How to Suceed in Your Green Infrastructure Project

How to Succeed with
Your Green
Infrastructure Project
March 26th, 2015
Presented by: Kari Mackenbach, CFM, BCES
Melissa Hess, PE, CFM

| West Virginia Construction & Design Exposition | March 25th and 26th, 2015
Agenda
10:00-10:15 Welcoming Remarks and Overview
10:15-10:45 Steps to a Good Green Infrastructure Project
10:45-11:15 Focused Lessons Learned from Communities’
11:15-11:30 O&M Dictates the Type of Practice to Install
11:30-11:45 Common Pitfalls of Green Infrastructure Projects
11:45-12:00 Wrap-up and Questions/Answers
2

Overview of Green
Infrastructure
3

Definition of Green Infrastructure (GI)
No standard definition, but described as addressing:
 Storm water management
 Energy efficient buildings
 Climate change
 Heat stress
 Biodiversity
 Food production/urban agriculture
 Air quality
 Clean water and healthy soils
 Quality of life through recreation, shade, and shelter in and
around towns and cities
4

American River’s Definition
Green infrastructure is an approach to water management that:
 Protects,
 Restores, or
 Mimics the natural water cycle
5

EPA Definition of Green Infrastructure
Also known as low-impact development principles:
 Preserving and recreating natural landscape features
 Minimizing effective imperviousness to create functional and
appealing site drainage
 Treating storm water as a resource rather than a waste
product
6

What else is Green Infrastructure?
 Helping communities come closer to attaining the
CWA standards
 Public Perception (sustainable cities)
 Helps with your floodplain management strategies
 Leverage State and Federal Program Dollars
 Opportunity to “marry” multiple public work efforts
(streetscaping, sidewalks, parks, floodplain &
stormwater management)

| West Virginia Construction & Design Exposition | March 25th and 26th, 2015 8
Natural Water Cycle: Pre-Development
8

Natural Water Cycle:
Post-Development
 Increased
imperviousness
increases flows
 Puts structures
and people in
harm’s way
9

Distributed
Stormwater Features
Traditional Regional
Technique
Distributed Stormwater Controls
Close to Runoff Sources
Integrated Stormwater
Controls

How much does
an individual home affect stormwater runoff?
Street
Driveway
House
Stormdrain

How much does
an individual home affect stormwater runoff?
Street
In a 1” rainfall
Potential Runoff:
5,422 gallons
2,500 s.f.
“impervious” x 1” rain =
1,542 gallons
of runoff
Stormdrain
1,500 s.f. house (& patio) x 1” rain =
925 gallons of runoff
+ “Green Concrete” Compacted Lawn
8,390 s.f. “impervious” x 1” rain (if infiltrates first ¼” of rain)
= 3,880 gallons of runoff
1,000 s.f. driveway
x 1” rain = 617
gallons of runoff

| West Virginia Construction & Design Exposition | March 25th and 26th, 2015 13Photos: David Dods, URS
Consequences
• Property Loss
• Public Safety Hazard
• Damage to Public Infrastructure
• Major Sediment Source

How is Green Infrastructure &
Flooding Connected?
Seeing the Significance of the
Hydrologic Impacts of
Urbanization Over Time

How is GI Important for Floodplain
Management?
 Combining with water quality projects/initiatives
– NPDES permits
– Storm water utility fees
– Erosion issues (due to high flow volumes)
 Land use planning
 Post-flood rebuilding
 Mitigation projects
 Require for development in the floodplain
 Reducing flows from development
 Other?
15

Green Infrastructure Flood Benefits
 Not going to impact:
– 100-year flood
 May impact:
– 1-year flood
– Frequent nuisance
flooding
– Frequent storms
 Often significant financial
benefit for controlling frequent
storms
16

AFTER
BEFORE
• Residential
Neighborhood
• Rain Garden Retrofits
• Long-Term Monitoring
2006 Neighborhood Application

Burnsville, MN
Paired Study of Residential Street
Runoff Control

17 Rain Gardens Installed
Diagram courtesy of the City of Burnsville, MN from their
Burnsville Stormwater Retrofit Study
• 5.3 acres treated and 7.5 acres controlled
• Average treated lot < .5 acres
• Average total rain gardens < 1 acre

Blue: Control
Red: With Rain
Gardens
Diagram courtesy of the City of
Burnsville, MN from their Burnsville
Stormwater Retrofit Study

Steps to a Good Green
Infrastructure Project
21

Project Goals
 CSO/SSO mitigation
 Storm water concerns
 Distressed Parcels
 Community Reinvestment
 Floodplain Management
 Visual impacts
 Other CIP projects
 Costs

Selected Sites Overview – Putting the
Puzzle Together
 Is the land public?
 What are the limiting factors?
 Does it make cost effective sense?
 Is it an all green solution?
 How much do I have to capture?
 What about maintenance?
 Is it already functioning as green?

Green Infrastructure Types

Rain Gardens
Retrofit between existing curb & sidewalk
URS PictureURS Picture

Photo URS
Rain Gardens
Slow the Water Down & Innovative Plant Media

Sediment & Trash Control at Inlet

Photo: Lisa Treese, KCMO Water Services
Permeable Pavement
Retrofit between existing curb & sidewalk
URS Picture
URS Picture

Permeable Pavement
Within the ROW

Permeable Pavement
Within the ROW
URS Picture URS Picture

Photos: URS
Curb Extensions
With below-grade storage

Commercial Street
Pavers, below-grade storage, bioretention
Pervious Sidewalks Below Grade Storage
URS Picture
URS Picture

Tree Boxes
Below-grade storage, multiple applications

Step by Step
4
3
1/
2
5
1 2 3
4
5

What is it going to look like?
40

Evaluate the Limiting Factors

Trees….We Love Them and Hate Them!

Soil conditions is a key consideration
GI can work well in clay soils but………

Green Infrastructure Quantification

Green Infrastructure Quantification
 Impervious land uses
 Change land use characteristics without changing the land
use

Right-Sizing or Other Evaluation
48

Photo URS
Neighborhood Improvements
Photos URS

| West Virginia Construction & Design Exposition | March 25th and 26th, 2015 Photo URS
Photos URS

Photos URS

Photo URS
Photos URS

Focused Lessons Learned
from Other Communities’
56

Columbus Blue Print Areas

Blueprint Columbus Schematic (City of Columbus)
Defining Green Infrastructure for LOS Investigation

O&M Dictates the Type of
Practice to Install
60

Design with the end in mind…..
Key Green Infrastructure Considerations

Consideration: Evaluate the Existing
Conditions of the Area
Trees are great but……..

Consideration: Interconnection of
Systems
Rain Garden, Gravel Parking, Bioswale, & Below Grade Storage
Photo URS
URS Picture

Consideration: Purpose of GI
Stormwater by-passes GI feature entirely

Consideration: Location & Maintenance
Leaves & debris kill grass if not cleaned

Consideration: Long-term Maintenance
Sediment affects performance
URS Picture

Consideration: Long-term
Maintenance
Sediment affects performance

Consideration: Skilled Construction
Oversight and Construction
Sequencing
GI is still new to most construction contractors

Considerations: Inlet and Outlet Designs
Inlet designs for debris management are key
URS PictureURS PictureURS Picture

Consideration: Knowledgeable
Maintenance Crew
GI Maintenance is different
URS Picture
URS Picture

Consideration: Trash will find its way
into the GI Practice
Whether at the Inlet or Outlet or Outright in your Practice

Consideration: Small spaces can
equal great impact
Small footprint GI Practices work if you have good infiltration

Consideration: Location soil
conditions is a key consideration
GI can work well in clay soils but………

Consideration: Pilot Tested Design
Details
Inlets, Fore-bays, Edging and Filter Strips…..Oh my!

Consideration: Evolution of GI
Practices
GI Science is evolving……
75

Lessons Learned and Leveraged
Devil is in the Details
76
1. Be thoughtful of your current surroundings.
2. Get out from behind your computer and experience your basin.
3. Not all green infrastructure will work in every location, you have to be flexible.
4. You will run into utilities‘, you have to be flexible.
5. Design with the end in mind. Operation and Maintenance of these
practices are still evolving.
6. When in doubt go with something that is tried and true!

Common Pitfalls of Green
Infrastructure Projects
77

Bioinfiltration

Rain Gardens Bioretention
Cheaper but requires
more space in tight
soils
More to go wrong but
can require less space

“On-Line” vs. “Off-Line” Designs
On-Line
Off-Line
Off-Line Reduces Erosion Problems

Curb Cut
Curb Cut Details
Inlet

Maintaining Infiltration
Keep Equipment out of
Garden

Soil Preparation
to Maintain
Infiltration

Underdrain Designs
Filter Fabric only wraps the drain layer.
This design allows plant roots to
penetrate subsoils, and improve
infiltration with time

Underdrain Designs
An Older Design Approach
Gravel & Filter Fabric Prevent Root
Penetration to Subsoils. This may be
appropriate in some situations, but
detrimental in others.

Engineered Soils
(Bioretention or Biofiltration Systems)

Bad Soil Mix
Contractor substituted
on-site soil for compost
in the mix to save money

Plant Selections
Illustration: Dan Shaw
•Proper plants improve infiltration
• Rain gardens are not wetlands
• Remember planting zones
• Use pots & plugs, Not seed

Maintenance – Weeding & Mulching
Routine maintenance is required
Ease of maintenance begins with
thoughtful design

Photo: Lisa Treese, KCMO Water Services
Pervious Pavements
URS Picture
URS Picture

Construction Pervious Concrete
91
 Works well when turf grass is
used in conjunction with practice
 Collector of sediment and fines
 Tends to clog and get
permanently clogged in areas of
high sediment and fines
 Aesthetic concerns by residents
 Can be costly
 Long term maintenance
research has not be addressed

Permeable Pavement– Maintenance

Permeable Pavement
Exfiltration rate varies with
water depth and strata.
With deep trenches acting as the
storage gallery, it appears that
more exfiltration occurs through the
sidewalls than through the bottom.

Permeable Pavement
• Differential settlement occurred
due to aggregate getting into
arch of articulated concrete
block
• Some vendors are still new to
market and have steep learning
curve

Tree Boxes

Construction Tree Boxes
 Choosing the correct variety of tree
 Interconnected tree boxes vs. individual boxes
 Proprietary boxes vs. custom design
 Infiltration considerations
 Less surface area
 Media type
– Water quality or water quantity only
 Pretreatment/trash and debris
Enclosing the tree storage
area
• Grated boxes
• Curbs
• Railings
• Mulch or pea gravel

In Summary…
97

Maintenance
 No BMP (green or gray) is maintenance free
 Selecting the appropriate type of practice based on maintenance
considerations
 Long term maintenance plan
 Frequency of maintenance
 Equipment need
 Routine maintenance
 As needed maintenance
 Maintenance based on monitored performance
 Re-evaluation of practice types
 Skilled maintenance providers
98

$ $ $
GREEN DOES NOT REPLACE GRAY…
Can reduce the capital costs and O & M costs of gray
technology.

Acknowledgements
100
 URS
 AECOM
 Burnsville, Minnesota
 David Dods, AECOM
 BARR Engineering
 US EPA
 City of Columbus, DOSD
 CDM
 NY DEP
 Louisville MSD
 Anyone else that we forgot to mention…..Thank you for helping
us promote the wise use of Green Infrastructure!

For more information…
101
Contact Kari Mackenbach
info@msconsultants.com
614.898.7100

How to Suceed in Your Green Infrastructure Project

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