At least $1.6 billion in federal funding -- the second-largest allotment in FEMA's history -- has been secured to finance repairs and upgrades at four city-run hospitals damaged by superstorm Sandy, Mayor Bill de Blasio and Sen. Charles Schumer said Thursday.

The Federal Emergency Management Agency commitment will reimburse the city for purchases and fixes made in the aftermath of the 2012 storm and pay for measures such as water pumps, flood-proof elevators and flood walls to protect against future disasters.

It comes on top of $142 million that city hospitals have already received from FEMA.

"We were caught off-guard after Sandy because we never had such a flood before, but we will take what we learned from that experience and build back better and stronger," Schumer (D-N.Y.) said at Brooklyn's Coney Island Hospital, which will receive a new critical services building.

The funding will also benefit Bellevue Hospital Center, Metropolitan Hospital Center and Coler Specialty Hospital, all in Manhattan.

FEMA previously allotted money in small increments, making it more difficult for governments to plan their recoveries, Schumer said. A recent restructuring of how the agency distributes cash has made rebuilding in New York post-Sandy more efficient than on the Gulf Coast after Hurricane Katrina, he said.

The funding has already been appropriated through Congress and so won't be affected by the Republican takeover of the Senate, officials said.

The $1.6 billion comes in part from a $20 billion resiliency plan introduced during former Mayor Michael Bloomberg's tenure.

"Lord knows there were people in Washington trying to lowball New York City, New York State, New Jersey, and the senator fought for the actual amount needed to get us back and get us strong," de Blasio said. "That $20 billion in resiliency money is an act of law."

Coney Island Hospital will get $923 million for the critical services building, with an emergency room unit on the second floor in addition to a 1,720-foot flood wall and other updates. The facility's basement and first floor were inundated by Sandy stormwaters and 200 patients were evacuated.

Bellevue Hospital Center on Manhattan's East Side will get $376 million in reimbursement for removable flood barriers at its two loading dock entrances and to fund a new 2,350-foot flood wall, among other improvements. It evacuated 500 patients after Sandy when the basement was flooded by millions of gallons of water.

Metropolitan Hospital Center in East Harlem will get $120 million in part for electrical repairs and a flood wall, and Coler Specialty Hospital on Roosevelt Island will get $181 million to replace a destroyed generator, electrical repairs and a flood wall. De Blasio called flood walls "the most foundational type of protection."