Case studies - Living Roofs in Integrated Urban Water Systems - page 157

with additional water from the municipal supply during extensive, increasingly
frequent drought periods in order to irrigate the gardens.
This allows making a general careful assumption by the authors, in this case,
that the living roofs of the Potsdamer Platz have high stormwater holding capaci-
ties. With the research currently available, more precise stormwater retention
capability can be predicted on living roofs. In this context, this project example
serves as a lesson to demonstrate the importance of accurately modeling storm-
water runoff, so that water availability for cisterns (water harvesting) and supply
to at-grade LID elements are adequately designed and do not compromise design
goals.

5.2.5 Neighborhood scale: Headwater at Tryon Creek, Portland, Oregon,
USA
5.2.5.1 Project objectives
The Tryon Creek Headwater Development exempliies a neighborhood-scale
project that was conceived of and successfully executed as a way to champion
LID as both an ecologically and socially responsible design approach (see Table
5.5 and Figure 5.5 ). It also showcases a system- based thinking that is innately
geared toward the celebration of stormwater management and of water as an
ecological resource with intrinsic social value. Through the holistic LID strategy
and emphasis on stormwater management and other environmental sustainabil-
ity targets, this project's goals for urban development, social and ecological
investment, and ecological regeneration were permitted to unfold.
This project is also an example of a development where living roofs have been
implemented within a LID system and applied at a neighborhood scale. Runoff
from the living roofs is directed to at-grade, vegetated, runoff retention elements

Table 5.5 Project speciications: Headwater at Tyron Creek

Location Portland, OR, USA

Completion Architecture and wetland enhancement: December 2006

Rain garden: 2008

Project area 11,650 m 2

6,900 m 2 capturing and treating stormwater

Project Type • mixed, multi-family residential

Project budget/cost • $27.25 million US$

Roof area • 1 large and 6 smaller extensive, netting 1,390 m 2

Volume of water mitigated/treated • 6,000,000 l

Awards/recognition • Silver LEED (Dolph Creek Townhomes)

• 49th Gold Nugget Awards 2011: two merit awards

Consultant team (selected) • Landscape Architect: GreenWorks PC

• Architects: Sullivan Architects (Dolph Creek Townhomes) and
Vallaster & Corl Architects (Village at Headwater and Headwaters
Apartments)
• Civil Engineer: mGH Associates
• Stream Restoration: Inter-Fluve Inc

Client/owner • Jim Winkler, Winkler Development Corp.