Ravalli County commissioners seek engineer sign-off, HOA maintenance agreement after major drainage work at 1 Horse Estates

Ravalli County commissioners on May 13 reviewed outstanding final‑plat requirements for the 1 Horse Estates subdivision phases 2–5 and directed staff to obtain clearer engineering documentation and a homeowners association maintenance commitment for a large drainage system installed by the developer.

The discussion centered on three outstanding items from a prior April 2 review and a preliminary‑plat decision: a mail collection box, a school bus shelter and lining an existing irrigation ditch required by the final‑plat application. Planning staff reported the mail collection boxes were installed and photographed on April 23; Florence School District said it did not require a bus shelter; and the developer installed a comprehensive subsurface drainage system instead of lining the irrigation ditch specified in the preliminary‑plat decision.

County staff said the preliminary‑plat decision required lining the irrigation ditch under the 2005 subdivision regulations (final‑plat application requirement No. 13, page 35) unless the Board of County Commissioners granted a written deviation. The developer submitted a response, including a letter from engineer Ron Uymera describing on‑site seepage observed during a 2006 walkthrough, subsequent approvals of engineering plans by the Ravalli County Environmental Health Department and the Montana Department of Environmental Quality in February 2009, and a resumption of work by a new developer in 2019.

Uymera’s letter, as read into the record, described the mitigation implemented: two 8‑inch perforated PVC drain pipes installed in trenches roughly 4 to 5 feet wide and about 10 to 15 feet deep, backfilled with crushed rock; the system runs along the western boundary and around the subdivision, with a total length the engineer described as about 3,500 linear feet and a total cost exceeding $500,000. The engineer wrote that the system has mitigated the groundwater intrusion.

Commissioners noted two concerns: (1) the preliminary decision called for lining the ditch and they needed a clear, professionally signed engineering statement that the installed drainage “unequivocally” satisfies or exceeds the ditch‑lining requirement; and (2) long‑term maintenance responsibility for the installed system. One commissioner cited the South Hills drainage litigation as a cautionary precedent and said the county needs assurance that taxpayers will not be held liable if the drainage system later fails.

County staff and the developer said the developer sought but did not obtain permission from a western neighbor to access and line the adjacent ditch; that neighbor declined access. Commissioners asked the developer to ask Uymera to amend or clarify his letter to state definitively that the installed system “exceeded” or “unequivocally exceeded” what lining the ditch would have produced, and to provide drawings or photos documenting what was installed. Commissioners also asked the developer to secure a homeowners association maintenance agreement that places long‑term repair responsibility with the HOA rather than the county.

Planning staff said they would amend the county’s letter to the applicant to remove the bus‑shelter and mailbox items (those have been addressed) and to request the engineer’s clarified statement and HOA maintenance documentation, and to return the package to the commissioners within about a month so the county’s file contains written approvals or the requested documentation.

No formal vote or final deviation approval was taken at the May 13 meeting; the board recorded the direction to obtain the engineer’s signed clarification, documentation (drawings or photos), and a homeowners‑association maintenance commitment before final plat approvals or formal deviations would be advanced.

Next steps: county staff will circulate an amended letter to the developer reflecting the commissioners’ requests; the developer will ask Uymera for a clarified, signed engineering statement and provide any available photos/drawings; and the developer was asked to secure HOA language accepting long‑term maintenance of the drainage system.