http://www.azcentral.com/community/s...ima0325ON.html
'Hanging Gardens of Babylon' condo project is a green retreat
Diana Balazs
The Arizona Republic
Mar. 24, 2008 11:30 AM
SCOTTSDALE - Around 600 B.C., the fabled Hanging Gardens of Babylon was considered one of the original Seven Wonders of the World.
According to Greek historians, the project featured terraces and roofs filled with topsoil to accommodate even large trees. There was an elaborate system to pump water from the Euphrates River to the garden beds and a seal made of reeds, tar, brick and concrete kept soil moisture from penetrating the roof structure.
Fast forward to 2008 to Scottsdale's Optima Camelview Village condominium project northwest of Highland Avenue and Scottsdale Road.
The 700-unit glass-and-steel project features terraced and rooftop gardens where 25 to 30 different kinds of colorful plants from groundcovers to trees grow. All the plants were selected for their low water use. A computerized drip watering system is used and a special fertilizer mix is added to the water to nourish the plants.
"Most of these plants just take off. I mean, they just grow incredibly rapidly," said architect and Optima founder David Hovey.
He mentioned one cascading vine called wedelia used in the project that will grow 10 or 12 feet in 3 months.
"They all hang over the edge of the buildings, so it's almost like the Hanging Gardens of Babylon," Hovey said.
Growing green up top
Hovey has been incorporating green roofs in his building designs for about 30 years, originally on a much smaller scale.
"This is, I think, the largest green roof installation of any residential development in the world," Hovey said.
Three landscape architects and a landscaping contractor, ISS Grounds Control, keep the Optima Camelview Village project beautiful and growing. The project site is about 14 acres with 23 acres of landscaping."The only way we can do it is by these green roof areas, and some of these buildings are seven stories high, they vary in height from two stories to seven stories," Hovey said.
Each of the project's units have a private outdoor area with in-ground landscaping.
"Most condominiums will have a balcony or no balcony at all for outdoor space," Hovey said.
How it works
Hovey said on top of each of the units' concrete deck structure is placed a waterproofing membrane. And over that a protection board and a drainage mat about a half inch thick.
"So what happens when it rains, the water goes through all the soil and then drains through the mat to a vertical downspout and from there is either recaptured or goes into the storm sewer system," Hovey said.
Between 6 inches and 2 feet of custom mixed local dirt is placed on top of everything depending on how the big the plants are.
Hovey said an entire year's lifecycle of soil mixtures and plants were tested at Mountain States Wholesale Nursery in Glendale. There were 12 test beds. Different plants were selected for different areas because of the project's design and the orientation of the sun in summer and winter.
"Some plants are mostly in the shade and there are some plants that are always in the sun and they're entirely different. Ones in the shade would never work in the sun and ones in the sun would never work in the shade. It's a very complex situation. We've analyzed it both on the computer and by taking sun readings where we actually measured the sun scientifically at different locations so we know ahead of time what the exact condition is," he said.
The drainage system can be adjusted based on how much water needs to be siphoned.
"We have a double system. For example, if it rains too fast too quickly, we have releases where it goes over the edge. One of the great things about green roofs is that when you get sudden storms, the soil absorbs the rain and it slowly lets it into the storm drain system so the city of Scottsdale is very happy because they are not getting millions of gallons of water thrown at them all at the same time," Hovey said.
Benefits abound
Another advantage of green roofs is that the plants create oxygen out of carbon dioxide and the green roof also provides insulation for the building below.
"There's just all kinds of benefits that go beyond the aesthetics," Hovey said.
And all that landscaping combined with less concrete and asphalt helps lower the ambient temperature between 10 to 12 degrees in urban situations, Hovey said.
"It's both working together. Of course, naturally being an architect, my main objective of the plants is to provide an aesthetically very pleasing environment," he said.
Hovey's love of plants is deep rooted.
"I've always as an architect have been very interested in landscaping. My idea would be that the building is just a backdrop and the landscaping is sort of the main feature," he said.
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