European Airport GreenroofsLSV

Photo Copyright and courtesy ZinCo International
EUROPEAN AIRPORT GREENROOFS A POTENTIAL MODEL FOR NORTH AMERICA
Updated February 6, 2008*
By Linda S. Velazquez, ASLA Associate, LEED AP
Greenroofs.com Publisher & Design Consultant
Copyright © 2005 Greenroofs.com, LLC, All rights reserved.
NOTE: This is the updated version of Linda’s paper presented at the Greening Rooftops for Sustainable
Communities 2005 in Washington, D.C. Additional information and photos were submitted after the
original paper went to publication on the Conference CD, e.g., project examples from Pittsburgh Corning
Europe, optima, Phoenix Benelux, Fraport AG Frankfurt Airport Services, the King County International
Airport, and subsequent commentary from the USDA. This paper also includes new graphics from
Linda’s PowerPoint presentation. *When calculating m2 to sf, an error was made in regards to the sf of
the Frankfurt International Airport, which has now been corrected.
Benjamin Taube, former City of Atlanta Environmental Manager, contributed to this paper with photos
and information pertaining to the Atlanta airport.
Abstract:
Airports occupy and consume huge areas of land mass, destroying ecosystems and creating
massive urban heat islands of impermeable, hot surfaces. For example, the area of roofs and
pavement at the Atlanta Hartsfield-Jackson International Airport (ATL) is estimated at over
70,500,000 square feet, or 1,619 acres! When compared to surrounding undeveloped areas, ATL
infrared imagery, provided by NASA, clearly shows up to over 55°F thermal variations between
the terminal, concourses, runways, parking decks and lots, cargo and other airport support
buildings. The resulting loss of natural greenspace greatly impacts stormwater management,
loss of habitat and biodiversity, creates noise, air and water pollution, and on a large scale,
contributes to global warming.
In addition, we know how the numerous ecological advantages of extensive greenroofs could
help mitigate each and every one of these environmental problems. Yet airports, as a unique
development type, also offer their own particular set of construction design prerequisites and
issues that are not applicable to a typical urban environment – in particular, security and safety
concerns.
Specifically, stormwater infrastructure engineering must immediately provide fast and efficient
drainage to all paved surfaces. And the recreated natural areas of runways and surrounding
fields are designed to avoid attraction of birds, which many times get drawn into jet engines
creating a potentially hazardous and life threatening situation.
Even given greenroofs’ ability to reduce stormwater infrastructure concerns, to date airport
authorities outside of Europe have been hesitant to consider vegetated roofs mainly for fear of
attracting birds. However, many airports in Europe have successfully constructed greenroofs
atop parking garages, hangers, and even terminal buildings, without increasing their yearly
number of “bird strikes.” Bird and wildlife hazard statistics and accompanying industry support
will be identified. This paper will attempt to examine the impacts of using a greenroof within
airports as well as address some of the potential barriers to greenroofs, in particular the real
danger of attracting birds.
To make the case for the implementation of airport greenroofs worldwide, greenroofed buildings
will be reviewed at the following international airports, offering insight as to local motivating
factors or market drivers; the resulting ecological, aesthetic and economic benefits; and their
specific design considerations including appropriate system and plant types, and other elements
necessary for a safe yet green environment:
•
•
•
Schiphol International Airport, Amsterdam, the Netherlands (AMS);
Frankfurt International Airport, Frankfurt, Germany (FRA);
Kloten International Airport, Zürich, Switzerland (ZRH)
Bird and wildlife management techniques and design considerations will be discussed, along
with “Lessons Learned” from our successful European airport greenroof counterparts. Finally,
using the Atlanta Hartsfield-Jackson International Airport - “the World’s Busiest Airport” – as an
example, we will present a design scenario of how Atlanta’s largest urban heat island could be
significantly mitigated by incorporating greenroofs. We aim to help further airport greenroof
interest by encouraging continued research into these international examples of sustainable
design and development.
~~~~~~~
EUROPEAN AIRPORT GREENROOFS - A POTENTIAL MODEL FOR NORTH
AMERICA
By Linda S. Velazquez, ASLA Associate, LEED AP
Greenroofs.com Publisher & Design Consultant
Updated February 8, 2008
Air transportation is an international growth industry and forecasts indicate that air traffic volumes will
continue to grow, even after the massive decline in 2001 following the 9/11 terrorist attacks, and
“Thousands of airports will need to be expanded, or built, to handle the Federal Aviation Administration's
projected 45% increase in flights by 2020.” According to the U.S. Environmental Protection Agency and
the General Accounting Office, this tremendous growth will undoubtedly contribute to the existing
pollution as medical studies reveal pollutants from jets can cause heart failure or respiratory disease. On
a large scale, sealed airport surfaces contribute to global warming and cause crop damage, acid rain and
reduced visibility1.
Airports across the world occupy and consume huge areas of land mass, destroying ecosystems and
creating massive urban heat islands of impermeable, hot surfaces with their immense amount of
concrete and asphalt. By incorporating greenroofs within these vast airport facilities, it is extremely
probable to offset the temperature increases caused by the amount of impervious surface.
Airport Land Use Created Problems:
Destruction of Ecosystems
Air Pollution
Stormwater Management
Water Pollution
Noise Pollution
Urban Heat Islands
The Current Situation at ATL
Atlanta has the dubious distinction of claiming our airport as “The World’s Busiest Airport.” Aviation
General Manager Benjamin R. De Costa states that as the Metro Atlanta and the southeast continue to
grow both in terms of population and economic development, so does Atlanta Hartsfield-Jackson
International Airport (ATL). Like many high traffic airports worldwide planning for future traffic demands,
ATL must modernize and expand its current airport. The City of Atlanta and the airlines at HartsfieldJackson have authorized the Airport to spend an impressive $5.4 billion towards a 10-year development
program. Currently, the ATL passenger terminal complex measures 130 acres (52.6 hectares), or 5.7
million square feet2. Take into consideration that the total area of roofs and pavement at ATL is
estimated at over 70,500,000 square feet (65,496,643 m2), or 1,619 acres3.
Atlanta Hartsfield –Jackson International Airport
Aerial Photo courtesy Ben Taube
NASA has been conducting a land use analysis study of Atlanta through its Project ATLANTA (ATlanta
Land use ANalysis: Temperature and Air quality) since 1996. Studies show that the temperature in
downtown Atlanta is often 10° F warmer than the surrounding outlying areas and the added heat also
contributes to Atlanta’s air quality problem as the 10-degree rise in temperature doubles the amount of
ozone that is produced4. According to NASA Senior Research Scientist Dr. Dale A. Quattrochi, Atlanta's
urban heat island is also creating its own weather5. Situated just 10 miles south of downtown Atlanta, the
massive amount of impervious cover at Atlanta Hartsfield-Jackson International Airport adds to the huge
heat island and contributes to the area’s rising temperatures.
Color satellite photo of the greater Atlanta
area. The Chattahoochee River and green
areas are clearly noticeable among the
developed areas.
Thermal infrared photo of the greater Atlanta
area including the airport, seen in red, on the
lower right side.
Photos May 1997 courtesy NASA.
The study has also measured and modeled the rapid growth of the Atlanta, Georgia metropolitan areas
since the early 1970’s and analyzed the impact on the region’s climate and air quality. The NASA chart
below shows the effects of urbanization and how land use affects the magnitude of the heat.
When compared to surrounding undeveloped areas, the ATL infrared imagery shown below clearly
shows up to over 55°F of thermal variation between the terminal, concourses, runways, parking decks
and lots, cargo and other airport support buildings. The absence of natural greenspace here greatly
impacts stormwater management, loss of habitat and biodiversity, creates noise, air and water pollution,
and on a large scale, contributes to global warming.
NASA
Infrared
Imagery
May 1997
I-85
Asphalt
Parking
Lots
Asphalt
Parking
Lots
Atlanta
Airport
Concrete
Parking
Deck
Concourses
Terminal
Concrete
Parking
Deck
Concrete Runways
Greenroofs.com
May 1997 infrared imagery of ATL terminal, concourses, runways, parking and cargo areas.
Notice how the highest temperatures, shown in red, are the roof surfaces.
NASA research recommends planting or preserving more trees and greenspace and using light-colored
building materials that reflect solar energy to improve Atlanta's air6. And we know how the numerous
ecological advantages of extensive greenroofs could help mitigate other environmental problems such as
reducing noise volumes and providing habitat for small animals.
Yet airports, as a unique development type, also offer their own particular set of construction design
prerequisites and issues that are not applicable to a typical urban environment – in particular, security
and safety concerns. One issue is the stormwater infrastructure engineering which must immediately
provide fast and efficient drainage to all paved surfaces.
Atlanta airport stormwater facts indicate that two main drainage basins handle most of the
detention/drainage within the airport infrastructure and prior to the 5th runway; the stormwater detention
on the SE side of the airport is supported by about 75% of all runoff from the airport. South of the 5th
runway a large detention structure is being installed and under the concourses, ramps, and south cargo
are holding systems to catch the first flush for pollutant removal7. According to a recent edition of
Grading and Excavating magazine, the newer airport facility features four separate glycol
retention/detention systems, each using 180 ft. of 48-in.- and 15-in.-diameter pipe buried 25 ft. deep. The
pipe serves as a containment system for stormwater and deicing-solution runoff from the deicing pads.
Beneath each deicing area is a retention/detention system to capture deicing fluid and/or stormwater
runoff. Hartsfield's system is four 100- x 100-ft. holes containing three rows of Advanced Drainage
System (ADS) polyethylene (PE) pipe buried 22-25 ft. deep. The pipe serves as a fluid-holding pen,
slowing dispersal to the allowable outflow rate8.
This airport example is representative of aviation facilities worldwide and identifies some of the
developmental impacts on the land, illustrating the complex, strategic engineering necessary for the
quick and safe removal of airport stormwater volumes. Thousands of lives are at stake daily on these
impermeable airport surfaces of runways, taxiways, and shoulder areas. Yet impermeable airport roof
surfaces also cover a large percentage of total paved surfaces and greenroofs offer an attractive
opportunity to help alleviate the two greatest environmental concerns of stormwater and heat islands
while possibly providing other ecological advantages.
Wildlife and Airport Specific Design Considerations
An airport environment creates its own flight safety design challenges, necessitating specialized spatial
planning measures to consider both aviation and nature. Most public-use airports have large tracts of
open, unimproved land that are desirable for added margins of safety and noise mitigation, but they often
attract hazardous wildlife. The recreated natural areas of runways and surrounding fields are designed to
avoid attraction of birds, which many times get drawn into jet engines creating a potentially hazardous
and life threatening situation. Correct siting separation criteria of aircraft movement areas, approach or
departure airspace regulations, and controlling land uses are measures used to discourage wildlife from
interfering at airports.
Recognizing existing wildlife attractants, as well as mitigating the creation of new wildlife attractants on or
near the airport will help to reduce the risk of wildlife strikes, says the Federal Aviation Administration
(FAA)9. The wildlife species and the size of the populations attracted to the airport environment are
highly variable and may depend on several factors, including land-use practices on or near the airport. It
is important to identify those land use practices in the airport area that attract hazardous wildlife as large
flocks near or above airfields are not simply acceptable.
FAA Prohibited Land Use Practices and Habitats
Within 5 Statute Miles of an Airport:
Municipal Solid Waste Landfills
Putrescible-waste disposal operations
Wastewater Treatment Facilities
Artificial Marshes
Wastewater Discharge and Sludge Disposal
Dredge Spoil Containment Areas
Certain Crop Production, e.g., cereal grain and sunflower
Livestock Production
Fish Production (Aquaculture)
Bird Management Measures
Birds use airfields as a biotope for habitat, nesting and finding food and different species will dictate
different habitat preferences. In the medium and in the long term bird strikes on airfields may only be
minimized by identifying the ecological conditions that attract birds to an airfield and then using habitat
deterrence methods to make the airfield less attractive for species relevant to flight safety10.
For example, U.S. Biologist Patrick Smith says grasses cut too low will attract flocks of birds or geese.
Grasses that grow too high will bring rodents, which in turn attract raptors11. Birds prevail as do other
living creatures by surviving through adaptation and specialization, and eventually learn to live among
humans and our built environments. For additional information on habitat modification or other
procedures for controlling hazardous wildlife at airports, see FAA's Wildlife Hazardous Management at
Airports12 and the Transport Canada Control Procedures Manual Habitat Modification13.
Common Methods of Chasing Birds Away
This management can be as diverse as habitat manipulation to the use of predators to repelling wildlife
to lethal control of wildlife. Gunshots, blaring horns, crackers fired off with gas canisters, hand-held laser
devices, noisemakers, natural predators such as sheepdogs, border collies and even falcons have all
been employed in addition to bird warning systems like the “Bird Avoidance Model (BAM), the U.S. Air
Force's primary bird strike risk assessment tool. BAM is an historical archive of bird information, taking
data from more than 10,000 locations over the past 30 years, for over 50 different bird species14.
Even given greenroofs’ ability to reduce stormwater infrastructure and other concerns, to date airport
authorities outside of Europe have been hesitant to consider vegetated roofs mainly for fear of attracting
birds. However, many airports in Europe have successfully constructed greenroofs atop parking garages,
hangers, and even terminal buildings, without increasing their yearly number of “bird strikes.” So why
shouldn’t we consider incorporating greenroofs on airport area structures?
Some Bird Strike Statistics:
•
•
•
•
•
•
•
•
•
•
•
•
Over 195 people have been killed world-wide as a result of bird strikes since 1988.
Every year, over 1 billion dollars is wasted and lives are endangered worldwide when birds and
other wildlife collide with aircraft.
Wildlife strikes cost U.S. civil aviation over $500 million/year, 1990-200315.
Birds make up 97% of the reported strikes, mammals about 3% and reptiles less than 1%16.
Over 4,300 bird strikes were reported by the U.S. Air Force in 2003.
Over 5,900 bird strikes were reported for U.S. civil aircraft in 2003.
An estimated 80% of bird strikes to U.S. civil aircraft go unreported17.
In Germany, an average of 1,500 bird strikes is reported annually for civil and military aircraft18.
Waterfowl (32%), gulls (28%), and raptors (17%) represented 77% of the reported bird strikes
causing damage to U.S. civil aircraft, 1990-2003.
A 12-lb Canada goose struck by a 150-mph aircraft at lift-off generates the force of a 1,000-lb
weight dropped from a height of 10 feet.
At least 15,000 gulls were counted nesting on roofs in U.S. cities on the Great Lakes during a
survey in 1994.
About 90% of all bird strikes in the U.S. are by species federally protected under the Migratory
Bird Treaty Act19.
Bird strikes are common, but they rarely do much damage to an airplane, and most strikes happen
without anyone on board knowing about it. The most infamous encounter happened in 1960 when an
Eastern Airlines jet struck a flock of starlings and crashed into Boston Harbor, killing 62 people20.
Bird Strike Industry Support
A large international industry support exists to facilitate the exchange of information, promote the
collection and analysis of accurate wildlife strike data, the development of new technologies for reducing
wildlife hazards, and professionalism in wildlife management programs on airports. For example, Bird
Strike Committee USA is a volunteer organization directed by a 9- to 12-person steering committee
consisting of 2-3 members each from the Federal Aviation Administration (FAA), U.S. Department of
Agriculture (USDA), Department of Defense, and aviation industry21. Richard Dolbeer is the
USDA/Wildlife Services National Coordinator, Airport Safety and Assistance and his office manages the
national database that records wildlife strikes with aircraft each year and finds ways to keep the nation's
air traffic safe from wildlife. The FAA has an Airport Wildlife Hazard Mitigation website22. The German
Bird Strike Committee (DAVVL e.V.) is very comprehensive and publishes the scientific journal Bird and
Aviation (ISSN 0721-4521), a technical periodical appearing usually twice annually since 1981, offering a
wealth of information on the subject in German and English23. And yearly regional and international
conferences meet to discuss trends.
Given all the concerns of flight safety and the bird population, conservation biologists still estimate that
by 2100 about 10% of all bird species probably will be extinct, killed off by habitat loss, hunting and
climate change24. With all this daunting information isn’t it still possible to design airport buildings and
areas with both human and wildlife safety and preservation in mind? The answer is yes, of course.
European Airport Greenroofs
The notion of airport greenroofs may be new to many of us here in North America, but when I started
asking the Germans in particular about airport greenroofs, I was told that there are thousands of square
meters of greenroofs on airport buildings. Within Germany alone are various airport greenroofs at
Stuttgart, the new airport in Münich, Bremen and Düsseldorf. France has greenroofs at Charles de
Gaulle in Paris, Paris’ Orly International Airport and Bordeaux Airport. I have also seen an airport
terminal greenroof in Milan, Italy and more exist. See additional examples below.
Fire Brigade extensive greenroof at Stuttgart
International (STR); Photo courtesy Jörg
25
Breuning of Green Roof Service .
Airport Terminal, Bremen, Germany;
Photo courtesy Dr. Michael Marrett-Foßen
of optima Dachbegrünungs GmbH.
Simple intensive greenroof, at the Airport
Hotel in Hannover, Germany;
Photo courtesy Dr. Michael Marrett-Foßen.
Jetfighter Garage, military base in Northern
Germany; Photo courtesy Dr. Michael Marrett26
Foßen of optima Dachbegrünungs GmbH .
Additional European Airport Greenroofs:
The Cointrin Hall de fret, the Freight Handling and
Administration Building, at the Geneva International
Airport (GVA). Left: Close-up of one of the atriums;
Right: Aerial view. Photos courtesy Jean Melchior,
Pittsburgh Corning Europe.
Although not an airport, Le Hospital Cantonaire Universitaire de
Geneve (Geneva University Hospital) maintains a Helicopter Landing
Pad for emergency airlifts. The Hospital is covered in intensive
27
greenroofs. Photo courtesy Jean Melchior, Pittsburgh Corning
Europe.
After security issues, noise abatement, air quality, and preservation of greenspace are the top
environmental concerns of area residents and airport management. Many greenroofing companies have
established themselves in Europe offering many system types and materials, and manufacturers and
providers. The following airport greenroof studies are based on European aviation authorities and
company representatives responding to my initial information request, and are not intended to be
exhaustive in scope.
Schiphol International Airport, Amsterdam, the Netherlands (AMS)
Schiphol International
Airport - Amsterdam,
the Netherlands (AMS)
Photo courtesy
Phoenix Benelux bvba
§ Total airport area greenroofed at AMS
and Schipholrijk neighbourhood:
73,730 m2 or 793,624 sf
§ Number/Area of Extensive Greenroofs:
3 = 13,330 m2 or 143,483 sf
§ Number/Area of Intensive Greenroofs:
8 = 60,400 m2 or 650,141 sf
Greenroofs.com
In 2002, the Schiphol International Airport management began defining their sustainable development
policy and six themes were identified. Of particular interest are “Safety” and "Nature and Landscaping at
Amsterdam Airport Schiphol" where they are planning to create more awareness in the next few years
for the flora and fauna located on the airport grounds as well as for nature and landscaping activities.
Schiphol ownership strives to ensure that the airport landscape blends into the natural surroundings in
the best way possible. For example, they designed a system of canals and dense hedging to enclose
the area around the new runway. The policy prerequisite to avoid bird strikes includes deterring birds
from coming to the airport grounds by growing a longer species of grass and employing a team of
specially trained dogs to chase the birds away. Approximate number of bird strikes at AMS in 2003: 122
(KLM figures not complete); 2002: 188; 2001: 122; 2000: 233; 1999: 20028.
The majority of roofs greened at Schiphol International Airport buildings have used Xero Flor and ZinCo
products. In fact, Xero Flor manufactures a specially designed vegetation mat specifically for airport use.
From research and respondents, the estimated total airport area greenroofed at Schiphol International
Airport and its surrounding Schipholrijk neighborhood is approximately 73,730 m2 or 793,623 square feet
(sf). The Schiphol airport itself contains three buildings with extensive greenroofs of 8500 m2 (91,493 sf),
3500 m2 (37,674 sf), and1330 m2 (14,316 sf). Schiphol also has two intensive greenroofs totalling 400
m2 (4,306 sf) bringing the airport total to 13,730 m2 or 147,789 sf. The Schipholrijk neighbourhood has
six buildings with intensive greenroofs measuring approximately 10,000 m2 (107,639 sf) each for a total
of 60,000 m2 or 645,835 sf29.
Schiphol Plaza extensive greenroof - Constructed in 1994, the Schiphol Plaza Xero Flor greenroof is
situated over the main terminal and measures approximately 8,500 m2 (91,493 sf), serving as a parking
garage and train railway station. Designed by Benthem Crouwel NACO, Mostert De Winter, Dutch
licensees of the firm Strodhoff & Behrens Begruennungs GmbH of Gross Ippener, Germany, installed the
largest extensive greenroof at Schiphol using the Xero Flor moss-sedum combination pre-vegetated
mats Type XF 300c. The sedums and drought resistant mosses are set in a mineral-based Xero Terr®
substrate formula with a system maximum saturated weight of 35 kg/m2 (7.168 lbs/sf); the substrate
depth is just 40 mm (1.57”)30.
Schiphol Plaza; System: Xero Flor;
31
Source: Mostert De Winter website .
Varying colors at Schiphol Plaza;
32
Photo: Haven Kiers .
Schiphol Real Estate and Sky-Master extensive greenroofs - Aart Veerman, President of the
International Green Roof Association and Commercial Director of Van der Tol b.v., estimated the total
area on the grounds of Schiphol-Airport greenroofed by Xeroflor with sedum mats to include three roofs
at 13,330 m2, to equal 143,483 sf. The other two large extensive roofs are situated on the head office of
"Schiphol Real Estate" and the “Sky-Master” building.
Mr. Veerman’s company, Van der Tol b.v., holds the maintenance contract on both. He states that the
maintenance of the sedums is really simple - the only extra measure is the filling of the open space
between the sedum mats to account for normal yearly shrinkage. Regarding bird populations Aart says
“So far as I can remember the facility-manager of Schiphol never spoke of a bird problem in relation to
the sedum-roofs.”
Schiphol Real Estate Building; System: Xero Flor; Source: Aart Veerman
Schiphol Vertrekhal Noord intensive greenroofs - Inside the departure and arrival buildings are two
small 400 m2 intensive patio roof gardens at Vertrekhal Noord that were built in 2001, but they are not
easy to visit because of strict security regulations. These are ZinCo greenroofs utilizing Floradrain FD
25 green roof systems.
Schipholrijk intensive greenroofs - The roof gardens in the neighborhood of Schiphol-airport located in
Schipholrijk measure approximately 10,000 m2 each. Office park area residents include Microsoft and
Mitsubishi. Three of six greenroofs are made with ZinCo system solutions. Due to the intensive nature of
these greenroofs, the ZinCo Elastodrain EL200 system was used for the driveways, because of the car
traffic on the roof. Mixed systems were used on the remaining roofs using different trademarked drainage
and filter material. For example, one roof garden not pictured here is made with the BACEL-system, a
Dutch trademark based on Styrofoam drainage33.
Large intensive greenroof projects in Schipholrijk; System: ZinCo;
Left: Mitsubishi Office Park; Source: Aart Veerman
Frankfurt International Airport, Frankfurt, Germany (FRA)
Germany and Europe’s largest airport, Frankfurt International (FRA) is ranked no. 7 in the world. At 20
square kilometers (4,942 acres) in size, FRA is also one of the most compact of the larger world
airports34. As a result, one of Frankfurt International’s key issues is ecological land conservation as they
strive for optimum land use with minimal negative environmental impacts in the densely populated RheinMain region.
The maneuvering areas between the taxiways equal approximately 500 hectares and this nature
conservation area has become home for many plants and animals that are endangered elsewhere.
Management techniques include developing part of the area into a heath because this type of vegetation
is the best to minimize the bird strike danger here. The green areas are not watered and no fertilizer is
applied. Rare birds such as the wheatear and whinchat are observed along numerous endangered toads
and frogs with over 300 different plant species also found on these grounds. In contrast to many other
international airports, FRA does not scare birds but relies on biotope management, which focuses on
designing the airport grounds in such a way that birds are not attracted in the first place. The bird strike
count at FRA averages 3 to 5 per 10,000 aircraft movements and is at the top in terms of international
comparison, equal to the annual strikes at Schiphol International Airport. Furthermore, FRA operators
harvest rainwater from roofs and other surfaces and are committed to nature conservation by running
reforestation programs to make up for land consumed for airport purposes35.
FRA greenroofs - Fraport has installed numerous greenroofs during the last 15 years on different types
of buildings, including on the two terminal buildings, the tower office building, maintenance, cargo and
other office buildings. A few roofs were designed for use and visibility by the public, and some are visible
only from overhead buildings36. Plants are also used extensively on building facades, within inside courts
and on top of the terminal roofs. Planning and upkeep are usually handled by airport specialists who run
their own airport greenhouse shops. According to Fraport AG, the total approximate greenroofed area is
40,000 m2 (430,556 sf) with Optigrün’s having greened about 11,700 m2 (125,938 sf) of this total.
Optigrün estimates that 2,400 m2 are intensive, and the rest are extensive greenroofs. Optigrün has
used the following substrates depths for these greenroofs: Intensive: (40 – 60 cm 16 – 24”); Extensive 8
– 10 cm (3 – 4”).
FRA Terminal 1 holds the largest extensive greenroof which is 15 years old;
Photo courtesy Sabine Eder, Fraport AG.
Frankfurt International Greenroofs:
FRA extensive greenroof; Photo courtesy
Sabine Eder, Fraport AG.
FRA Terminal Extensive Greenroofs; Photos courtesy Silke Kühlmann, Fraport AG.
37
Intensive FRA greenroofs by Optigrün international AG ; Photos courtesy Uwe Hartzmann.
Kloten International Airport, Zürich, Switzerland (ZRH)
Kloten International
Airport - Zurich,
Switzerland (ZRH)
§Total airport area greenroofed at ZRH: 12,000
m2 or 129,167 sf
§Number/Area of Extensive Greenroofs:
2 = 12,000 m2 or 129,167 sf
§Number/Area of Intensive Greenroofs: 0
Greenroofs.com
Zurich-Kloten International Airport in Zürich (ZRH) is the largest airport in Switzerland and strives to
symbolize a modern, comfortable and green airport. ZRH is home to a nature conservation area that
covers an area of approximately 74 hectares and is only a few meters away from the edge of the
runways. ZRH operations and management focus strongly on communication in the area of
environmental protection, and publish an annual environmental report38.
ZRH has two recent large greenroof projects which demanded a high level of effort, coordination, and
communication from all participants because of its sensitive location and accompanying security
measures. No data was found for bird strike counts at ZRH.
Dock E (Dock Midfield) extensive greenroof - One of the largest greenroof building sites in
Switzerland, the new dispatch building at Kloten International Airport is Dock E, previously known as
Dock Midfield, situated between take-off runways and landing strips. Sporting an extensive greenroof
measuring 4,000 m2 (43,056 sf), Dock Midfield represents a perfect example how green space can be
regained on roofs. Completed in November 2002 after years of detailed discussions, the planning group
decided to install ZinCo greenroof systems. Admittance to the Dock Midfield project was limited to
trained staff using registered vehicles, and strict regulations had to be followed to obey the demanding
security measures of airport Zurich-Kloten.
A pneumatic pump reaches across
photovoltaic panels to place the
substrate onto the roof’s perimeters.
Installing the 80 mm (3”) depth substrate.
Photos Copyright and courtesy ZinCo.
Dock E recently seeded in June 2002;
Photos Copyright and courtesy ZinCo.
The ZinCo Green Roof System vegetation strip
next to the 14 m wide photovoltaic installation.
Along the perimeter between the fascia and
vegetation, a safety strip of gravel is installed as
fire prevention.
Limited movement dictated careful planning, for example one issue dealt with how to bring up the
substrate and gravel to the 18 – 22 m (59 – 72’) high roof surface while crossing a 14 m (46’) wide
photovoltaic installation at the roof’s perimeters without any damage. In response, a ZinCo partner’s
special vehicle utilized a pneumatic pump and placed the substrate materials onto the roof’s perimeters
at three locations, where it was then spread on to the entire surface using flexible pipes at a depth of 80
mm (3”).
View of ZRH’s Dock E (Dock Midfield) – Up to 27 aircraft
can be handled simultaneously.
Photos Copyright and courtesy ZinCo.
The roof construction illustrates the not often used variation of the inverted roof in Europe. Particular to
inverted roofs is the fact that the insulation layer is situated over the waterproofing. “There are two main
subjects that have to be taken into consideration when planning a well functioning Green Roof System
on top of an inverted roof,” says Jürgen Ullrich of ZinCo. “First of all, the insulation material must
maintain its insulating effect even during penetration by water. That means that inverted roofs require
extruded insulation. Secondly, the Green Roof build-up must be designed so that vapour pressure can
be built up.”
A flowering meadow-like roof at ZRH three years after installation; Copyright ZinCo
Separation and slip membrane TGV 21 covers the extruded insulation mats and serves as the base for
the recycled ZinCo substrate. TGV 21 is permeable for vapour but resistant to water, necessary qualities
for the installation of a ZinCo Green Roof System on inverted roofs. The vegetation consists of Sedum
shoots at 20 – 25 pieces /m2 (2-3 pieces /sf) which are drought and frost resistant Sedum plants.
Generally, Sedum vegetation is a low demanding type of vegetation, yet fertilizing and maintenance,
especially weeding once to twice/ year, has to be done. Credits – client: Unique Flughafen Zürich AG;
landscape installation: Behlke GmbH; design company: ARGE Zayetta; project designer and
architecture: David Munz; site supervision and structural engineering: Urs Strickeisen; greenroof
systems: System ZinCo; technical advice: Jürgen Ullrich, ZinCo AG; construction: Behlke GmbH & Co.
KG39.
Multi-story Car Park B (Parkhaus B) extensive greenroof –Completed in 2001, the 8,000 m2 (86,111
sf) multi-story Car Park B at ZRH also demanded specific logistic skills and equipment in bringing up the
substrate to the high 50 m (164’) roof level, and a pneumatic pump was required to blow substrate and
gravel onto the roof's surface.
Multi-story Car Park B (Parkhaus B) before
40
greenroof installation .
The extensive ZinCo Green Roof System used
here is in its second vegetation season after
installation.
Construction work was performed during daily airport vehicle and airplane traffic. The extensive ZinCo
Green Roof System contains a combination of planted Sedum shoots and hydro-seeding in a sedum
carpet. An anti erosion jute control net "JEG" was installed afterwards to protect the plants against wind
uplift41.
The structured grid of sky lights is softened by the
surrounding ZinCo greenroof vegetation shown
three years after installation.
Multi-story Car Park B is now covered by a
carpet of yellow. In the background an
airplane is just taking off.
Credits for the ZRH Multi-story Car Park B - architect and design firm: Stutz & Bolt, Winterthur;
construction: Behlke GmbH, Lennestadt; greenroof system: ZinCo System "Semiramis"42
The European Experience and Outlook
Not all European countries have experience with airport greenroofs and some officials are
understandably cautious. Referring to airport greenroofs, Dr. John Allan, Head of the Birdstrike
Avoidance Team of the Central Science Laboratory in York, England, believes smaller species should
not present a problem but says “I would be very concerned about the possibility of roof nesting by gulls,
which is becoming an increasing problem here as it is in the U.S.” The question appears to be whether
they would be any more attractive than a bare flat roof43. British ornithologist and greenroof advocate
Dusty Gedge agrees that in parts of the UK there are big problems with gulls nesting on roofs general.
But as director of Livingroofs.org he believes such roofs around airports could be beneficial as they
would in some way mitigate some of the less desirable environmental consequences of airports and
airlines.44
Yet, Dr. Allan is most interested to hear about existing airport greenroofs elsewhere in Europe, of which
he was not aware. He adds, “We are responsible for checking and approving planning applications at
U.K. civil and military airports in relation to birdstrike issues and, although it has not happened here yet,
the use of greenroofs in Europe suggests that it is a matter of time before we will need to address this
issue in the UK.”45
Greenroofs are simply one sustainable design element incorporated into an overall ecological airport
land use plan. Stormwater retention rates, improved air and water quality, and area temperature
reduction advantages can be expected to have the same effects whether situated on an airport greenroof
or any other landscaped roof, as they are more dependent upon local climate factors than a type of
application. Perhaps since the Europeans have been managing these natural airport areas with
ecological conservation in mind from the start, bird and other wildlife design considerations and
regulations are not separated in terms of natural areas of taxiways or recreated natural areas on a roof.
The European Experience:
No one identified any problems for airport greenroofs simply because they are
located in an airport;
Birds and wildlife are considered integral to site;
Greenroofs are part of the initial design process and designed according to the
physical needs of that particular geographic area;
Greenroof maintenance is integrated into the overall airport management plan and
is either done by the airport itself or is handled through landscape contracts with
industry professionals;
Excellent maintenance is a result of the established market.
Does the European experience indicate birds on greenroofs are causing problems for air traffic by
increasing incidences of bird strikes? Simply, there don’t seem to be any issues pertaining to increased
bird strikes associated with airport greenroofs among any of the manufacturers and providers contacted
within Europe. Not one person identified any specific maintenance problems or concerns for airport
building greenroofs simply because they are located in an airport – in other words, greenroofs are part of
the initial design process and designed according to the needs of that particular geographic area.
Greenroof maintenance is integrated into the overall airport management plan and is either done by the
airport itself or is handled through landscape contracts with industry professionals.
The respondents argued that birds use greenroofs as much as any other green space in nature, and
usually only small birds settle on greenroofs. Moreover, birds also rest and settle on barren, naked roofs.
Do they cause problems?
A Green Lining
Yes, they do, says Richard A. Dolbeer, PhD, USDA/Wildlife Services National Coordinator, Airport Safety
and Assistance Program, as is illustrated in the photos below. “Based on my experience evaluating
wildlife attractants around airports, I do not believe that properly designed "green roofs" would attract
hazardous birds beyond background levels. In fact, such roofs might actually reduce the presence of
large birds that are hazardous to aviation,” he says. “One chronic problem that we find around coastal
airports in USA and Canada is nesting and roosting by gulls on flat roofs, especially gravel-covered roofs
but sometimes even metal roofs. A survey we did in 1994 revealed 16,000 gulls nesting on rooftops in
cities along the USA portion of the Great Lakes. This survey missed a lot of roof colonies so the actual
numbers were much higher” 46.
Traditional flat roofs often do attract hazardous
birds. Left: Ring-billed gulls with chicks
Right: Herring Gulls nest on a rubber
roof. Photos: Richard Dolbeer
He said a similar question about 15 years ago regarding yard-waste compost facilities (would they attract
hazardous birds if located near airports?) resulted in conducting two objective studies in which bird
numbers by species were observed at yard-waste facilities and then compared to background levels of
birds in undeveloped grassy areas of comparable size. They found fewer birds in the compost areas;
thus, yard-waste composting was not incompatible with aviation safety47.
Richard Dolbeer continued, “Thus, it would be a good idea to have a study conducted to document the
numbers and types of birds seen on green roofs so that you will have objective data. As I said at the
start, I do not think green roofs should attract hazardous birds but the only way to definitively answer the
question is to conduct a study. We already know that traditional flat roofs often do attract hazardous
birds.”48
Facts & Greenroof Factors that May Reduce Birds at Airports:
1. Reduced Stormwater Runoff Effect:
Disposal is usually diverted into retention ponds or ditches;
Artificial wetlands create attractive habitats for waterfowl, gulls, & other large water
birds;
Standing fresh water is a magnet;
Greenroofs’ ability to increase water retention will reduce stormwater volumes into
airport retention ponds, thereby reducing the # of problematic birds.
2. Cooler Roofs Less Attractive than Warm Roofs to Birds:
Greenroofs are cooler than dark, sealed roofs;
Birds are attracted to warm roofs for nesting;
Hot surfaces support lift-off, e.g., paragliders prefer hot spots like dark roofs and huge
parking lots49;
On cooler days, a hot roof, relative to the environment, may be an attraction for warmth
& ease in lift-off;
The reduction in thermal lift properties on greenroofs may act as a bird deterrent.
Richard Dolbeer pointed out a few facts: “One factor related to green roofs that might help reduce birds
near airports is reduced water run-off. A big issue at airports right now is disposing of all the water that
runs off hard surfaces (concrete and roofs) after rain storms. When this water is diverted into retention
ponds (like "Lake O'Hare") or into ditches, these artificial wetlands create a very attractive habitat for
waterfowl, gulls, and other large water birds that are hazardous to aviation, especially if the water does
not drain away within a day or two. Standing fresh water is a magnet for many large bird species. If
green roofs will reduce the roof run-off at airports (via transpiration and respiration by roof vegetation),
then there will be less water going into these ponds and ditches that are attractive to birds. “
He added that Dr. Brad Blackwell at the USDA Research office in Sandusky, Ohio, in cooperation with
FAA, is studying bird use of artificial wetlands (used for run-off management) in the vicinity of airports.
His goal is to come up with design and management criteria for these wetlands to minimize bird use, and
it might prove fruitful if green roofs could have a bearing on this issue50.
Successful Design Parameters
Therefore, success appears to be based on various site specific design parameters all directly relating to
the local ecology. Bird species that may form large flocks and feed on airfield grassland are a concern.
Another issue is the possible attraction of pigeons or gulls on roofs that are used by airport staff during
break times when feeding of birds becomes likely. If flat gravel and barren roofs actually do attract larger
birds, it can be argued that greenroofs can be designed to not attract the larger birds with correct
vegetation, and actually deter these more hazardous types from nesting. Maintenance agreements need
to be in place with either airport personnel or specific greenroof service companies.
Primary Design Strategy Against Wildlife Hazards:
Identify those responsible for implementing the plan – the
team: airport operator, wildlife biologist; designers;
Identify and provide information on hazardous wildlife
attractants on or near the airport - Provide list of
attractants (food, cover, and water);
Design roofscape against identified attractants;
Implement maintenance regime accordingly – the
greenroof is simply another open vegetated area to be
monitored;
Every design is site specific, highly variable and may
depend on several factors, including land-use practices on
or near the airport, climate, geography, and the wildlife
species!
Proposed Airport Landscape Management Plan
Greenroof Design Considerations:
Design against bird species larger size than Finches;
Due to large expanses of grass and forbs a vegetation cover and mowing regime
should be established to minimize rodent populations and the production of seeds,
insects, and forage desired by birds;
Trees and other plants should not produce fruits or seeds attractive to birds. Avoid the
creation of areas of dense cover for roosting and nesting;
All standing water on airports should be eliminated to the greatest extent possible;
All unnecessary structures that can be used as perches by raptors and other birds
should be removed;
All landscaping plans should be reviewed by a wildlife damage management biologist.
Landscaped areas should be monitored on a continuing basis for the presence of
hazardous wildlife.
Vegetation
One of Germany’s leading landscape architects and foremost expert on greenroofs is noted researcher
and designer Bernd W. Krupka. Mr Krupka advises that construction techniques of green roof systems
must be used against bird populations that are dangerous to aviation, i.e., bird species of a larger size
than finches. “These construction techniques must provide a higher growth of the grass and herb
vegetation in order to prevent bigger birds from landing on the roofs, though such areas with higher
vegetation must be mowed or cut - the same as any meadow – in order to prevent shrubs or bushes from
growing and to reduce the fire risk. In this regard it is essential that the airport management provides a
job profile which shall also be applied to the remaining green spaces.” He adds that the subject still
needs more research51.
Mr. Krupka contributed the following information, graciously translated into English by Julia Schumayer of
ZinCo International: “Bird repelling green roofs can be realized with extensive and intensive green roof
build-ups. For roofs with low load bearing capacities (of approx. 30 to 40 kg/m²) pre-cultivated vegetation
mats made of mosses and herbs (approx. 20-40 mm in height) can be used with reinforcement of
entangled filaments. Past experience has shown that birds are deterred by the entangled filaments
because of a trap or snare effect. Higher grass and herb vegetation (approx. 150 to 200 mm in height) is
less attractive for birds as habitats can be created with a substrate depth starting at approximately 150
mm.
“For intensive green roofs ground-covering woody plants with low to medium height are predominantly
eligible. There are a number of deciduous and coniferous trees available with no berries (e.g. Lonicera
pileata, Juniperus sabina, Pinus montana). These trees can be successfully be used for larger green roof
areas. However, monocultures should be avoided, as well as scattered tall trees which are very attractive
for birds.
“According to past observations, only a few little ground birds like larks or meadow pipits use extensive
green roofs as habitats. On ground-covering woody vegetation types, only greenfinch or blackbirds have
been observed in Germany as breeding birds so far. Gravelled roof areas are on the other hand in many
cases resting places for larger birds: These can be kept off completely or at least temporary by mediumhigh vegetation.”52
As has been stressed, each biotope is unique and management is site specific. The mowing specifics for
the grassy areas at Atlanta Hartsfield-Jackson International Airport, for example, dictate a maximum
height of 3 inches for wildlife control53.
The Future for ATL and Elsewhere
Another updated feature of this paper is the information from the only known existing airport greenroof in
the U.S., found at the King County International Airport. The County’s largest green roof to date was
completed in October 2003 on this historic building, and the 8,000 sf extensive green roof was planted
with a variety of rye grass. Although not registered for LEED™, this project may be eligible for LEED™
certification in the future. The good news is that according to Maureen Thomas, the Project Manager,
during the first four or five months or so the greenroof flourished and they had absolutely no problems
associated with bird nuisances. However, the living portion of the greenroof failed soon after from the
apparently incorrect specification of growth media for the substrate depth and selected plant material. A
review is currently underway to replace the both the substrate and vegetation choices.54
In addition to the greenroof, other
sustainable strategies include: Addition
of alternative fueling stations in the
parking lot; Incorporation of water
conserving plumbing fixtures; Reuse of
the original structural shell;
Construction debris recycling; Energy
efficient lighting; Low VOC building
materials and Day lighting in occupied
spaces. Photos: King County Green
55
Building Initiative 2003 Annual Report .
Interest in smart, energy-efficient buildings has been steadily growing, especially among those who
manage large facilities such as airports because lifetime building operating costs can be hundreds of
times more expensive than the original building itself. Lucie Griggs, director for Atlanta’s Cool
Communities non-profit organization, says NASA's air-quality modeling research in Atlanta could lead to
the creation of financial incentives for doing heat-sensitive construction, or changes in development laws,
which in turn could lead to more possibilities with greenroofs56. The City of Atlanta is already on track
with a greenroof atop Atlanta City Hall with plans for other government buildings and possible measures
to increase greenroof development in the future.
From the successful European experience we can see that certainly greenroofs are viable alternatives to
the average hot, barren airport rooftops, detached from and detracting from our natural environments. It
is easy to understand how Atlanta’s largest urban heat island, Atlanta Hartsfield-Jackson International
Airport, can be significantly mitigated by incorporating greenroofs, and can serve as a representative
scenario of world airport architecture.
Conclusion: A Balancing Act
Using the Airport as a metaphor for the City, it is clear that through utilizing greenroofs as part of its
urban infrastructure of runways, managed greenspaces, etc., we can mitigate many of our
developmental impact ecological problems such as the heat islands, stormwater, habitat destruction and
the like. In a similar vein "underground architect" Malcolm Wells' vision of a new American landscape
includes placing infrastructure underground, and believes even airports could be located underground.
Similarities remain in that humans may reconnect with nature and each other. In 1994 Wells told The
Futurist magazine “The question of how to design an airport appropriate for the future can be answered
as follows: Build huge, high, roofed-over spaces, allow for floor-to-floor heights of ten feet or more
indoors, and pull a blanket of earth over the whole thing.57
Economic impacts of airport facilities and operations affect many sectors, both private and public. But we
must also balance the needs of current airport land/building management and expansion plans in
environmental impact terms.
Next Steps to a Greener Airport Rooftop Environment
Yet what may appear to be a call for an immediate action or an obvious environmental solution to the
many developmental woes presented by airport construction does need to be tempered with continued
review and research of airport wildlife mitigation design principles at regional airports worldwide. Our
position is to encourage safe, site specific design and maintenance strategies which include the
technology of organic greenroof architecture. Public policy stakeholders worldwide can benefit from
further study of numerous European regional planning and zoning procedures which include various
types of airport greenroofs and systems. We hope to encourage further dialogue and information sharing
between international governments and bring to light that not only are airport greenroofs possible, they
are currently in existence without mishap. Here then is opportunity to form an international multidisciplinary team of airport stakeholders including greenroof design professionals, safety experts, wildlife
biologists, ornithologists, researchers, and government policy makers.
We believe we need to not only embrace this concept, but further study and develop it to best fit our wide
geographic and regulatory needs. Land use practices known to threaten aviation safety are not
acceptable, and agree with Dr. Richard Dolbeer in that we need to have studies conducted to document
the numbers and types of birds seen on existing European airport greenroofs and representative North
American greenroofs across our various climate zones to accumulate objective data. The FAA will most
certainly discourage the development of any questionable sites, including sustainable greenroofs, if
studies show that they support or encourage potentially hazardous wildlife species. Once local problem
bird populations are clearly identified the judicious selection of the correct vegetation palette should
ensure a comfortable margin safety.
So, in this case, it appears necessary to err on the side of caution before we jump wholeheartedly into
promoting airport greenroofs worldwide. Do we hear any student, policy or government takers willing to
document the European airport greenroof experience, please?
- Linda S. Velazquez with contributions by Benjamin Taube
“Are human beings and the natural world destined to be at odds forever? Or can we, so long estranged
from the world that produced us, learn to live as gently, as gracefully, and – with great good luck – as
beautifully here as do all the rest of the world's creatures?” – Malcolm Wells58
“Droompark” – Green Airport of the Future?
Drawing Courtesy of Erik Steegman of Phoenix Benelux
bvba
All rights reserved, Greenroofs.com, LLC. Permission is granted to Green Roofs for Healthy Cities to
include paper in the proceedings of the Third Annual Greening Rooftops for Sustainable Communities
Conference, Awards and Trade Show, 2005.
Footnotes Page
1
Gary Stoller, “Inventor takes airport design to new heights,” USA TODAY 12 Jan. 2004:
<http://www.usatoday.com/money/companies/management/2004-01-12-starry_x.htm>.
2
< http://www.atlanta-airport.com/Default.asp?url=sublevels/airport_info/gmpage.htm>.
3
Benjamin Taube and Georgia Tech.
4
Dr. Jeffrey Luvall, NASA, Personal Communications, 19 Jun. 2001.
5
Dr. Dale A. Quattrochi, Personal Communications, 22 Jun. 2001.
6
Dr. Jeffrey Luvall, NASA.
7
Atlanta Department of Aviation.
8
Grading and Excavating magazine, Nov./Dec. 2004: 4-5
9
<http://www.faa.gov/arp/pdf/5200-33.pdf>.
10
K. Hahn-Becker, “The natural environmental features of the airfield of Holzdorf and measures for birdstrike prevention,” Bird and Aviation, Vol. 24 2004:
<http://www.davvl.de/Volu%20englisch/2004/Hahn.pdf>.
11
Matthew Barrows, “FAA Targets Bird-airplane Collisions,” Sacramento Bee, 19 Nov. 2001:
<http://wildlife.pr.erau.edu/News.htm>.
12
<http://www.faa.gov/arp/pdf/manfin.pdf>.
13
<http://www.tc.gc.ca/civilaviation/aerodrome/menu.htm>.
14
<http://www.birdstrike.org/>.
15
Ibid.
16
<http://wildlife.pr.erau.edu/WildlifeManagement.htm>.
17
<http://www.birdstrike.org/>.
18
German Bird Strike Committee: <http://www.davvl.de/Seite53e.htm>.
19
<http://www.birdstrike.org/>.
20
Matthew Barrows, “FAA Targets Bird-airplane Collisions,” Sacramento Bee, 19 Nov. 2001:
<http://wildlife.pr.erau.edu/News.htm>.
21
<http://www.birdstrike.org/>.
22
<http://wildlife.pr.erau.edu/index.html>.
23
<http://www.davvl.de/Seite2e.htm>.
24
Dan Vergano, “1 in 10 bird species could vanish within 100 years,” USA TODAY, 13 Dec. 2004:
<http://www.usatoday.com/news/science/2004-12-13-bird-species_x.htm>.
25
Jörg Breuning, Green Roof Service, Personal Communications, 21 Dec. 2004.
26
Dr. Michael Marrett-Foßen, optima Dachbegrünungs GmbH, Personal Communications, 25 Apr. 2005.
27
Project Info: “Geneve Hopital Cantonal” (Foamglas, May 1995).
28
Sustainable Development at Amsterdam Airport Schiphol 2003 PDF:
<http://www.schiphol.nl/media/portal/_schiphol_samenleving/pdf/pdf_files/verslag_vo_2003_uk.pdf>.
29
AART Veerman, the International Green Roof Association, and Heidrun Eckert, ZinCo International,
Personal Communications, 27 Oct. 2004 and 11 Jan. 2005.
30
<http://www.bam.nl/baminternet/baminternet/portalen/mostertdewinter_nl/index.jsp>..
31
Ibid.
32
Haven Kiers, Landscape Architect.
33
AART Veerman, the International Green Roof Association, and Heidrun Eckert, ZinCo International,
Personal Communications, 27 Oct. 2004 and 11 Jan. 2005.
34
<http://www.ausbau.fraport.com/cms/default/rubrik/2/2230.why_expand.htm>.
35
<http://www.fraport.com/cms/environment/rubrik/2/2866.nature_conservation.htm#Bird%20Strike>.
36
Silke Kühlmann, Landschaftsarchitektin, Dipl.-Ing., Fraport AG Frankfurt Airport Services, Personal
communications, 2 May 2005.
37
Uwe Harzmann, Personal Communications, 115 Nov. 2004.
38
2003 Environmental Report, Zurich Airport, April 2004:
<http://www.unique.ch/dokumente/?ID_site=2&sp=en&doku=Environmental%20Report_2003.pdf&dtit=U
nique+2003+Environmental+Report>.
39
Jürgen Ullrich, ”Dock Midfield Under a ‘Green Hat’,” ZinCo Press Report PDF, October 2004, prepared
for Linda S. Velazquez.
40
< www.zinco.de>.
41
Jürgen Ullrich, “Dock Midfield Under a ‘Green Hat’,” ZinCo Press Report PDF, October 2004, prepared
for Linda S. Velazquez.
42
<www.zinco.de>.
43
Dr. John Allan, Birdstrike Avoidance Team, Central Science Laboratory, Personal Communications, 7
Dec. 2004.
44
Dusty Gedge, Livingroofs.org and Black Redstarts, Personal Communications, 13 Dec. 2004.
45
Dr. John Allan, Head, Birdstrike Avoidance Team, Central Science Laboratory, Personal
Communications, 7 Dec. 2004.
46
Dr. Richard Dolbeer, USDA/Wildlife Services, National Coordinator, Airport Safety and Assistance
Program, Personal Communications 14 Dec. 2004 and C. P. Dwyer, J. L. Belant, and R. A. Dolbeer,
“Distribution and abundance of roof-nesting gulls in the Great Lakes region of the United States,” Ohio
Journal of Science, 1996: 96:9-12.
47
Dr. Richard Dolbeer, USDA/Wildlife Services, National Coordinator, Airport Safety and Assistance
Program, Personal Communications, 4 Dec 2004, and S. W. Gabrey, J. L. Belant, R. A. Dolbeer, and G.
E. Bernhardt, “Bird and rodent numbers at yard-waste compost facilities in northern Ohio,” 1994. Wildlife
Society Bulletin 22:288-295; S. W. Gabrey, “Bird and small mammal abundance at four types of wastemanagement facilities in northern Ohio,” Landscape and Urban Planning, 1997: 37:223-233.
48
Dr. Richard Dolbeer, USDA/Wildlife Services, National Coordinator, Airport Safety and Assistance
Program, Personal Communications, 6 Dec. 2004.
49
Jörg Breuning, Green Roof Service, Personal Communications, 24 Jan. 2005.
50
Dr. Richard Dolbeer, USDA/Wildlife Services, National Coordinator, Airport Safety and Assistance
Program, Personal Communications, 3 May 2005.
51
Bernd W. Krupka, Landscape Architect, BDLA, Personal Communications, 2 Dec. 2004.
52
B. W. Krupka, “Flat roofs on airports - advantages by vegetation,” Bird and Aviation (ISSN 0721-4521):
Volume 10, Issue 1 - translated from Bernd W. Krupka by Julia Schumayer of ZinCo International, 12
Jan. 2005.
53
Ken Martin, Atlanta Hartsfield-Jackson International Airport Environmental Programs Manager,
Personal Communications, 28.Apr. 2005.
54
Maureen Thomas, Project Manager, King County International Airport, Personal Communications, 2
May 2005.
55
King County Green Building Initiative 2003 Annual Report:
<http://www.metrokc.gov/dnrp/swd/about/green-building-team/2003GBI_AnnualReport.pdf>.
56
Kevin Duffy, "NASA studies how to cool area as heat builds up," The Atlanta Journal-Constitution, 18
Apr. 2004: <http://www.ajc.com/news/content/business/horizon/0404/19pavement.html?urcm=y>.
57
Natural Life Magazine, # 40: <http://www.life.ca/nl/40/underground.html>
58
The Futurist magazine, Sep./Oct. 1994.