sediment control
practice. Silt fences are intended to be installed where sediment-laden
water can pond, thus allowing the sediment to fall out of suspension
and separate from the runoff. It is not intended to be an erosion
control practice. Improperly applied or installed silt fences
can increase erosion. Silt
fences should be constructed at the edge of the construction site
parameter. Silt fences and filter barriers should be inspected
weekly and after each significant storm event. Any required repairs
should be made immediately.
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STRAW
BAILS & FIBER ROLES- Straw
bales and fiber rolls can also be used as
a sediment control practice. They are intended to be installed
where sediment-laden water can pond, thus allowing the sediment
to separate from the runoff. It is not intended to be an erosion
control practice. Straw
bales and fiber rolls should be constructed
at the edge of the construction site parameter or to protect stockpiled
materials. Straw
bales and fiber rolls should be inspected
weekly and after each significant storm event. Any required repairs
should be made immediately.
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BERMED
WASHOUT PITS - Bermed washout pits should be used for
cleaning concrete equipment. Washout stations can be a plastic
lined temporary pit or bermed areas designed with sufficient volume
to completely contain all liquid and waste concrete materials
plus enough capacity for rainwater. The designated area should
be located away from storm drain inlets, or watercourses. For
small cleaning jobs, manually rinsing equipment into a wheelbarrow,
plastic bucket or pail, and then empty the bucket into the concrete
washout area.
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STORMWATER
DETENTION /RETENTION BASINS - Stormwater Detention/retention
ponds are erosion control structures commonly installed to prevent
erosion and to keep stormwater on construction sites. These structures
control erosion by diverting water flows from erosion prone areas.
The topography of the erosion prone area must be suitable for
the installation of a detention/retention basin system.
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CHEMICAL
SPILL CONTROL
- Spill containment should be implemented anytime chemicals and/or
hazardous substances are stored in drums or tanks. Substances
may include, but are not limited to fuels, lubricants, soil binders,
paints, solvents, coolants, and sewage. Spills of materials or
chemicals should be contained and cleaned up immediately. Secondary
containment systems must be able to hold the volume of the largest
container in the storage area, plus provide sufficient additional
capacity for storm events.
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STOCKPILED
CONSTRUCTION MATERIAL - Protection of stockpiles must
be implemented whenever there is a potential for transport of
materials by a water source (forecast precipitation or any non-storm
water runoff). Protect stockpiles from stormwater run-on using
a temporary perimeter sediment barrier such as berms, silt fences,
fiber rolls, covers, sand/gravel bags, or straw bale barriers,
as appropriate. Stockpiles
left on site should be covered, stabilized, or protected with
a perimeter sediment barrier prior to the onset of precipitation.
Keep stockpiles organized and surrounding
areas clean. Implement dust control practices as appropriate on
all stockpiled material.
Bagged
materials such as cold patch, concrete mix, and other materials
with the potential to pollute runoff should be placed on pallets
and under cover. Repair
and/or replace covers, and perimeter containment structures as
needed.
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| Examples
of Poor BMP Implementation: |
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EXCESSIVE
SEDIMENT DEPOSITS - This picture demonstrates excessive
track-out at the entrance of a construction site. Implementing track-out
controls can reduce offsite tracking of sediment and other pollutants.
Areas of track-out should be cleaned-up by sweeping or vacuuming.
Limit the points of entrance/exit to the construction site and require
all employees, subcontractors and others to use them. Implement
construction access stabilization using aggregate or constructed/manufactured
steel plates with ribs for entrance/exit access. |
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POORLY
MAINTAINED DROP INLET PROTECTION
- This picture demonstrates how a poorly maintained drop
inlet is one of the leading causes of sediment entering the storm
drain system. Gravel bags, silt sacks or dandy bags should be used
to intercept runoff, reduce flow velocity, and provide some sediment
removal from the construction site. It is important to maintain
and inspect inlet protection devices after each storm event, and
routinely throughout the construction project. |
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IMPROPERLY
INSTALLED STORM DRAIN INLET PROTECTION - This picture
demonstrates the isolation of a drop inlets in a public street.
Isolating a drop inlet in a public street is not allowed. Stormwater
runoff entering the drop inlet can result in ponding into road traffic
or onto erodible surfaces or slopes, or overflowing onto the sidewalk.
Protection of drop inlets is only allowed on the construction site
itself where sediment laden surface runoff may enter a storm drain
inlet and watercourses. |
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POORLY
MAINTAINED SILT FENCES - This picture demonstrates a
poorly maintained silt fence. When inspectors visit construction
projects, they often find silt fences installed incorrectly or poorly
maintained. A properly installed silt fence holds water back long
enough so that much of the sediment from runoff settles out on the
construction site. Silt
fences and filter barriers should be inspected weekly and after
each significant storm event. Any required repairs should be made
immediately. |
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POOR
TRASH REMOVAL AND HOUSEKEEPING - This picture demonstrates
poor trash removal at a construction site. Practice good housekeeping
and keep your site clean. Collect site trash regularly, especially
before rainy or windy conditions. It is important to perform routine
inspections of your site, including storage areas, dumpsters, stockpiles
and other areas where trash and debris are collected. Close trashcan
lids and dumpster covers before rainy or windy conditions. |
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EXPOSED
CONSTRUCTION MATERIALS AND CHEMICALS - This picture demonstrates
how exposed construction materials and chemicals are susceptible
to runoff and may enter a storm drain system. Practice good housekeeping
and keep your site clean. Bagged
materials such as cold patch, concrete mix, and other materials
with the potential to pollute runoff should be placed on pallets
and under cover. Repair
and/or replace covers, and perimeter containment structures as needed. |
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NO
SECONDARY CONTAINMENT FOR TANKS AND CHEMICALS - This
picture demonstrates how unprotected fuel, oil, or chemical tanks
without secondary containment is the leading cause of contaminated
soil. Spill control procedures must be implemented anytime chemicals
and/or hazardous substances are stored on site. All contaminated
soils must be removed and managed as hazardous substances, if
applicable, in accordance with applicable laws and regulations.
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| Photos
courtesy of the Nevada Division of Environmental Protection Storm
Water Branch |
