The size and capacity of all drainage structures shall be computed using the "rational method". The minimum length of culverts shall be at least equal to the distance from edge of shoulder to edge of shoulder, plus six times the vertical distance from the edge of shoulder to the flow line of the culvert less end section length. No driveway culvert shall have a diameter of less than 12 inches, and no crossroad culvert shall have a diameter of less than 15 inches. In no case shall a driveway culvert be less than 20 feet in length. Material in culverts which exceed 100 feet in length shall be limited to those permitted for storm sewers as specified in the Standard Specifications. All crossroad culverts shall have end protection in the form of either concrete headwalls or prefabricated end sections.
(Ord. 76-O-10, passed 9-21-76)