In a Chesapeake Bay Bridge resurfacing job that has gone on for years, old material scraped from the bridge is recycled into small chunks sterilized, donated and dumped by Maryland’s Transportation Authority into the Severn River. This creates man-made reefs that should help restore native oysters. Divers and geologists ensured the river bottom would support 2,500 cubic yards of concrete rubble, creating a reef two feet high. The depth has to be just right for spat, the baby oysters that are attached to the shells. To grow to adults, they must survive disease carried on the bay’s saltier waters. Restoring native oysters on man-made reefs is a project funded by private, state and federal funds.