Some South Florida beaches are running low on one very critical supply: sand. The Army Corps of Engineers had been bringing in sand for beaches in Miami-Dade and Broward counties from offshore sources, but now those reserves have run out. That's a problem not just for castle-building enthusiasts, but also because sand protects the beaches from erosion and natural disasters like hurricanes, reports AP via ABC News. "If we get hit by a large storm, unlike in the past where we knew we had resources right off our coast, those simply don't exist now," says a spokesperson from Miami-Dade county. "That vulnerability is very real."
The corps is now looking into alternative sand sources for its "beach renourishment" projects, from trucking it in from inland sand mines to borrowing it from the Bahamas. But it isn't as easy as raiding your local sandbox—grains have to be the right size and the right color to work. "The general perception is the ocean is full of sand," says a senior corps engineer, "but to get the sand in an environmentally responsible way, to get sand compatible with what's on the beaches, it's difficult at times." (Read more Florida stories.)