§ 165-201.09

Other

• Storm drainage conveyance design for 100-year storm100 year frequency

  Conveyance systems for such developments shall be designed to convey a storm with a one-hundred-year frequency within a controlled spillway.

• Storm drainage conveyance design for 10-year storm10 year frequency

  Storm drainage conveyance systems for developments requiring site plan approval shall be designed to convey a storm with a ten-year frequency without surcharging inlets.

• Drainage easement requirement

  Whenever a development requiring site plan approval is traversed by a watercourse, drainageway, channel or stream, a drainage easement shall be provided.

• Erosion and sediment control compliance

  All development in Frederick County shall meet the requirements of Chapter 79, Erosion and Sediment Control, of the Frederick County Code.

• Use of natural drainageways

  In developments requiring site plan approval, natural drainageways shall be used whenever possible to carry stormwater runoff.

• Runoff rate limitation

  All developments requiring site plan approval shall limit the rate of stormwater runoff so that no greater rate of runoff from the site is permitted than that occurring prior to development for storms with a two-, ten- and twenty-five-year frequency.

• Sinkhole protection

  Stormwater from developments shall not be discharged into sinkholes. Sinkholes capable of absorbing substantial amounts of stormwater shall be protected by diverting runoff from the sinkhole.

• Stormwater storage requirement

  Where necessary, a stormwater storage system shall be provided to accommodate a postdevelopment storm with a twenty-five-year, twenty-four-hour frequency, to be released at a rate not to exceed the predevelopment discharge for a storm with a ten-year, twenty-four-hour frequency.