Stormwater Academy: Green Roofs

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Stormwater Academy Green Roofs

Green Roof Seminar Background and
Advances September 20, 2005
By Marty Wanielista
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OUTLINE OF DISCUSSION Green Roofs

• History
• Green roof basics
• UCF research projects.
• Research Discussion - Application to stormwater
  mgt., stormwater quality, evapotranspiration,
  energy and heat, etc
• The state of the industry - practical
  applications and practices
• Future directions - discussion

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5000 year old Passage Grave near Dublin

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Hanging Gardens of Babalon Green Roofs

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English Tea Time Green Roofs

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Stuttgart Germany About 60 Years
Over 30 of the roofs are green Photo of the
Mercedes Offices

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Stormwater Academy Green Roofs

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European Examples Green Roofs

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A US Office View Green Roofs

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Some Definitions Green Roofs

What is a Green Roof? Covered with
vegetation Intensive - deep overburden roof
garden Extensive - thin overburden large
area
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Intensive Green Roofs

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Extensive Green Roofs

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Stormwater Academy Green Roofs

TYRONE, PA ROOF PLANTED JULY 2001
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Benefits of Green Roofs

Why should we plant green roofs? aesthetically
pleasing, useful space reduce city heat
island effect, reduce noise, reduce air
conditioning, lengthen roof life 2-3X,
remove nitrogen in rain, neutralize acid
rain, reduce stormwater runoff volume.
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Irrigated Florida Native Plant Green Roofs

• Four Main Objectives
• maintain water balance,
• reduce stormwater pollution mass,
• reduce internal energy demand for cooling and
  heating, and
• enhance the aesthetic appeal compared to
  conventional roofs. 
• USING an irrigated plant and 6 inch media
  roof in Central Florida

A cistern is used to recycle green roof runoff
as irrigation water.
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Appreciate the support of

• Eric Livingston, FDEP
• Steve Iwinski, Applied Polymer Systems Inc.
• Charlie Miller, Roofscapes, Inc
• SchenkelShultz Architects
• Burton Braswell Inc, Structural
• UCF Student Government and students
• Randy Jones, Hardin Construction Co.
• Mark Towle, Big River Industries
• Harvey Harper, ERD

• Eric Livingston, FDEP
• Steve Iwinski, Applied Polymer Systems Inc.
• Charlie Miller, Roofscapes, Inc
• SchenkelShultz Architects
• Burton Braswell Inc, Structural
• UCF Student Government and students
• Hardin Construction Co.
• Mark Towle, Big River Industries
• Harvey Harper, ERD

UCF Team Marty Wanielista Martin Quigley Jeff
Sonne Clint Finstad Mike Hardin Kelley
Dragon Matt Kelly Steve Maxwell Jen
McDaniel Natalie Shaber
UCF Team Mart Wanielista Martin Quigley Jeff
Sonne Clint Finstad Mike Hardin Kelley
Dragon Matt Kelly Steve Maxwell
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Typical Section Student Union UCF
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The Construction Process
Temperature sensors installed
Protection fabric (no metal)
1600 square feet of Green roof and 1600 square
feet of Control roof (Conventional Materials
polyester made By Fibertite)
Drainage media over protection fabric
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The Construction Process (continued)
Growth Media Expanded Clay
Irrigation Pipe
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Construction Completed in March 2005
March 2005
July Growth
Weather measures
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Media Blends Green Roofs

Media Selection Criteria

• Lightweight
• Plants can take root in it
• Capacity to hold water

Selected Media Blending of

• Expanded Clay 42-48 LBS/CF
• 25-32 water holding
• Tire Black and Gold 30 LBS/CF
• 30 water holding (estimated)

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Two Media Blends for Testing

Selected Media Blending of

• Expanded Clay
• 60 Expanded Clay (Big River)
• 15 each Peat Moss, and Perlite
• 10 Vermiculite
• 2. Tire Black and Gold
• 40 Tire Black and Gold
• 20 Expanded Clay
• 15 each Peat Moss and Vermiculite
• 10 Perlite

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Polymer Blended Tackifier Results
Expanded Clay Mix before PBT 8.90 NTU Expanded
Clay Mix after PBT 2.90 NTU Tire Crumb Mix
before PBT 5.40 NTU Time Crumb Mix after PBT 0.59
NTU
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Results after 24 inches of rain Added to each cell
Source Applied Polymer Inc. and UCF
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Design Of the Cistern Assume a reuse rate of
0.3 inches per day per equivalent green roof area.
Source www.stormwater.ucf.edu and click on
publications
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The Cisterns
Designed to hold 1.5 inches of runoff (90 of the
runoff assuming no initial abstraction)
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Updated Estimated Mass Balance and Discharge
from Green Roof Cistern
For a 3 month period P is approximately 26
inches I is approximately 7.5 inches Estimated
are 1. ET 0.20 inches per day 2. For a
dry substrate, no rain or irrigation for
three days, 0.73 inches of irrigation
resulted in 0.06 inches of runoff. 3.
of rain not discharge 80
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Water Quality Comparisons for 6-22-05 Sampling
from the Cisterns
Quality control source Environmental Research
Design, Inc.
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Quality control source Environmental Research
Design, Inc.
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Water Quality Comparisons Using two Green Roofs
in Florida
Note limited number of samples.
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Input Concentrations for Sand media and Grass 4
foot of media and irrigated using 3 (2x2)
chambers
Year of operation June 2004 June 2005 Rainfall
Input Volume was 67.22 inches (high) 63
events sampled for water quality pH Mean
6.22 SD 1.44 NO3-N Mean 0.41mg/L SD
0.28 mg/L NH3-N Mean 0.16mg/L SD 0.23
mg/L Irrigation Input Volume was 23.24 inches
(low) 43 events sampled for water quality
from the source water pH Mean 7.20 mg/L SD
0.37 NO3-N Mean 0.02 mg/L SD 0.01
mg/L NH3-N Mean 0.14 mg/L SD 0.18
mg/L OrgN Mean 0.39 mg/L SD 0.38
mg/L Notes chamber 1 NO3-N input was
increased to 1 mg/L chamber 2 NO3-N input
increased to 2 mg/L and chamber 3 was the source
concentration (0.02 mg/L)
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Effluent Concentrations from Sand Media and
Grass 4 foot of media and irrigated 3 chambers
Notes The effluent pH was similar to that of
the soil (pH6.6). NO3-N decreased, and NH3-N
increased. There was significant Org-N and NH3-N
(750 mg/kg) in the sandy soil. The ET was
estimated as 42.3 inches per year (from mass
balance).
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Comparative Water Quality and ET Experimental
Design
Control Roof
SU alternative
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18 - 4 feet x 4 feet Chambers
Comparing two growth media Comparing two
irrigation schedules (volumes) Controls
(conventional roof and no-vegetation) Duplicate
of each
Water tight and Insulated
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Chamber Mass Balance Results
For a one month period P is approximately 5.9
inches I is approximately 3.8 inches Estimated
are 1. ET 0.20 inches per day 2. For a
dry substrate, no rain or irrigation for
three days, 0.50 inches of irrigation
resulted in 0.05 inches of runoff. 3.
of rain not discharge 60 (held in
cistern for irrigation)
S1P1I1-F1-ET1S2
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Native Plants Green Roofs

Plant Selection based on
1. Perennial with color, preferably woody (having
secondary growth) creeping prostrate, or shrubby
plants with full sun, high temperature, low soil
nutrient, and severe drought tolerances.2. Shallo
w, fibrous rooting habit.3. Cold hardiness to
just below freezing.
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Plant Selection Green Roofs

Continued Plant Selection based on
4. No severe pest problems or special
horticultural requirements.5. Florida native
species preferred when suitable and available.6.
Evergreen foliage preferred, to maintain higher
ET and cover and attractiveness all year.7.
Bloom or fruit display desirable but not
mandatory.
Florida Native Dune or Beach Sunflower Helianthus
Deblis
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Lonicera sempervirens (Coral honeysuckle) A
perennial vine-like shrub with bright red flowers
in a shape much loved by hummingbirds. Common to
central and north Florida. Typically found in
wooded areas.
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Gaillardia pulchella (Firewheel Daisy) Large
flowers, have a wide variation in form and
yellow/red combinations. This is a hardy annual
that easily grows from self-sown seeds. Often
found growing in hot, dry, difficult areas
throughout Florida. Grows up to 24 inches tall.
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Myrcianthes fragrans (Simpsons stoppers) This
evergreen shrub has fragrant white flowers that
produce a red fruit with edible seeds. The
leaves, when crushed, smell of eucalyptus. They
start out red, turning green later in the growing
season. Found throughout south and central
Florida, these shrubs provide shelter and food
for a variety of birds and animals.
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Muhlenbergia capillaris (Muhly grass) Various
natural varieities found in pine flatwoods,
sandhills, moist hammocks and beach dunes. Grown
throughout the entire state, and very drought
tolerant. This grass reaches up to 3 ft when in
flower. The flowering part resemble pink or
purple plumes. Blooms in the summer and early
fall.
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Helianthus debilis (Beach or Dune daisy) A
low-lying, spreading daisy that tolerates harsh
conditions salt spray, drought, acid or alkaline
soils. Often used to stabilize dunes that are
subject to erosion.
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AESTHETICS AND HABITAT CONSERVATION
A HAVEN for POLLINATORS
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Future native candidates for use on green
roofs Salvia coccinea (Tropical sage) Monarda
punctata (Spotted Beebalm) Hamelia patens
(Firebush) Erythrina herbacea (Coral bean) Mimosa
strigillosa (Powderpuff) Solidago spp
(Goldenrod) Hypericum hypericoides (St. Andrews
Cross) Oenothera laciniata (Cutleaf
primrose) Scoparia dulcis (Sweet broom) Phyla
nodiflora (Carpet flower) Scutellaria
integrifolia (Rough scullcap)
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Surface Temperatures and Heat Islands
Washington, DC
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Example Temperature Comparisons oF
Conventional Roof (red) versus Green Roof (green)
at the roof surface
In the evening, radiation is present and
conditioned space losses to the roof.
Source www.stormwater.ucf.edu and click on roof
monitoring data
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Top of Media (green) to Bottom of Media (red) at
green roof surface
Example Temperature Comparisons oF
Source www.stormwater.ucf.edu and click on roof
monitoring data
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For additional information Marty Wanielista,
407.823.4144 wanielis_at_mail.ucf.edu
For web cam and other publications
www.stormwater.ucf.edu