Cincinnati plans to shut down intake valves along the Ohio River to protect the city's drinking water from a chemical spill in West Virginia. Mayor John Cranley announced Monday that the valves will be shut down for at least 20 hours beginning Tuesday night. Cranley says that will allow the water to pass the city without any chemicals entering the drinking supply. The city plans to use a reserve of 60 hours of treated water, built up specially following the West Virginia spill. On Thursday, a chemical used in coal processing leaked from a plant into the nearby Elk River in Charleston, W.Va. The Elk River feeds into the Ohio River. The spill caused a days-long crisis in which officials banned the use of tap water for 300 thousand people.