COLUMBIA, S.C. (AP) — Hundreds were rescued from fast-moving floodwaters Sunday in South Carolina as days of driving rain hit a dangerous crescendo that buckled buildings and roads, closed a major East Coast interstate route and threatened the drinking water supply for the capital city.The powerful rainstorm dumped more than a foot of rain overnight on Columbia, swamping hundreds of businesses and homes. Emergency workers waded into waist-deep water to help people trapped in cars, dozens of boats fanned out to rescue others in flooded neighborhoods and some were plucked from rooftops by helicopters.With so much water, officials said it could take weeks or even months to assess every road and bridge that’s been closed around the state. Several interstates around Columbia were closed, and so was a 75-mile stretch of Interstate 95 that is a key route connecting Miami to Washington, D.C. and New York.“This is different than a hurricane because it is water, it is slow moving and it is sitting.