Clemson stormwater manager outlines flooding risks, maintenance gaps and how residents can help

Ethan Barnett, the city’s stormwater manager, told the Clemson City Police Advisory Board on April 23 that clogged catch basins, failing detention ponds and watershed flows from 18 Mile Creek are the chief drivers of local flooding and that coordinated work with police is critical during storm responses.

Barnett explained that Clemson is regulated as an MS4 (municipal separate storm sewer system) and must implement a stormwater management plan and six minimum control measures under its permit. He said the city updates that plan annually and participates in a regional outreach partnership, the Anderson–Pickens County Stormwater Partners, to share public-education efforts.

Why it matters: Barnett said flash flooding from short, intense storms is the local pattern and that maintenance gaps—blocked catch basins and overgrown or failing detention ponds—can rapidly convert heavy rain into dangerous road‑flooding and property damage. “When we do have flooding, we definitely call in the police department,” Barnett said, noting that police assist with traffic control so crews can clear obstructions.

Key details from the presentation included Barnett’s inventory and maintenance practices: he cited roughly 1,348–1,400 catch basins the city owns and operates and said the city inspects those on a multi‑year cycle (inspection frequency varies with equipment and staffing). He also noted about “a little over 80” post‑construction BMPs (best‑management practices) in the city—some publicly maintained, some privately owned—that the city inspects annually.

Barnett described common failure modes: debris and leaf piles that clog roadside ditches, rusted or undersized outlet pipes that meter flow incorrectly, and beaver dams or stream blockages that create backwater. He showed photos of failing detention ponds that had to be cleared or reconstructed and said repairs restored intended function.

On maps and rules, Barnett used FEMA’s FIRM (Flood Insurance Rate Map) to show the blue 100‑year special flood hazard areas that include corridors where Berkeley and Aquina trail meet, portions of College Avenue/Lake Parkville, and other neighborhoods. He said the building official (Stacy Blackwell) administers the city’s floodplain ordinance (Chapter 5, Article 2) and that FEMA and the state regulatory agency provide mapping and permitting guidance. Barnett cautioned that some local streams have not been modeled by FEMA and therefore lack a regulatory floodplain.

Regional limits: Several board members asked whether local work can eliminate chronic flooding at Nettles Park and in Delwood. Barnett said Nettles sits in a mapped flood hazard area fed by a tributary of 18 Mile Creek and that much of the contributing watershed lies outside city limits (into Easley and Anderson County). “You’re almost at the end of the pipe,” he said, which constrains what local mitigation alone can achieve without broader basin‑level intervention.

Funding and reporting: Barnett said stormwater operations are funded through an enterprise fund (a small fee on utility bills) and permitting fees. He asked residents to report clogged catch basins or drainage problems by calling the utilities main line at (864) 653‑2046 (ask for Susan) or by submitting a stormwater work order through the MyCivic app on the city website with a photo or nearest address.

What’s next: Barnett offered to share his slides and contact information for follow‑up and encouraged board members and citizens to spread educational messages that reduce debris in ditches and help maintain drainage function.

Quote: “If you see catch basins that are blocked or filled with debris, leaves or litter, call the utilities main line at (864) 653‑2046 or submit a work order through MyCivic,” Barnett said.

Ending: The board thanked Barnett for the overview and invited additional technical follow‑up; Barnett said he would provide his slides and contact details to staff and individuals who requested more detail.