Transcript Creating a Storm Water Pollution Prevention Plan

Creating a Storm
Water Pollution
Prevention Plan
For Construction
Activities
Creating a Storm Water
Pollution Prevention Plan
A requirement of the construction
storm water permit is to develop a
storm water pollution prevention plan
(SWPPP) before construction activities
begin. The SWPPP should be
complete before submitting the Notice
of Intent (NOI). The following slide
show will step through each item that
is to be addressed in the SWPPP. By
following this guide, you will be able to
develop a SWPPP that fulfills the
requirements of the Arkansas
Department of Environmental Quality.
SWPPP Organization
Guideline

Site Evaluation and Design
Development:
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Collect site information
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Develop Site Plan

Prepare pollution prevention site
map
SWPPP Organization
Guideline

Assessment:

Measure the site area

Determine the drainage areas

Calculate the runoff coefficient
SWPPP Organization
Guideline

Control Selection / Plan Design:

Select erosion and sediment controls

Select other controls

Select storm water management
controls

Indicate the location of controls on
the site map

Site map requirements
SWPPP Organization
Guideline

Control Selection / Plan Design
Continued:

Prepare an inspection and
maintenance plan

Prepare sequence of major activities

Incorporate State or local
Requirements
SWPPP Organization
Guideline

Certification / Notification:
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Certify the plan

Submit Notice of Intent

Plan location
SWPPP Organization
Guideline

Construction / Implementation:
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Implement controls

Inspect and maintain controls

Update / change the plan

Report releases of reportable
quantities
SWPPP Organization
Guideline

Final Stabilization / Termination

Final stabilization

Notice of Termination
SWPPP
The following is a step-by-step
description of each item in the
organizational list that was
previously supplied. By addressing
each item in the list, an acceptable
SWPPP can be developed that meets
ADEQs basic criteria.
Site Evaluation and Design

Collect site information

Existing conditions site map

Soils information

Runoff water quality

Name of receiving stream / water

Rainfall data
Site Evaluation and Design

Develop Site Plan

Disturb the smallest vegetated area
possible

Keep the amount of cut and fill to a
minimum
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Limit impacts to sensitive areas such as:
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Steep and / or unstable slopes
Surface waters, including wetlands
Areas with soil is likely to erode
Existing drainage channels
Site Evaluation and Design

Prepare Pollution Prevention Site
Map

Approximate slopes after grading
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Indicate areas of soil disturbance
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Indicate drainage patterns
Assessment

Measure site area

Indicate the total site area and the area
which will be disturbed
Assessment

Determine the Drainage Area

Measure the size of each drainage basins
for each point where concentrated flow
will leave the site

Use the calculated concentrated flow to
determine the appropriate sediment
control measures
Assessment

Calculate the Runoff Coefficient
 Develop
an estimate of the development’s
impact on runoff after construction is
complete. This can be done by estimating a
runoff coefficient for post-construction
conditions
Q = (C) * (I) * (A)
where
Q = the rate of runoff from an area
C = partial amount of the total rainfall
that will become runoff
I = rainfall intensity, and
A = the area of the drainage basin
Assessment Continued

Calculate the Runoff Coefficient
Continued

Calculating a “weighted” runoff
coefficient:
where
A = acres and
C = coefficient
Assessment Continued
Typical "C" Values (ASCE 1960)
Description of Area
Runoff Coefficients
Business
Downtown Areas
Neighborhood Area
0.70 - 0.95
0.50 - 0.70
Single-family areas
Multiunits, detached
Multiunits, attached
0.30 - 0.50
0.40 - 0.60
0.60 - 0.75
Residential
Residential (suburban)
0.25 - 0.40
Apartment dwelling areas
0.50 - 0.70
Industrial
Light Areas
Heavy Areas
0.50 - 0.80
0.6 - 0.90
Parks, cemeteries
0.10 - 0.25
Playgrounds
0.20 - 0.35
Railroad yard areas
0.20 - 0.40
Unimproved areas
0.10 - 0.30
Streets
Asphalt
Concrete
Brick
0.70 - 0.95
0.80 - 0.95
0.70 - 0.85
Drives and walks
0.75 - 0.85
Roofs
0.75 - 0.95
Lawns - course textured soil (greater than 85% sand)
Slope:
Flat, 2%
Average, 2-7%
Steep, 7%
0.05 - 0.10
0.10 - 0.15
0.15 - 0.20
Lawns - fine textured soil (greater than 40% clay)
Slope:
Flat, 2%
Average, 2-7%
Steep, 7%
0.13 - 0.17
0.18 - 0.22
0.25 - 0.35
Control Selection / Plan
Development

Select erosion and sediment
controls
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Stabilization measures for disturbed areas
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Structural controls to divert runoff and
remove sediments

Erosion and sediment controls can include
temporary or permanent measures
Control Selection / Plan
Development

Select other controls
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Proper waste disposal

Control of offsite vehicle tracking
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Compliance with applicable State or local
waste disposal
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Sanitary sewer or septic system
regulations
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Control of allowable non-storm water
discharges
Control Selection / Plan
Development

Select storm water management
controls
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Storm water detention structures
(including wet ponds)

Storm water retention structures
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Open vegetated swales
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Natural depressions
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Infiltration measures
Control Selection / Plan
Development

Indicate location of controls on
the site map
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Areas of permanent seeding
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Areas of sod stabilization
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Silt fence
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Straw bale barrier
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Earth dikes
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Brush barriers
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Drainage swales
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Sediment traps
Control Selection / Plan
Development
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Indicate location of controls on
the site map
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Pipe slope drains
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Level spreaders
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Storm drain inlet protection
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Reinforced soil retaining systems
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Gabions
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Temporary or permanent sediment basins
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Stabilized construction entrances
Control Selection / Plan
Development
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Site map requirements
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Drainage patterns
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Approximate slopes after grading
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Area of soil disturbance
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Location of major structural and
nonstructural controls
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Areas where stabilization practices are
expected to occur
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Location of surface waters
Control Selection / Plan
Development

Prepare an inspection and
maintenance plan
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Qualified personnel shall inspect
disturbed areas of the construction site at
least once every seven calendar days and
within 24 hours of the end of a storm that
is 0.5 inches or greater
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A description of procedures to maintain in
good condition and effective operating
condition
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Vegetation
Erosion and sediment control measures
Other protective measures identified in the
site plan
Control Selection / Plan
Development

Prepare sequence of major
activities
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The sequence of major activities should
include a timeline for:
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Construction of control measures
Earth disturbing construction activities
Maintenance activities for control
measures in the order in which they will
occur
Down slope and side slope perimeter
controls should be installed before the land
disturbing activity occurs
Do not disturb an area until it is necessary
for construction to proceed
Cover or stabilize as soon as possible
Control Selection / Plan
Development

Prepare sequence of major
activities continued

The sequence of major activities should
include a timeline for:

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Time activities to limit impact form
seasonal climate changes or weather events
Construction of infiltration measures
should be delayed to the end of the project
when upstream drainage areas have been
stabilized
Control Selection / Plan
Development

Incorporate state or local
requirements

Permittees shall incorporate all applicable
requirements specified in State or local
sediment and erosion control plans or
permits, or storm water management
plans or permits. This should include
requirements such as

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City ordinances
City grading permit requirements
Certification and Notification

Certify the Plan

Your NPDES storm water permit requires
that authorized representative(s) of the
operator(s) sign and certify the plan. The
authorized representative(s) should be
individuals at or near the top of the
management chain, such as:
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The president
Vice-president
General partner, who has been delegated
the authority to sign and certify this type of
document
Certification and Notification

Notice of Intent

You are required to submit a Notice of
Intent (NOI) prior to commencement of
construction

The NOI cannot be submitted until the
SWPPP has been prepared
Certification and Notification

Plan location

SWPPPs for construction activities shall
be maintained onsite of the activity unless
the Director, or authorized representative,
the operator of a large or medium MS4, or
a State or local sediment and control
agency requests that the plan be
submitted.

Permittees should keep a copy of the plan
at the construction site until the site is
finally stabilized

Permittees are required to keep the plan,
all reports and data for at least three years
after the project is complete
Construction / Implementation

Implement controls
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The controls should be constructed or
applied in accordance with State or local
standard specifications

If there are no State or local specifications
for control measures then the controls
should be constructed in accordance with
good engineering practices

Improperly installed controls can have
little or no effect and may actually increase
the pollution of storm water
Construction / Implementation

Inspect and maintain controls

Inspection should be performed at the
frequency specified in the SWPPP and / or
the permit

The inspector should note any damage or
deficiencies in the control measures in an
inspection report

The inspector should correct damage or
deficiencies as soon as practicable after the
inspection
The operator should keep records of the
construction activity on the site, such as:
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Dates when major grading activities occur
in a particular area
Dates when construction activities cease in
an area
Dates when an area is stabilized
Construction / Implementation
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Update / change plans

SWPPPs are developed based on sitespecific features and functions. Where
there are changes in design, construction,
operation, or maintenance, and that
change will have a significant effect on the
potential for discharging pollutants in
storm water at a site, the SWPPP should
be modified by the permittee to reflect the
changes and new conditions

The permittee is required to update the
plan as necessary to reflect any changes
onsite which may affect the potential for
discharges of pollutants from the site
Construction / Implementation
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Releases of reportable quantities

If the construction site has a release of a
hazardous substance or of oil in an amount
which exceeds a reportable quantity (RQ)
as defined at 40 CFR Part 110, 40 CFR
Part 117, or 40 CFR Part 302, then the
permittee shall do several things:
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The person in charge of the site at the time
of the spill shall call the National Response
Center to report the spill – 800-424-8802
Within 14 days after the release is detected,
modify the site SWPPP
Within 14 days of the release, submit a
written description of the release to ADEQ
Final Stabilization / Termination
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Final stabilization

A site can be considered finally stabilized
when all soil disturbing activities at the site
have been completed and a uniform
perennial vegetative cover with a density
of 70 percent for the unpaved areas and
areas not covered by permanent structures
has been established or equivalent
permanent stabilization measures have
been employed
Final Stabilization / Termination
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Notice of Termination

The Notice of Termination (NOT) is the
final task required to comply with the
requirements of an NPDES storm water
permit for a construction activity. The
NOT form is sent to the permittee with the
confirmation letter. Additional NOTs can
be obtained by contacting the storm water
staff at ADEQ