Sammamish Sustainable Infrastructure Plan

Summary In March 2009, GGLO assembled a team to respond to a design competition for the Infrastructure Plan for Sammamish Town Center. Capitalizing on GGLO's extensive experience in town center revitalization, and on ARUP's proven record in sustainable infrastructure, the team produced an innovative plan that seamlessly integrates the needs of the residents and business owners with the requirements of ecologically sensitive infrastructure. GGLO Team: Bill Gaylord, Beth Dwyer, Don Vehige, David Cutler Partners: Civil Engineering: ARUP Financial Consulting: FCS Group Further Information: Click here to request a high-resolution copy of the proposed plan.




Design Statement The site for the Sammamish Town Center is currently defined by dynamic topography, a highly functioning ecosystem, a distinct natural character, and extraordinary views. Building on the goals of the City’s adopted Town Center Plan, this proposal suggests that the Green Spine be a vital link between the new neighborhood, Civic Center Plaza, the City’s extensive open space network and the regional watershed. It should serve as physical, pyschological, and functional “heart” of the neighborhood. Hidden within block interiors adjacent to the retail core, large lots provide parking ratios comensurate with current requirements for development financing. The lots are ideally situated toshare the nighttime parking demands of housing and the daytime loads of commercial, civic, and retail uses. To provide ample capacity for car traffic while ensuring a vibrant and walkable public realm, the plan offers an interconnected street grid with a hierarchy of types - ranging from urban at the core to natural at the edges. An off-street trail system is woven throughout the neighborhood providing pedestrians and cyclists with opportunities to explore a variety of different environments, from thick forests, to bucolic park meadows, to urban parks and plazas. Block configurations and street alignments correspond to the rolling landscape and minimize the need for expensive regrading of the site. The vast majority of individual building lots are laid out to provide optimal orientation for passive solar heating and natural ventilation.

Natural Drainage The proposed plan integrates water management strategies into the physical layout of the site and structure of the street system. The street network is designed to maximize opportunies for use of natural drainage systems to convey and treat stormwater. This management strategy is augmented by permiable paving in public parking lots, plazas and parks; and harvesting rainwater from public roofs, stored in undeground structures, later used for irrigation in public ROWs and parks. A spectrum of street types were proposed to provide options appropriate for character ranging from urban, village, residential, and rural. Shown below is a proposed typical street section for the Green Spine boulevard, with a 19'-wide vegetated swale in the median strip, along with space for bike lanes and parallel parking.