Stormwater CGP Reissuance Major Changes

DHEC is preparing to reissue the stormwater construction general permit. Below are the major changes being adopted. The new permit is set to go into effect around the middle of February. The HBA of SC Regulatory Affairs Committee met last year along with HBA staff members Mark Nix, Bugsy Graves, and Alex James to discuss the proposed permit and we submitted comments to DHEC, almost all of which were included in this final draft. If you should have any questions or comments please do not hesitate to reach out to Alex James, HBA of SC Director of Government Affairs, at

• In addition to contractor certifications, Primary and Secondary Permittees covered by the permit must provide either a copy of the Annual Blanket Coverage letter, or documentation of a request to the utilities for their Annual Blanket Coverage Letter.

• If it is not possible to maintain a copy of the OS-SWPPP on the construction site copies of the plans, either printed or easily readable digital, must be available within a reasonable time-frame agreed upon by the department or other regulatory staff.

• For Major Modifications for sites located in an area under the authority of a regulated MS4, or an entity delegated under Regulation 72-300, an updated NOI, along with any supporting documentation, must be submitted to DHEC for review and approval when the modification includes:

(a). Addition of Disturbed Area.

(b). Changes to Navigable Water Crossing.

(c). Changes that include impacts to Waters of the State/ Waters of the U. S.

(d). Coastal Zone only, changes to the site design that may impact the project’s CZC.

(e). Other changes as deemed appropriate by the Department that may affect the site’s authorization to discharge under this permit.

• The C-SWPPP must now identify all Waters of the State (WoS), including wetlands, on the site; however, delineation is not required if a 100-ft undisturbed buffer can be maintained between the WoS and all construction activities.

• It is recommended that BMPs be assessed by the contractor within 24 hours of the end of a storm event of 0.51.0 inches or greater, as well as during the first rain event after the initiation of construction activities, after the installation of BMPs.

• Inspection of BMPs, such as sediment basins, sediment traps, which may receive flow from land development and/or construction on individual lots, may be required to resume if areas that drain to them become disturbed during future construction.

• It is strongly recommended that permittees maintain an on-site rain gauge during active construction, to record rainfall records from any significant rainfall event, 0.5 inches or greater. Permittees may utilize data from a certified weather record (such as a personal weather station or an airport) located within reasonable proximity of the construction site in lieu of an on-site rain gauge.

• Secondary Permittee BMP Maintenance Requirement. It shall be the responsibility of the Secondary Permittee to either maintain or coordinate maintenance with the primary permittee or the party responsible for permanent maintenance of any stormwater BMP (silt fence, sediment trap, sediment basin, etc.) accepting stormwater discharges from any area associated with the secondary permittee’s construction activities. SCBJ