Pond Boss Forums POND CONSTRUCTION Building a dam Best way to keep spillway from washing out?

Two Quickrete bags is roughly one cubic foot or roughly 12 sq. ft. at 1" thick when they are MIXED. At that rate, you would need 250. I am guessing that 1" dry wouldn't be too much of a difference, but I don't know for sure. If anything, you would have more coverage and can take back the extra bags as long as they don't get wet.