Zoomazium at Woodland Park Zoo

Challenge

The zoo wanted a sustainable new building that would demonstrate its commitment to ecological responsibility and reinforce its systems-based approach to education and its Pacific Northwest biome concept for the zoo visitor experience. Though a green roof was a consideration, there were few successful precedents on which to base design and plant selection.

Solution

Zoomazium helps the zoo achieve a range of goals from reducing stormwater runoff, mitigating the urban heat island effect and creating habitat to educating new generations about how to build respectfully. The building and vegetated roof reflect and support the Zoomazium’s education programs on sustainable forest practices.

• Locating the Zoomazium on the footprint of the old primate house limited site disturbance. Adjacent vegetation was preverved, including a champion black cherry tree.
• The 8,000-sf “floating forest floor” of over 22,000 native plants on the roof of a new education-focused building enhances Pacific Northwest forest habitat. Species such as Salal and Kinnikninnick are critical components of the forest floor habitat, connecting the Zoomazium to the larger zoo landscape.
• Local pumice was used in the roof planting medium and a 6” depth was chosen to allow for better water retention and more diverse plant selection.
• Choosing self-sowing native plants, like lupine and nodding onion, helped the roof vegetation establish quickly.
• A study was done to map areas of the roof that receive shade from adjacent mature trees. Shade-adapted vegetation, like salal and sword fern, was planted in these areas.
• No permanent roof irrigation system was installed. Staff hand water when needed.
• Because bird strikes on windows were a major concern, the fritting was selected through extensive research with ornithologists. No bird deaths have been reported.
• 72% of wood used in the construction is Forest Stewardship Council (FSC) certified.
• The roof is the subject of ongoing monitoring and research , which has contributed to local understanding of greenroof systems and appropriate native plants.

The decision to substitute the vegetated roof for a standard metal roof added $150,000 to the total project cost, averaging out at an additional $19 per square foot. This cost includes the installation of structure required to support 6” of planting medium and an increased density of installed plant material.

• Active maintenance is required, particularly during plant establishment.
• The roof slope, planting medium, and sun exposure greatly affect water availability during periods of drought.
• The green roof coir blanket, used to reduce weeds and stabilize lightweight soil, was not soaked prior to installation; as a result, water was observed sheeting off rather than passing through it.

Project Team

Client: Woodland Park Zoo

Prime Consultant/Landscape Architect, Architect, Planner: Mithun, Inc. 

Exhibits: AldrichPears Associates

Design and Fabrication: Dillon Works!

Green Roof System: American Hydrotech

Mechanical and Plumbing: Flack + Kurtz

Natural Daylighting Consultants: BetterBricks Daylighting Lab

Energy Use Consultants: Hultz/BHU/Cross Engineers

Contractors: Kirtley-Wall Associates LLC

Role of the Landscape Architect

Integrated design team member from the beginning of the project through completion.