The National September 11 Memorial Museum is keeping in place plans to store the unidentified remains of World Trade Center victims in an underground repository, saying they can be protected from flooding, writes The New York Times.

The museum site is in New York’s most at-risk area for flooding, and the unfinished structure’s bedrock-level chamber was under seven feet of water after Superstorm Sandy. A group of 17 victims’ relatives all 9/11 family members surveyed on whether to move the remains.

Joseph C. Daniels, head of the memorial foundation, said Sandy’s floodwaters got into the chamber because adjacent underground construction was not yet finished. He said those openings will be sealed by solid concrete walls and other steps will be taken to make the repository itself watertight.