Borough planning staff brief commissioners on land suitability analysis used in regional rezones

Fairbanks North Star Borough Community Planning staff presented the borough's Land Suitability Analysis Tool to the Planning Commission on Sept. 9, outlining how seven mapped criteria are combined to score land suitability for development and how recent updates changed several inputs.

Melissa Kellner, Community Planning Department staff and the presenter, said the tool "has been in our toolbox for over 10 years now" and is used to inform recommendations during regional planning and rezones. She told commissioners the analysis combines seven layers — including elevation, slope, solar aspect, flood hazard, wildfire susceptibility, soils and subsidence indicators — into a composite score that helps staff compare large areas of the borough.

Kellner described updates completed around 2020'21. The wildfire layer now incorporates fire-modeling based on historical fires rather than relying on vegetation alone. Scoring was reworked so all values are positive integers and neutral zero scores were removed; "anything with a 0 now is just excluded, it's not an option at all for development," she said. The subsidence input was broadened in 2021 from flagging areas with more than 1 foot of potential subsidence to including any potential subsidence, increasing sensitivity to ground instability risks.

The presenter emphasized that borough-wide permafrost maps are not available, so staff rely on soil-survey indicators as proxies: hydric soils and subsidence potential. "We conducted site visits to... do some spot checking and verification of the data," Kellner said, but she reiterated the tool is intended for regional decisions (for example, a roughly 600-acre rezone in the Goldstream area) and is not a substitute for parcel-scale site visits or new land-use policy.

Kellner used a Goldstream rezone as an example, showing publicly owned parcels of about 600 acres where the composite map rated western portions as less capable for development and eastern portions as more buildable. Staff recommended zoning that reflected those differences, such as larger minimum lot sizes in the less-capable west and smaller lots where more buildable area exists.

Commissioners questioned some methodological choices. One commissioner asked whether the seven criteria are effectively weighted equally and suggested giving greater weight to permafrost and flood risk; Kellner replied they "are not all weighted equally," and said hydric soils, subsidence and flood-zone inputs are weighted more heavily. The chair asked about update frequency for imagery and other data; Kellner said there is no set update schedule and updates occur when significant new data and funding are available. Commissioner Fisher asked whether the borough's lidar acquisition (about five to six years ago) contributes to the analysis; Kellner confirmed lidar informs elevation, slope and flood-zone inputs and helped prompt the update.

The presentation concluded with no formal action; commissioners received the briefing and asked clarifying questions. The work session adjourned at 8:47 p.m.