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Municipal Stormwater
Management Overview
For ConstrucÆŸon Contractors
TABLE OF CONTENTS
Purpose & Disclaimer
Temporary Erosion & Sediment Control
· SWPPP
· TESC Tips
· Site Log Book
· Good Housekeeping
· Prohibited Discharge
· Perimeter Controls
· Stabilize Site
· Inlet and Outlet ProtecƟon
· Establish Site Access
Low Impact Development (LID)
· Why is LID important?
· LID Principles
Underground InjecÆŸon Control (UIC)
· Why are UICs Important?
Best Management PracÆŸces (BMPs)
· Why are BMPs important?
· Common BMPs
Municipal Stormwater Codes
PURPOSE & DISCLAIMER
The purpose of this flip book is to assist in the
protecÆŸon of water quality from sources of polluÆŸon.
This booklet contains informaÆŸon about temporary
erosion and sediment control (TESC), low impact
development (LID), underground injecÆŸon control
(UIC), and best management pracÆŸces (BMPs). This
informaÆŸon includes ways to prevent and correct
some of the most commonly observed concerns on
construcÆŸon sites as well as the importance of each
pracÆŸce.
This document does not include all possible pracÆŸces
but rather highlights some of the most common. For
more informaÆŸon, reference the weblinks on the back
page of this document.
TEMPORARY EROSION &
SEDIMENT CONTROL (TESC)
Temporary Erosion and Sediment Control Plans
outline pracƟces for prevenƟng sediment runoff from
construcÆŸon sites through the use of man-made
structures, land management techniques, or natural
processes. The ConstrucÆŸon Stormwater General
Permit requires a CerƟfied Erosion and Sediment
Control Lead (CESCL) to inspect sites. The link below
provides more informaÆŸon about becoming a CESCL.
This secÆŸon provides highlights from the CESCL
training course.
hƩps://ecology.wa.gov/RegulaƟons-Permits/Permits-
cerƟficaƟons/CerƟfied-erosion-sediment-control
Replace and/or delete items in
green text on the cover as well as
pages 35 and 36 with information
that is specific to your jurisdiction.
Then change text color to black.
WHY IS TESC IMPORTANT?
UnmiÆŸgated site development can result in soil
erosion that can adversely impact adjacent property,
infrastructure, and environmental and recreaÆŸonal
resources. EffecƟve erosion and sediment control
(ESC) BMPs on construcÆŸon sites can greatly reduce
undesirable environmental impacts and costs.
MunicipaliÆŸes may apply escalaÆŸng enforcement
measures to developers who fail to implement proper
erosion and sediment control procedures. Not
complying with municipal codes can result in project
delays, fines, or even imprisonment.
SWPPP
A stormwater pollution prevention plan (SWPPP) details the
BMPs used to avoid environmental loss and degradation
from poorly managed construction activity. A TESC plan
must address the following elements, which are consistent
with the thirteen SWPPP elements outlined in Special
Condition S9 of Ecology’s Construction Stormwater General
Permit and in Chapter 7 Construction Stormwater Pollution
Prevention of the Ecology Stormwater Management
Manual for Eastern Washington (SWMMEW).
· Element 1: Mark Clearing Limits
· Element 2: Establish ConstrucƟon Access
· Element 3: Control Flow Rates
· Element 4: Install Sediment Controls
· Element 5: Stabilize Soils
· Element 6: Protect Slopes
· Element 7: Protect Drain Inlets
· Element 8: Stabilize Channels and Outlets
· Element 9: Control Pollutants
· Element 10: Control Dewatering
· Element 11: Maintain BMPs
· Element 12: Manage Project
· Element 13: Protect LID BMPs
TESC TIPS
1. Budget for Temporary BMPs
Purchase – InstallaÆŸon – Maintenance – Removal
Factor in labor costs.
2. Grade and Excavate in Dry Season
Dry season is May 1st – October 1st
Phase construcÆŸon to preserve naÆŸve
vegetaÆŸon and reduce exposure.
3. Use Your SWPPP
Review – Reference – Revise
Keep SWPPP posted on-site at all ÆŸmes.
4. Keep Up-to-Date Records
Log Books – Reports – Maintenance – InspecÆŸon
Forms
Required by Department of Ecology and
JurisdicÆŸons
5. Protect Permanent Stormwater Controls
Ponds – Treatment Systems – Low Impact
Development (LID)
Reduce the need for maintenance at final
inspecÆŸon.
SITE LOG BOOK
Keep ongoing records of:
Changes to TESC plans
BMP implementaÆŸon
BMP maintenance or replacement
Visual inspecÆŸons
All relevant field notes
Spill informaÆŸon (date, ÆŸme, amount, locaÆŸon,
material, clean-up method, noƟficaƟons made,
and disposal)
Discharge monitoring reports (DMRs) and
sampling
GOOD HOUSEKEEPING
Keep site clean.
Regularly inspect and maintain BMPs.
Cover and store hazardous materials (use
secondary containment).
Use concrete washout controls.
Follow solid waste BMPs.
Hold regular tailgate check-ins with crew.
Have spill kit on site.
Looking for photos to go here
PROHIBITED DISCHARGE
· Untreated construction stormwater over 25 NTUs
· Washout from concrete (slurry), stucco, paint,
and concrete form release oils
· Soaps or solvents used for vehicle or equipment
washing
· Equipment leaks and toxic substances from a spill
· Wheel wash wastewater
· Sediment track-out from vehicles
PERIMETER CONTROLS
Proper installaÆŸon is key:
– Key in and backfill to prevent runoff from
going under silt fences.
– Space support posts a maximum of 6 feet
apart.
– Overlap adjacent fence secƟons generously
to prevent escape of runoff.
Mark project area correctly.
Perform required maintenance.
Add BMP reinforcement for sites with high flow
or wind potenÆŸal.
Select BMPs by filtraƟon and retenƟon needs.
Consider public safety.
Use BMPs in combinaÆŸon.
STABILIZE SITE
Minimize exposed areas.
Preserve naÆŸve vegetaÆŸon.
Phase grading and excavaÆŸon.
Minimize slope length and pitch whenever
possible.
Stabilize slopes.
Cover stockpiles.
Use BMPs in combinaÆŸon.
INLET AND OUTLET PROTECTION
Install early in project.
Perform required maintenance; inspect regularly.
Inlet ProtecÆŸon BMPs:
Inserts/socks
Coir pads
Bio-bags/sand bags
Compost socks
Outlet ProtecÆŸon BMPs:
– Rip rap
– Sediment fence
– WaƩles/socks/sand bags
Use protecÆŸon BMPs as last line of defense.
ESTABLISH SITE ACCESS
Install stabilized pad 12-inch thick of 4-inch to
8-inch quarry spalls, or a 4-inch course of asphalt
treated base, or use exisÆŸng pavement at all site
entrances and exits.
Install geotexÆŸle fabric underlayment beneath
spalls.
Do not use crushed concrete.
Use wheel wash when a stabilized pad fails to
prevent sediment track-out.
Sweep track-out as necessary (at least daily).
Inspect site access regularly, especially aÅŒer large
storm events.
LOW IMPACT DEVELOPMENT (LID)
Low impact development applies stormwater
and land use management approaches that strive
to imitate natural processes by emphasizing
conservaÆŸon, uÆŸlizing on-site natural features,
site planning, and distributed stormwater
management pracÆŸces in the project’s design.
Developers are encouraged to use LID techniques
and non-structural methods to minimize impervious
surfaces and disturbing naÆŸve soils and vegetaÆŸon.
Factor in site condiÆŸons and long-term maintenance
when considering using LID approaches.
ConstrucÆŸon Stormwater General and Municipal
Permit Requirements:
Use and maintain erosion and sediment controls
on areas that drain to infiltraƟon BMPs. Restore
BMPs by removing sediment and, if applicable,
replace sediment-laden soils with those meeÆŸng
the BMP’s design specificaÆŸons.
LOW IMPACT DEVELOPMENT (CONT.)
Keep construcƟon equipment and foot traffic off
infiltraƟon BMPs to avoid compacƟon. Similarly,
protect landscaped and protected natural areas
from compacÆŸon by construcÆŸon equipment.
Clean permeable pavements fouled with
sediments as well as those failing SWMMEW or
manufacture infiltraƟon tests.
WHY IS LID IMPORTANT?
LID improves stormwater management and protects
surface waters. Installing LID systems can result in
cleaner air and water, as well as enhance flood
protecÆŸon, habitat, and green spaces.
LID may help meet or, in some cases, completely
saƟsfy Ecology’s requirements for runoff water
quality treatment (Core Element #5) and flow
control (Core Element #6).
LID PRINCIPLES
Follow the key principles of LID for site design,
construcÆŸon, and long-term maintenance:
Preserve naÆŸve vegetaÆŸon.
Protect criÆŸcal areas (e.g., wetlands, groundwater
recharge areas, flood-prone areas, geologically
unstable areas, and habitat conservaÆŸon areas).
Minimize surfaces that prevent water from
seeping into the ground.
Minimize disturbance and compacÆŸon of site
soils.
Preserve exisƟng flow paths.
Infiltrate stormwater runoff.
Disperse stormwater.
UÆŸlize natural surfaces.
UÆŸlize small-scale, distributed LID BMPs.
UNDERGROUND INJECTION CONTROL (UIC)
Stormwater Underground InjecÆŸon Control wells
are structures used to direct stormwater runoff
underground, usually under the force of gravity.
UIC wells consist of:
A hole whose depth exceeds its largest surface
dimension.
An underground fluid distribuƟon system (e.g.,
perforated pipes or dry wells) to distribute the
stormwater below ground.
WHY ARE UICS IMPORTANT?
UIC wells are another approach to managing
stormwater runoff, which includes the added benefit
of replenishing groundwaters. As such, federal and
state regulaÆŸons govern the use of UIC wells to
prevent groundwater contaminaÆŸon. UIC wells not
designed, operated, and maintained according to
these laws may result in penalÆŸes, including
prevenÆŸng further use of the well.
WHY ARE UICS IMPORTANT? (CONT.)
UIC wells require frequent inspecÆŸon and
preventaÆŸve maintenance to ensure they perform as
intended. As such, UIC wells require protecÆŸon from
runoff with sediment generated during construcƟon
as it could quickly prevent infiltraƟon. If necessary,
remove debris and sediment to eliminate the buildup
of materials that could prevent infiltraƟon. Also see
Inlet and Outlet ProtecÆŸon on Page 11 for addiÆŸonal
ways to protect drywells during construcÆŸon.
BEST MANAGEMENT PRACTICES (BMPS)
Best Management PracÆŸces consist of measures,
approved by the Department of Ecology, used to
prevent or reduce the release of pollutants and other
adverse impacts (e.g., high flows) to surface and
groundwaters. ConstrucÆŸon stormwater BMPs may
be used individually or required in combinaÆŸon. They
can be structural (e.g., silt fence, wheel wash, seƩling
ponds) or nonstructural (e.g., street sweeping, source
control polluÆŸon prevenÆŸon measures, maintenance
procedures, prohibited pracÆŸces).
This secÆŸon introduces common BMPs uÆŸlized during
construcÆŸon. InformaÆŸon about the BMPs included in
this document can be found at the QRL
code on this page. QRL codes for each
BMP are provided on the subsequent
pages, with more informaÆŸon about
installaÆŸon and maintenance pracÆŸces.
WHY ARE BMPS IMPORTANT?
Unmanaged runoff during a project’s construcÆŸon
phase can harm surface and groundwaters,
vegetaÆŸon, habitat, property, and infrastructure.
Avoiding these harms requires pre-project planning,
including the gathering of site-specific informaƟon
based on the site’s characterisÆŸcs. It also requires
ongoing site awareness and diligence during the
construcÆŸon phase, including monitoring weather
forecasts, proper installaÆŸon and maintenance
of BMPs, and polluÆŸon prevenÆŸon pracÆŸces.
CollecÆŸvely, these acÆŸons can contribute to
reducing construcÆŸon-related impacts on the site
and surrounding areas.
Used properly, BMPs provide erosion and sediment
control, provide polluÆŸon prevenÆŸon, minimize
unwanted compacƟon, and protect on- and off-site
infrastructure, property, and natural areas.
COMMON BMPS
BMP C233E Silt Fence
Silt fence reduces the transport
of coarse sediment from a
construcÆŸon site by providing
a temporary physical barrier to
sediment and reducing the runoff
velociƟes of overland flow.
COMMON BMPS (CONT.)
BMP C106E Wheel Wash
Wheel washes reduce the amount of
sediment transported onto paved
roads by washing dirt from the wheels
of motor vehicles prior to the motor
vehicles leaving the construcÆŸon site.
COMMON BMPS (CONT.)
BMP C105E Stabilized ConstrucÆŸon Access
Stabilized construcÆŸon entrances
reduce the amount of sediment
transported onto paved roads by
vehicles or equipment. This is done by
construcÆŸng a stabilized pad of quarry
spalls at entrances and exits for
construcÆŸon sites.
COMMON BMPS (CONT.)
BMP C107E ConstrucÆŸon Road / Parking Area
StabilizaÆŸon
Stabilizing roads, parking areas, and
other on-site vehicle transportaÆŸon
routes immediately aÅŒer grading re-
duces erosion caused by construcÆŸon
traffic or stormwater runoff.
COMMON BMPS (CONT.)
BMP C103E High-Visibility Fence
High-visibility fencing:
Restricts clearing to approved
limits;
Prevents disturbance of sensiÆŸve
areas, their buffers, and other
areas required to be leŌ
undisturbed;
Limits construcƟon traffic to designated
construcÆŸon entrances, exits, or internal roads;
and
Protects areas where marking with survey tape
may not provide adequate protecÆŸon.
COMMON BMPS (CONT.)
BMP C235E WaƩles
WaƩles are temporary erosion and
sediment control barriers consisÆŸng of
straw, compost, or other material that
is wrapped in biodegradable tubular
plasÆŸc or similar encasing material.
They reduce the velocity and can
spread the flow of rill and sheet runoff and
can capture and retain sediment.
COMMON BMPS (CONT.)
BMP C209E Outlet ProtecÆŸon
Outlet protecÆŸon prevents scour at
conveyance outlets and minimizes the
potenÆŸal for downstream erosion by
reducing the velocity of concentrated
stormwater flows.
COMMON BMPS (CONT.)
BMP C201E Grass Lined Channels
Grass lined channels are channels with
a vegetaÆŸve lining for conveyance of
runoff to help prevent the transport
of sediment and erosion.
COMMON BMPS (CONT.)
BMP C202 Riprap Channel Lining
Riprap channel lining is used when
natural soils or vegetated stabilized
soils in a channel are not adequate
to prevent channel erosion.
COMMON BMPS (CONT.)
BMP C241E Sediment Pond (Temporary)
Sediment ponds are temporary ponds
used during construcÆŸon to remove
sediment from runoff originaƟng from
disturbed areas of the site. Sediment
ponds are typically designed to
remove sediment no smaller than
medium silt (0.02 millimeters). Consequently,
they usually reduce turbidity only slightly.
COMMON BMPS (CONT.)
BMP C207E Check Dams
ConstrucÆŸon of check dams across
a swale or ditch reduces the velocity
of concentrated flow and dissipates
energy at the check dam.
COMMON BMPS (CONT.)
BMP C101E Preserving Natural VegetaÆŸon
The purpose of preserving natural
vegetaÆŸon is to reduce erosion
wherever pracÆŸcable. LimiÆŸng site
disturbance is the single most effecƟve
method for reducing erosion. For
example, conifers can hold up to about
50% of all rain that falls during a storm. Up to 20% to
30% of this rain may never reach the ground but is
taken up by the tree or evaporates. Another benefit is
that the rain held in the tree can be released slowly
to the ground aÅŒer the storm.
COMMON BMPS (CONT.)
BMP C162 Scheduling
Sequencing a construcÆŸon project can
reduce the amount and duraÆŸon of
soil exposed to erosion by wind, rain,
runoff, and vehicle tracking.
MUNICIPAL STORMWATER CODES
The EWA MS4 Phase II Permit requires implemenÆŸng
and enforcing programs to reduce pollutants in
stormwater from construcÆŸon acÆŸviÆŸes that disturb
one…