Dive brief:
- New York City’s Metropolitan Transportation Authority has not fully implemented a plan to protect the subway system against climate change, according to a New York State Comptroller’s audit Thomas DiNapoli was out on Friday. The vulnerabilities of the system were on full display that very day when heavy rains flooded the city, flooding of subway lines and commuter rail.
- According to the report, New York City’s MTA transit agency approved capital projects without ensuring they were flood-resistant, and also inconsistently activated extreme weather plans and failed to he checked the equipment enough to make sure it could withstand the bad weather. The audit covered 2009 to 2022.
- In 2009, the MTA issued the Blue Ribbon Commission’s Sustainability Report with 93 policy recommendations and capital projects. The audit found that MTA failed to implement the most important one: developing a master plan on climate change. He also found that projects were often incomplete, not completed on time or on budget, or insufficiently documented.
Diving knowledge:
The MTA has done nearly $8 billion in federally funded resilience work since Superstorm Sandy damaged the transit system in 2012, the audit found, but the climate action plan is not expected to published until the end of this year, almost a decade after its date. Meanwhile, climate change poses a serious problem for the system, according to the audit.
“In the decade since Superstorm Sandy, weather prediction models have indicated that, as sea levels rise, the extent and depth of storm surge will increase in New York City. With the ‘sea level rise, future storms will inundate more properties,’ the report said. “Without adequate investment in adaptation measures, climate change will have even more adverse impacts on the MTA’s vital infrastructure.”
However, the agency’s efforts alone likely won’t be enough to prevent the subway system from flooding, as New York City Sewers were designed to handle less water per hour than is now customary, according to The New York Times.
The city’s drainage systems can handle 1.75 inches of rain per hour, but Friday’s storm brought more than 2 inches between 8 a.m. and 9 a.m. and kept coming, dropping 6 inches in total. Stormwater runoff backed up into the streets and flooded subway stations in Brooklyn and Queens, causing system-wide delays.
Experts say the city will likely continue to experience such flooding as it struggles to adapt its infrastructure to extreme weather patterns, according to The New York Times.
The city has resilience efforts underway. The New York Department of Design and Construction is under construction infrastructures that will allow it to recover of extreme weather, according to Deputy Commissioner of Infrastructure Design and Engineer Thu-Loan Dinh. This includes solutions such as flood barriers, seepage basins, green roofs and permeable pavers. Retention tanks and curbside gardens can also absorb rainwater.
Across the country, the climate is changing faster than building codes are being updated, National Institute of Building Sciences panelists said at a recent conference, and the US lacks consistent flood design standards for infrastructure. To help mitigate the impact of flooding, the National Weather Service last week launched a four-year Flood forecast map experiment which shows when, where and how much floodwaters are expected to affect specific areas before a storm.
The new maps have limits: They still can’t predict urban flash floods like New York City’s caused by heavy rain on pavement and overwhelmed stormwater systems, rather than rivers and streams. “This is at the edge of our scientific limits,” said David Vallee, director of the Office of Water Prediction’s Partnership and Service Innovation Division, but the team is working on it.
