Story County adopts 2025 Carson River floodplain management plan update

Ed James, general manager of the Carson Water Subconservancy District, presented the Carson River floodplain management plan 2025 update during the July 1 meeting and asked commissioners to readopt the plan as county guidance.

James described the plan's purpose as reducing flood risk across the Carson watershed, outlining eight mitigation strategy areas and 49 suggested actions. He traced the plan's history to post-1997 flood regional coordination, reviewed earlier plan updates (2008, 2013, 2018) and said the 2025 update broadened emphasis on stormwater and alluvial-fan flooding as development patterns change.

James stressed the plan is a nonregulatory guidance document counties can incorporate into local planning, and he highlighted goals such as protecting natural river functions, improving mapping and data, reducing infrastructure impacts and promoting outreach. He said planning and maintaining open floodplains and alluvial channels can reduce long-term damage costs.

After the presentation, Commissioner Mitchell made a motion to readopt the Carson River floodplain management plan with the 2025 update; the motion passed unanimously.

The plan update and presentation materials are intended to guide county planning and flood-awareness efforts; counties retain authority to adopt implementing measures within their planning and permitting processes.