1182.03   DESIGN.
   (a)    Runoff and Volume Calculation Methods.  The methods outlined in the City Subdivision Rules and Regulations and City of Fairfield Construction and Materials Specification Handbook (latest edition) shall be used to determine the runoff and storage volumes.
   (b)    Quantity of Runoff.
      (1)    The peak rate of runoff during the 100 year post-development storm cannot exceed the peak rate of runoff during the two year pre-development storm.
      (2)    For those areas where a study of the downstream area indicates the extended time of high discharge and/or velocity due to restricted release rate and storage may cause flooding and/or excessive erosion, the City Engineer may require additional controls.
   (c)    Quality of Runoff.
      (1)    The design of stormwater quality controls, also known as post-construction Best Management Practices, shall comply with standards and requirements as contained in the latest edition of the Ohio EPA General (NPDES) Permit for Stormwater Discharges associated with construction activity (See Part IIIG2E of the Ohio EPA's NPDES Permit).
   (d)    Basin Construction.
      (1)    The side slopes of a detention/retention basin shall not exceed four to one and shall be seeded or sodded.
      (2)    The bottom of the basin shall be seeded or sodded and sloped to the outlet flow control device. A method of carrying low flow through the basin shall be provided and include appropriate erosion control.
      (3)    The maximum water depth for detention basins shall be six feet.
      (4)    The top of the embankment shall have a minimum width of eight feet.
      (5)    Outlet flow control devices may be either single-stage or multi-stage.
      (6)    Other requirements may be imposed for specific cases.   
         (Ord. 25-14.  Passed 4-14-14.)