On May 26, 2016, Michele Adams of Meliora Design and Tavis Dockwiller of Viridian Landscape Studio gave a presentation on green infrastructure during a workshop put together by New Jersey Future. The workshop was held for design professionals like engineers, landscape architects, and architects who design and/or review stormwater management systems in the Highlands of New Jersey.

1. Highlands Regional Green Infrastructure Workshop
For Engineers and Design Professionals
May 26, 2016
Presented by New Jersey Future

2. Our Partners
ANJEC
Highlands Coalition
Sustainable Jersey
Highlands Council
Rutgers Cooperative
Extension

3. Workshop Participants
Design engineers
Landscape architects
Architects
Maintenance facility/ property
managers
Construction managers

4. Agenda
Welcome and Introductions
Green Infrastructure 101
Small Storm Volume Management
Why Green Infrastructure?
Policy, Highlands Stormwater, and the Market
Case Studies: Lessons Learned, Triple Bottom Line
and Myth Busting
Stormwater “Credit for GI”
Break to Get Lunch
Lunch Discussion: Getting Past Barriers
Groups Report Out
Closing remarks

5. The Hydrologic Cycle

6. 15”
45
”
22”
8”
Natural Water Cycle Pennsylvania
50”
26”
12”
12”

7. It wants to be a forest – a tree is the best practice
99% of North America was covered by forest from the
Atlantic shoreline to the prairies of the Great Plains.
Today only fragments remain.
Pre-European settlement Present
http://earthobservatory.nasa.gov 14 October 2003

8. It wants to be a forest, but…
43,480 square miles of blacktop = 5.5 the size of
New Jersey

9. 45”/YR
2”
43”
Altered Water Cycle – Impervious Surfaces
50”
3”
0”
47”!

10. How compacted is this soil?
Common Bulk Density Measurements
David B. Friedman, District Director -- Ocean County Soil Conservation District
Golf Courses, Parks, Athletic Fields
1.69 to 1.97g/cc
Undisturbed Lands:
Forests & Woodlands
1.03g/cc
CONCRETE
2.2g/cc
Residential
Neighborhoods
1.69 to 1.97g/cc
Bulk Density is defined as the weight of a unit volume of soil including its pore space (g/cc or grams/cubic centimeter). Water and air are
important components of soil and we must frame our soil concepts so that factors affecting water and air dynamics are included. Thus, we are
primarily interested in bulk density and pore space as they affect water and aeration status, and root penetration and development.

11. Despite decades of detention basins, we still have
flooding from development.

15. • Stream channel erosion
releases sediment
• Pools and riffles are lost
• Large storms cannot reach
floodplains
• Less recharge = less
baseflow
• Small streams can go dry
• La

16. Two important observations:
96% of the annual rainfall volume is from storms 3 inches or less
Frequency: Most of the time, it rains 1 inch or less
Annual Percentages of Volume from Storms

18. Section 438 of the Energy Independence and Security Act (Dec 2009)
Design, construct, and maintain stormwater
management practices that mimic natural hydrology
OR
Retain the 95th percentile Rainfall (around 1.7”)
EPA’s Direction for Federal Facilities
We are seeing
variations of this
requirement in MS4
NPDES permits in
different states.
Municipal Separate
Storm Sewer System

19. Creating a Built Environment That Looks Like a Forest
26 in.
12 in.
12 in.
Evaporation
Infiltration
Runoff
Annual Rainfall
50 in.

20. How we BUILD and how we PLAN
Low Impact Development (LID)
or Green Infrastructure (GI)
“Allow natural infiltration to occur as close as possible to the
original area of rainfall. By engineering terrain, vegetation,
and soil features to perform this function, costly conveyance
systems can be avoided and the landscape can retain more of
its natural hydrologic function.”
National Association of Home Builders

21. DuPont Barley Mills Office Complex
1986
• Preserve Woodlands
• Reduce Site
Disturbance

26. Morris Arboretum, Phila
Morris Arboretum

28. Diagram of infiltration bed at
Morris Arboretum

29. 22
”
8”
Tools for how we build:
• Green roofs
• Porous Pavements
• Rain Gardens and Bioretention
• Cisterns and Reuse

30. New Development: Residential
• High Density Residential
• 59 acres
• 269 homes:
• 146 Townhouses
• 96 Quads
• 17 Singles
• Sinkholes and limestone
Can Water be Managed within the landscape?127 small measures, no detention basins.

36. • Quad homes without
basements have down
spouts connected to
infiltration beds beneath
impervious driveways.
• Paths made of pervious
asphalt.

37. • Stormwater beds beneath
driveways (standard
asphalt).
• Overflow to swales along
streets

41. • Each home manages its own
runoff in a Rain Garden and
Stone Seepage Bed, located
in the right-of-way.

42. New Development: Suburban Commercial Mixed-Use
• Pervious asphalt, stormwater infiltration beds, vegetated swales, rain gardens.
• Protect stream, wetlands, woodlands.
• Reduce flooding by 33%.

43. Site Analysis – Existing features inventory
• Existing Natural Features
• Waterbodies
• Floodplains
• Riparian areas
• Wetlands
• Woodlands
• Natural drainageways
• Sinkholes
• Steep slopes
• Undisturbed area
• Manmade Features / Historic
Land Use
• Former Land Use (ag,
indust., etc.)
• Abandoned utilities
• Active utilities
• Easements/Deed
Restrictions

44. Existing Site

45. Existing Site

47. Mixed Use Development at Valley Square Town Center
• Porous Pavement
• Subsurface Infiltration Beds
• Bioswales
• Bioretention Systems
• Reduced pre-development peak rates by 67.5% for 1-100 year storms
•Distributed infiltration design, mostly under porous pavement – almost 10
acres (plus multiple rain gardens and vegetated infiltration beds)
•Total infiltration area – 16 ac

48. Bio-retention
Infiltration Bed below Standard Asphalt

49. Porous Paving
Conventional
Paving
Porous Pavement

50. Valley Square
Warrington, PA
- Protected
Areas
Porous
Pavement
Bio-retention

52. Green Infrastructure Retrofits: Schools, Streets, and Parking

53. Greening Greenfield School

54. Green Infrastructure for Areas with Combined Sewers
Greening Schoolyards for Education and
the Environment

55. “Schools make up 2% of all
impervious cover in the City,
but because they are highly
visible and associated with
education, making them critical
components in a green
stormwater infrastructure
program, they present a high
priority target for greening.
The goal is to retrofit up to half
of all schools in the City in the
coming 20 years. PWD plans to
support the retrofitting of up to
5 school campuses per year,
utilizing an array of stormwater
measures such as rain gardens,
green roofs, rain barrels and
cisterns.”
Section 10 • Recommended Plan Elements 10-23
City of
Philadelphia
Goal: Capture 1” Rainfall
Volume

56. Location:
Schuylkill River Combined Sewer

57. Aerial looking East

58. Site Photos

59. Water Assessment Practices:
Drainage Area to Capture

60. Water Assessment Practices: Site Inventory Existing Hydrology
3’ dia. combined sewer
Roof leaders

61. The Vision
Stormwater Plan

62. Viridian Landscape Studio • SMP Architects • Meliora Environmental Design
Design: Engage all users
Address age preferences
Society: Encourage collaboration and engage the
public
Develop Community Stewardship
Education: Design to Inform the Public
Teach Future Generations
Effect Transformation of Future Generations

63. South Swale Experimentation
Rain chain and gauge

64. West Play Yard:
Cross Section at Infiltration Swale
Evapotranspiration
by plants
Excess Runoff is
Infiltrated

65. East Play Yard: Entry Feature

66. East Play Yard: Entry Feature

67. East Play Yard: Entry Feature

69. Materials: Salvaged Stone
Granite from the Philadelphia Zoo
Marble and granite from Independence Mall
Sandstone Bridge Abutments from Schuylkill River Bridges

71. Planted in the style of the Wissahickon
Forest
Photo: Wissahickon Creek near Philadelphia c.
1865 from the National Gallery of Art by John
Moran
Painting: View on the Wissahickon by James
Peale 1830
Observation

72. Materials
Rubber Play Surface
Recycled
Percolates at 11”/HR
Need proper base course
design to accept stormwater

73. Planting
Experts and
Volunteers
• TreeVitalize
PA Dept of Conservation and Natural Resources and The Pennsylvania
Horticultural Society
• CSX Corporation
Used Greenfield as a kick-off to their monumental initiative – the planting of
one tree for every mile of the 21,000 miles of its commercial track.
• ACT (Alliance for Community Trees
• Greenfield Home and School Association
• Parents/ Children
• Teacher
• Design Team
• Contractors
• Philadelphia Water Department Office of Water Sheds

75. Participation

78. Greening Lea
Master Plan
January 9, 2013
SMP Architects
meliora environmental design
viridian landscape studio

79. 2
3
1

80. 1
2
3

81.  Security: The smaller play lot is remote and not supervised, site is
dark and 47th St. can be quite deserted and unsafe.
 Only blacktop/ no shade on the playground
 Vehicular access to dumpsters is bad
 Basketball court orientation is a problem
 Lack of age-range in equipment
CONCERNS AND CHALLENGES
NEEDS & DESIRES – BIG IDEAS
 Replicate the feel of the “secret garden” within the school
yard
 Create a link between neighborhood garden center/ existing
garden beds/ curriculum
 Create a “vibrant community node”
 Foster partnership with adjacent tennis facilities
 Incorporate stormwater management projects that PWD
would like to help realize

83. Street
Runoff

84. Street Runoff into Schoolyard = $$ for Greening Schoolyards

85. Lea School – Captures 2 acres of
school and street right-of-way

86. Waterview Recreation Center
Philadelphia, PA
1. Underground infiltration beds
with porous concrete surface
2. Porous concrete pavement
3. Trees in trenches
4. Flow-through planter boxes

87. Before
Waterview Recreation Center
New Sidewalk that captures street runoff

88. After

89. Bio-retention
Water from the street enters through
a trench drain
Overflow water
exits to an inlet

90. Passyunk and 63rd

91. Site Analysis
Existing Conditions

92. Passyunk and 61st

93. Sunoco Refinery

94. Passyunk and 28th

95. Porous Paver Plaza

96. Erie Canal MuseumCity Hall Canal
Water Street
Syracuse NY

97. Stormwater PipingPorous Pavers Planter Cells Structural Soil Extents
Stormwater Capture Enlargement

98. 6-8” S-1 Soil Layer: Planting Soil Surface layer. A layer consisting of material with a USDA Texture of
sand to loamy sand (S2) amended with organic matter. (must be tested to meet specs after compost is
approved and added)
24” S-3 Soil Layer: Planting Soil Drainage Layer consisting of a 6 layer of material with a USDA
Texture of coarse sand
Stormwater Section

99. 1st Comprehensive Green Street

100. Year Completed: 2011
Construction Cost: $837,000
Capture Area: 53,000 sf
Square Foot Cost: $15.79/SF
Runoff Reduction: 924,000 gal/yr
Green Technology: Bioinfiltration
Trenches, Porous Pavement,
Native Plantings
The Facts

101. Erie Canal MuseumCity Hall Canal
Case Study: Water Street, Syracuse NY

102. Alternative Technologies

103. 1 Million gallons of
runoff / year

104. 1ST Comprehensive
Green Street

105. Year Completed: 2011
Construction Cost: $837,000
Capture Area: 53,000 sf
Square Foot Cost: $15.79/SF
Runoff Reduction: 924,000 gal/yr
Green Technology: Bioinfiltration
Trenches, Porous Pavement,
Native Plantings
The Facts

106. 1ST Comprehensive
Green Street
Erie Canal Museum
City Hall
Small Businesses

107. Stormwater Capture
Enlargement
Stormwater PipingPorous Pavers Planter Cells Structural Soil Extents

108. 6-8” S-1 Soil Layer: Planting Soil Surface layer. A layer consisting of material with a USDA Texture of
sand to loamy sand (S2) amended with organic matter. (must be tested to meet specs after compost is
approved and added)
24” S-3 Soil Layer: Planting Soil Drainage Layer consisting of a 6 layer of material with a USDA
Texture of coarse sand
Stormwater Section

109. A 4’ x 5’x 3’ tree pit
(typical in urban settings)
only provides 60 cubic
feet of soil!
A 10’ x 34’x3’ tree
trench provides the
1000+cf necessary for
successful tree
canopy cover
120 cf 500 cf 1000 cf
The success to street tree longevity is credited to the amount of soil volume available for
tree growth. A large tree, with a desired lifespan beyond 15 years (average life of a
downtown street tree is just 13 years) needs a minimum 500 – 1200 cubic feet of soil
to reach a size that significantly contributes to a healthy community and ecosystem.
60cf
With thanks to the work of Jim Urban, Edward Gilman and Tim Craul
The Truth about Trees

110. PERENNIAL PLUGS SMALL CALIPER TREECONTAINER SHRUBS
Things We Specify

111. Things Contractors Understand
Stone
Compaction
Curbs
Inlets

112. Utility vault uncovered during
construction is located directly in
proposed plant bed
ADA ramp conflict with
snow plows
No option to reject based on root
issues as nursery stock is already
dug and covered without tree tagging
Expect the Unexpected

113. MAINTENANCE: Hire the Contractor via a
Separate Contract for at least 1 year
RAIN GARDEN
I. 1st Year Maintenance: Inspect 2x/year
(Late May to early July, and/or late
August/early September)
II. Inspection: 1x/year minimum (Late May to
early July, and/or late August/early
September)
III. Weeding: 3x/year minimum (Spring clean
up, summer maintenance, fall put to bed)
IV. Mulching: Minimum 1x/year (Spring)
V. Pruning: 1x year (Spring)
Stuff We Try to Require

114. Keep it Simple Stupid

115. How are the streets swept?
Who cleans out inlets?
Who repairs the road?
Are their codes that must change?
What are the tools for collaboration?
Who is vested in the big picture?
Were the Long-Term Caregivers vested in
THE PLAN?
You Asked for it !

116. Volunteers are not enough

117. Show Me the Money

118. A landscape architect’s fairy tale: our dream of happily every after
Vincent Van Gogh: The Road Menders
The Phillips Collection, Washington, DC. Acquired 1949

119. Case Study: East Liberty Ave Pittsburgh PA

122. Cathedral of Hope
East Liberty Presbyterian Church

123. Site Plan
Existing
Walk
RaingardenRaingarden
LawnLawn
Benches in
Groundcover
Large Canopy Allee
Bus Stop

124. Stormwater Management Plan: Infrastructure
Stormwater Storage bed
Raingardens
Downspouts &
Infrastructure

125. Trench Configurations and Sizes: Soil Volume
What happens underground / who maintains it?
Soil & Stormwater Infiltration Bed/ Root Zone
Planting Trench
Standard or Porous
Paving
Soil Cells or
Structural Soil
Porous Hardscape or
Groundcover

126. Management Plan: Public vs. Private

127. Maintenance Plan: Tree Ownership?

128. East Liberty Cathedral of Hope
Pittsburgh PA

129. East Liberty Cathedral of Hope
Pittsburgh PA
“The prior landscaping. . .looked postcard-perfect from a distance, but it was functionally unwelcoming up
close. Now we have broken that stone border with a series of benches and tables. As people wait for the bus
or simply pause on their way up and down Penn Avenue, they can sit on benches . . . Our building now has a
living, active link to the neighborhood, modeling a renewed and faithful spirit of hospitality.” East Liberty
Presbyterian blog June 9, 2014

130. East Liberty Cathedral of Hope
Pittsburgh PA

131. Haddon Township Van Sciver School
Haddon Township, NJ
Philadelphia

132. PROJECT SITE
xxxx
Photo Source: Google Maps
Van Sciver School
Saddlers Woods
Project Site

133. STORMWATER FEATURES

134. Construction

135. 1
4
2
3
CONSTRUCTION

136. 5/31/2016
Retrofitting Suburban Basins: Hold 1”

137. Retrofitting Suburban Basins: Hold 1”

138. Questions?

139. Calculations
How can we give credit for the volume
management of Green Infrastucture
when we calculate peak flow rates and
flood mitigation?

140. 142
Maryland
Environmental Site Design (ESD)
Approach
An approach to credit volume management in
peak rate calculations

141. 143
Multiple Land Uses and Soil Types:
• Weighted CN
Runoff Depth 10 year, 24 hr
Q = (P-0.2S)2
(P+0.8S)
- 10 =S = 1000
CN
= 78
Weighted CN and
Runoff Depth
B
C
Residential 36% imp
Residential 36% imp
75
83
22.8
15.2
38
1,710
1,261
38
2,791
2,791
5.0 in
78
10 year
78
1000
78
-10 = 2.82
Q = (5.0 - 0.2 (2.82))2
(5 + 0.8(2.82))
in
Initial Abstraction = 0.2S = 0.56 in
Volume Runoff = Q x Drainage Area
= 2.71 in x 38 acres = 373,817 ft2
= 2.71 in

142. 144
Time of Concentration
(tc) is the time it takes
for runoff to travel from
the most hydraulically
distant point in the
watershed to the outlet.
Time of Concentration (tc) affects the shape and peak of the hydrograph.
Small tc changes can sometimes have big qp impacts
SCS Dimensionless Unit Hydrograph

143. 145
• Curve Number determines Runoff Depth (inches) and
Volume (ft3)
• Hydrograph represents volume (flow over time)
• Can we adjust CN to represent LID practices that
reduce volume?
• Q is adjusted Runoff Depth managed by infiltration or
volume reduction practices
Adjusted CN McKuen

144. 146
Site Data
Total Drainage Area: 38 acres
Soil Types: 60% B (22.8 acres) 40% C (15.2 ac)
Land Use: Woods Good Condition (existing)
Proposed Land Use: ½ acre lots, impervious 36%
P = 10 year = 5.0 in
Existing Proposed
CN 61 78
Q runoff depth (in) 1.37 in 2.71 in
Volume (area x Q) 188,978 ft3 373,817 ft3
Ia (in) 1.27 in 0.56 in
Suppose we add SMPs that manage 93,800 ft3 of runoff? (that’s equivalent to
about 1.89 in from 13.68 acres of impervious, or about 0.68 in over entire 38
acre site)
Example – Residential Development
Let’s Add Volume Management

145. 147
Site Data
Total Drainage Area: 38 acres
Soil Types: 60% B (22.8 acres) 40% C (15.2 ac)
Land Use: Woods Good Condition (existing)
Proposed Land Use: ½ acre lots, impervious 36%
P = 10 year = 5.0 in
Existing Proposed
CN 61 78
Q runoff depth (in) 1.37 in 2.71 in
Volume (area x Q) 188,978 ft3 373,817 ft3
Ia (in) 1.27 in 0.56 in
93,800 ft3 managed / (38 acres x 43,560 ft/ac) x 1ft/12in =0.68 in
Q – QE = Q ADJ = 2.71 in – 0.68 in = 2.03 inches
Example – Residential Development
Adjusted Q (runoff depth)

146. 148
Existing Proposed
CN 61 78
Q runoff depth (in) 1.37 in 2.71 in
Volume (area x Q) 188,978 ft3 373,817 ft3
Ia(in) 1.27 in 0.56 in
Q – QE = Q ADJ = 2.71 in – 0.68 in = 2.03 inches
Our new CN of 70 can be used to calculate peak discharge rate.
Example – Residential Development
Calculate New CN

147. 149
• Infiltration or Volume Management
distributed evenly over site
• Each house has its own SMPs
• Tc is not adjusted
• Maryland’s goal is to replicate “woods in good
condition”
• Lookup Tables and Spreadsheet Tool
Important Assumptions

148. Maximum Extent Practicable is defined as maintaining
predevelopment site runoff to “woods in good condition.”
The resulting ESD volume typically ranges between 1.7
and 2.6 inches, depending on soils and development
intensity
Maryland ESD

149. Agenda
Break to get lunch

150. Agenda
Lunch Discussion: Getting Past Barriers
1. Can GI benefit your clients, and what tools would help you?
2. What are the regulatory constraints to wider GI implementation?
3. What are the municipal constraints? Application Process?
4. Are there issues related to design standards and specifications?
5. are there issues related to property owner lack of demand/awareness?
6. Are design costs an issue?
7. Is permitting uncertainty an issue?
8. Are there construction considerations?
9. Are there maintenance concerns?
10. Is this a market opportunity for you?

151. Agenda
Lunch Exercise:
1. On your Colored Sticky Notes write:
Yellow: something that surprised you today
Purple: something you learned today
Blue: something you plan to do as a result of
the workshop
2. Stick the notes on the flip chart