According to the Chatham County Emergency Management Agency, all eastbound River Street traffic is being routed up Drayton Ramp due to a cooking oil spill. A sizeable grease spill was caused by a private hauler at the Abercorn Ramp, and the Abercorn and Bull ramps have been closed as well, said Bret Bell, city of Savannah spokesman.The estimated cleanup time is about 5 hours.