Colleton County, SC Stormwater Regulations

Colleton County is not designated as an MS4 community, so it doesn't operate under a municipal stormwater permit. However, state NPDES construction permits from SCDES still apply to projects disturbing one acre or more. The county's coastal areas fall under OCRM jurisdiction, and state penalties up to $10,000 per day apply for violations.

Primary source: South Carolina Department of Environmental Services (SCDES)

Permit Requirements

Despite lacking MS4 designation, Colleton County is still subject to state stormwater permitting requirements. SCDES requires coverage under the NPDES Construction General Permit (SCR100000) for any project disturbing one acre or more. The permit requires a Stormwater Pollution Prevention Plan (SWPPP) and implementation of erosion and sediment controls throughout construction.

Properties within the OCRM coastal zone, particularly along the Edisto River, ACE Basin, and Edisto Beach, must obtain Critical Area Permits for development activities. The ACE Basin is one of the largest undeveloped estuaries on the East Coast, and OCRM applies strict standards to protect its ecological value.

Colleton County's land use regulations include basic grading and drainage requirements through the development review process, but these are less detailed than the stormwater ordinances found in MS4 communities like neighboring Charleston or Beaufort counties.

Inspection Obligations

Under the NPDES Construction General Permit, active construction sites in Colleton County must be inspected at least once per week and within 24 hours of any rainfall event of 0.5 inches or more. These inspections are the responsibility of the permit holder and must be documented.

Without MS4 designation, Colleton County doesn't have a formal post-construction BMP inspection program. However, SCDES can inspect any permitted stormwater facility at any time, and property owners who received NPDES permits must maintain their BMPs according to the approved SWPPP.

Properties with maintenance agreements recorded as part of the development approval process are still obligated to maintain their stormwater systems. The lack of active county oversight means enforcement typically happens through SCDES when problems are reported or discovered.

Penalty Structure

State enforcement is the primary mechanism for stormwater violations in Colleton County. SCDES can assess civil penalties up to $10,000 per day per violation under the SC Pollution Control Act. Common violations include unpermitted land disturbance, failure to implement erosion controls, and discharging sediment or pollutants to state waters.

OCRM can impose additional penalties for unauthorized work within the coastal critical area, including mandatory restoration requirements and fines. Development within the ACE Basin area receives particularly close scrutiny from OCRM.

The absence of a local stormwater enforcement program means that violations in Colleton County often go undetected longer than in MS4 communities, where county inspectors actively monitor construction sites and permanent facilities. However, when violations are discovered, the state penalties are the same as anywhere else in South Carolina.

Key BMPs

Colleton County's rural character and varied terrain, from upland forest near Walterboro to coastal marsh at Edisto Beach, influence BMP selection:

• Wet detention ponds - Common in residential developments and commercial sites. Sizing requirements follow SCDES standards for the first inch of runoff treatment.
• Vegetated swales - Well-suited to Colleton County's rural roads and low-density development patterns. Provide conveyance and water quality treatment.
• Riparian buffers - Critical along tributaries of the Edisto River and ACE Basin waterways. Natural vegetation buffers are the most effective BMP for protecting these sensitive receiving waters.
• Sediment basins - Required during construction on larger sites. Must be maintained throughout the construction period and either converted to permanent facilities or removed at project completion.
• Natural drainage patterns - Colleton County's low development density allows for preservation of natural drainage features as BMPs, which is often the most effective approach in rural areas.

Local Ordinances

Colleton County's land use and development regulations include basic stormwater management requirements through the zoning and development review process. However, the county lacks the comprehensive stormwater management ordinance found in MS4 communities.

The Town of Edisto Beach has its own development regulations that address stormwater management for coastal properties. Given Edisto Beach's vulnerability to storms and erosion, the town's requirements for beachfront and near-beach construction include drainage provisions.

Colleton County participates in the National Flood Insurance Program, and development within FEMA-designated flood zones must comply with floodplain management regulations. This includes elevation requirements and restrictions on fill within floodways that affect stormwater management design.