On July 17, the Portland City Council adopted changes to the City’s floodplain development regulations, effective July 31, adopting Pre-Implementation Compliance Measures (PICMs) established by the Federal Emergency Management Agency (FEMA). The PICMs are interim measures required by FEMA to bring the National Flood Insurance Program (NFIP) in Oregon into compliance with the Endangered Species Act (ESA).
Highlights of changes to City’s floodplain development code
The main changes to Portland City Code Chapter 24.50, Flood Hazard Areas, focus on:
- Requiring plans for new development projects located in floodplains (flood hazard areas) to compensate for the loss of flood storage volume, through the excavation of soil or rock or the removal of permanent structures that displace floodwater, or both
- Ensuring requirements for stormwater management are met as outlined in the City of Portland Stormwater Management Manual
- Providing for tree replacement within the special flood hazard area
These changes follow actions taken by the Portland City Council in October 2023 to better align the City’s floodplain development code with the State of Oregon’s Model Flood Hazard Ordinance and to increase flood storage compensation requirements, coupled with Zoning Code changes enhancing environmental requirements, for certain flood hazard areas.
Overview of Pre-Implementation Compliance Measures
As a result of a Biological Opinion issued to FEMA by the National Marine Fisheries Service in 2016, changes to the NFIP in Oregon are required to demonstrate how development within the Special Flood Hazard Area (100-year flood hazard area) is compliant with the ESA. FEMA is requiring communities to adopt the PICMs to ensure compliance with the ESA, maintain their participation in the NFIP, and qualify for federally backed flood insurance.
The PICMs apply to areas of the FEMA 100-year flood hazard area where enhanced floodplain development requirements were not adopted by code changes approved by the city council in 2023. Those changes took effect in October 2024.
PICMs prevent the loss of natural floodplain function by regulating flood storage (fish habitat), stormwater management (water quality), and tree replacement requirements (vegetated habitat). In addition, the PICMs require planting of natural vegetation in an area equal to 5% of the new development area within 170 feet of the ordinary high water mark within the 100-year flood hazard area, unless the project qualifies as a functionally dependent use as defined in Chapter 24.50.
To prevent a net loss of flood storage, the PICM regulations require flood storage compensation for the placement of fill or structure below the 100-year flood elevation. They establish areas where the ratios of flood storage compensation volume are required to be at least one-and-a-half times or two times the volume of floodwater displaced due to the placement of fill or structure based on the distance of the development relative to the source of flooding.
To prevent a net loss in water quality, the PICM regulations apply the City’s Stormwater Management Manual to development within the 100-year flood hazard area.
To prevent a net loss of vegetative habitat, PICM regulations require tree replacement within the 100-year floodplain. Per these regulations, when removing trees six inches in diameter at breast height or larger, they must be replaced by trees planted in the 100-year flood hazard area at ratios that vary from at least three trees for every tree removed to at least six trees for every tree removed. These ratios are based on the size of the tree removed and the location relative to the source of flooding.
Where the Pre-Implementation Compliance Measures apply
Portland Maps provides information on individual properties where PICMs may apply. You can search for a property by address or click on a parcel on the map. Then click on the “Public Safety” tab and scroll to the “Hazard” section. There is an item labeled “FEMA PICM Requirements Area” that indicates whether the PICMs apply to that parcel and opens a map with different flood hazard layers.
What comes next
Permits submitted on or after July 31, 2025, are subject to the PICM regulations as described in Chapter 24.50. The PICMs are expected to remain in effect until the City adopts long-term compliance measures approved by FEMA. That effort is likely to be completed in mid to late 2027.
FEMA’s Draft Implementation Plan outlining long-term compliance is subject to the National Environmental Policy Act review process. FEMA recently announced that a Draft Environmental Impact Statement is expected to be released to the public in late summer 2025.
For more information
Property owners and developers seeking to build on properties that may be located in flood hazard areas are encouraged to schedule a free 15-minute appointment with a site development professional to discuss whether the updated requirements apply to their projects.
Additional information on FEMA’s efforts to bring Oregon’s NFIP into compliance with the ESA can be found here.