Today NRDC released “Thirsty for Answers,” a first-of-its kind compilation of findings from researchers about local climate changes and their water-related effects on major cities across the United States. NYC is one of a dozen cities profiled. While people may often think of drought-prone Western states as bearing the brunt of climate change, the report makes clear that New York’s water resources and infrastructure face their own set of vulnerabilities. It also explains how NYC is ahead of other cities in developing strategies to prepare for these impacts, by making our water supply, wastewater treatment, sewer, and other key infrastructure more resilient.
Some of the most serious threats relate to our low-lying sewage treatment plants and our already-overburdened sewer systems. Sea level rise, increased coastal flooding, more frequent and intense rainstorms, and increased annual precipitation all threaten the functioning of this critical infrastructure.
For example, as the report explains:
The flow of wastewater from the discharge pipes at New York City’s 14 wastewater treatment facilities and combined sewer overflows relies on gravity. Rising sea levels could reduce the ability of these pipes to function properly, causing sewage backups. Without pumps to force treated effluent or sewage-contaminated stormwater out of the discharge pipes, rising seas could cover pipe openings, forming a blockage that could extend a distance up into the pipes. If discharges cannot exit, they have nowhere to go except back in the direction from which they came—potentially flooding through storm drains into streets or back into the wastewater treatment plants.
Last week’s four-alarm blaze at the North River sewage plant in West Harlem reminds us how dearly we rely on our water infrastructure. With that one facility completely out of commission for over 48 hours (and not yet fully treating the waste that flows through it today), hundreds of millions of gallons of raw sewage poured into the Hudson River and Harlem River. With record-breaking heat enveloping the city, the spill has made most of New York Harbor unsafe for water-contact recreation or fishing for nearly a week so far, and triggered health advisories (changed on Monday to official closures) at four local beaches.
The North River spill also served as a reminder that, even under “normal” conditions, raw sewage is regularly dumped into waterways all around the city when rain overwhelms our aging sewer systems.
As “Thirsty for Answers” explains, climate change will bring more annual rainfall and more frequent and intense storms to the NYC region. That will only exacerbate our current sewage overflow problem -- unless we can succeed in making our sewage and stormwater management systems more resilient.
And those are just some of the water-related climate changes and impacts in NYC. Higher sea levels, coupled with the likelihood of more frequent and intense storms, also are expected to cause coastal flooding, threatening all of the city’s low-lying infrastructure, including roads, subway and rail lines, and LaGuardia airport. By 2050, so-called "100-year floods" may occur every 30 to 55 years. By 2070, the NYC metro area is projected to have $1.7 trillion in property at risk from coastal flooding due to storm surges and damages from high winds.
Here’s a graphic from the report showing a more complete list of the risks NYC faces:
Fortunately, as shown in the report, NYC is ahead of many other cities in terms of evaluating its climate change vulnerabilities and scoping out potential adaptation measures. The city has already implemented some common-sense measures to protect key water infrastructure, such as “rais[ing] pump motors, circuit breakers, and controls at the Rockaway Wastewater Treatment Plant from 25 feet (7.6 meters) below sea level to 14 feet (4.3 meters) above sea level.” Many more actions and policy changes will be needed in the years to come.
Notably, PlaNYC, the city’s long-term sustainability plan, emphasizes the use of “green infrastructure” to manage storm runoff before it reaches our overburdened sewer systems, and acknowledges that this approach will be increasingly important to prepare the city for climate changes that are already underway. Permeable, urban, green spaces like green roofs, greenstreets, and street trees will better equip the city to handle increased precipitation -- while also helping to counteract the urban heat island effect.
Check out the full report here, to learn more about the effects of climate change on water resources and water infrastructure in cities nationwide, and for NRDC’s recommendations on how cities can take action at the local level to increase their resilience to the water-related impacts of climate change.