Flood Information


What is the one-hundred year flood? 

The “one-hundred year flood” gets a lot of attention, but its name is a bit misleading. It simply refers to a flood that has a one percent or greater chance of occurring within any given year. It is increasingly referred to as the Base Flood to avoid confusion. The area expected to be inundated by the Base Flood is known as the Special Flood Hazard Area (SFHA). Some sites located within the mapped SFHA may actually be affected by a smaller flooding event. It is even possible to be inundated by multiple ‘one-hundred year floods’ within the same year, although statistically unlikely. The Federal Emergency Management Agency (FEMA) estimates about 25 to 30 percent of floods occur outside of the SFHA.
Flood of 1964 in Eugene

Eugene - Flood of 1964
In 1968 Congress made FEMA responsible for the creation of flood maps nationwide. These maps are used to regulate development by local jurisdictions and to assess flood risk by property owners, insurance companies and lenders. Our currently adopted maps are based upon the maps FEMA original created. As part of this mapping effort FEMA performed detailed hydrological studies for the Willamette and Amazon rivers. Other flooding sources in our area used approximate methods to determine the floodplain boundary.

Stay Informed

On the left is a variety of links regarding specific flood topics including information on the Flood Insurance. Please be aware that there is significant recent information that is not covered due to recent Flood Reform.

Want to know if a property is in the SFHA?


For information on how to prepare for a flood visit the FEMA or CDC web site.

Know What the Different Weather Terms Mean
  • Flood Potential Outlook means heavy precipitation and/or snow melt could produce flooding
  • Flood Watch means conditions are favorable for flooding but the occurance is not certain
  • Flood Warning means longer, more gradual flooding beginning after 6 hours of excessive rainfall or during spring snow runoff.
  • Learn more from the National Weather Service
Flood Damage Prevention & Mitigation Video

Flood Information Assistance

The City of Eugene provides free information regarding the flood hazard for specific sites within our community and related issues at the Permit and Information Center. We can be reached by phone at 541-682-8400 or in person at 99 West 10 th Avenue. We are open to the public from 9:00 am to 5:00 pm, Monday through Friday. We strive to return all calls within one business day. 

 Flood Hazard Related Links

Flood Related Documents