Building a more resilient T

When Hurricane Ida passed through the Northeast last week, New Yorkers were reminded, yet again, that their subway system was not designed for the 21st century. Dumping over three inches of rain per hour in parts of the city, the hurricane poured water into subway stations, turning staircases into waterfalls and train tracks into canals. Naturally, most lines were disrupted and inundated with delays, while some were partially suspended. And all this happened despite the billions of dollars that had been spent repairing subway damage from Hurricane Sandy nine years ago and strengthening New York’s transit systems against future flooding.

Of course, New York City is not alone. From the Washington, D.C., Metro to the London Underground, subway stations around the world have been overwhelmed by more frequent heavy rainfall and flash floods, and transit authorities are having to rebuild their systems to adapt to a changing climate. Boston is no outlier: In a single winter a few years ago, the Blue Line’s Aquarium Station flooded on many occasions and caused the Massachusetts Bay Transportation Authority to temporarily close the station.

Boston is also especially vulnerable to coastal flooding, and a new study, commissioned by the MBTA, found — unsurprisingly — that rising sea levels are posing an “existential threat” to the transit service because certain lines will become inoperable. The MBTA has taken several steps in recent years to make the T more resilient and capable of withstanding some flooding, but Massachusetts has to make significantly more costly investments in the transit system’s infrastructure if it hopes to continue having an underground rail system well into the future.

In order to build a more resilient T, the MBTA has to build both passive and active flood protection systems. Passive systems are those that prevent or mitigate flood risk on their own, while active ones require deployment, like flood gates or aluminum planks to block water from gushing into subway tunnels through their entry points. So far, the MBTA has built flood doors in Aquarium Station on the Blue Line and near Fenway Station on the Green Line, and has also created the infrastructure necessary for crews to install aluminum planks to block entrances in the event of a flood.

While these investments are extremely helpful, they can only go so far on their own. Planks, for example, take several minutes for crews to deploy and cover stairwells, and when a flash flood takes a city by surprise, being just a few minutes late can make all the difference. That’s why Michael Martello, the lead author of the recent MBTA study, believes that while active flood protection systems are helpful for the near term, they have to be reinforced by more sustainable and permanent passive systems that require some structural overhaul.

MBTA workers at Wollaston Station in Quincy set up pumps to empty out the foot-plus deep water that shut the station down on Sept. 18, 1996.Tom Landers/Globe Staff/File

An example of this would be elevating the station entrances or vent openings — especially those in low-lying areas — so that stations can be protected from any street flooding. That means following the examples of subway systems like those in Taiwan or Singapore, where subway riders have to climb a ramp or a few steps before going down into the station. Building canopies above entry points is also critical for preventing water from entering stations rapidly during flash floods.

Any MBTA flood resilience projects should also be part of a broader investment in reducing flood risk in Boston and its surrounding areas as a whole. And one of the most effective ways to reduce flooding — while also building a more habitable city for both residents and wildlife — is building green space along the coastline that can soak up a significant amount of water during rainfalls and coastal floods. Marshland parks, like the Belle Isle Marsh, which helps prevent Orient Station on the Blue Line from flooding, ought to be protected against rising sea levels; raising the bank by the park, for example, might allow it to survive rising seas.

Building new wetlands in areas that can flood is also critical. That’s why there should also be more investments like the Muddy River Restoration Project, which resurfaced the Muddy River that had been tunneled underground, and will turn the pavement around it into a park, as it once was. Doing so should also help prevent Kenmore Station from flooding.

The MBTA is keenly aware of the risks that climate change poses to its system. And though the transit agency has been trying to prepare against future flooding, the reality is that it needs more money to be able to build a T for the 21st century. Lawmakers in Massachusetts should make securing those funds — from the federal government, or from state-led programs like the long-planned Transit and Climate Initiative — a top priority, because reactionary spending on flood repairs will probably be more costly than sensible proactive solutions. Until those critical investments are made, residents will continue to have an unreliable T that’s prone to delays and service suspensions. And that’s hardly a system that people will want to ride for much longer.

Editorials represent the views of the Boston Globe Editorial Board. Follow us @GlobeOpinion.

If Greater Boston wants to have a functional T well into the 21st century, then it must make significant investments in the transit system’s infrastructure to mitigate flood risk.

Globe Opinion