Continuing our coverage of the 2014 AIA COTE Top Ten green projects, this article is part of a series of 10 pieces that examine a specific, defining design challenge or innovation of each of this year's winners.
During bouts of even modest rain in New York City, stormwater overwhelms the city’s combined sewer overflow (CSO) system, causing a fetid mixture of urban runoff and untreated sewage to spill into the city’s waterways. Not only is it acutely unpleasant to witness, it also presents costly environmental and public health risks. Now that those risks are better understood, there is a growing imperative to better manage stormwater runoff. Bushwick Inlet Park, in Brooklyn, N.Y., has become a model for just how to do that.
Designed by New York architecture firm Kiss + Cathcart, Architects with New York’s Starr Whitehouse Landscape Architects and Planners, the 6.2-acre waterfront park has become a well-trafficked neighborhood public space, even while setting a new benchmark for best practices in designing for runoff. As Starr Whitehouse principal Stephen Whitehouse says, “There are no storm connections for any water that falls inside the property line.” In other words, the park is not complicit in the sludge that pours into the waterways during rain.
This ambitious approach is the result of a comprehensive, multipronged water strategy. One of the centerpieces of that strategy is water capture. The design brief included a 13,300-square-foot building, so rather than give up park space for the structure, the designers tucked it under a green roof that heaves up from the ground plane above the building. Under this slope, they also included a 15,000-gallon water harvest tank that collects water from several sources: drains on the green roof, the spray from a children’s water feature, and photovoltaic panels that double as rainwater harvesting surfaces. This stored water is then used to root-drip irrigate the green roof. No potable water is used for irrigation.
The park also features a soccer field made with artificial turf. Surfaces like this typically have poor water performance because they are normally rolled out onto impermeable surfaces. But with Bushwick Inlet Park, the architects placed the turf on top of crushed stone, allowing it to absorb water. “Any rain that hits that field,” Whitehouse says, “goes right into the ground.”
Because the New York region must contend with intense bursts of heavy rainfall, the architects also included measures to manage beyond what capture and infiltration can accommodate. During heavy rainfall, the park sheds excess water into the East River. Rather than sending urban runoff (water plus any imaginable pollutant) shooting into the river, though, the park deals with the water more systematically. Drains capture stormwater flowing toward the river through the field. A swirl separator filters out any unwanted material before the water moves to outflow pipes at the waterfront. There, a bioswale contributes another layer of filtration, before reaching the park’s riprap edge. “This is more like a natural cycle,” says Whitehouse, “like what a stream does as it moves water to the sea. It’s not just urban runoff.”
The biggest measure of success, though, is that all of this happens invisibly. People read near the bioswales, the soccer field is nearly always in use, and families picnic on the green roof, directly above the water cistern. To the architects’ great credit, the future of water management looks good.