(A)   Drainage system required. An adequate piped storm drainage system including appurtenances such as catch basins and manholes shall be provided for proper drainage of storm water collected in public streets and areas tributary to the public street system. Appropriate conveyances for outlets to drainage systems must be provided. A minimum easement width of 30 feet is required along the centerline of any pipe system or drainage course. If ponding will occur at culvert inlets or if permanent erosion control measures extend outside of the right-of-way, then easements on abutting property are required.
   (B)   Design standards.
      (1)   All storm water systems for public streets shall be designed to meet the criteria of a ten-year storm based on rainfall data from the National Weather Service in Jackson County, Indiana. Flows shall be computed by a method acceptable to the Town Council or its designee. Design computations of flows shall be submitted for approval.
      (2)   Upstream drainage shall be accommodated by an adequately sized system for existing conditions and an estimation of future potential development in the upstream drainage area or tributary areas.
      (3)   Existing downstream drainage facilities shall be studied to determine the effect of development on downstream drainage. The applicant shall demonstrate to the satisfaction of the Town Council that the storm drainage will not, in any way, overload existing downstream drainage systems.
      (4)   No storm water shall be permitted to drain across a public street or across an intersection.
      (5)   Design standards for drainage systems shall be approved by the Town Council or its designee. The minimum diameter for any storm drainage pipe shall be 12 inches for enclosed drains and 15 inches for culverts.
   (C)   General construction requirements
      (1)   All trenching shall be accomplished in accordance with all appropriate federal and state safety requirements.
      (2)   Maximum trench width at the pipe crown shall be the outside diameter of the pipe plus two feet.
      (3)   Pipe shall be bedded in a granular material with a minimum depth of six inches below the bottom of the pipe and extending to six inches above the top of the pipe.
      (4)   Drain alignment shall be straight in both horizontal and vertical an alignment.
      (5)   Manholes shall be provided at all changes in vertical and horizontal alignment, and at all junctions. On straight runs, manholes shall be placed at intervals of no more than 300 feet.
      (6)   Catch basin leads shall enter the drainage system only at manholes. The difference in elevation between the inverts of the lead and the main drain shall not exceed 12 inches.
      (7)   All drain outlets shall be riprapped to prevent erosion. Facilities for energy dissipation shall be provided.
      (8)   Underdrains shall be laid with perforation down with a backfill of three-quarter inch crushed stone wrapped in a filter fabric envelope.
(2011 Code, § 154.19) (Ord. 2007-02, passed 3-5-2007) Penalty, see § 10.99