Floodplains

We have had several significant recent floods, such as the Sandy River flood of January 2011. In 1996, a warm-weather system known as a "Pineapple Express" caused many rivers and creeks throughout the region to rise to 100-year flood levels.

Although the floods of 1996 represented a large-scale disaster, they are not unprecedented within the recent past. The Christmas Flood of 1964 caused $157 million in damage, and 20 Oregonians lost their lives. Records dating back to the mid-1800s show at least seven significant Willamette River floods in the county. Flooding from the Clackamas River has dramatically affected the county at least five times.

Learn more about flooding preparedness on Disaster Management's webpage.

Floodplain Management District

The county regulates development in the floodplain through its Floodplain Management District, which may include requirements to elevate or floodproof new construction, or retrofit and elevate older structures being renovated that do not meet current floodplain development standards. Floodplain regulations also apply to streambank stabilization projects, and most development in the floodplain requires a floodplain development permit. For application requirements or to find out if you’re in a designated floodplain, contact the Planning and Zoning Division at zoninginfo@clackamas.us or 503-742-4500. 

Floodplain Development Materials

Contacts