Revised 100-Year Floodplain

The City has a floodplain overlay district which shows the areas the Federal Emergency Management Agency (FEMA) has identified as Special Flood Hazard. Those are the areas of land that have a one percent chance of being underwater in any year. This used to be known as the 100-year floodplain, but these floods can and do happen more often than once every hundred years. 

2019 map and code revisions

FEMA adopted a new flood map and required the City to make some minor code changes to stay in the National Flood Insurance Program. Being a part of this program enables owners of property within the floodplain to purchase affordable, federally subsidized flood insurance to insure against property damage during flooding events.

Summary of changes

• Adopt definitions to match FEMA definitions
• Clarify floodplain permits and reviews
• Adopt standards for drainage
• Clarify information applicants provide to the City
• Clarify development language in the floodway
• Adopt standards for manufactured home park
• Clarify how variances will be processed
• Clarify requirements for document retention
• Add a provision for notification of jurisdictional boundary changes

Gresham resources

• Check if your property is in the floodplain area

Gresham code has rules for development in the floodplain. Section 5.0100 Floodplain Overlay District regulates what is and is not allowed in the floodplain. If you want to do work in the floodplain (including digging, putting up small sheds and fences, or storing things), contact the Planner on Duty at 503-618-2780 or POD@GreshamOregon.gov. They will help ensure you follow the right steps. 

Contact us

For more information, contact floodplain administrator Jim Wheeler at 503-618-2881 or Jim.Wheeler@GreshamOregon.gov.