Study: North Mesa site can support 210–360 units but needs $14.7M in infrastructure upgrades, officials say

Los Alamos County and Los Alamos Public Schools presented a joint update on Feb. 26 on the North Mesa housing and transportation study, describing how the 30-acre, school-owned site could accommodate between roughly 210 and 360 housing units but would require significant water, sewer and transportation work before development could proceed.

The study team — Dan Osborne, Los Alamos County housing special project manager, and Steven Luhan of engineering firm Wilson & Company — said planners used prior concept plans, a 2024–25 feasibility analysis and transportation modeling to assess utility capacity, crash history and intersection performance. “We now have all of the information that we would need to get this out to the development community to see if we could solicit a partner,” Osborne said.

Why it matters: the site sits adjacent to Los Alamos Middle School and has been the subject of planning work since 2019. County and school officials said a development could supply workforce housing and provide long-term revenue to the school district if structured as a lease, but that would require coordinated land-use changes, engineering design and financing steps.

What the study shows: Wilson & Company analyzed 11 intersections on Diamond Drive and the surrounding corridor, using Institute of Transportation Engineers trip rates and a 2045 horizon. Officials reported that most intersections remain at level-of-service C or better under the projected growth scenario, but the Diamond Drive/North Road intersection could degrade from LOS D to LOS E in morning peak conditions with full build-out. “There were a total of 94 crashes reported during this period,” Luhan said about 2019–2023 crash data, noting two fatalities in the record.

On utilities, the engineering review identified two sewer "pipe drops" that convey flows from the mesa; one (pipe drop B) showed severe corrosion from CCTV inspection and was judged beyond rehabilitation. The consultant recommended full reconstruction, with horizontal directional drilling suggested to reduce exposure to elements; a planning-level estimate to replace that pipe was cited at approximately $1,350,000. Capacity modeling estimated existing average wastewater production at about 73,000 gallons per day (≈17% of the modeled pipe capacity) and projected peak demands under full-build scenarios that the presenters said remain below plant limits but would approach thresholds warranting investment (presenters flagged ~50% utilization as a policy trigger to consider upgrades).

Costs and funding: presenters offered planning-level cost estimates, emphasizing 20% contingencies and that amounts are preliminary. On-site development estimates were given as roughly $7.3 million for the North Mesa (Area A) concept and about $4.53 million for the adjacent Arbolada site (Area B), totaling about $11.88 million in on-site development. Combined with CIP/off-site infrastructure work (estimated at roughly $2.82 million with contingency), the total preliminary planning estimate presented was approximately $14.7 million.

Questions from councilors, board members and residents focused on the assumptions behind the 0.5% annual growth rate (the presenters said that was applied to the county population and is conservative for the town site), how many dwelling units currently exist on North Mesa, localized traffic impacts near Barranca Elementary and existing roundabout bottlenecks, and how a development would affect school capacity. Presenters said detailed, design-level traffic counts and signal warrant analyses would be required to identify corridor- or intersection-specific mitigations, and school officials noted the district has contemplated a five-acre site reservation and a potential sixth-grade wing reconfiguration to accommodate growth.

Public comment: multiple residents thanked staff for the study and raised concerns about evacuation routes, morning queuing, student pick-up/drop-off impacts and long timelines to implement roads and utilities. A former steering-committee chair urged the school district to lead any formal approval or solicitation process, noting past procurement steps and budget history.

Next steps: staff recommended the county, if the board and school district concur, prepare a solicitation for development partners (regional and national outreach was discussed) and further design work. No formal sale, lease or development agreement was voted on at the meeting; the session served as an informational work session and public comment forum.

The county and school board adjourned the joint work session without taking a binding development action; staff said next steps would include design-level engineering, potential amendments to the comprehensive plan and rezoning if pursued, and solicitation terms that could preserve district objectives for affordable or workforce housing.