Long-term sea level rise in Washington, D.C., could have significant impact through flooding and infrastructure damage, researchers say. The rise is linked to thermal expansion of the oceans and melting of global ice sheets as a result of global warming, researchers at the University of Maryland report in a new study examining real-estate property and government infrastructure impacts. Writing in the journal Risk Analysis, researchers said predictions of a sea level rise of 4 inches by the year 2043 would flood about 103 properties and other infrastructure, costing the city about $2.1 billion. If a long-term rise were to reach 16 feet, they said, it could bring damages in excess of $24.6 billion to commercial buildings, military installations, museums and a number of government agencies in the nation\'s capital. \"Decisions must be made in the near future by lawmakers or city planners on how to reduce the impact of and adapt to SLR (sea level rise),\" the researchers wrote. \"A planned retreat is not an option when dealing with SLR in such an important area. Cost-effective methods to deal with SLR should be developed, and long-term solutions that extend well into this millennium are necessary.\"