Dutch Kills Green

Challenge

The project team sought to humanize a central, high-volume corridor and improve environmental quality by realigning circulation and creating a new pedestrian plaza. The program called for simultaneously providing transit access and a safe and desirable pedestrian experience while improving environmental performance and meeting strict regulatory requirements. The primary challenge of such a complex project was coordinating the multiple stakeholder agencies and departments that represented a range of jurisdictions and services, including utilities, transportation, transit, bridge, parks, water, sewer, electric, gas, and telephone.

Solution

Dutch Kills Green and the associated streetscape improvements are an integrated solution, resolving the competing needs and criteria of numerous stakeholders. Through careful design, the landscape architect was able to reduce the space required for a central, high-volume corridor by separating opposing traffic lanes and creating a wide median to accommodate bike lanes, sidewalk, planting areas, and space for seating and signage. Community and agency groups actively participated in all stages of the decision making process. Following practice unusual for a project of this scale, the landscape architect led and coordinated multiple public meetings, design charettes, and focus-group workshops with all stakeholders during the planning and preliminary design phases. City leadership also actively involved the public; for example, a contest to name the site received over 600 submissions.

• Spanning 175-225 ft, Queens Boulevard is the widest street in New York City. The design reorganized twelve traffic lanes to clarify fragmented circulation and reclaim over 35,000 sf as usable green space. These improvements reduced impervious surfaces by 20%, adding 65,000 sf of planting, including 63 native plant species, and creating 0.5 acre of wetland.
• 32,145 sf (803 tons) of concrete were reused for median “No-Go” barriers that direct pedestrians and cyclists toward safe passage through the new crosswalk and bike path system while allowing for stormwater infiltration.
• 2,200 linear ft of a dedicated, protected two-lane bike path connect the borough of Queens to Manhattan via the Queensboro bridge. The 10-ft wide painted asphalt path flows through the road median buffered by vegetated beds and pedestrian walkways. The NYC DOT Pedestrian Safety Study Action Plan estimated that, controlling for other factors, crashes on streets with bike lanes involving pedestrians injuries were 40% less deadly than crashes on other streets.
• The project’s streetscape improvements include 19 accessible, grade-level pedestrian crossings with painted roadway markings and countdown signals. In San Francisco, pedestrian countdown signals have been associated with a 52% reduction in pedestrian injury collisions at pilot locations; in addition, about 92% of post-installation interviewees explicitly said the countdown signals were “more helpful” than conventional pedestrian signals, primarily because they showed the time remaining to cross.
• Amenities include fixed benches for seating and gathering that can accommodate over 150 people, including median-area seating along the new bike path.
• Two 17th century millstones were unearthed during construction. The designers incorporated these into the the green after other organizations declined to keep the relics. Users can view and sit on the stones and read about the community’s history on an educational display.
• The artist Michael Singer worked with the landscape architect to create a modular system of interlocking, permeable pavers that channels stormwater into infiltration areas. The pavement strategy also incorporated light colored, high albedo asphalt aggregates, recycled asphalt from roadway reconstruction, and reused demolition material for the sub-base.
• Native and adapted tree, shrub, and grass species were selected to reference historical landscape types such as wetland and upland conditions that were common to the area before development. All plants are also selected for drought, salt, and pollution tolerance.

• To create the median “No-Go” barriers, 32,145 sf (803 tons) of concrete were reused. Paving this area with 214 tons of new concrete would have cost $135,000. An equivalent area of permeable paving would have cost $270,000. Reusing concrete on-site also avoided adding over 30 tons of carbon dioxide to the atmosphere through the production of new cement, as well as the transportation and tipping fees associated with removal of the debris after demolition. Tipping fees for the demolished material would have come to over $75,000 and transporting this material to a nearby transfer station would have cost close to $400,000. As a result the total cost avoided from this design solution is estimated to be $500,000-$630,000.

• Extremely complex layers of urban infrastructure, including roads and transit as well as water, sewer, electric, gas and telephone utilities, severely limited the opportunity to retrofit the entire section of the corridor. Cost effective stormwater management for ultra-urban public sites such as Dutch Kills must be developed as fully contained systems that maintain separation of water from other infrastructures while allowing vegetative and biologically-enhanced filtration media for water quality improvement.
• While the design team initially intended to capture stormwater from the streets for treatment in the park areas, this proved to be very complex because the NYC DOT does not allow infiltration within a specified distance of buried infrastructure like conduits and subway tunnels. As a result, the designers altered the plan so that park areas close to infrastructure were for storage only,  not infiltration. Early coordination with the DOT may have allowed for increased management of street runoff in the park/median areas, including infiltration in locations that would not impact subway tunnels and other buried infrastructure.
• Construction observation by the landscape architect, especially in the concrete reuse portion, could have resulted in a more sustainable and aesthetically pleasing project. The design documents show a mounding landscape with a tightly-arranged surface of vertically-placed, reused concrete. This mounding would have allowed smaller concrete pieces to be used while still creating the intended height variation. Instead, the built condition has no mounding, with large slabs standing alone. These large slabs caused the contractor to run out of material and some concrete had to be imported from off-site. In addition, the contractor left 4-6 inch gaps between rows. These gaps collect more trash than a tight surface would have allowed, leading to a greater maintenance burden.

Project Team

Client: New York Economic Development Corporation, New York City Department of City Planning
Prime Consultant / Landscape Architect: WRT/ Margie Ruddick Landscape (MRL)
Civil Engineering: Langan Engineers
Urban Design and Architecture: Marpillero Pollak Architects
Public Artist: Michael Singer Inc.
Lighting Design: Leni Schwendinger Light Projects
Traffic Engineer: Taub & Associates
Construction Oversight: LiRo Engineers, Inc., Site Works Landscape Architecture, Matthews Nielsen Landscape Architecture
General Contractor: Triumph Construction Company, MC Landscaping

Role of the Landscape Architect

The landscape architecture team led and coordinated all phases of design, including initial planning, substantial public meetings and stakeholder consultation, schematic design, final design and construction documentation. Landscape architects also worked closely with the engineering team on many aspects of the infrastructure improvements including sidewalk design, tree pit and structural soil design, stormwater management, and reused concrete area design.