cfs 1.0 N 2. Calculate the optimum culvert size using the information that is shown. The size of the culvert chosen must be a commercially available size. The culvert will be a circular HDPE or CMP. The culvert will have a headwall and wingwalls (45) with grooved edge. The length of the culvert is 55 feet. Also state the minimum cover required over the culvert. # Flow Culvert Allow HW Tailwater Q Slope Depth Depth f/f ft. ft. 1 14 0.010 2.5 16 0.012 2.5 1.5 3 20 0.013 2.5 2.0 4 20 0.014 2.5 2.5 5 30 0.015 3.0 2.5 6 24 0.016 2.5 2.0 7 20 0.017 3.5 4.0 8 30 0.018 3.0 1.0 9 30 0.019 3.3 1.5 10 50 0.020 4.0 2.0 11 40 0.021 3.5 2.5 12 0.022 5.0 3.0 13 60 0.023 4.0 3.5 14 80 0.024 5.2 4.0 60