Natural Security: Staten Island, New York
Natural Drainage Systems
Challenge
Staten Island experienced rapid growth following the completion of the first direct road link to New York City in 1964. Sewage and stormwater infrastructure, however, did not accompany the construction boom. While part of the island received stormwater and sanitary sewers in the 1960s and 1970s, the southern portion of Staten Island, known as South Richmond, remained without sewers because the City could not come up with a strategy for building sewers that did not damage protected wetlands. Residential septic systems proliferated in the absence of sanitary sewers and leaked untreated sewage into homes and waterways due to inadequate upkeep. The lack of storm sewers, in combination with naturally high water tables, led to significant flooding problems. During heavy rainstorms, chronic flooding resulted in property damage, eroding foundations and impassable streets. Stormwater runoff and leaking septic systems also posed a threat to the health of residents and wildlife in the area.
Staten Island’s Approach
In an effort to address these problems, the New York City Department of Environmental Protection (NYC DEP) developed a two part plan that included a sanitary sewer system routed around protected wetlands and an innovative stormwater management program. The stormwater plan consists of storm sewers that carry runoff from streets and parking lots to existing streams and wetlands. Before stormwater reaches the streams, it passes through a variety of constructed wetlands, basins and filters, called Bluebelt facilities. These Bluebelt facilities slow runoff, remove contaminants, minimize erosion and flooding and promote groundwater infiltration. The filtered stormwater runoff then flows into streams, which serve as natural drainage corridors that transport runoff from the urban area. The city has restored a number of these streams by re-establishing their naturally meandering channel to reduce water velocity and prevent erosion. The result is an interconnected system of stormwater pipes, wetlands and streams that drain runoff, filter out pollutants and recharge groundwater and streams around the island.
Since 1991, the DEP has purchased over 250 acres of natural waterways and over 12,000 acres of land which are known collectively as the Bluebelt system. 40 Bluebelt facilities have been completed, with another eight under construction, two in the design stage and 40 yet to go. The program currently covers 16 watersheds and is in the process of expanding to wetlands in three additional watersheds.
Benefits
The Bluebelt program has been highly successful in resolving flooding and improving water quality across the island. It has won numerous awards from environmental, engineering and landscape architecture groups and is widely viewed as a leading example of innovative stormwater management. Since the project began, South Richmond has witnessed little to no flooding even during large storms, while other parts of the city experienced considerable property damage. The stormwater and sewage infrastructure investments have also reduced the threat to public health throughout South Richmond. The construction of separate sanitary sewers allows homeowners to phase out on-site septic systems which have a history of contaminating local water resources. In 1998, approximately 60 percent of homes relied on septic tanks, while less than 30 percent currently use them. The constructed wetlands also contribute to improved water quality by removing pollutants such as nutrients and pathogens from stormwater runoff. Finally, the improvements in stormwater drainage and sewage disposal benefit local communities and wildlife. The value of homes near the Bluebelt system has consistently appreciated in recent years, enhancing the city’s tax base. Linkages between existing parks and protected lands have resulted in increased habitat connectivity and the return of native wildlife. Red-backed salamanders, green frogs, white egrets, Canada geese, red-tailed hawks and a number of turtle species have returned to the island.
Adapting to a Changing Climate
By building sanitary sewers and the Bluebelt system, South Richmond has solved much of its chronic water quality and flooding problems, and it has also taken steps that will protect public health and the island’s ecosystems in an uncertain future. The pathogens from failing septic systems and stormwater runoff posed a significant threat to residents, and that threat would have only grown as the climate shifts. More extreme storms would have caused additional flooding and runoff, and soil saturation would have increased septic system failures. In addition, the risk of waterborne disease is likely to increase in a warmer climate as higher water temperatures and increased turbidity improve conditions for pathogen survival. The construction of sanitary sewers and Bluebelt facilities will limit the impact of these changes by reducing the number of failing septic systems and preventing extreme storms from creating more polluted runoff. In addition, the Bluebelt system has saved New York $80 million in construction costs compared to traditional approaches, providing the city with additional financial flexibility to face future challenges. As a result, South Richmond is better prepared to absorb the impacts of a changing climate without witnessing a rise in waterborne disease or other health problems.
