(a) Generally. All necessary facilities, including underground pipe, inlets, catch basins or open drainage ditches, as determined by the City Engineer, shall be installed to provide for the adequate disposal of stormwater within the subdivision and shall connect to an adequate drainage course.
(b) Storm sewers. All storm sewers located under pavement shall be concrete or polypropylene corrugated double wall pipe meeting the requirements of ODOT Item 603, Type B Conduit, as amended. All storm sewers not located under pavement shall be concrete, vitrified clay or corrugated polyethylene smooth-lined pipe meeting the requirements of ODOT Item 611, Type C Conduits, as amended. The minimum diameter of a storm sewer pipe shall be 12 inches.
(1) All drainage facilities within the right-of-way shall be piped.
(2) Any proposed drainage course having a grade in excess of five percent or under two percent shall be a storm sewer with adequate appurtenances.
(c) Culverts and bridges. When natural drainage channels intersect a street right-of-way, the subdivider shall have satisfactory bridges and culverts designed and constructed. Where culverts are required, the following minimum requirements shall be observed:
(1) Culverts shall extend across the entire right-of-way width of the proposed road. The culvert capacity, the culvert material and construction and the cover over the culvert shall be subject to the approval of the City Engineer. The culvert shall be 12 inches larger than the size needed for hydraulic conveyance, and the bottom 12 inches shall be filled with natural stone so as to mimic natural habitat. The minimum diameter of a culvert pipe shall be 30 inches. Head walls are required; and
(2) For green roads driveway culverts shall have a minimum length of 20 feet and a minimum diameter of 12 inches. The length and diameter of driveway culverts for each lot shall be identified on the subdivision improvement plans, subject to the approval of the City Engineer. The driveway culverts shall be laid so as to maintain the flow line of the ditch or gutter. Head walls may be required.
(d) Construction and material specifications. Construction and material specifications for drainage shall meet the requirements of the following ODOT Items:
Item 601, Slope and Channel Protection, as amended;
Item 602, Masonry, as amended;
Item 605, Underdrains, as amended;
Item 611, Pipe Culverts, Sewers, Drains and Drainage Structures.
(Ord. 17-O-35, passed 11-20-2017)