Transcript Slide 1

Stormwater Academy: Green Roofs
Green Roof Design and
Operation
(Part III)
2006 FSA Annual Conference
June 14, 2006
By Marty Wanielista and Mike Hardin
FSA
DESIGN and CONSTRUCTION
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Type of Plants?
Maintenance?
Source of make-up water cistern water?
Infrastructure (location of cistern, electrical)?
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. Shallow, fibrous rooting habit.
3. Cold hardiness to just below freezing.
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.
8. Due to irrigation plant selection no longer dependent
on drought tolerance
Florida Native Dune or Beach Sunflower Helianthus Deblis
Florida: Green Roofs
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.
Florida: Green Roofs
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.
Florida: Green Roofs
Myrcianthes fragrans
(Simpson’s 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.
Florida: Green Roofs
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.
Florida: Green Roofs
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.
Florida: Green Roofs
AESTHETICS AND HABITAT CONSERVATION
A HAVEN for POLLINATORS
Additional Plant Selections
See a Landscape Architect for local plants.
Some additional ones being considered are:
Salvia coccinea (Tropical sage)
Monarda punctata (Spotted Beebalm)
Hamelia patens (Firebush)
Erythrina herbacea (Coral bean)
Mimosa strigillosa (Powderpuff)
Solidago spp (Goldenrod)
Hypericum hypericoides (St. Andrew’s Cross)
Oenothera laciniata (Cutleaf primrose)
Scoparia dulcis (Sweet broom)
Phyla nodiflora (Carpet flower)
Scutellaria integrifolia (Rough scullcap)
Cost Considerations
Construction:
• Generally $7-$15 per square foot
• For retrofits add about $3 per square foot
• This price can vary significantly depending on the
needs of the client
• The most important part of the construction process
is the water proof membrane
• Leak detection must be done before
construction proceeds
• The price for this will vary per project but is
about $0.06-$0.10 per square foot
Cost Considerations
Construction (cont):
• Added features can be incorporated into any green
roof design (price will vary with feature)
• These features are typically associated with an
active roof
• Water feature
• Putting green
• Benches and tables
• Pervious Concrete Basketball court
• More…
• Care must be taken in the design and construction
process to ensure safety and successful
implementation
Cost Considerations
Maintenance:
• Will vary with design
• Most active roofs will be about the same as yard or
garden maintenance
• Most passive roofs require minimal maintenance
(twice per yr)
• Use of Herbicides and pesticides will be minimized
• Leak Detection
• Electric Field Vector Mapping
• Able to detect pin hole size leaks
Cost Considerations
Maintenance (cont.):
• Irrigation system
• Clogging of drip system
• Broken or misplaced pipes
• Replacement of filters
• Cistern
• Cleaning about once every 2 years
• Check pressure gage regularly
• Plants
• Replacement of dead or damaged plants
• Pruning and trimming
• Weed pulling
• Fertilization
The cistern operation
The cistern is supplied with water from the green roof,
however, during dry periods, the stored water in the
cistern may not be sufficient to meet the demand.
THUS
• Source of alternative water supply during the “dry
season”?
• Filtration of the alternative source water?
• Some alternative sources are stormwater from other
areas, reclaimed water (subject to constraints), potable
water, groundwater, and others that meet plant growth
conditions (Salinity, pH, SAR, Conductivity, and others)
FSA
Questions and Comments