York County is seeking proposals from qualified consulting firms to develop and implement a Dry Weather Field Screening and Analytical Monitoring (Dry Weather Screening) Program for areas within the State-designated Small Municipal Separate Storm Sewer System (SMS4) boundary of York County. Adoption of this Program is intended to fulfill the requirements of the South Carolina Department of Environmental Services (SCDES) National Pollutant Discharge System (NPDES) General Permit for Storm Water Discharges from Regulated SMS4.
York County is one of the oldest and fastest growing political jurisdictions in one of the oldest and fastest growing states in the country. It is situated at the northern extent of the South Carolina Piedmont region, with a land area of approximately 695 square miles and an estimated 2026 population of more than 311,000, making it the 7th largest of the state’s 46 counties.
Under the federal Clean Water Act, the EPA delegated authority for regulating the NPDES Stormwater Program within the State to the State of South Carolina. SCDES is the state agency responsible for permitting, administration and enforcement of the NPDES Stormwater Program. On August 7, 2007, York County was designated by SCDES as a regulated small MS4 under the Phase II Rule and obtained initial coverage under the South Carolina NPDES SMS4 General Permit.
A core requirement of the NPDES SMS4 General Permit is the development and implementation of a Dry Weather Screening Program for the detection, investigation, and elimination of non-stormwater discharges, including illegal dumping, into the County’s waterways. The standards and procedures, to be developed as part of the Dry Weather Screening Program, are to be included as part of the County’s overall Illicit Discharge Detection and Elimination (IDDE) Program, and incorporated into the County’s Stormwater Management Plan (SWMP) document as a requirement of the State of South Carolina. A Dry Weather Screening program shall be structured around the following major components:
A. Develop a System Map: Develop and update a storm sewer system map of public and private storm sewer system outfalls for all areas within the SMS4 boundary. Show the location of all outfalls, and names and location of all waters of the United States that receive discharges from those outfalls.
B. Identify Priority Areas: Identify priority areas for more detailed screening of the system based on higher likelihood of illicit connections or by conducting ambient sampling to locate impacted reaches.
C. Field Screening to Detect Illicit Discharges: Inspect stormwater pipe outfalls, located on both public and private lands, during periods with no measurable stormwater flow to identify non‑stormwater discharges that may indicate illicit connections, failing septic systems, or industrial/commercial pollutant entry.
D. Field Screening Assessment: Assess the effectiveness of field screening to determine if the level of effort is adequate in attaining the effective prohibition of non-stormwater discharges into the SMS4.
E. Establish Procedures for Tracing the Source of an Illicit Discharge: Develop written procedures for conducting investigations into the source of identified illicit discharges, including approaches to requiring such discharges to be eliminated.
