Commission grants floodplain variance to allow moved caretaker house to remain after engineering and neighbor support

Gallatin County commissioners approved a variance allowing a residential structure that had been moved onto a property east of Belgrade to remain within the regulated floodplain, subject to conditions and a follow‑up floodplain permit that must demonstrate compliance with elevation and encroachment limits.

The property, roughly 23.5 acres and bisected by Highlight Creek, had previously received a conditional use permit for a guest house/caretaker residence conditioned to remain outside the 100‑year floodplain. County floodplain staff later learned, during a septic permitting review, that a structure had been placed within the regulated floodplain without a required floodplain permit.

The applicant requested a variance from Section 7.2.9 of the county’s Floodplain Hazard Management Regulations, which allows the floodplain administrator to issue a permit only when no reasonable alternate location outside the regulated floodplain exists. Floodplain Administrator Sean O’Callaghan’s staff report noted potential buildable locations on both the west and east sides of the property outside the mapped floodplain, but the applicant and neighbors described practical obstacles to using those locations, including structural limits on moving the house across a private bridge and objections from neighbors that would cause “sprawl” and reduce rural clustering.

The applicant team provided a detailed engineering analysis. WWC Engineering’s Scott Dunkelberger said the finished floor elevation of the house is 3.8 feet above the 100‑year base flood elevation derived from a higher‑detail study used for permitting. The engineer presented an encroachment analysis showing the house foundation would increase a cross‑sectional base flood elevation by about 0.04 feet (roughly half an inch), well under the county’s 6‑inch allowance for permitted encroachments. The applicant’s engineer also committed to correct minor elevation details for the crawl space and the proposed garage floor in the floodplain permit application; the garage slab had not been poured at the time of the hearing.

Neighbors and some adjacent landowners spoke in favor of allowing the structure to remain where it is. Multiple neighbors said they had consented earlier to the structure being moved through their properties and that moving the house to alternative sites would reduce the clustered, rural layout envisioned by East Gallatin zoning and could trigger legal objections. Belgrade Planning staff and local residents generally described the structure as tucked into the trees and of limited visual impact.

County counsel explained the statutory authority and the commission’s discretion: without sufficient protest, the commission must consider whether the transfer meets the ordinance’s variance criteria, including whether the variance is the minimum necessary, whether failure to grant would cause exceptional hardship, and whether the variance would increase flood hazards or impede public safety. O’Callaghan recommended conditions that the applicant must meet before a floodplain permit is issued.

After deliberation the commission made affirmative findings on the required variance criteria, including that (1) allowing the structure to remain is the minimum relief necessary in this specific case, (2) denial would impose exceptional hardship on the elderly owners seeking a caretaker arrangement, and (3) with the engineered mitigations and the finished floor elevation the encroachment would not substantially increase flood heights or hazards. The commission approved the variance with conditions requiring the applicant to complete the floodplain permit and satisfy remaining technical items before occupancy.

The decision resolves the immediate enforcement issue but requires the applicant to complete a formal floodplain permitting process and satisfy any additional engineering refinements before occupancy or further construction.