The subdivision of Problem 6.8 drains to the upstream end of a circular price that has an n value of 0.013 and a slope of 0.005 ft/ft. Determine the size of pipe needed to carry the flow from the 5-yr storm. Standard diameter in the United States start at 12 in. and increase in 6-in. increments 60 in, then continue to increase in 12-in. increments)?