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/
statewide-lid-training-program-
plan
• 2014: Training program built
from state LID Training Plan.
PROJECT LEAD
ADDITIONAL TRAINING SUPPORT
OVERVIEW OF PROGRAM
CORE TEAM
PROGRAM OVERVIEW
• Implement first phase of
trainings (September 2014
through May 2015)
• 64 trainings offered in first
phase
• Three levels: Introductory,
Intermediate, and Advanced
• Train the Trainer program for
service providers and LID
topic experts
Introduction to
LID for Eastern
Washington
INTRODUCTORY
INTERMEDIATE
ADVANCED
TRAIN THE TRAINERS
Service Providers
Introduction to
LID for Inspection &
Maintenance Staff
Introduction to
LID for Developers &
Contractors: Make
Money be Green
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 Modelling
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
LID Topic Experts
Advanced Topics in
LID Design: Rainwater
Collection Systems &
Vegetated Roofs
Advanced Topics in
LID Design:
Bioretention Media
OVERVIEW OF PROGRAM
Advanced Topics for
LID Operations:
Bioretention
Intermediate
LID Design:
Bioretention
Advanced Topics for
LID Operations:
Permeable Pavement
Intermediate LID
Design: Site
Assessment, Planning
& Layout
INTERMEDIATE
TRAIN THE TRAINERS
Service Providers
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 Modelling
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
LID Topic Experts
Advanced Topics in
LID Design: Rainwater
Collection Systems &
Vegetated Roofs
Advanced Topics in
LID Design:
Bioretention Media
TODAY’S TRAINING
Advanced Topics for
LID Operations:
Bioretention
Intermediate
LID Design:
Bioretention
Advanced Topics for
LID Operations:
Permeable Pavement
Intermediate LID
Design: Site
Assessment, Planning
& Layout
Introduction to
LID for Eastern
Washington
3.2
ADVANCED
INTRODUCTORY
Introduction to
LID for Developers &
Contractors: Make
Money be Green
Introduction to
LID for Inspection &
Maintenance Staff
INSTRUCTORS
CHRIS WEBB, PE
LEED FELLOW
Associate Engineer
Key project experience:
permeable pavement,
bioretention, rainwater
harvesting
CURTIS HINMAN
Senior Scientist
Key project experience:
Research specialist in the
performance and design of
LID applications
introduction & regulations
AGENDA
BMP specifics
site assessment, planning, layout
wrap up
cost comparisons & resources
introduction & regulations
LOGISTICS
SCHEDULE
• 4-hour classroom training with one break
OTHER LOGISTICS
• Restroom location
• Food
• Turn off cell phones
• Sign in and sign out
LEARNING OBJECTIVES
Efficient application of LID BMPs.
New LID regulatory requirements.
How LID development process and cost compares with
conventional stormwater practices.
The basic principles of site assessment, site layout and
construction sequencing to improve the design and long-
term, effective operation of LID best management
practices (BMPs) and projects.
How to minimize construction impacts.
Minimum requirements for construction and protection
of LID BMPs during construction.
Why LID?
LOW IMPACT DEVELOPMENT (LID):
Stormwater Management Strategy
INTRODUCTION & REGULATIONS
• Site design & planning techniques
emphasizing conservation
• Use of small-scale & distributed
engineered controls to closely mimic
pre-development hydrologic processes
• Minimizing the concentration of
stormwater
• Careful assessment of site soils and
strategic site planning to best use those
soils for stormwater management
LID Principles: Pre-developed forest
INTRODUCTION & REGULATIONS
2012 LID Technical Guidance Manual for Puget Sound
LID Principles: Developed condition
INTRODUCTION & REGULATIONS
2012 LID Technical Guidance Manual for Puget Sound
LID Principles: Site Design And Planning
INTRODUCTION & REGULATIONS
• Minimize disturbance
• Reduce impervious
surface
• Protect and restore
native soils and
vegetation
• Manage stormwater
close to the source in a
system of distributed
practices
• Disconnect impervious
surfaces
Traditional
LID
LID BMPs: Small-Scale Engineering Controls
INTRODUCTION & REGULATIONS
• Infiltration
• Filtration
• Storage
• Evaporation
• Transpiration
Synonyms for LID BMPs:
Green Stormwater Infrastructure (GSI), Integrated Management Practices (IMPs), and On-Site Stormwater Management BMPs
Conserve or regain
pre-developed hydrologic
functions
Washington Municipal Stormwater Permits
National Pollutant Discharge Elimination System (NPDES) Municipal Stormwater
Permits (2013-2018 permit cycle)
Municipal Stormwater Permittees in Washington State
Phase 1 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
INTRODUCTION & REGULATIONS
NPDES PERMIT LID REQUIREMENTS:
Implementation Timeline Varies By Permittee
INTRODUCTION & REGULATIONS
Review and revise development related codes, rules & standards (i.e. adopt the
2012 Stormwater Manual)
Western WA Phase I and II timeline for updating local codes
Phase I
Per Section S5.C.5.b of
the Phase I Permit
Phase II
June
2014
June 30,
2015
Dec. 31,
2016*
June 30,
2017
June 30,
2018
Most
Permittees
Lewis Co. and
Cowlitz Co.
City of
Aberdeen
Per Section S5.C.4 of the Phase II Permit
* = Or GMA update deadline
NPDES PERMIT LID REQUIREMENTS:
Minimum Requirements
INTRODUCTION & REGULATIONS
Preparation of Stormwater Site
Plans
Construction SWPP
Source Control of Pollution
Preservation of Natural Drainage
Systems and Outfalls
On-Site Stormwater
management
Runoff Treatment
Flow Control
Wetlands Protection
O&M
NPDES PERMIT LID REQUIREMENTS:
Minimum Requirements (MRs)
INTRODUCTION & REGULATIONS
• MR #2 – Construction Stormwater
Pollution Prevention Plan (SWPPP)
• 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 PERMIT LID REQUIREMENTS:
Minimum Requirements (MRs)
INTRODUCTION & REGULATIONS
• MR #6 – Runoff Treatment
• Water quality treatment for pollution-
generating areas
• MR #7 – Flow Control
• Control of flow peaks and flow
durations
NPDES PERMIT LID REQUIREMENTS: List #1 &
2 vs. LID Performance Standard
INTRODUCTION & REGULATIONS
• List #1 (MR 1-5) and List #2 (MR 1-9)
• For each surface, consider the BMP’s in
the order listed for that type of surface.
Use the first BMP that is considered
feasible
• Example: Hard surfaces other than roof
Full dispersion
Permeable Pavement
Bioretention
Sheet Flow Dispersion
• Achieve the LID Performance Standard
(Duration Flow Control)
Note: achieving LID Performance Standard will
require very large ponds that may significantly
reduce buildable area without incorporating
LID practices.
List #1 & List #2 (HANDOUT)
NPDES PERMIT LID REQUIREMENTS:
On-Site Stormwater Management BMPs
INTRODUCTION & REGULATIONS
• Used to help meet MR #5
• May be used to help meet MR #6
(Treatment) and/or MR #7 (Flow
Control)
• “On-site Stormwater Management
BMPs”= LID BMPs
NPDES PERMIT LID REQUIREMENTS:
On-Site Stormwater Management BMPs
INTRODUCTION & REGULATIONS
• Includes the following LID 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)
Concentrated Flow Dispersion (BMP T5.11)
Sheet Flow Dispersion (BMP T5.12)
Compost Amended Soils (BMP T5.13)
Not “Engineered”
“Engineered”
NPDES PERMIT LID REQUIREMENTS: Treatment
and Flow Control BMPs/Facilities
INTRODUCTION & REGULATIONS
Subset of On-site Stormwater Management BMPs used to meet MR #6 or MR #7 (may
also be used to meet MR #5)
BMP
Flow Control
Treatment1
Compost Amended Soils (BMP T5.13)
Dispersion (BMP T5.30, T5.12, T5.11, T5.10B)
Retaining & Planting Trees (BMP T5.16)
Bioretention (BMP T5.14B)
Bioretention (underdrain)
Permeable Pavement (BMP T5.15)
Green Roofs (BMP T5.17)
Rainwater Harvesting (BMP T5.20)
1. Meets basic, enhanced and phosphorus treatment when infiltrating through soil meeting Ecology treatment requirements
2. Bioretention (underdrain) systems where the underdrain is elevated within the underlying base course can have some peak flow
reduction benefit.
3. Where permeable pavement is over soils meeting the suitability criteria or a treatment layer (sand or soil meeting criteria) is included,
then permeable pavement can provide treatment.
Q&A
site assessment, planning, layout
TRADITIONAL V. LID DEVELOPMENT
SITE ASSESSMENT, PLANNING & LAYOUT
• Minimize disturbance
• Reduce impervious
surface
• Protect and restore
native soils and
vegetation
• Manage stormwater
close to the source in a
system of distributed
practices
• Disconnect impervious
surfaces
Traditional
LID
TRADITIONAL V. LID DEVELOPMENT
SITE ASSESSMENT, PLANNING & LAYOUT
TRADITIONAL V. LID DEVELOPMENT
SITE ASSESSMENT, PLANNING & LAYOUT
Typical grid road layout
alley
Impervious coverage: 27-36%
Less adaptive to site features.
Promotes transit and
connectivity with more direct
access to services.
alley
TRADITIONAL V. LID DEVELOPMENT
SITE ASSESSMENT, PLANNING & LAYOUT
Typical curvilinear road layout
Impervious coverage: 15-29%
More adaptive to site features.
Generally discourages transit
with longer, less connected
system.
TRADITIONAL V. LID DEVELOPMENT
SITE ASSESSMENT, PLANNING & LAYOUT
Impervious coverage: similar
percentage to other layouts.
Adaptive to site features and
uses site features (particularly
water as an organizing theme).
Can provide good connectivity
and fire and safety access.
Hybrid or LID road layout
TRADITIONAL V. LID DEVELOPMENT
SITE ASSESSMENT, PLANNING & LAYOUT
Traditional
LID
TRADITIONAL V. LID DEVELOPMENT
SITE ASSESSMENT, PLANNING & LAYOUT
Hydrologic modeling comparing a conventional development and the flow reduction
benefits from individual practices for a low impact development design. The 24-acre
till-mantled site in southern Puget Sound has 103 lots and was modeled with Western
Washington Hydrologic Model (adopted from AHBL, 2000).
Detention storage
reduced (ft3)
Detention storage
required (ft3)
Conventional development
270,000
Low impact development
• reduce development envelope
• and use bioretention
• and use minimal excavation foundation
• and use 20’ wide permeable road
Total
-149,019
-40,061
-7,432
-29,988
-226,500
43,500
SITE ASSESSMENT, PLANNING & LAYOUT
General Layout Strategies
• Cluster development to preserve
vegetation and protect soils
• Grade to create small basins
• Maximize infiltration potential by
locating BMPS on best soils
Kensington Loop Road, 2012 LID Technical Manual
Site Layout: New Suburban Development
TRADITIONAL V. LID DEVELOPMENT
SITE ASSESSMENT, PLANNING & LAYOUT
Site Layout: New Suburban Development
Shared Driveways, 2012 LID Technical Guidance Manual
SITE ASSESSMENT, PLANNING & LAYOUT
Roads, Driveways and
Parking
• Reduce TIA by reducing overall
road network cover and
minimize or eliminate EIA
• Use stormwater BMPs to
infiltrate, slow, and filter storm
flows
• Minimize overall site disturbance
• Create connected walking,
biking, vehicular, and transit
services
• Create and use open space as a
community amenity and
stormwater management area
Site Layout: New Suburban Development
Shared Driveways, 2012 LID Technical Guidance Manual
SITE ASSESSMENT
SITE ASSESSMENT, PLANNING & LAYOUT
Preliminary Site Analysis
• Collect information from existing
analyses, inventories, and historic
information
• Conduct site reconnaissance and
characterization
• Info needed varies depending on which
Minimum Requirements are triggered
Potential Existing Site Conditions to Inventory
SITE ASSESSMENT
SITE ASSESSMENT, PLANNING & LAYOUT
Minimum Requirements for 1-5
• A survey prepared by a registered
land surveyor
• Include features from existing site
conditions table
• Contour map
• Intervals are dependent on site slopes
and elevations
• Soils report
• Survey of native soil and vegetation
areas
• Drainage report / Stormwater Site
Plan
SITE ASSESSMENT
SITE ASSESSMENT, PLANNING & LAYOUT
Minimum Requirements for 1-9
(Larger projects)
• More in-depth Geotechnical
assessment than conventional
project
• Ideally in 2 phases
Infiltration soils reconnaissance
(similar to septic reconnaissance)
for planning level design
information across entire site
Infiltration soils testing for design
level design information at the
location of the BMP
• Geotechnical Report or Soils
Report need to include infiltration
feasibility and design discussion
LID Site Reconnaissance with a Hand Auger
SITE ASSESSMENT
SITE ASSESSMENT, PLANNING & LAYOUT
Critical sub-surface assessment for
BMPs
• Bioretention
• Infiltration test at proper depth
• Permeable Pavement
• Staging and access
• Subgrade protection and remediation
• Infiltration test at proper depth
• Additional testing for Design
• PIT tests
• Depth to groundwater
• Mounding Analysis (if required)
Pilot Scale Infiltration Test (PIT)
SITE ASSESSMENT, PLANNING & LAYOUT
ECOLOGY SMALL-SCALE PIT METHOD
• PIT Timing
• Test between December 1 and April 1
• Number of PITs
• Recommend one PIT at each
bioretention site
• For larger site, one PIT every 5,000 sf
• For long narrow facilities, one PIT
every 200 lineal feet
(unless borings indicate consistent soil
characteristics)
• Important for Infiltrating
facilities ONLY
• Infiltrating facilities sized
based on infiltration rates
• Minimum “feasible” initial
infiltration rate of 0.3 in/hr
• Locate infiltrating BMPs in
areas with best soils
SITE ASSESSMENT, PLANNING & LAYOUT
SITING CONSIDERATIONS: Native Soils
SITE ASSESSMENT, PLANNING & LAYOUT
SITING CONSIDERATIONS: Soil Variability
Site 1
Site 3
Site 2
Broadview Green Grid, Seattle, WA
SITE ASSESSMENT, PLANNING & LAYOUT
SITING CONSIDERATIONS: Soil Variability
Broadview Green Grid, Seattle, WA
Site 1: Loam
SITE ASSESSMENT, PLANNING & LAYOUT
SITING CONSIDERATIONS: Soil Variability
Broadview Green Grid, Seattle, WA
Site 2: Sand
SITE ASSESSMENT, PLANNING & LAYOUT
SITING CONSIDERATIONS: Soil Variability
Broadview Green Grid, Seattle, WA
Site 3: Glacial till…