Several pols, community groups and Upper East Side residents filed two lawsuits yesterday in an effort to block the planned construction of a massive garbage-transfer station along the East River at 91st Street.

Both suits seek to overturn a permit granted by the Army Corps of Engineers, saying the approval violates the federal Clean Water Act and other environmental-protection laws.

The Manhattan federal court filings also note the floating trash center would be located in the city’s flood-prone “Zone A,” with one charging that “Hurricane Sandy has recently and dramatically shown that the plant will be exposed to tidal surges and other weather events that could overwhelm it.”

An Army Corps of Engineers spokesman declined to comment.