Here's part of the MTA's problem in post-Sandy world: six subway stations are located in the Lower Manhattan flood zone, and those stations have 540 openings -- manholes, stairways, elevators, hatches and vents -- that could allow water to flow underground. As the authority prepares for future storms, it needs to figure out how to secure each one of those openings.
On Thursday, MTA interim executive director Tom Prendergast sketched out options for doing that. They include removable floodwall panels that could be popped on top of street entrances at subway stations, and over sidewalk vents. The authority is also looking into a removable floodwall that could surround large subway entrances, such as the one at Bowling Green (see image).
Prendergast said engineers in the authority's new Sandy Recovery and Resiliency Division are examining various kinds of "barriers, dams and dikes" to keep the water out of vulnerable parts of the system, including "stations, fan plants, under-river tubes, tunnels, ground-level tracks, signals, train shops and yards, traction power substations, circuit breaker houses, bus depots, train towers and public areas."
The MTA has hired six engineering and design firms to come up with repairs and resiliency solutions. The authority already has $250 million in Sandy repair and recovery projects underway. Prendergast said he expects to pay for future hardening projects using grants from FEMA and the Federal Transit Administration's Emergency Relief Program.