Prohibited Development


Special provisions apply to development that is proposed within the area referred to as the floodway and to any watercourse alterations within the Special Flood Hazard Area (SFHA). The floodway is the part of the floodplain that is necessary to discharge the base flood without the cumulative increase of the base flood’s elevation by more than one foot. It is specifically the areas designated as a floodway by FEMA on our locally adopted FIRM (Flood Insurance Rate Map). Generally speaking, these areas are the stream and river channels.
The floodway is usually an extremely hazardous area during flooding due to the velocity of flood waters and the debris these floodwaters carry. It is important for floodways to remain unobstructed in order to hold and convey floodwaters out of our community.

All encroachments, including fill, new construction, substantial improvements, and other development are prohibited unless certified by a registered professional engineer or architect with sufficient documentation demonstrating that encroachments shall not result in ANY increase in flood levels during the occurrence of the base flood.

Watercourse Alterations

Special requirements also apply to watercourse alterations. The watercourses that are regulated are those shown on the FIRM; they are usually labeled, such as Spring Creek. Alterations to watercourses must maintain the hydraulic capacity of the watercourse and must meet other requirements.

For More Information

Anyone interested in altering a watercourse or in purchasing, developing, or redeveloping property that is even partially within the floodway is encouraged to contact Public Works Engineering staff. 
The City of Eugene provides free information regarding flood hazards for specific sites within the community and can answer many of your flood-related questions. Public Works Engineering staff can assist with flood protection and mitigation design questions and with local flooding concerns. And we can make site visits.
Visit us:
    The Permit and Information Center
    99 West 10th Avenue
Contact us:
    Phone - 541-682-8400
    Email -
Offices are open to the public from 9:00 am to 4:00 pm, Monday through Friday. We strive to return all calls within one business day.