One year ago, the remnants of Hurricane Ida deposited a record-breaking amount of rain on New York City and the surrounding region. The storm left a trail of destruction in its wake, including 13 city fatalities and $936 million in federal dollars given for personal property damages across New York state and New Jersey.

It also left behind some clues.

In the storm’s aftermath, surveyors from the United States Geological Survey canvassed the hardest-hit parts of the city, estimating the height of floodwaters based on the debris left behind. A line of dried mud on a garage door, for example, could indicate that the rainwater reached that level.

These high-water marks paint a picture of Ida’s devastating effects — in both low-lying areas near waterfronts and in places higher up with poorer sewers and flood control. Parts of Middle Village in Queens, which sits nearly 100 feet above sea level, experienced 3 feet of flooding.

The data isn’t comprehensive, since the clues disappear not long after the floodwaters recede. But overall, the high-water marks indicate where urgent action is needed to protect against the next severe rainstorm.

In the Bronx, the surveyors found high-water marks of close to 6 feet around Van Cortlandt Park. Ida’s deluge turned the Major Deegan Expressway into a river, stranding cars and prompting closures.

But Eric Dinowitz, the councilmember for the affected district, said it wasn’t the first time residents there weathered water damage.

“Hurricane Ida was an extreme weather event, but District 11 experiences significant flooding even without the kind of weather we saw one year ago,” he told Gothamist in an email.

Dinowitz said he felt that the city hasn’t prioritized the Bronx for rain gardens, green roofs, and other so-called “green infrastructure”: projects that help absorb excess rainwater and reduce the strain on the city’s overwhelmed sewer system. So far, the city has installed 565 new rain gardens and rainfall-catching basins in the borough.

To protect against future storms, Dinowitz and others are urging the city to “daylight” an underground waterway in the Bronx, a change that would also reroute floodwaters away from sewers. As Gothamist previously reported, the project has been stalled for years because CSX Transportation, a rail company, is charging an exorbitant sum for the land through which the newly risen waterway would run.

Shortly after Ida, the city’s Department of Environmental Protection told Gothamist that the work could kick off in 2024. On Thursday, at a press conference commemorating the anniversary of the storm, city officials mentioned the effort but didn’t provide any updates on the timeline or the stalemate with CSX.

Rain gardens and pilot programs

Queens experienced severe flooding and bore the brunt of casualties from the storm. The USGS data shows flood heights of 4 feet or more at multiple locations in Woodside, Jackson Heights, and Forest Hills, as well as substantial flooding elsewhere in the borough. Photos from the USGS show floodlines approaching the tops of sheds and low-lying garages.

A USGS worker records a high-water mark outside a garage in Woodside, Queens, after the remnants of Hurricane Ida struck New York City in September 2021.

Between natural topography and overwhelmed sewer systems, parts of the borough are especially vulnerable to flooding from rainfall. Queens is also home to a large portion of the city’s basement apartments, which trapped some residents during the 2021 storm.

In recent years, the borough has gotten more than 1,800 new rain gardens and stormwater collectors, which the city said this week will be able to absorb more than 260 million gallons of water each year. Several Queens neighborhoods are also receiving upgrades to their outdated sewer systems, although many of these projects pre-dated the storm. This past spring, the city finished a $50 million sewer renewal project in southeast Queens. Hollis and Queens Village also received new sewers last year.

And in Jamaica, where a mother and son drowned in a basement apartment during the 2021 storm, the city is testing out some ideas borrowed from Copenhagen, Denmark, another coastal city threatened by climate change and flooding.

At the South Jamaica Houses, a NYCHA development, engineers will build a sunken basketball court and absorbent green spaces to soak up excess rainwater from sudden storms.

Representatives from the affected neighborhoods said they’ve seen some of the changes firsthand. City Councilmember Robert Holden, whose district was heavily affected by Ida, spoke to the ongoing sewer projects and rain garden installations. But he said his constituents are still awaiting relief from the city, which denied their flood damage claims.

“There are many families who have not received any financial aid,” he said. “The process was really bungled.”

A USGS worker measures flood levels outside a home in Pomonok, Queens, after the remnants of Hurricane Ida struck New York City in September 2021.

City Councilmember Julie Won, whose district includes Woodside, said she’s giving out rain barrels and is hounding the Department of Environmental Protection to keep the city’s sewer grates clear of debris. Won is also calling on the city to make sure its evacuation warnings and other flood-related communications are multilingual.

“With proper notifications in their native languages, residents will know what to do without losing a second, so that they can fight for their lives,” she said.

At Thursday’s press conference, city officials described a slew of flood protections — from the ongoing sewer upgrades and rain gardens, to a fleet of high-tech flood sensors and an expansion of its “Bluebelt program,” which pairs storm sewers with bodies of water to store massive quantities of water during downpours. The city will release more details in April of next year as part of a broader sustainability plan, city officials said.

“We are not going to stand by,” New York City Mayor Eric Adams said. “We are taking actions to protect our city and prevent future tragedies.”

But many of these projects pre-date the Adams administration, and the majority of them won’t be completed anytime soon.

“This is not something that can be done overnight,” said City Councilmember James Gennaro, who is also chair of the Council’s Committee on Environmental Protection. “It will require billions of dollars in investment and years to complete.”

In the meantime, the city is relying on its Rainfall Ready action plan, which aims to inform New Yorkers about their flood risk and get the word out to especially vulnerable people, like tenants of basement units. The Department of Environmental Protection will also hand out sandbags and flood barriers to residents in the path of floodwaters.

Bernice Rosenzweig, professor of environmental studies at Sarah Lawrence College, applauded the city’s efforts but warned that adaptation to climate change must be coupled with attempts to mitigate it. Otherwise, she said, all the infrastructure in the world won’t be enough to protect New York City against the rapidly changing weather.

“We have to improve our infrastructure to deal with these types of events, to account for climate change that’s locked in,” she said. “But the most important thing we can do globally is decrease greenhouse gas emissions, because at some point it won’t be possible to keep up.”