Colusa County, CA Environmental Rules: Flood Zones (2026)

10(B) defines the Flood Management (F-M) zone as land other than River Frontage areas which have been inundated by overflow floodwaters in the past, and which may reasonably be expected to be inundated by such floodwaters in the future, created to limit the use of areas subject to such inundation and flooding to protect lives and property from loss, damage, and destruction due to floodwaters. Appropriate uses are restricted to agricultural activities and resource management activities that do not impede flood flows. 5 acre in the adjoining River Frontage zone), 60-foot minimum parcel width, 100-foot minimum depth, a single dwelling unit per parcel, a 10-foot front, side and rear setback, and a 30-foot maximum structure height.

Footnote 3 to the table allows that maximum to be measured differently where flood protection requires it: if buildings are required to be elevated on stilts to protect against flood damage, maximum structure height is 25 feet above building floor elevation. 20(B)(b) further requires that development shall comply with Chapter 33 (Flood Damage Prevention), the county's separate floodplain ordinance, for water and sewer capacity, drainage, roadway access and fire protection before a project moves forward. 030(C)(3).