NYC tackles Sewer Overflows, at long last


Steven Cohen

Steven Cohen

Executive Director, The Earth Institute, Columbia University
Posted: October 4, 2010 09:43 AM

New York City’s Green Infrastructure Plan and Sustainability Management

The issue of combined sewer overflows is one of the most difficult water-quality issues faced by cities with old infrastructure like New York City. Simply put, the sewage from our homes is combined with the sewers in the street before it is piped to the local sewage treatment plant. If a large amount of rain suddenly sends a torrent of water through the streets and into the sewers, it can overwhelm our treatment plants and allow raw sewage to be dumped into local waterways before it is treated. The traditional approach to dealing with this problem is to build tanks and other facilities designed to hold storm water during inclement weather and then release it into the sewers once the storm has ended.
Recently, New York City released a “Green Infrastructure Plan” which modifies:

… the existing approach for sewer overflow control, which relies solely on traditional investments like holding tanks and tunnels, with a mix of green infrastructure and cost-effective traditional infrastructure that will reduce sewer overflows into waterways by 40 percent by 2030 by capturing more storm water. The plan will reduce the City’s long-term sewer management costs by $2.4 billion over the next 20 years, helping to hold down future water bills.

The city’s plan includes traditional “grey” infrastructure built of steel and concrete tanks and pipes, but also green infrastructure such as green roofs, increased planting, greening medians, rain barrels and the use of permeable surfaces in streets and parking lots. The advantage of the green infrastructure approach is that it delivers the same degree of water retention as “grey,” but at a much lower price. When coupled with the traditional approach, it will allow the city to reduce sewer overflows into our waterways by 40% by 2030. If an entirely “grey” approach had been followed, these reductions would have cost an additional $2.4 billion, according to an analysis by the New York City Department of Environmental Protection. Moreover, the pace with which reductions are implemented by green infrastructure is faster than those brought about by traditional grey infrastructure. It takes much less time to plant some greenery or put out some rain barrels in your backyard, than to site, design, build and operate a holding tank.
While New York is by no means the first city to develop green infrastructure, the scale and ambition of this effort is impressive. The Bloomberg administration has again demonstrated its ability to marry sound business and environmental principles. They have once again placed themselves at the forefront of the emerging field of sustainability management. Commissioner Cas Holloway and his team at the Department of Environmental Protection should be applauded for this extensive and cost-efficient plan.
The effort to maintain the city’s drinking water and improve the quality of its surrounding waterways is a major expense for New York City. While the press release announcing the city’s green infrastructure initiative includes typical and expected self-congratulation, the data presented in the release can’t be spun and demonstrates the city’s operational commitment to a clean environment:

Approximately $21 billion has been allocated for water system capital projects, including:

  • $2.6 billion invested and committed to City Water Tunnel No. 3 — more funding for the tunnel than the previous five administrations combined;
  • Acquisition of nearly 77,000 acres of land upstate to protect the City’s watershed — allowing New York City to remain one of only five large cities in the country to obtain the majority of its water from unfiltered sources;
  • $2.8 billion for the Croton Filtration Plant, which will filter drinking water from the Croton Watershed;
  • $1.6 billion for the Ultra-Violet Disinfection Facility, which will provide an extra level of drinking water protection for water from the Catskill and Delaware Watersheds; and
  • $6 billion for upgrading the City’s 14 wastewater treatment plants and more than $1 billion to reduce combined sewer overflows, which has helped bring harbor water quality to an all-time high since testing began 100 years ago and allowed wastewater treatment plants to meet the Federal Clean Water Act’s secondary treatment standards for the first time ever.

While it is federal law and regulation that is pushing the city to act, we really should give the administration credit for maintaining this level of spending in the current recessionary, anti-tax environment. When people judge a city’s level of cleanliness they think about litter, air quality and water pollution. If New York loses its high quality drinking water and reasonably healthy air, it will also lose its ability to attract and retain people and businesses. Mayor Bloomberg understands the relationship between water quality and the city’s economic well-being. The green infrastructure plan demonstrates an increasingly sophisticated approach to maintaining and enhancing the city’s environment.
The need for sophisticated management of our natural environment grows with the size and complexity of the global economy. As the economy grows more interdependent we are also seeing increased consumption along with growing stress on our ecological resources. The field of sustainability management is now being developed and requires managers to move beyond an understanding of an organization’s financial, human and strategic resources; managers must develop a more sophisticated understanding of their organization’s use of resources and their impact on the ecosphere. The move from over reliance on “grey infrastructure” to the combined use of green and “grey” techniques is an indication of the growth of sustainability management in New York City’s government. My hope is this represents the beginning of a trend that will expand as we learn more and as our large institutions adapt creatively to the challenges of growing our economy while preserving our planet.