Williamson County panel approves 167‑lot Patterson Road subdivision, grants floodplain variance after residents raise flooding, septic and traffic concerns

The Williamson County Regional Planning Commission on Thursday approved a concept plan and granted a variance to permit filling within the 100‑year floodplain for a proposed 143.32‑acre subdivision off Patterson Road, permitting up to 167 lots with a nontraditional wastewater treatment system, after an extended public hearing in which nearby residents raised concerns about flooding, septic systems and traffic.

The commission’s action, which was moved, seconded and carried by voice vote, includes conditions noted by staff: completion of required off‑site road improvements before submission of the first final plat containing residential lots; construction of a greenway segment before the final plat that contains it; demonstration of compensatory floodplain storage and a final grading plan showing no increase in off‑site flood elevations; and landscape buffers around wastewater facilities. The applicant must satisfy county engineering, floodplain and highway requirements before final plats are recorded.

Why it matters: The plan affects residents on Patterson Road, Atwood Lane and surrounding properties in the College Grove/Triune area, where speakers told the commission that flooding already affects homes and that a large development with more impermeable surfaces and a 19‑acre emergency wastewater pond could worsen drainage problems and pose public‑health and traffic risks.

Staff presentation and required public improvements Kayla Ferguson of Birch Transportation, the project traffic consultant, summarized traffic mitigation the county will require if the development proceeds. “We are requiring them to improve approximately 5,000 linear feet of Patterson Road,” Ferguson said, adding the upgrade will include 11‑foot travel lanes and 4‑foot shoulders. She also said the developer must construct a southbound left‑turn lane on Horton Highway with a minimum of 100 feet of storage to serve site traffic.

The concept plan, previously approved in September 2022 but expired after a final plat was not recorded, calls for 167 lots on 143.32 acres at a density staff described as about 1.17 units per acre in the current TCA‑4 zoning. Staff reported 69.35 acres would remain as open space and that the developer proposes to retain about 72% of existing tree canopy. Water service is proposed from the Nolensville‑College Grove Utility District; wastewater from a nontraditional treatment and disposal system that includes an emergency storage pond.

Public comments: flooding, septic and traffic concerns Several adjacent property owners said the plan threatens existing drainage and rural character. Dennis McCandless, who lives at 8213 Atwood Lane, told the commission he and his neighbors have already spent “close to $30,000 on French drains and underground gravel catchment basins” and asked whether third‑party runoff studies had been done. “Flooding is already a problem for those living in this vicinity, and the proposed 143‑acre, large dense housing project will only make matters worse,” McCandless said.

His wife, Edith McCandless, said the planned density — many lots of roughly 8,000–10,000 square feet — would “forever change the way of life in that rural setting and community.”

Brad Jennings, 8209 Atwood Lane, asked specifically about the wastewater storage pond shown on the plat and raised health and pest risks associated with wastewater facilities. He cited research on airborne pathogens and nuisance pests near treatment plants and asked whether the storage pond could leak or flood into nearby yards.

Garrett Pare, 8254 Patterson Road, described recent high water in local creeks and said culvert blockages already cause dangerous conditions near Horton Highway. Multiple speakers also questioned a 10‑foot asphalt trail shown at the north edge of the property, saying it appears to end at or near private property lines and could encourage unwanted foot traffic.

Applicant and engineer responses Developer Michael Natelli (4403 Arno Road, Franklin) and project engineers said the wastewater system design follows county standards. Natelli said the storage pond is an emergency‑only feature required by the county’s regulations and that “in our 25 years of doing this, we’ve never had to use the wastewater pond.” He also said the step system’s location is driven by where suitable soils occur: “We can’t import soils to put it where we want to.”

County staff and the county floodplain administrator said the developer must provide compensatory cut‑and‑fill calculations and demonstrate the final grading plan will not raise flood elevations for neighboring properties. The floodplain administrator told the commission the main drainage area feeding the site includes roughly 10 square miles in adjacent Rutherford County and about 16 square miles total, and that the county requires models to show no off‑site increase in flood elevations.

Commission deliberations and outcome Commission members asked staff and the applicant detailed questions about the compensatory storage, the construction of off‑site road improvements and whether traffic signal warrants would be met. Staff said off‑site easements for road widening had been acquired in the interim since the 2022 approval and that the county’s traffic review found a 90th‑percentile queue for the proposed Horton Highway left‑turn storage of about one vehicle at peak hour; the commission’s conditions require a minimum of 100 feet of storage, a conservative design length equivalent to roughly four vehicle lengths.

After discussion the commission voted to grant the requested floodplain variance and to approve the concept plan with the standard and site‑specific conditions noted by staff. The motion passed by voice vote; details of individual commissioners’ votes were not read into the record.

What remains: next steps and outstanding details The approval is for concept‑plan stage only. Before the developer may record any residential final plat the applicant must provide final engineering that (1) demonstrates compensatory floodplain storage and no increase in off‑site flood elevation, (2) completes the required off‑site road improvements, and (3) completes the greenway segment where it is located on the plan. The final location, buffers and landscaping for the wastewater storage pond will be determined during preliminary/final plat and construction plan review; staff noted the plan meets county setback standards including a 100‑foot buffer from development boundaries and 300‑foot buffer from drinking water wells.

Resources referenced at the hearing included Williamson County subdivision regulations (including a cited variance request to Section 3.04(d)), the Triune area master plan and state (TDOT) standards for turn‑lane storage and signal warrants.

Residents may return in subsequent hearings when the applicant files preliminary and final plats for sections of the development.