The plan was commissioned to find ways to streamline the existing stormwater management mechanisms that have been deemed unacceptable due to their inability to handle the growing population of New York City, which has resulted in countless damage to both the city's ecology, infrastructure, and private property.
The intention of the plan is to improve the quality of water surrounding New York City in order to increase recreational use, but it will have enormous effects on not only the ecology of the city but also the rampant flooding which has become an enormous problem over the last several years.
The plan, which was released last week, outlines both short- and long-term solutions to the city's failing sewage infrastructure. Built near the turn of the century, the existing system takes in both sewage and stormwater. The increase in New York City's population over the last century has led to a larger amount of sewage running through the system, therefore accommodating less stormwater runoff.
The increase in pavement and decrease in green space has additionally led to more stormwater, and when the sewer system is beyond capacity it leads to flooding in the streets and homes, as well as the discharge of untreated sewage into the water surrounding New York City. The untreated sewage is wreaking havoc in many different ways, including the rapid depletion of saltwater marshes in Jamaica Bay, and the continued lack of sea life in several portions of the East River.
The plan includes several short- and long-term improvements to the city's stormwater management plan, many of which utilize a modern "green" mentality. Most cities, New York included, have traditionally handled combined stormwater overflows by building holding tanks that could temporarily store the excess sewage and stormwater until the weather had subsided and the water could be properly treated and discharged.
The study reveals that the construction of more holding tanks would be inefficient, considering costs, real estate, and the actual amount of water that could be held. Though more of these tanks will be built, the plan indicates that they are not a wholly effective solution, nor are they wholly sustainable.
The city's plan primarily utilizes "source controls," which are methods to reduce stormwater where it initially falls, rather than somewhere further down the pipe. The plan operates under the premise that pollution is easier to prevent than to treat or control.
Many of these source controls are rooted in sustainable, long-term development that includes increased green space, permeable pavement technology, and new standards for design and construction.
The city has already mandated an increase in green space and trees as part of the PlaNYC 2030 plan, and this alone will go a long way to reducing stormwater overflow by creating more permeable space in streets, parks, and even rooftops. The stormwater management plan also seeks to increase permeable space by forbidding the paving of lawn space, utilizing types of permeable pavement and gravel in new city projects, and increasing planters and "green walls."
Other methods of controlling stormwater at its source include retention and detention methods, including the use of rain barrels, underground holding tanks, and rooftop storage tanks. The plan indicates that while these strategies are effective, they are not as efficient as the green, biology-based solutions. These solutions will be accompanied by several educational outreach programs that will inform the public of what is being done and how they can do their part. Additionally, a number of new building and zoning codes, along with financial incentives, will encourage private developers to utilize these green techniques in new construction projects.