Local governments participate in this program by regulating development in floodplains. Cowlitz County's Floodplain Management Ordinance, based on federal guidelines, is contained in Chapter 16.25 of the Cowlitz County Code. By regulating where and how development occurs within floodplains, Cowlitz County provides for federally subsidized floodplain insurance which significantly reduces flood insurance rates for home owners.
Local governments have the authority to enforce the rules.
FEMA conducts studies of rivers and streams throughout the United States and publishes maps for insurance and regulatory purposes. However, this flood event, called the base flood, or, more commonly, the 100 year flood, has occurred in Cowlitz County twice in the last decade. Development can be allowed in 100-year floodplains provided it can meet certain construction standards. Development adjacent to, but above or beyond the 100-year flood are not subject to floodplain regulations. Floodplain certifications are issued to applicants who obtain development permits within the 100-year floodplain.