An enclosed storm sewerage system shall be provided by the subdivider in accordance with the following requirements:
(a) The system shall be designed for a minimum ten-year storm, with the capacity to accept fully developed upstream drainage into the system.
(b) Hydraulic gradients shall be shown in profile where the gradient is above the top of pipe, and shall be a minimum of one foot below the top of inlet structures.
(c) Profiles for sewers shall indicate casting elevations, length and grade of runs, pipe size and class and type of backfill and bedding. Velocities in the pipe shall be sufficient for self-cleaning and shall not exceed eight fps. Minimum cover, where possible, shall be four feet.
(d) Catch basins shall be a minimum of five feet from corner radii and shall be so located that a maximum of 150 feet of street drainage will flow around a corner. They shall be placed at all low points and at intermediate points to maintain a maximum gutter flow distance of 600 feet. Maximum drainage into a basin shall be 800 feet from two directions.
(e) Manholes shall be placed at all angle points in sewers forty-two inches and smaller and opposite catch basin batteries. Maximum distances between manholes shall be 300 feet for pipe thirty inches or smaller, 400 feet for thirty-six inch pipe and 600 feet for pipe larger than thirty-six inches. Direct taps will be permitted only in storm sewers forty-eight inches and larger in size.
(Ord. 260. Passed 12-7-77.)