The "Memorial Union Roof Garden Project" was a creative concept for a roof garden and water harvesting system on the West Plaza area of Iowa State's iconic Memorial Union building. The idea for the project was first conceived in an Independent Study course - where I collaborated with the Director of the Memorial Union and the Student Society of Landscape Architects (SSLA) to work out initial designs. Then, the following semester, I was able to further develop the concept through a project for my Landscape Architecture class.

1. Implementation of a Roof Garden & Water Harvesting System on the MU’s West Plaza
DESIGNOBJECTIVES
STRUCTURAL LIMITATIONS
The following structural limitations of the West
Plaza were determined following an evaluation
conducted by Charles Saul Engineering (CSE),
Inc.:
General structural loading capacity of West
Plaza is 100 psf
Limited growing medium used to 10” depth
(Typical 1’ green roof soil mix = 120 psf)
DESIGN IMPLICATIONSa
No shrubs or trees
Loads focused on outside perimeter of structure
(Ability to withstand 20 more psf than center)
“Soften” the space.
ABSTRACT
An original part of the iconic Memorial Union building, the west
plaza area offers a scenic view of the nearyby Lake LaVerne and
serves as a high-traffic area utilized by students, university em-
ployees, and and other campus visitors.As evident in the aerial
view to the right, however, this space is currently a barren, “con-
crete wasteland,” with little-to-no amenities to support the area’s
plethora of potential uses - eating, studying, hosting university or
prrivate events, etc.This creative project explored how the incorpo-
ration of semi-intensive green roof planters - in synchronization
with a green fascade and water harvesting system - could better
accommodate for these uses and exemplify Iowa State’s committ-
ment to educating & implementing sustainable practices.
West Entrance & Plaza Area
ISU Memorial Union
Ames, IA
Andrew Foy
Horticulture - Landscape Design, Maintenance & Installation Option
GREENING THE MEMORIAL UNION
Offset the surrounding, concrete-dominated arh-
citecture of the MU buildng with a diverse and
colorful plant pallet. In aesthetically improving
the current, dull west plaza space, plants will en-
courage and invite students, staff, and other visi-
tors to make better use of the space.
Provide ample amenities. Resurface the plaza. Educate plaza visitors.Utilize surrounding architecture.
Since the Memorial Union’s construction in 1922, the
West Plaza’s membrane has only been re-surfaced
once, and, as depicted in the images above, the cur-
rent plaza membrane lacks integrity and aesthetic
appeal.To address this issue, an American Hydrotech
Waterproofing & Architectural Roof Paver System is
proposed in the green roof design.
Located in such a high-traffic area of campus, the West
Plaza green roof concept not only has the potential to
transform the way in which the space is currently being
used, but it also has the potential to act as an educate
hundreds of its visitors of the university’s committment
to sustainability. For this reason, signage and on-site
pamphlets are planned to be available on-site.
Aside from giving the building its iconic, rustic appear-
ance and scale, the architecture surrounding the west
plaza area currently serves no other purpose and is some-
what disconnected from the space.The proposed design
accounts for this by transforming the static roofs and
walls of the Memorial Union into aesthetic green fas-
cades and functional water harvesting systems.
SITE CONSIDERATIONS
SUN WIND RAIN
Two distinct areas:
1.) Sun-Exposed Area
2). Shaded Area
- East side of plaza - against building
- 1-2 hours partial sunlight per day
- 6-8 hours full shade per day
CURRENT SITE
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1
2
2
3
3
View when approaching north
plaza entrance.
View of south plaza area with
access to C-store & bookstore.
Overview of plaza area outside
Food Court & cafeteria.
The plaza’s convenient location enables it to have a number of poten-
tial uses, including: outdoor studying space for students, additional
space to enjoy a meal from the nearby cafeteria, a destination for
socializing with friends & work colleagues, and even a space to host
university-sponsored or private receptions.To accomodate for these
activities, the proposed design features ample areas for seating and
overhead shade structures that maintain a comfortable atmosphere
and frame the view of nearby Lake LaVerne.
CIRCULATION PATTERNS
The diagram to the right highlights the primary means of
access & egress to and from the west terrace area. On a
daily basis, the area experiences heavy traffic due to its
close proximity to a number of popular destinations inside
the Memorial Union.Adhering to university standards, un-
obtruded, 10’-wide walkways were maintained in the
design to promote adequate space for circulation during
periods of heavy use.
8’
8’
8’
Average Iowa rainfall for central Iowa is around 36”
- normally an adequate amount of moisture to
support typical landscape plants found in the
region. However, due to the more re-occurent peri-
ods drought and the unique, drought-prone char-
acteristics of the plaza, supplemental irrigation will
be required to ensure plant health & longevity.
- West side of plaza
- 8-10 hours of full sunlight per day
West and southwest edges will be
exposed to harsh, winter winds.
Vegetation in these area may need
winter protection from wind scorch
or freezing damage.

2. HUNTER PDL SUB-SURFACE IRRIGATION SYSTEM
SOURCES “The Ultimate Assembly.” American Hydrotech.
<http://www.hydrotechusa.com/assemblies/ultimate-assembly>.
“Modular,Wall Hung Trellis Panels.” Green Screen.
< http://www.greenscreen.com/home.html>.
WEST PLAZA DESIGN
PLANTER & ROOF DECK
CROSS-SECTION
RAINWATER HARVESTING
SYSTEM
WEIGHING THE WATER
EXISTING ROOF DECK
PROTECTION COURSE
INSULATION
THEULTIMATEASSEMBLY
FROMAMERICANHYDROTECH
HANOVER ARCHITECTURAL PAVERS
(Gray Finish)
WATERPROOFING MEMBRANE
(Hot Rubberized Asphalt)
VEGETATION
(SUCCULENTS, COLORFUL FLOWERS, GRASSES)
1’ ROOFLITE SEMI-INTENSIVE
GROWING MEDIA
STYRAFOAM INSERTSTM
2’ X 4’ CUSTOMIZED ALUMINUM PLANTER
FILTER FABRIC
PLANTERCOMPONENTS
“Rainwater Harvesting Products.” Jay R. Smith Manufacturing Company.
<http://www.jrsmith.com/product-category.aspx?ProductCategoryID=124>.
Hershfield, David S. “Rainfall Frequency Atlas of United
States.” U.S. Deptartment of Commerce. May, 1961.
“PDL Sub-Surface Irrigation.” Hunter Industries. <http://www.hunterindustries.-
com/irrigation-product/micro-irrigation/eco-matr-and-pld-esd>.
DRAINAGE LAYER
(Empties to Nearby Roof Deck Drain)
PVC DRAINAGE PIPE
Comparing the Runoff Rates of the Current Plaza vs.Anticipated
Rates of the Proposed Green Roof Design
CALCULATION ASSUMPTIONS:
8’
8’
8’
Underground Water Starage Tank
(3,500 Gallon Tank)
Connected Irrigation System
(Use for both Green Roof & N.Turf area)
Multi-Functional Overflow Device
Storage Tank Floating Filter
Irrigation Pump
PVC Feed Pipe
(Water Planters)
RainwaterHarvestingProducts
Initial Water Capture
Storage, Filtration & Utilization in the Landscape
Gravity Tranfer to Planters & Storage Tank
After the rainwater reaches the planters via the PVC piping, it is
then emptied in specially-crafted water resevoirs at the bottom of
the planters. Once in the reservoirs, the water continues to be grav-
ity-fed down a sloped surface to an underground water storage
tank buried within the NE retaining wall.
During the first stage of
rainwater harvesting,
water is collected from
the roof above the West
Plaza entrance.Water
from the drain then
moves to a connected
PVC pipe, which transfers
it to the planters below.
The final stage of rainwater collection involves the pumping of rainwater into a 3,500
gallon, underground storage tank through a PVC intake pipe. Once in the tank, the
water is processed and either pumped back into the landscape to be used for irriga-
tion or released into the stormwater sewage system in the event of a tank overflow.
CIRCULATION PROCESS
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4
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6
6
Water Reservoir
Foam Slope
IMPLICATIONS
In this single rain event, the proposed green
roof design reduces the amount of site
runoff by 331 cubic feet of water (the
equivalent of 2,478 gallons) in comparri-
son to the current plaza.When taking into
account the average yearly rainfall received
by Ames, IA - 35.8”- the wider-scale, storm-
water management benefits offered by the
proposed green roof design can be realized.
Total Impervious Concrete Area 11,237 SFa
Total Permeable Surface Area 0 SFa
Yield of Precipitation in Rain Event 2.2” (0.1875’)a
Runoff Coefficient of Concrete 0.88
CALCULATIONS
a
Runoff from Impervious Surface:a
11,237 SF x 0.1875’ x 0.88 = 1,854 cu. ft.
+
Runoff from Permeable Surface: N/A = 0 cu. ft.
a
TOTAL RUNOFF FROM SITE: 1,854 cu. ft.
(SOURCE: Kuichling, 1989)
CURRENT PLAZAPROPOSED GREEN ROOF DESIGN
ROOF RUNOFF = AREA OF ROOF x PRECIPITATION YIELD x RUNOFF COEFFICIENT
(of Specific Rain Event) (of Respective Roof Materials)
Total Impervious Concrete Area 8,848 SFa
Total Permeable Surface Area ~2,400 SF
a
Yield of Precipitation in Rain Event 2.2” (0.1875’)a
Runoff Coefficient of Concrete 0.88
a
Runoff Coefficient of Planters 0.14
CALCULATIONS
a
Runoff from Impervious Surface:a
8,848 SF x 0.1875’ x 0.88 = 1,460 cu. ft.
Runoff from Permeable Surface: +
2,400 SF x 0.1875’ x 0.14 = 63 cu. ft.
a
TOTAL RUNOFF FROM SITE: 1,523 cu. ft.
(SOURCE: Kuichling, 1989)
(SOURCE: Kuichling, 1989 - “Meadow” with Type A Soil)
(4’-wide Planters Lining ~2,400’ Perimeter of Plaza)
Assuming the occurrance of a 1 year, 12 hour rain event in Ames, Iowa - which yields 2.2” inches of rain.
(Source: NOAATechnical Report on Rainfall Frequency in U.S.)
Runoff from a site can be determined by taking the area of the roof multiplied by the average precipitation yield
expected in a specific precipitation event; multiplied by the specific runoff coefficient of the materials that compose
the roof.The equation is given below:
Bergenia cordifolia
Pigsqueak
Astilbe ‘Fanal Red’
Fanal Red Astilbe
Hosta ‘Blue Umbrella’
Blue Umbrella Hosta
Liriope spicata
Lilyturf
Liatris spicata
‘Floristan White’
White Gayfeather
Echinacea purpurea
Purple Coneflower
Asclepias tuberosa
Butterfly Weed
Sporobolus heterolepis
Prairie Dropseed
Salvia sylvestris ‘May Night’
Perennial Sage
Rudbeckia fulgida
‘Goldsturm’
Black-Eyed Susan
SUN-LOVING
Sun-loving, drought tolerant flowers &
grasses embody the colorful plant
palette seen on plaza edge.
Well-adapted to the harsh, dry condi-
tions in this area, the majority of these
plants are native to the Iowa prairie.
SHADE-TOLERANT
A number of shade-tolerant flowers,
grasses, and groundcovers are also
featured in the design. These plants
are well-adapted to the low-light and
cooler conditions experienced by the
planters closest to the building.
SELECTION
PLANT
Hosta ‘The Rocket’
Rocket Ligularia
PHASE 1
PHASE 3
1 2 3 54
The West Plaza green roof design
brings a very noticeable improvement
to the area’s aesthetics and more ap-
propriately accomodates for the areas
potential uses. Lush greenery invigo-
rates the space - sparking visitors’ in-
terest and curiosity - while ample site
amenities invite students and staff to
stay, sit, and enjoy the outdoors.
3
2
1
PHASE 2
PROPOSED
DESIGN
Main Seating Area1
Shaded Seating AreaPergola Leisure Area2 3