New York City Department of Environmental Protection

Nevin Cohen teaches sustainable food systems, environmental policy and urban planning at the New School, and focuses on the evolution of municipal food policy. Kubi Ackerman is a research coordinator at the Urban Design Lab at the Earth Institute at Columbia University; he focuses on food systems and urbanization projects. I’m an admirer of the work both of them do and invited them to write about the New York City Department of Environmental Protection’s important proposals for environmental infrastructure initiatives.

New York City’s Department of Environmental Protection (DEP) recently funded three new urban agriculture projects: a rooftop garden at a settlement house, a vegetable garden near the Gowanus Canal and a commercial rooftop farm atop a Brooklyn Navy Yard building. These projects are part of an innovative green infrastructure program to turn impervious roofs, vacant lots and streets into spaces that soak up the rain and prevent water pollution. Supporting urban farms and gardens as a means of keeping our waterways clean is an excellent idea, and should be dramatically scaled up.

New York has already spent billions on 14 wastewater treatment plants that handle the dry-weather sewage that flows from homes and businesses. Thanks to this technology, the harbor is cleaner than it has been in generations. But our sewers also collect rainwater, which mixes with raw sewage (called “combined sewer overflow,” or CSO) and is dumped into nearby rivers and creeks through hundreds of pipes to avoid inundating the treatment plants. Tens of billions of gallons of CSOs pollute our harbor each year, hindering the recovery of our estuarine ecosystem. The Clean Water Act requires New York City to control these overflows.

To do so, DEP has committed to investing $187 million in green infrastructure over the next four years, including “blue roofs” that hold rainwater, extra-large street tree planters, “green streets,” parking lots paved with porous concrete, and vacant paved lots turned into gardens. Over 20 years, the total cost for this green infrastructure will be $2.4 billion – $1.5 billion in public dollars (paid by water fees and state and federal funds) and $0.9 billion in private investments, plus $2.9 billion in cost-effective conventional improvements.

The green expenditure is a bargain compared to the estimated $6.8 billion over the next 20 years that would otherwise be required for “bricks and mortar” infrastructure like underground storage tanks and tunnels. Moreover, green infrastructure reduces air pollution, cools the city during hot summer months, increases property values and provides other ecological and quality of life benefits valued at between $139 and $418 million. When the green infrastructure is a farm or garden, it supplies fresh fruit or vegetables as an added bonus.

DEP’s green infrastructure program represents a unique opportunity for New York City to substantially expand its already robust network of urban farms and community gardens while simultaneously tackling the CSO problem. There are nearly 2,000 acres of vacant land in the areas contributing to sewage overflows, mostly impervious surfaces. There are also thousands of buildings that could support rooftop farms. Interest in growing food locally is at an all-time high, and gardeners, farmers, entrepreneurs, and farming organizations would jump at the chance to have access to additional space to farm. In locales such as the Bronx River watershed, in which CSO problems coincide with limited food access, the benefits to the environment and to public health would be substantial.

This clear win-win requires only that DEP direct its investments in green infrastructure to many more food-producing projects beyond the three already funded. Agriculture is not formally included in its green infrastructure plan, but at a time when the budget for the Parks Department’s GreenThumb community gardening program may be slashed, and teachers struggle to raise money to build school gardens, using DEP’s resources to expand urban agriculture could be one of the most effective means of achieving a greener and healthier city.