Summary: Brochure Template Instructions, Construction site compliance with Muni Phase II Permit EW, Developer, planner, engineer, plan review staff information, information for designers to comply with Muni Permit
FOR MORE INFORMATION
CONTACT US
MUNICIPAL STORMWATER CODE
REQUIREMENTS
Municipal stormwater code promotes public health,
safety, and welfare in compliance with state and
federal laws. The Eastern Washington Phase II
Municipal Stormwater Permit (Permit) requires
jurisdictions to develop and administer code to:
• Prohibit non-stormwater discharges into their
stormwater system.
• Require erosion and sediment controls, and other
construction-phase stormwater pollution controls.
• Require post-construction stormwater controls.
BEST MANAGEMENT PRACTICES
FOR REDUCING ADVERSE IMPACTS
FROM STORMWATER RUNOFF
FROM DEVELOPMENT SITES
Best Management Practices (BMPs) include a
schedule of activities, prohibited practices,
maintenance procedures, and structural and/or
managerial practices approved by the Department of
Ecology that, when used singly or in combination,
prevent or reduce the release of pollutants and other
adverse impacts to receiving waters.
The Permit requires project proponents and
property owners to adhere to the Permit’s
minimum technical requirements. These include
BMP selection, design, installation, operation,
and maintenance standards for projects meeting
the threshold triggers in the SWMMEW and/or
[insert local standards/manuals].
Failure to adequately select, design, and install
required BMPs violates local code and may result in
penalties.
Bioinfiltration BMP in Eastern Washington.
MUNICIPAL STORMWATER
This brochure introduces topics essential to
stormwater design and includes resources for
engineers, development review staff, and land use
planners.
ADDITIONAL INFORMATION
[Insert Permittee’s Name] stormwater code can be
found here: [Insert stormwater code link].
Not complying with municipal codes can result in project
delays, fines, or even imprisonment.
TECHNICAL STANDARDS
The Stormwater Management Manual for Eastern
Washington (SWMMEW) [Insert Local Manual Title
or Delete] provides technical guidance in the design,
operation, and maintenance to control the quantity
and quality of stormwater runoff from development
projects in Eastern Washington.
Applying these measures can support achieving
compliance with state and federal water quality laws,
contributing to the protection of the beneficial uses of
surface and groundwaters.
ADDITIONAL INFORMATION
SWMMEW: https://ecology.wa.gov/Regulations-
Permits/Guidance-technical-assistance/Stormwater-
permittee-guidance-resources/Stormwater-manuals
[Insert Local Manual Title or Delete]:
Provide link to local technical standards
ADDITIONAL INFORMATION
SWMMEW Chapter 1.5
Permit Appendix 1: https://ecology.wa.gov/DOE/
files/7f/7f049302-50bb-4b67-9724-1a43cd521922.pdf
Jurisdictions Logo
Name
Position
Phone Number
Email
Jurisdictions Logo
Name
Position
Phone Number
Email
Bioretention BMP in Eastern Washington.
Constructed stormwater wetland during construction.
[Jurisdiction Name][Jurisdiction Address][City, WA Zip Code][Add Jurisdiction Phone Number]Developed for Engineers,
Development Review Staff,
& Land Use Planners
Municipal
Stormwater
Management
Requirements Overview
Replace and/or delete items in red
boxes with information that is
specific to your jurisdiction.
DEVELOPMENT OF STORMWATER
SITE & EROSION CONTROL PLANS
A Stormwater Site Plan (SSP) contains the technical
information and analysis necessary for regulatory
agencies to evaluate a proposed development
project for compliance. Contents of the SSP vary
with the type and size of the project, individual site
characteristics, and local jurisdictional requirements.
Developing a SSP consists of the following steps:
1. Collect and analyze information on existing
conditions.
2. Prepare preliminary development layout.
3. Perform off-site analysis.
4. Determine applicable SWMMEW core elements.
5. Prepare a permanent stormwater control plan.
6. Select construction stormwater pollution
prevention BMPs (projects may require a
Construction Stormwater Pollution Prevention
Plan).
7. Complete the SSP.
8. Check compliance with all applicable SWMMEW
core elements.
The Permit requires proactively managing erosion-
related risks during construction. Developers must
consider each of the following elements of pollution
prevention to determine appropriate controls for the
project site:
1. Clearing Limits
2. Construction Access
3. Flow Rates
4. Sediment Controls
5. Soil Stabilization
6. Slope Protection
7. Drain Inlet Protection
8. Channel and Outlet Stabilization
9. Pollutant Controls
10. Dewatering
11. BMP Maintenance
12. Project Management
13. Low-Impact Development Facility Protection
UNDERGROUND INJECTION
CONTROL
Underground Injection Control (UIC) wells are
structures used to direct stormwater runoff
underground, usually under the force of gravity.
UIC wells consist of:
• A dug hole whose depth exceeds its largest
surface dimension.
• An underground fluid distribution system (e.g.,
perforated pipes).
Examples of stormwater UIC wells: drywells, an
infiltration trench containing perforated pipe,
bioretention systems with a perforated pipe below
the treatment soil, and stormwater infiltration
chamber systems.
The Department of Ecology regulates UIC wells
under the statewide UIC program to prevent
groundwater contamination. Owners of
stormwater UICs must apply the guidance in
the SWMMEW and submit UIC registration
applications 60 days prior to construction to
allow for sufficient review time.
All UIC wells not operated in accordance with
the law may result in a violation, including
action for injunctive relief.
Drywells are an example of a UIC.
LOW IMPACT DEVELOPMENT
Low Impact Development (LID) applies
stormwater and land use management strategies
that strive to mimic natural processes utilizing the
following principles:
• Preserve native vegetation.
• Protect critical areas.
• Minimize impervious surfaces.
• Minimize grading and compaction of site soils.
• Preserve existing flow paths.
• Infiltrate stormwater runoff.
• Disperse stormwater.
• Utilize natural surfaces.
• Utilize small-scale, distributed LID BMPs.
Examples of practices adhering to these
principles include: bioretention, rain gardens,
dispersion, and permeable pavements.
Implementing LID principles and practices
manages runoff in a way that reduces the impact
of built areas and promotes ecological functions.
The Permit requires jurisdictions to implement a
policy encouraging project proponents to maintain
natural drainages to the Maximum Extent
Practicable. This includes minimizing the disturbance
of native soils and vegetation, reducing the total
amount of impervious surfaces, non-structural
preventive actions, and pollutant source reduction
approaches. In utilizing LID approaches, consider
site conditions and long-term maintenance.
Bioretention cells are an example of LID BMPs.
INFILTRATION
The SWMMEW defines infiltration as the downward
movement of water from the land surface to the
subsoil. Infiltration BMP design allows stormwater
runoff to soak into the ground as a means of filtering
out pollutants and recharging groundwater.
Examples of infiltration BMPs: dispersion,
bioinfiltration, drywells, infiltration ponds and
trenches, bioretention, and permeable pavement.
ADDITIONAL INFORMATION
SWMMEW Chapter 3 (SSP) & Chapter 7
(ECP): WSDOT Temporary Erosion and Sediment
Control Manual:
https://wsdot.wa.gov/engineering-standards/all-
manuals-and-standards/manuals/temporary-erosion-
and-sediment-control-manual
[Insert link to local code/regulations/resources, if
applicable]ADDITIONAL INFORMATION
SWMMEW Appendix 3-D: Guidance on Low Impact
Development Site Planning Principles and Design
Strategies
[Insert link to local code/regulations/resources,
if applicable][Jurisdictions Name] local code/regulations/
ADDITIONAL INFORMATION
SWMMEW Chapter 5.6: Defines site suitability,
treatment requirements, and stormwater discharges
to UIC well design criteria.
Ecology’s UIC Program: https://ecology.wa.gov/
Regulations-Permits/Guidance-technical-assistance/
Underground-injection-control-program
UIC Registration: https://ecology.wa.gov/
Regulations-Permits/Guidance-technical-assistance/
Underground-injection-control-program/Register-UIC
-wells-online
ADDITIONAL INFORMATION
SWMMEW Chapter 5.4 and 6.3: [Insert link to local
code/regulations/resources, if applicable]SWMMEW Chapters 5.4 and 6.3, as well as/or
[insert local standards/manuals] include design and
installation information for infiltration BMPs. Some
infiltration BMPs qualify as UIC wells and must follow
requirements of the statewide UIC program (see UIC
section for more information).
Dispersion BMPs allow runoff to infiltrate over a large area.
Runoff infiltrates through permeable pavement.
CONTACT US
MUNICIPAL STORMWATER CODE
REQUIREMENTS
Municipal stormwater code promotes public health,
safety, and welfare in compliance with state and
federal laws. The Eastern Washington Phase II
Municipal Stormwater Permit (Permit) requires
jurisdictions to develop and administer code to:
• Prohibit non-stormwater discharges into their
stormwater system.
• Require erosion and sediment controls, and other
construction-phase stormwater pollution controls.
• Require post-construction stormwater controls.
BEST MANAGEMENT PRACTICES
FOR REDUCING ADVERSE IMPACTS
FROM STORMWATER RUNOFF
FROM DEVELOPMENT SITES
Best Management Practices (BMPs) include a
schedule of activities, prohibited practices,
maintenance procedures, and structural and/or
managerial practices approved by the Department of
Ecology that, when used singly or in combination,
prevent or reduce the release of pollutants and other
adverse impacts to receiving waters.
The Permit requires project proponents and
property owners to adhere to the Permit’s
minimum technical requirements. These include
BMP selection, design, installation, operation,
and maintenance standards for projects meeting
the threshold triggers in the SWMMEW and/or
[insert local standards/manuals].
Failure to adequately select, design, and install
required BMPs violates local code and may result in
penalties.
Bioinfiltration BMP in Eastern Washington.
MUNICIPAL STORMWATER
This brochure introduces topics essential to
stormwater design and includes resources for
engineers, development review staff, and land use
planners.
ADDITIONAL INFORMATION
[Insert Permittee’s Name] stormwater code can be
found here: [Insert stormwater code link].
Not complying with municipal codes can result in project
delays, fines, or even imprisonment.
TECHNICAL STANDARDS
The Stormwater Management Manual for Eastern
Washington (SWMMEW) [Insert Local Manual Title
or Delete] provides technical guidance in the design,
operation, and maintenance to control the quantity
and quality of stormwater runoff from development
projects in Eastern Washington.
Applying these measures can support achieving
compliance with state and federal water quality laws,
contributing to the protection of the beneficial uses of
surface and groundwaters.
ADDITIONAL INFORMATION
SWMMEW: https://ecology.wa.gov/Regulations-
Permits/Guidance-technical-assistance/Stormwater-
permittee-guidance-resources/Stormwater-manuals
[Insert Local Manual Title or Delete]:
Provide link to local technical standards
ADDITIONAL INFORMATION
SWMMEW Chapter 1.5
Permit Appendix 1: https://ecology.wa.gov/DOE/
files/7f/7f049302-50bb-4b67-9724-1a43cd521922.pdf
Jurisdictions Logo
Name
Position
Phone Number
Jurisdictions Logo
Name
Position
Phone Number
Bioretention BMP in Eastern Washington.
Constructed stormwater wetland during construction.
[Jurisdiction Name][Jurisdiction Address][City, WA Zip Code][Add Jurisdiction Phone Number]Developed for Engineers,
Development Review Staff,
& Land Use Planners
Municipal
Stormwater
Management
Requirements Overview
Replace and/or delete items in red
boxes with information that is
specific to your jurisdiction.
DEVELOPMENT OF STORMWATER
SITE & EROSION CONTROL PLANS
A Stormwater Site Plan (SSP) contains the technical
information and analysis necessary for regulatory
agencies to evaluate a proposed development
project for compliance. Contents of the SSP vary
with the type and size of the project, individual site
characteristics, and local jurisdictional requirements.
Developing a SSP consists of the following steps:
1. Collect and analyze information on existing
conditions.
2. Prepare preliminary development layout.
3. Perform off-site analysis.
4. Determine applicable SWMMEW core elements.
5. Prepare a permanent stormwater control plan.
6. Select construction stormwater pollution
prevention BMPs (projects may require a
Construction Stormwater Pollution Prevention
Plan).
7. Complete the SSP.
8. Check compliance with all applicable SWMMEW
core elements.
The Permit requires proactively managing erosion-
related risks during construction. Developers must
consider each of the following elements of pollution
prevention to determine appropriate controls for the
project site:
1. Clearing Limits
2. Construction Access
3. Flow Rates
4. Sediment Controls
5. Soil Stabilization
6. Slope Protection
7. Drain Inlet Protection
8. Channel and Outlet Stabilization
9. Pollutant Controls
10. Dewatering
11. BMP Maintenance
12. Project Management
13. Low-Impact Development Facility Protection
UNDERGROUND INJECTION
CONTROL
Underground Injection Control (UIC) wells are
structures used to direct stormwater runoff
underground, usually under the force of gravity.
UIC wells consist of:
• A dug hole whose depth exceeds its largest
surface dimension.
• An underground fluid distribution system (e.g.,
perforated pipes).
Examples of stormwater UIC wells: drywells, an
infiltration trench containing perforated pipe,
bioretention systems with a perforated pipe below
the treatment soil, and stormwater infiltration
chamber systems.
The Department of Ecology regulates UIC wells
under the statewide UIC program to prevent
groundwater contamination. Owners of
stormwater UICs must apply the guidance in
the SWMMEW and submit UIC registration
applications 60 days prior to construction to
allow for sufficient review time.
All UIC wells not operated in accordance with
the law may result in a violation, including
action for injunctive relief.
Drywells are an example of a UIC.
LOW IMPACT DEVELOPMENT
Low Impact Development (LID) applies
stormwater and land use management strategies
that strive to mimic natural processes utilizing the
following principles:
• Preserve native vegetation.
• Protect critical areas.
• Minimize impervious surfaces.
• Minimize grading and compaction of site soils.
• Preserve existing flow paths.
• Infiltrate stormwater runoff.
• Disperse stormwater.
• Utilize natural surfaces.
• Utilize small-scale, distributed LID BMPs.
Examples of practices adhering to these
principles include: bioretention, rain gardens,
dispersion, and permeable pavements.
Implementing LID principles and practices
manages runoff in a way that reduces the impact
of built areas and promotes ecological functions.
The Permit requires jurisdictions to implement a
policy encouraging project proponents to maintain
natural drainages to the Maximum Extent
Practicable. This includes minimizing the disturbance
of native soils and vegetation, reducing the total
amount of impervious surfaces, non-structural
preventive actions, and pollutant source reduction
approaches. In utilizing LID approaches, consider
site conditions and long-term maintenance.
Bioretention cells are an example of LID BMPs.
INFILTRATION
The SWMMEW defines infiltration as the downward
movement of water from the land surface to the
subsoil. Infiltration BMP design allows stormwater
runoff to soak into the ground as a means of filtering
out pollutants and recharging groundwater.
Examples of infiltration BMPs: dispersion,
bioinfiltration, drywells, infiltration ponds and
trenches, bioretention, and permeable pavement.
ADDITIONAL INFORMATION
SWMMEW Chapter 3 (SSP) & Chapter 7
(ECP): WSDOT Temporary Erosion and Sediment
Control Manual:
https://wsdot.wa.gov/engineering-standards/all-
manuals-and-standards/manuals/temporary-erosion-
and-sediment-control-manual
[Insert link to local code/regulations/resources, if
applicable]ADDITIONAL INFORMATION
SWMMEW Appendix 3-D: Guidance on Low Impact
Development Site Planning Principles and Design
Strategies
[Insert link to local code/regulations/resources,
if applicable][Jurisdictions Name] local code/regulations/
ADDITIONAL INFORMATION
SWMMEW Chapter 5.6: Defines site suitability,
treatment requirements, and stormwater discharges
to UIC well design criteria.
Ecology’s UIC Program: https://ecology.wa.gov/
Regulations-Permits/Guidance-technical-assistance/
Underground-injection-control-program
UIC Registration: https://ecology.wa.gov/
Regulations-Permits/Guidance-technical-assistance/
Underground-injection-control-program/Register-UIC
-wells-online
ADDITIONAL INFORMATION
SWMMEW Chapter 5.4 and 6.3: [Insert link to local
code/regulations/resources, if applicable]SWMMEW Chapters 5.4 and 6.3, as well as/or
[insert local standards/manuals] include design and
installation information for infiltration BMPs. Some
infiltration BMPs qualify as UIC wells and must follow
requirements of the statewide UIC program (see UIC
section for more information).
Dispersion BMPs allow runoff to infiltrate over a large area.
Runoff infiltrates through permeable pavement.
