$7\mathrm{.}4.$ A hydraulically short horizontal culvert is to be placed at the end of a drainage channel to pass a peak flow rate of $1\frac{m^3}{s}$ under a roadway. The allowable ponding depth in the drainage channel leading to the culvert is $1m.$ The culvert is to be made of $($commercial size$)$ circular concrete pipe that is square to the headwall, and the minimum allowable culvert diameter is $150mm.$ Use the applicable NIST equation to determine the required culvert diameter. How would the required diameter change if you used a grooved$-$end culvert entrance instead of a square$-$edged entrance? How would this design compare to using the appropriate non$-$NIST equation. What conclusion can you draw from your analysis?