Case studies - Living Roofs in Integrated Urban Water Systems - page 151

adheres to the principles of smart growth: urban sprawl is mitigated by concen-
trating community resources, investing and connecting to public transportation,
treating and mitigating stormwater runoff, improving water quality, and minimiz-
ing the overall community's environmental footprint.
Each high-density city block is comprised of public hard-scape spaces, public
vegetated spaces, walkable streets and living roofs, and an overall stormwater
treatment strategy. Living roofs are an important aspect of managing the storm-
water in the South Waterfront District as well as creating amenity spaces for the
residents of high-density residential towers.
5.2.3.2 Project overview/objectives
Inspiration for the Mirabella project, a 30-storey retirement community, was
based on the notion that human health and access to nature have a direct cor-
relation. That access can be characterized as the fundamental connection to
the natural processes that sustain health. These processes include food produc-
tion, provision of fresh air, and the creation of a comfortable outdoor environ-
ment, which permits residents with the ability to exercise outside while being
surrounded by a community. Since Portland is home to a large aging popula-
tion, the goal of providing a higher quality of life for the aging portion of Port-
land's population catalyzed the overall design schema and objectives of this
project.
Sustainability objectives transcended the goal of achieving LEED Platinum cer-
tiication, which was obtained through close collaboration between the land-
scape architects and other technical team designers and engineers. This project
can be considered a microcosm of its host neighborhood, because its philosophy
and approach toward environmental and social sustainability was to become a
pioneer for other retirement communities. To this end, the incorporation of
extensive and intensive living roofs for management of rainwater, water conser-
vation, drought-tolerant plantings and attraction of wildlife were central to the
design and function of the project. Rain gardens and vegetated swales were also
incorporated into the overall garden terrace strategy to treat and manage storm-
water runoff.
5.2.3.3 Key living roof design features
1 PROCESS
The design team carefully considered microclimate and wind, shade and glare
control to make the Mirabella's outdoor spaces as versatile, appealing and usable
as possible. Five levels of terrace gardens and three levels of eco- roofs over struc-
ture were incorporated into and spread out throughout the building, from the
twenty-ifth loor to street level. Sweeping views of the Portland city center and
forested hillside beyond were created from the outdoor garden terrace that
extends to the west. Planters and trellises separating this living roof into a
number of outdoor rooms were designed for programmed activities and private
use. Because residents were thought to be most likely outside in the late spring