1117.05 DESIGN OF STORM SEWERS.
(a) The design and construction of all sanitary sewers and water facilities shall be done in compliance with the "Design, Construction and Material Specification Handbook."
(b) All storm sewers, open ditches and driveway culverts shall have a minimum size
adequate for a ten year storm frequency.
(1) All road culverts on primary and secondary thoroughfares and collector streets shall be adequate for a twenty-five year storm frequency and be designed in accordance with the latest State Department of Transportation requirements.
(2) In all cases where there are flood hazards, the developer's engineer shall insure that all drainage courses, ditches, sewers and other such facilities are adequate for a fifty year storm frequency and in addition will prevent flooding of residential, commercial and public buildings or that would endanger health, life or property.
(c) The minimum grade for all ditches shall be one percent (1%) except for streams, large channels with a paved bottom, and slopes paved to a height approved by the City Engineer.
(1) All proposed channels shall be properly lined to prevent erosion unless waived by the Public Works Director. All ditches having a velocity of five feet per second or less shall be sodded, except that ditches not along the roadway may be seeded if the velocity is under two feet per second. All ditches with a velocity of over five feet per second shall be lined.
(2) Where possible, natural streams, including growth along the banks, shall not be disturbed. Roughness coefficients and increased peak flows and velocities shall be evaluated to determine stability.
(3) When part of a storm drainage system is outside of the road right of way, the developer shall provide an easement for storm drainage and maintenance. All easements for water courses or ditches shall be wide enough to contain such ditches, including side slopes, plus ample clearance for maintenance operations. Easements shall be shown and shall be provided for all existing or proposed channels. Easements shall provide ingress and egress for maintenance equipment from a public right of way.
(Ord. 25-14. Passed 4-14-14.)