A concrete culvert is required to convey a design flow of 654 cfs over a length of 330 ft. and a slope of 0. 0 l S ft/ft. Because there is a large lake downstream, the tail water elevation is constant at 526.4 ft MSL, which will submerge the culvert outlet. The headwater elevation cannot exceed 544.4 ft. MSL without overtopping the roadway embankment. Find the required diameter for (a) a single barrel culvert and (b) twin barrels, assuming a square-edged entrance.