§ 151.051  DRY DETENTION BASIN DESIGN.
   (A)   Wherever practicable, dry detention basins shall be designed to serve a secondary purpose for recreation, open space or similar type of uses which will not be adversely affected by occasional, intermittent flooding.
   (B)   Dry detention basins shall be designed to completely drain within 48 hours after the end of storm events. Underdrains should be utilized if necessary to meet this requirement.
   (C)   Dry detention basins shall have a minimum bottom slope of 2%. Underdrains directed to the outlet control structure shall be installed if the minimum bottom slope cannot be obtained, provided that there are no inlets or other direct connections to the underdrain.
   (D)   Velocity dissipation measures shall be incorporated into dry basin designs to minimize erosion at inlets and outlets and to minimize the resuspension of pollutants.
   (E)   To the extent feasible, the distance between detention inlets and outlets shall be maximized. If possible, inlets and outlets should be located at opposite ends of the basin.
   (F)   An emergency overflow weir able to pass the 100-year frequency flow without damage to the basin shall be provided.
   (G)   A minimum of one foot of freeboard shall be provided between the 100-year frequency high water level and the top of the basin berm.
(Ord. 07-02, passed 4-16-2007)