A. The subdivider shall, subject to riparian rights, dedicate a right-of-way for storm drainage purposes conforming with the lines of any natural watercourse, channel, stream or creek that traverses the subdivision, or at the option of the subdivider, provide by dedication further and sufficient easements or construction, or both, to dispose of such surface and storm waters.

B. Stormwaters shall be carried in underground systems when the flow requires a forty-eight-inch (inside diameter) or less pipeline. The system shall be designed on the basis of criteria for a “ten-year storm,” calculated on the basis of practice found to be suitable for a particular area, shall be totally carried in the underground system with the hydraulic gradient in curb inlets maintained at least one foot below top of curb.

C. Pipe Size. The minimum size of pipe in the public right-of-way shall be twelve inches.

D. Velocity. All new storm drains shall be designed to maintain a minimum velocity of flow of two feet per second, when flowing one-quarter full.

E. Inlets. Curb inlets shall be installed at intersections and at intermediate points when the gutter flow for the “design storm” exceeds the top of curb for a minimum grade and when the gutter flow is higher than three inches below top of curb for fifteen percent grades. Valley gutters will normally be allowed across a cul-de-sac or low traffic volume street intersections only.

F. Manholes. A standard manhole shall be constructed at all pipe intersections, change in pipe size, abrupt change in horizontal and vertical alignment and at least every four hundred eighty feet for pipes between twelve inches and thirty inches in diameter, seven hundred fifty feet maximum for pipes from thirty-three inches to fifty-nine inches in diameter. (Ord. 90-1 (part), 1990)