Get Full Government Meeting Transcripts, Videos, & Alerts Forever!
Get email alerts on the Stormwater Monitoring E Coli topic
No spam. Unsubscribe anytime.
City staff reports elevated E. coli and identifies debris and erosion in stream assessments
Summary
City staff reported elevated E. coli geometric means on Hurricane Creek and Finch Branch, found debris and erosion at multiple sites, and outlined near-term cleanup and source-tracking steps.
City staff reported to the La Vergne Stormwater Appeals and Advisory Board on Feb. 3, 2025, that recent visual stream assessments and E. coli monitoring identified debris, erosion and elevated pathogen levels in several local streams, and described planned cleanup and follow-up testing to locate sources.
Miss Thompson, a city staff member, said the city is required to complete stormwater monitoring and visual stream assessments every five years for streams listed as impaired. Staff contracted CEC Engineering to walk impaired reaches and sample for E. coli at Hurricane Creek and Finch Branch.
"When you do E. coli testing, you have to do five separate samples in the same place," Miss Thompson said, and reported that Hurricane Creek's geometric mean was 322 colony-forming units per 100 milliliters, above the state reference value of 126 CFU/100 mL. Finch Branch had a geometric mean of about 1,250 CFU/100 mL, she said.
Staff described nonpoint problems found on the walks: a tire accumulation on Finch Branch creating a fish barrier, an abandoned silt fence from a construction site that was later removed by the contractor, and severe bank erosion at several private-property locations. At one construction site near Hurricane Creek, staff noted plans for a constructed wetland to slow runoff and provide native vegetation.
Miss Thompson outlined next steps: organize targeted cleanups, coordinate monthly stream-cleanup events, reach out to private property owners about erosion risks, and begin presence/absence testing immediately to narrow where E. coli increases occur. She said presence/absence field tests will deliver initial results in about three days and could guide further source-tracking, including potential laboratory-based genetic (PCR) testing if needed.
On potential causes, Miss Thompson said high E. coli can come from several sources, including sewer-line breaks, malfunctioning on-site sewage systems, agricultural runoff or concentrated animal waste, and intentional dumping. She said the city has begun communications with neighboring Nashville authorities because Hurricane Creek runs along the La Vergne-Nashville boundary.
Board members asked about timelines and testing methods. Staff said presence/absence testing begins the week of the meeting; laboratory confirmation could take additional days and time depending on methods chosen. No formal decisions or votes were taken on monitoring actions during the meeting.
The city will continue routine monitoring, pursue cleanup events for debris and tires, coordinate with contractors on erosion-control measures at construction sites, and follow up with source-tracking tests to reduce pathogen levels over time.
