New York City Council Approves Urban Resiliency Measures

flooded tunnel nyc sandyIn less than a year since its devastating run-in with Hurricane Sandy, the City of New York is already adopting new measures geared towards higher levels of urban resiliency. Yesterday, the City Council approved the first batch of proposals from the Building Resiliency Task Force, marking the first step for updating codes that leave the city better equipped for future storm events.

Last October, Hurricane Sandy came ashore on the coast off New Jersey and tore its way across the New York Harbor. The Category 3 storm left a heavy wake costing an estimate $25 billion in damages to New York and New Jersey. The ill-prepared infrastructure buckled in numerous places. Subway lines and transit tunnels flooded. Power systems were submerged to leave hundreds of thousands of residents (this one included) without power for days. In the months that followed, the quick consensus was that the city was unprepared for what nature had to throw at it, leaving it vulnerable to subsequent storms that some scientists believe will only be more likely due to climate change.

Urban Times recently reported that a study was conducted by Arup, RPA and Siemens of the vulnerabilities in the New York City electrical grid and mitigation measures as part of a larger exploration of resilient infrastructure. Their “roadmap” for grid resiliency took the form of a 12-year investment program, in which city agencies and utilities will need to spend approximately US$3 billion to introduce an effective system of smart technologies. However, the financial value of these benefits could reach as much as $4 billion.

In order to improve the city’s degree of readiness at the local level, the Building Resiliency Task Force was formed at the joint request of Mayor Bloomberg and Speaker Christine Quinn who clearly believed that more resilient buildings are also greener buildings. With 200 members from various facets of the building and infrastructure industries, the group selected 33 proposals for recommendation to the City Council, all meant to help the city evolve into a more resilient urban landscape in the face of an uncertain climatic future.

While many of the proposals are still in the pipeline of review (and hopeful approval) five have been cleared to be inked into law for the five boroughs:

BRTF #8: Prevent Sewage Backflow
Requiring backflow preventers for all buildings in Special Flood Hazard Zones to keep sewage from flowing back into basements during a storm event.

BRTF #10: Clarify Construction Requirements in Flood Zones
Clarify flood zone construction requirements in code and through a Department of Buildings Bulletin. Allow more flexibility in requirements for enclosures below the flood line.

BRTF #12: Analyze Wind Risks
Enact more rigorous study & subsequent code requirements for wind testing on a variety of structures, including existing buildings.

BRTF #13: Capture Stormwater to Prevent Flooding
Require pervious, sidewalk planting strips for ⅓ of total sidewalk depth in order to facilitate the absorption of stormwater and decrease runoff.

BRTF #24: Ensure Toilets & Sinks Work Without Power 
Mandate that toilets with electrical components also have battery packs that can allow them to function without power for up to two weeks.

This quintet of measures spans across different aspects of the built environment, but mark a great primary step towards basic improvements that could make considerable difference in the event of another powerful storm.

I was particularly impressed with #13, requiring new planting strips for sidewalks throughout the five boroughs. Stormwater is an important issue for many cities like New York that still maintain a Combined Sewer Overflow (CSO) system, effectively combining sewer and stormwater into the same pipes. When the system becomes burdened with more rainfall than it can handle the sewage/stormwater mixture overflows into the East and Hudson rivers. When a Hurricane like Sandy brings with it a storm surge that raises the level of the rivers to flood low-lying areas of the city, the problem is only compounded. However, CSO overflow is not merely isolated to massive storms. On the contrary, it can take as little as ¼” of rain per hour to surpass the city’s treatment capacity, making this recommendation from the task force particularly relevant.

The measure is meant to interface with the street tree provisions that already exist (and most likely do their small part in helping to mitigate stormwater and solar heat gain). New sidewalks will now have a planted strip at least ⅓ of the overall width to capture stormwater and release it slowly over time. The text goes on to specify that turf grass is not an acceptable planting solution. Instead, the strips “shall consist of native meadow plantings and low herbaceous grasses or native ground cover.“ Though exceptions are made for key conditions like subway grates, curb cuts and electric vaults, the character of many of the city’s streetscapes could be notably different in the years to come.

Adding more planting medium to our streets is one small step in addressing the concentration of impervious material that defines our cities and only amplifies the damage that rain events can not only have on the city, but the surrounding ecosystems. Green roofs are another important piece to what the Bloomberg administration has termed “Green Infrastructure” as ways to use biological components to accomplish our infrastructural needs.

ARO wetland nyc

ARO & dandlstudio proposed wrapping Lower Manhattan with wetlands to regulate storm surge.

The proposal is akin to the theoretical project by design firms ARO and dandlstudio for adding vast swaths of wetlands around the perimeter of lower Manhattan in order to serve as a buffer for storm surge. The project was part of the “Rising Currents: A New Urban Ground” exhibit at MoMa. Combining wetlands with the urban fabric was also the topic for the winning entry to the Gowanus Lowlands Competition which proposed the restoration of a historical estuary while mixing it with new walking streets and residential towers.

This marks one of the first proactive steps by a major American city to prepare for what could be an increasingly normal occurrence for the coastal United States. Hopefully it is just the first of many changes to update our playbook for urban planning.

Image Credit: wikipedia