INTERMEDIATE LID TOPICS: NPDES PHASE I
AND PHASE II PERMIT REQUIREMENTS
WESTERN WASHINGTON
Training Program
Statewide LID
INSTRUCTORS
GEORGE IFTNER, CPESC
Senior Scientist
Key project experience: Stormwater
planning, monitoring, and NPDES
Permit compliance
REBECCA DUGOPOLSKI, PE
Senior Engineer
Key project experience: Stormwater monitoring,
design, and NPDES Permit compliance
introduction
AGENDA
345
permit background and definitions
minimum requirement #2
minimum requirement #5
O&M requirements
jeopardy
wrap up
code updates
introduction
AGENDA
345
LEARNING OBJECTIVES
1. Understand which BMPs are
considered on‐site SW Management
BMPs and which LID BMPs can also
be used to meet Minimum
Requirement (MR) #6 and/or MR #7.
2. Gain a general understanding of
Element #13 of MR #2.
3. Gain an in‐depth understanding of
the on‐site stormwater management
(MR #5) requirements.
4. Gain an in‐depth understanding of
the LID O&M requirements.
LOGISTICS
SCHEDULE
• 4‐hour training with one
break
OTHER LOGISTICS
• Restroom location
• Food
• Turn off cell phones
• Sign in and sign out
PROGRAM OVERVIEW
• 2012: Public and private
partners engage state
legislature to fund program.
• June 2012: LID Training
Steering Committee convened.
• 2012‐2013: Washington State
LID Training Plan developed:
www.wastormwatercenter.org/
lid‐background
• 2014: Training program built
from state LID Training Plan.
PROGRAM OVERVIEW
• 49 trainings in western and
eastern WA in 2014‐2015.
• 42 trainings in western and
eastern WA in 2015‐2016.
• 39 trainings offered in
western and eastern WA in
2017.
• Three levels: Introductory,
Intermediate, and Advanced.
• Statewide LID Certificate now
available.
PROJECT LEAD
ADDITIONAL TRAINING SUPPORT
OVERVIEW OF PROGRAM
CORE TEAM
Introduction to LID
for Inspection &
Maintenance Staff
INTRODUCTORY
INTERMEDIATE
ADVANCED
Intermediate LID
Design: Rainwater
Collection Systems &
Vegetated Roofs
Intermediate LID
Topics: NPDES Phase
I & II Requirements
Intermediate
LID Design:
Permeable Pavement
Intermediate
LID Design:
Hydrologic Modeling
Advanced Topics in
LID Design:
Bioretention
Advanced Topics in
LID Design:
Permeable Pavement
Advanced Topics in
LID Design:
Hydrologic Modeling
Advanced Topics in
LID Design: Site
Assessment,
Planning & Layout
Advanced Topics in
LID Design: Rainwater
Collection Systems &
Vegetated Roofs
Advanced Topics in LID
Design: Bioretention
Media and Compost
Amended Soils
OVERVIEW OF PROGRAM
Advanced Topics for
Long‐term LID
Operations:
Bioretention
Intermediate
LID Design:
Bioretention
Advanced Topics for
Long‐term LID
Operations:
Permeable Pavement
Intermediate LID
Design: Site
Assessment, Planning
& Layout
Introduction to LID
for Inspection &
Maintenance Staff
INTRODUCTORY
INTERMEDIATE
ADVANCED
Intermediate LID
Design: Rainwater
Collection Systems &
Vegetated Roofs
Intermediate LID
Topics: NPDES Phase
I & II Requirements
Intermediate
LID Design:
Permeable Pavement
Intermediate
LID Design:
Hydrologic Modeling
Advanced Topics in
LID Design:
Bioretention
Advanced Topics in
LID Design:
Permeable Pavement
Advanced Topics in
LID Design:
Hydrologic Modeling
Advanced Topics in
LID Design: Site
Assessment,
Planning & Layout
Advanced Topics in
LID Design: Rainwater
Collection Systems &
Vegetated Roofs
Advanced Topics in LID
Design: Bioretention
Media and Compost
Amended Soils
OVERVIEW OF PROGRAM
Advanced Topics for
Long‐term LID
Operations:
Bioretention
Intermediate
LID Design:
Bioretention
Advanced Topics for
Long‐term LID
Operations:
Permeable Pavement
Intermediate LID
Design: Site
Assessment, Planning
& Layout
AGENDA
345
permit background and definitions
NPDES MUNICIPAL STORMWATER PERMIT
National Pollutant Discharge Elimination System (NPDES) Municipal
Stormwater Permits (2013‐2018 permit cycle)
Municipal Stormwater Permittees in Washington State
Phase I Permittees
Western Washington
Phase II Permittees
Eastern Washington
Phase II Permittees
Seattle
Tacoma
Clark County
King County
Pierce County
Snohomish County
82 Cities
5 Counties
18 Cities
5 Counties
Secondary Permittees: Approximately 45; such as ports and universities
To see a listing of permittees visit
http://www.ecy.wa.gov/programs/wq/stormwater/municipal/MuniStrmWtrPermList.html
PERMIT BACKGROUND AND DEFINITIONS
NPDES MUNICIPAL STORMWATER PERMIT:
Minimum Requirements (MRs)
PERMIT BACKGROUND AND DEFINITIONS
Preparation of Stormwater Site Plans
Construction Stormwater Pollution
Prevention Plan (SWPPP)
Source Control of Pollution
Preservation of Natural Drainage
Systems and Outfalls
On‐Site Stormwater Management
Run‐off Treatment
Flow Control
Wetlands Protection
Operations and Maintenance
NPDES MUNICIPAL STORMWATER: MR #1
PERMIT BACKGROUND AND DEFINITIONS
• MR #1‐ Preparation of Stormwater Site
Plans
• Prepare a Stormwater Site Plan for local
governmental review in accordance
with Volume 1, Chapter 3 of the
SWMMWW
Site Analysis: Collect and Analyze
Information on Existing Conditions
Prepare Preliminary Development Layout
Perform Off‐site Analysis (at local government’s option)
Determine Applicable Minimum Requirements
Prepare a Permanent Stormwater Control Plan
Prepare a Construction Stormwater Pollution Prevention Plan
Complete the Stormwater Site Plan
Check Compliance with All Applicable Minimum Requirements
NPDES MUNICIPAL STORMWATER: MR #2 and
MR #5
PERMIT BACKGROUND AND DEFINITIONS
• MR #2 – Construction SWPPP
• New element #13 is now
required by Construction
Stormwater General Permit
(CSWGP): Protect LID BMPs
from sediment and compaction
• MR #5 – On‐site Stormwater
Management
• Infiltrate, disperse, and retain
runoff on‐site to the extent
feasible
Lotus Springs. Photo: Curtis Hinman
NPDES MUNICIPAL STORMWATER: MR #6, #7,
and MR #9
PERMIT BACKGROUND AND DEFINITIONS
• MR #6 – Runoff Treatment
• Provide water quality treatment for
pollution‐generating areas
• MR #7 – Flow Control
• Control peak flows and duration
• MR #9 – Operations and Maintenance
• Provide an O&M manual for all proposed stormwater treatment
and flow control BMPs/facilities
DEFINITIONS
PERMIT BACKGROUND AND DEFINITIONS
Hard Surface
• Impervious surfaces, permeable pavements, or vegetated roofs
Impervious
Surfaces
Permeable
Pavement
Vegetated Roofs
DEFINITIONS
PERMIT BACKGROUND AND DEFINITIONS
Pollution‐Generating Hard Surface (PGHS)
• Pollutant‐generating hard surfaces subject to vehicular use,
industrial activities, material storage
• Pollution‐generating impervious surfaces (PGIS) and pollution‐
generating permeable pavement
PG Permeable
Pavement
PGIS
DEFINITIONS
PERMIT BACKGROUND AND DEFINITIONS
Pollution‐Generating Impervious Surface (PGIS)
• Pollutant‐generating impervious surfaces subject to vehicular
use, industrial activities, material storage
• Roofs subject to venting significant amounts of dusts, mists, or
fumes from manufacturing, commercial, or other indoor
activities
DEFINITIONS
PERMIT BACKGROUND AND DEFINITIONS
Pollution‐Generating Pervious Surface (PGPS)
• Non‐impervious surface subject to vehicle use, industrial
activities, pesticides, fertilizers, erosion
• Pollution‐generating permeable pavement, lawn and landscaped
areas, golf courses, parks, sports fields
PG Permeable
Pavement
Golf Courses
Sports Fields
Surface Type
Pollution‐
Generating
Impervious
Surface
(PGIS)
Hard
Surface
Pollution‐
Generating
Hard Surface
(PGHS)
Pollution‐
Generating
Pervious
Surface (PGPS)
Conventional asphalt
parking lot
Permeable pavement
parking lot
Turf soccer field
Vegetated roof
Permeable pavement
sidewalk not subject
to vehicular traffic
Roof subject to
venting of dusts
DEFINITIONS
PERMIT BACKGROUND AND DEFINITIONS
• Used to help meet MR #5
• May be used to help
meet MR #6 and/or MR
• “On‐site Stormwater
Management BMPs”= LID
BMPs
DEFINITIONS
PERMIT BACKGROUND AND DEFINITIONS
“Distributed stormwater management practices, integrated into a project design, that
emphasize pre‐disturbance hydrologic processes of infiltration, filtration, storage,
evaporation and transpiration. LID BMPs include, but are not limited to, bioretention/rain
gardens, permeable pavements, roof downspout controls, dispersion, soil quality and depth,
vegetated roofs, minimum excavation foundations, and water re‐use.”‐ Western Washington
Phase II Municipal Stormwater Permit
On‐Site Stormwater Management BMPs
On‐Site Stormwater Management BMPs:
• Rain Gardens (BMP T5.14A)
• Bioretention (BMP T5.14B)
• Permeable Pavement (BMP T5.15)
• Vegetated Roofs (BMP T5.17)
• Downspout Full Infiltration (BMP T5.10A)
• Downspout Dispersion (BMP T5.10B)
• Perforated Stub‐Out Connections (BMP T5.10C)
• Concentrated Flow Dispersion (BMP T5.11)
• Sheet Flow Dispersion (BMP T5.12)
• Compost Amended Soils (BMP T5.13)
DEFINITIONS
PERMIT BACKGROUND AND DEFINITIONS
DEFINITIONS
PERMIT BACKGROUND AND DEFINITIONS
On‐Site Stormwater Management BMPs:
• Permeable Pavement (BMP T5.15): Pervious
concrete, porous asphalt, permeable pavers
or other forms of pervious or porous paving
material intended to allow passage of water
through the pavement section. It often
includes an aggregate base that provides
structural support and acts as a stormwater
reservoir.
• Vegetated Roofs (BMP T5.17): Vegetated roofs
(also known as ecoroofs and green roofs) are
thin layers of engineered soil and vegetation
constructed on top of conventional flat or
sloped roofs.
DEFINITIONS
PERMIT BACKGROUND AND DEFINITIONS
On‐Site Stormwater Management BMPs:
• Downspout Full Infiltration (BMP T5.10A): Trench or drywell
designs intended only for use in infiltrating runoff from roof
downspout drains.
• Downspout Dispersion (BMP T5.10B): Downspout dispersion
systems are splash blocks or gravel‐filled trenches, which serve to
spread roof runoff over vegetated pervious areas.
• Perforated Stub‐Out Connections (BMP
T5.10C): A length of perforated pipe
within a gravel‐filled trench that is
placed between roof downspouts and
a stub‐out to the local drainage system.
DEFINITIONS
PERMIT BACKGROUND AND DEFINITIONS
On‐Site Stormwater Management BMPs:
• Concentrated Flow Dispersion (BMP T5.11): Dispersion of
concentrated flows from driveways or other pavement through a
vegetated pervious area attenuates peak flows by slowing entry
of the runoff into the conveyance system, allowing for some
infiltration, and providing some water quality benefits.
• Sheet Flow Dispersion (BMP T5.12): The simplest method of
runoff control. This BMP can be used for any impervious or
pervious surface that is graded to avoid concentrating flows.
DEFINITIONS
PERMIT BACKGROUND AND DEFINITIONS
On‐Site Stormwater Management
BMPs:
• Post‐Construction Soil Quality
and Depth (BMP T5.13):
Regain greater stormwater
functions post development,
providing increased treatment
of pollutants that result from
development and habitation,
and minimizing the need for
some landscaping chemicals,
thus reducing pollution
through prevention.
DEFINITIONS
PERMIT BACKGROUND AND DEFINITIONS
On‐Site Stormwater Management BMPs:
• Rain Gardens (BMP T5.14A): Rain gardens are non‐engineered,
shallow, landscaped depressions with compost‐amended soils
and adapted plants.
• Bioretention (BMP T5.14B): Bioretention areas are shallow
landscaped depressions, with a designed soil mix and plants
adapted to the local climate and soil moisture conditions, that
receive stormwater from a contributing area.
DEFINITIONS
PERMIT BACKGROUND AND DEFINITIONS
Rain Garden vs. Bioretention
• Rain Gardens (BMP T5.14A)
• Usually do not include under‐drains
• May use less restrictive soil mix guidelines (e.g., existing soil
augmented with compost and sand)
• Can only be used to meet MR #5 requirement
• Bioretention (BMP T5.14B)
• Often includes surface and subsurface infrastructure
• Designed soil mix
• Meets requirements for MR #5, #6, and #7
SW Treatment & Flow Control BMPs/Facilities (MR #6 and/or MR #7):
“Detention facilities, treatment BMPs/facilities, bioretention,
vegetated roofs, and permeable pavements that help meet
Appendix 1 Minimum Requirements #6 (treatment), #7 (flow
control), or both”
Western Washington Phase II Municipal Stormwater Permit
DEFINITIONS
PERMIT BACKGROUND AND DEFINITIONS
Onsite SW Management BMP
Flow Control
Credit
Treatment
Credit1
Soil Amendment
Dispersion
Retaining & Planting Trees
Rainwater Harvesting
Bioretention3
Permeable Pavement3
Vegetated Roofs 3
DEFINITIONS
PERMIT BACKGROUND AND DEFINITIONS
Subset of On‐site Stormwater Management BMPs used to meet
MR #6 or MR #7
1 Meets basic, enhanced and phosphorus treatment when infiltrating through soil per Ecology treatment requirements
2 Where permeable pavement is over soils meeting the suitability criteria or a treatment layer is included
3Also considered SW Treatment & Flow Control BMPs/Facilities (additional requirements in regard to long term inspection,
operations, and maintenance apply)
Q&A
AGENDA
345
minimum requirement #2
#1 Preparation of
Stormwater Site
Plans
#2 Construction
Stormwater
Pollution
Prevention Plan
#3 Source Control
of Pollution
#4 Preservation of
Natural Drainage
Systems and
Outfalls
#5 On‐site
Stormwater
Management
#6 Runoff
Treatment
#7 Flow Control
#8 Wetlands
Protection
#9 Operation and
Maintenance
MINIMUM REQUIREMENT #2
MINIMUM REQUIREMENT #2: 13 Elements
#1 Preserve
Vegetation / Mark
Clearing Limits
#2 Establish
Construction
Access
#3 Control Flow
Rates
#4 Install Sediment
Control
#5 Stabilize Soils
#6 Protect Slopes
#7 Protect Drain
Inlets
#8 Stabilize
Channels & Outlets
#9 Control
Pollutants
#10 Control De‐
Watering
#11 Maintain BMPs
#12 Manage the
Project
#13 Protect Low
Impact
Development BMPs
New Element
also required by
the CSWGP
MINIMUM REQUIREMENT #2: Element #13,
Protect LID BMPs
• Install/maintain erosion &
sediment control BMPs to
protect bioretention, rain
gardens, and permeable
pavement
• Chapter 3, Section 3.3.3, of
Volume II
Good upslope stabilization, flow diverted
around bioretention area
MINIMUM REQUIREMENT #2: Element #13,
Protect LID BMPs
• Fully restore BMPs if they
accumulate sediment during
construction
• Keep construction equipment and
foot traffic off bioretention, rain
garden, and permeable pavement
MINIMUM REQUIREMENT #2: Element #13,
Protect LID BMPs
• Keep muddy equipment off
pavement or base material
• Keep runoff off permeable
pavements
• Keep heavy equipment off final
grades (don’t compact)
Bunyan Screed
Mechanical ecostone installation
MINIMUM REQUIREMENT #2: Element #13,
Protect LID BMPs
Suggested planning and sequencing techniques
• Re‐vegetation: plant when vegetation will establish quickly
(late fall, winter, or early spring); fertilize and protect plants,
restrict heavy equipment on areas designated for re‐
vegetation; provide soil amendments if necessary
MINIMUM REQUIREMENT #2: Element #13,
Protect LID BMPs
Suggested planning and sequencing techniques (cont.)
• Inspections: Pre‐construction, routine, and post‐construction
inspections to verify measures for protecting LID BMPs have
been taken
• Soils: preserve and/or utilize areas of the site with nutrient rich
soils
MINIMUM REQUIREMENT #2: Element #13,
Protect LID…