High Line, New York, NY
Green roof size: 230,000 square feet
Award recipient: Kelco Construction (green roof, vegetation and irrigation system installer) Project Team
Architect: Diller, Scofidio + Renfro
Client: Friends of the High Line
General construction Contractor: CAC Industries
Landscape architect: James Corner Field Operations
Lighting: L’Observatoire International
MEP engineering: Buro Happold
Planting design: Piet Oudolf
Signs: Pentagram Design
Structural engineering, historic preservation: Robert Silman

The High Line is a public park built on a 1.45-mile-long elevated rail structure running from Gansevoort Street to West 34th Street on Manhattan's West Side. Originally a freight rail line, the High Line was in operation from 1934 to 1980. Now, it re-purposes a piece of industrial infrastructure as public green space. The High Line landscape functions essentially like a green roof; porous pathways contain open joints, so water can drain between planks and water adjacent planting beds, cutting down on the amount of stormwater that runs off the site into the sewer system.

The High Line's green roof system is designed to allow the plants to retain as much water as possible. In addition, there is an irrigation system with options for both automatic and manual watering. This system will be particularly important in the first few years as the plants establish themselves, but less necessary over time.

The public space blends plant life (reminiscent of the quiet contemplative nature of the self-seeded landscape and wild plantings that once grew on the unused High Line) with long, narrow "planks," forming a smooth, linear, virtually seamless walking surface. The public environment on the High Line contains special features, including a water feature, viewing platforms, a sundeck, and gathering areas to be used for performances, art exhibitions and educational programs.

The High Line has rigorous maintenance requirements and the Friends of the High Line, many of whose members are volunteers, are responsible for maintaining the space. This organization seeks to preserve the entire historic structure and continue the transformation of an essential piece of New York’s industrial past. Through stewardship, innovative design and programming, and excellence in operations, the High Line is increasingly serving as a vibrant community hub. 

Steven W. Peck is the founder and president of Green Roofs for Healthy Cities, the non-profit industry association with a mission to develop the green roof and wall industry across North America. For more information visit greenroofs.org. Readers are invited to join GRFHC at CitiesAlive to meet the award winners and learn more about these outstanding green roof and wall projects: citiesalive.org.