Gowanus Canal Sponge Park™

Editor's Note: The SpongePark design marries stormwater engineering, urban design, and urban habitat concepts. This design has received much attention from the design and public works communities, winning national awards including the American Institute of Architects 2011 National Honor Award for Regional and Urban Design, and the American Society of Landscape Architects 2010 Honor Award for Analysis and Planning. The design includes ecological restoration components, and we asked its progenitors to introduce the ideas to the ER community.

The Gowanus Canal Sponge Park™, located in Brooklyn, NY, USA, is a multifunctional public open space system that slows, absorbs, and filters surface water runoff with the goals of remediating contaminated water, reducing stormwater runoff volumes, creating habitat, and providing open space and environmental education opportunities to underserved neighborhoods. The master plan of the 128-ha (316 ac), 70 street block site includes a series of street-end bioretention basins and curbside bioswales (Figure 1). The 1st phase of the project includes a pilot installation that will expand to include cisterns and constructed marshlands that help to restore hydrologic balance and ecological productivity to the site. This design is part of a larger system that communicates a broad vision for stewardship of the environment to a diverse urban community. The proposed ecologically

Figure 1.

Gowanus Canal Sponge Park master plan depicting the 128-ha (316-ac) stormwater management open space system as interconnecting element for the urban residential, commercial, and industrial neighborhoods surrounding the industrial Gowanus Canal, Brooklyn, NY.

productive urban landscape design involves collaboration among multiple public and private constituencies. The design will achieve its goals of reducing stormwater runoff volumes and pollutant loads into the Gowanus Canal, activating cultural and environmental resources, and reducing pressure on expensive sewer systems with Low Impact Development (LID) strategies. We intend to promote infiltration, evapotranspiration, detention, and remediation of stormwater generated from impervious street and sidewalk surfaces through a Sponge Park™ system to be installed on currently under-utilized space within the public rights-of-way (ROWs). Water management within the Sponge Park™ design is based on reconfiguration of sewer and storm water systems to include vegetative and biological structures that green the streets while reducing reliance on mono-functional hard engineered systems.

The Gowanus Canal, Kings County, New York, was constructed in 1881 to assist commercial shipping, barge traffic, and other commercial uses within the New York Harbor Estuary. Formed by the excavation of Gowanus Creek, the Gowanus Canal is a narrow channel passing through an industrial zone of Brooklyn, and is surrounded by the residential communities of Park Slope, Boerum Hill, Carroll Gardens, and Red Hook (Figure 2). The banks of the Canal are stabilized with bulkheads, providing shipping access for many industrial operations. Past uses have resulted in a number of contaminant releases over the past decades, and now pollutant-rich urban stormwater runoff and combined sewer outflows (CSOs) continue to impact water quality in the Canal (U.S. Army Corps of Engineers 2005).

The Gowanus Canal is 30.5 m (100 ft) wide and 2.25 km (1.4 mi) long from its head at Butler Street to where it opens to the Gowanus Bay, varying in depth from 1.2-4.9 m (4-16 ft). Physiographic and jurisdictional boundaries of the Gowanus Canal include 647 ha (2.5 sq mi) of Brooklyn's Park Slope, Carroll Gardens, and Boerum Hill neighborhoods. Surface water runoff from the 711-ha (1758-ac) watershed flows into the Gowanus Canal by means of CSOs, storm outfalls, and direct street surface runoff (Figure 3). The area is served by the Red Hook and Owls Head Treatment Plants in Brooklyn, NY. Within the total of 8 CSO outfalls on the Gowanus Canal, there are 2 Tier 3 CSO outfalls. Tier 1, 2 and 3 CSO outfalls drain large catchment areas and provide most of the drainage for New York City. The Tier 3 outfalls located in the New York Harbor collectively discharge 192-946 million L (50.7-250 million gal) of effluent per year, equivalent to 10% of the overall...