A rectangular concrete culvert (square-edged entrance) is placed on a slope of 0.09 ft/ ft. The culvert is 4. 0 ft × 4 . 0 ft and 140 ft long. The tail water level is 2. 0 ft below the culvert crown at the outlet. Determine the discharge if the headwater level is
(a) 1.5 ft above the crown at the inlet,
(b) Coincident with the crown, and
(c) 1.5 ft below the crown.