Mendon planners debate subdivision standards: hammerheads, water mains and vegetated swales vs. curb-and-gutter

MENDON — Mendon Planning & Zoning commissioners spent much of the meeting on detailed technical changes to the city’s subdivision ordinance, focusing on dead-end street designs, where developers must extend utilities and whether vegetated swales should replace curb-and-gutter in new subdivisions.

The commission did not adopt final language at the meeting but directed staff to refine the draft so it can return for future consideration.

Key outcomes of the discussion

- Cul-de-sacs vs. hammerheads: Public works and the fire district urged a preference for hammerhead (T-shaped) turnarounds rather than traditional cul-de-sacs. Kirk (public works) said past local cul-de-sacs created operational problems — water mains ended short of property, asphalt and sidewalk conflicts, and snowplow and fire access issues. "Kids tend to gather and play in cul-de-sacs," Kirk said, adding concerns about snow storage and plow maneuvering; the working preference is hammerheads with adapted lot setbacks for the two lots adjacent to the turnaround.

- Emergency-access width and lot impacts: Staff described a 120-foot emergency-access width consideration (discussed in the draft), and noted that accommodating a hammerhead can affect the frontage and setbacks of the last two lots on the dead-end. The commission discussed preserving usable lot area while ensuring required access and utility easements.

- Utility extension policy: The draft language under discussion would require developers to extend water mains and other utilities to the farthest boundary of the parcel being developed — generally to the end of roads in the submitted subdivision — so future adjoining development can connect without having to disrupt previously developed areas. Commissioners framed the requirement as applying to the original development parcel and its road termini, with plan reviewers (city staff) enforcing line extensions when plans are submitted.

- Swales (vegetated stormwater features) versus curb-and-gutter: Commissioners reviewed the tradeoffs between traditional curb-and-gutter and vegetated swales (called "swells" in the meeting). The town’s current right-of-way standard is 99 feet; standard road widths in new developments were discussed as 24 feet (where curb/gutter with a 36-foot road width would be wider). Staff and public works said swales can reduce point-source runoff and pollutant conveyance to single discharge points, but they also increase the easement area used for drainage and require maintenance standards. Kirk recommended consulting other towns that have switched to swales; he noted Wellsville uses similar approaches.

Technical numbers and examples raised in the meeting

- ROW and road widths: Mendon’s standard 99-foot right-of-way was discussed; road width options noted were 24 feet (conservative) vs. 36 feet with curb and gutter.

- Lot-size constraint without sewer: Staff said current minimum lot sizes without sewer cannot be smaller than about 5/8 acre (approx. 0.62 acres) because of on-site sewage and well constraints.

- Hydraulics and maintenance: Public works asked for a written cross-section and formal swale specifications (depth, rock/vegetation, curb edge details) to be prepared for the commission.

What happens next

Staff (including Eric and city public works) will refine ordinance language on hammerheads, clarify how the utility-extension requirement will be written (parcel boundary vs. end of road), and draft technical swale cross-sections and maintenance standards. The commission did not take a final vote; several members asked for model language and examples from neighboring towns before adopting changes.

Ending

The commission scheduled further review of the subdivision ordinance at a future meeting after staff redrafts the provisions and circulates example cross-sections and wording for review.