Freshwater Partners presents updated Yellowstone channel-migration map, urges planners to factor erosion risk into development

Jeanette, a representative of Montana Freshwater Partners, presented the updated 2024 Yellowstone Channel Migration Map to the Livingston City Land Use Board on Feb. 24, 2025, describing it as an update to the 2009 map that incorporates movement from the 2022 flood and a DNRC grant the county received in 2023.

The map shows the historic migration zone of the Yellowstone River, a calculated “erosion hazard” buffer (described as the average annual lateral migration rate multiplied by 100), avulsion-hazard areas where the river could cut new side channels, and a new geotechnical overlay that flags over-steepened bluffs. Jeanette said the map’s purpose is to give landowners and planners additional information about lateral river movement and erosion — distinct from floodplain mapping — so they can make informed decisions about property siting and bank stabilization measures. “Floodplain maps are regulatory. Channel migration maps are not,” Jeanette said during the presentation.

Why it matters: channel migration identifies where the river has historically moved and where it is likely to move in the future, highlighting erosion risks that…