Longmont Planning Commission backs reduced riparian setback for Alta Vita, forwards recommendation to City Council

The Longmont Planning and Zoning Commission on July 16 recommended City Council approve a reduced riparian setback for the Residences at Alta Vita senior-housing proposal, forwarding the request by a 5–2 vote with conditions.

The commission's recommendation narrows the city's standard 100-foot riparian setback (measured from the edge of riparian vegetation) to 50 feet for the project site at 2475 Bentway, and ties approval to the mitigation commitments the applicant presented, including native-tree plantings, pollinator plantings and low-impact stormwater features.

The recommendation matters because the requested change would allow portions of Alta Vita's proposed buildings and parking to be placed closer to Dry Creek No. 1 than the code now permits and because staff and outside reviewers flagged both environmental and floodplain issues that will be considered by City Council.

Zack Blazer, senior environmental sustainability planner for the City of Longmont, opened the commission's technical presentation and told commissioners this was the first riparian-setback variance to reach the commission: "This is the first time that one of these applications has actually made it this far into the process," he said, calling the presentation "lengthy" because the rule set and evaluation tool are new to staff and the commission.

Developer Don Macey of Macey Development Company said the family-owned parcel has been held for decades and that Alta Vita is seeking additional independent-living units to meet local demand. "Our independent living parcel right here is currently 100% occupied. We have 76 people on the waiting list," Macey told the commission.

Ecologist Heather Houston of Birch Ecology described the site as "low quality" habitat on the north side of the Dry Creek Greenway and proposed mitigation that, in her view, would improve conditions. Houston said the applicant's concept would add roughly 21 native trees and 154 shrubs in the area between the bike path and the creek, install rain gardens and bioswales for stormwater treatment, and remove Russian olive and other nonnative vegetation.

Staff and applicant used the city's Sustainability Evaluation System (SES) worksheet to score ecological and design categories. The applicant's SES score was 10 and staff's score was 5; the presentation noted agreement on 12 of 16 categories and differences on several categories including aquatic habitat, pollution-source reduction and heat-island effect.

Parks and Natural Resources staff supported a recommendation to council with conditions. "Parks and natural resources staff would recommend that the commission recommends the council to approve the variance, with the condition that they are able to ... meet the landscaping plans that they had for the improvements along the riparian corridor south of the bike path," Jim Crick, ecosystem manager for Parks and Natural Resources, told the commission.

City attorneys and staff cautioned commissioners the application is atypical because it is a variance that is being considered before a final site plan. Assistant City Attorney Jeremy Terrell told the commission that, in his view, the code allows the setback modification to be considered before a full site plan and that commitments made in the variance proceeding would be enforced during subsequent site-plan review.

Commission discussion focused on three recurring concerns: (1) whether the record included a sufficiently detailed species and habitat conservation plan under the land-use code, (2) the project's relationship to the 100-year floodplain, and (3) how narrow the area labeled "Track A" on applicant exhibits would be if the setback were reduced to the north edge of the bike path.

On the habitat-plan question, staff and the applicant said the documents provided (a 2023 general ecological resources survey, a 2024 riparian habitat assessment, and the SES worksheets) were sufficient for staff to complete its review; several commissioners said they wanted a more explicit species-and-habitat conservation plan that lists mitigation, monitoring and responsible parties. Chair Height read code language requiring the commission to consider findings from a detailed species and habitat conservation plan; multiple commissioners echoed the desire for clearer detail in the record.

Flood risk also featured prominently. Monica Bordellini, the city's floodplain administrator, told the commission Longmont regulates the 100-year floodplain and that, while there has been local debate about the 500-year floodplain, the city does not yet regulate to the 500-year standard. Commissioners pressed the applicant on whether proposed plantings on the creek's south side could widen or otherwise affect the floodplain and whether proposed structures would be kept out of the floodplain.

City stormwater staff said the concept includes rain-garden bottoms within detention basins and that the stormwater features will be required to meet the city's permanent stormwater control measures program and annual maintenance inspections. Tyler Dell, stormwater engineer for the City of Longmont, said the rain-garden design reduces risk of clogging and that the city requires maintenance inspections and annual reporting for permanent detention features.

After extended discussion, Commissioner Poland moved to recommend approval with a narrower, 50-foot setback (measured from the riparian edge) and to incorporate the landscaping and mitigation commitments the applicant presented in the SES and site exhibits; another commissioner seconded. The commission voted 5–2 in favor of the motion. Voting yes: Commissioner Lang, Commissioner Poland, Commissioner Saunders, Commissioner Wang and Commissioner Arment. Voting no: Commissioner Boone and Chair Height.

Formal action recorded by staff: motion to recommend City Council reduce the riparian setback for the Residences at Alta Vita project to 50 feet from the riparian edge, with conditions tying approval to the applicant's SES commitments, native plantings, invasive species removal and required stormwater design and maintenance. The commission's recommendation is advisory; City Council must make the final determination.

The matter will be scheduled for City Council consideration; staff said the applicant will be required to comply with city landscaping, floodplain, stormwater and site-plan standards at the next review stage.

Votes at a glance: Motion: "Recommend approval of PZRB-2025-06-B (Residences at Alta Vita riparian setback modification) with a 50-foot riparian setback and incorporation of applicant mitigation measures." Mover: Commissioner Poland. Second: not recorded in verbatim transcript (second acknowledged). Tally: Yes 5 (Lang, Poland, Saunders, Wang, Arment); No 2 (Boone, Chair Height). Outcome: recommendation to City Council approved 5–2. Legal threshold: majority — met.

What the commission asked for next: several commissioners asked staff and the applicant to ensure the City Council packet includes clear documentation of the species/habitat analysis, proposed planting palettes, stormwater details and a clear statement about floodplain avoidance of structures. Parks and Natural Resources asked that the council recommendation require successful establishment (including temporary irrigation or other measures) of woody vegetation south of the bike path.

The commission's recommendation does not permit structures in the 100-year floodplain; staff reiterated that buildings will still need to comply with floodplain rules and other development standards during site-plan review. The recommendation only reduces the riparian setback from 100 feet to 50 feet in the areas specified and binds the applicant to the mitigation commitments presented to the commission.

The full record, including the SES worksheets and the riparian assessment memos the commission reviewed, will be forwarded to City Council for its final action.