S.C. DHEC requires the submittal of As-Builts under specific circumstances when it comes to land disturbing activities associated with large and small construction sites. There are two (2) circumstances where the Department requires submittal of As-Builts. These circumstances are while submitting a Notice of Termination (NOT) for NPDES coverage that included the construction of permanent detention and/or retention structures, and when you are applying for NPDES coverage that includes using a pre-existing detention and/or retention structure to accept on-site flows. Other cases may arise where S.C. DHEC will request an As-Built.

As-Built Survey Requirements

• Include grades/contours/depths for pond(s)
• Elevations and dimensions of all outlet structures, including:
  • Pipe and orifice inverts and diameters
  • Weir elevations and dimensions
  • Riser dimensions and elevations
  • Emergency spillway dimensions and elevations
  • Locations and inverts for all pipes discharging into the pond
• If the elevations or dimensions of the structures listed above do not match those used in the approved plans, certification statement signed by the project's Registered is required. Under some circumstances a revised pond routing calculations will be asked to be submitted.

All As-Builts must be prepared by a South Carolina Licensed Land surveyor and must be provided for all previously approved detention ponds that will receive flows from new drainage areas.

For As-Builts that do not match the approved plans on record, the project's Registered Engineer must submit a certification statement indicating that the pond, as built, will function within all applicable standards provided. As-Builts that drastically differ from approved plans may be required to submit a new analysis of the pond routing.

Note: As-built survey and /or analysis must be submitted and accepted by the Department before Notice of Termination (NOT) is submitted.