Almost all of the territory is less than 3 feet above the high tide mark and most of its 55,000 residents live within 30 feet of the shore.
High tides during 2008 swamped the main Majuro Atoll, causing several million dollars in damage and forcing dozens of islanders from their homes.
Meteorologists from the U.S. National Weather Service predict that similar inundations are possible during the next two months.
The Marshall Islands government wants to initially build a 3-mile seawall on the windward coast of Majuro Atoll and to fill in small bays as a buffer against ocean flooding during storms.
The Marshall Islands was a U.S.-administered trust territory until gaining independence in 1986 under a Compact of Free Association between the two countries.
The U.S. conducted nuclear bomb tests there during the 1950s.