Nassau County, FL Stormwater Regulations

Nassau County operates under a Phase II Small MS4 NPDES permit, with stormwater managed through the dual authority of FDEP and the St. Johns River Water Management District. Fernandina Beach on Amelia Island is the primary coastal community. FDEP penalties reach $10,000 per day, and SJRWMD enforces ERP compliance separately.

Primary source: Florida Department of Environmental Protection (FDEP) NPDES Stormwater Program

Permit Requirements

Nassau County's permit framework mirrors the northeast Florida dual-authority model. SJRWMD administers Environmental Resource Permits (ERPs) for stormwater management system design and construction. FDEP's NPDES Construction Generic Permit applies to projects disturbing one acre or more.

The ERP process requires stormwater systems to meet specific pollutant removal standards, including treatment of the first inch of runoff and demonstration of adequate attenuation for post-development peak discharge rates. Nutrient removal requirements under Florida's SB 7040 may apply to projects discharging to impaired waterways.

Nassau County's development services department reviews stormwater management plans as part of the local development approval process. Rapid growth in the Yulee area, along the SR-200/A1A corridor between Jacksonville and Fernandina Beach, has significantly increased development review activity. Coastal projects on Amelia Island must also address FDEP's Coastal Construction Control Line requirements.

Inspection Obligations

Construction sites under the NPDES Construction Generic Permit must be inspected per the permit schedule. Nassau County conducts its own construction site inspections as part of its MS4 program, in addition to the self-inspection requirements.

Post-construction BMPs require annual inspections and maintenance certification. Property owners must document the condition and functionality of their stormwater management systems. Nassau County tracks permitted facilities and can conduct compliance inspections at any time.

SJRWMD may inspect ERP-permitted facilities to verify compliance with permit conditions. The district focuses on larger projects and facilities that have been the subject of complaints or known maintenance issues.

Penalty Structure

FDEP enforces stormwater violations with fines up to $10,000 per day per violation under the Florida Clean Water Act (F.S. 403). State enforcement covers NPDES permit violations, unpermitted discharges, and water quality exceedances.

SJRWMD enforces ERP violations through administrative orders, penalties, and permit modification or revocation. Operating a stormwater system that doesn't match the permitted design, or failing to maintain a permitted system, triggers district enforcement.

Nassau County enforces its local stormwater ordinance through notices of violation, stop-work orders, fines, and permit denial. The county can withhold development approvals for projects with outstanding stormwater violations and require corrective action as a condition of continued development activity.

Key BMPs

• Wet detention ponds - Standard for residential subdivisions and commercial development. Must meet SJRWMD design criteria for retention time and pollutant removal.
• Dry retention systems - Florida-specific BMP that retains the first flush of stormwater and allows infiltration. Well-suited to Nassau County's sandy soils in upland areas.
• Bioretention systems - Used in commercial projects and mixed-use developments. Must meet Florida nutrient removal standards.
• Coastal BMPs - Amelia Island properties require stormwater systems designed for sandy soils, saltwater influence, and storm surge vulnerability. CCCL requirements affect BMP placement on beachfront properties.
• Permeable pavement - Applied in commercial parking areas and low-traffic residential streets. Nassau County's sandy soils generally support infiltration-based approaches.

Local Ordinances

Nassau County's stormwater management ordinance implements the requirements of its MS4 permit and Florida's stormwater regulations. The ordinance covers construction site erosion control, post-construction stormwater management, illicit discharge prohibition, and BMP maintenance requirements.

The City of Fernandina Beach has its own development standards that apply within the city limits on Amelia Island. Fernandina Beach's historic district and waterfront location add considerations for stormwater management in the downtown area.

Nassau County participates in the National Flood Insurance Program, with significant flood zone areas along the Nassau River, St. Marys River, and Amelia Island coast. Flood zone development must comply with both county floodplain regulations and SJRWMD's flood management standards.