Community leaders in Clatsop County are taking stock of new draft flood risk maps presented by the Federal Emergency Management Agency.

Although the maps are still in the early stages, initial data indicates they could have significant impacts on Warrenton.

The maps are intended to give a snapshot in time of flood risks. FEMA began its Risk Mapping, Assessment and Planning program in 2009 and released its first map for Clatsop County under the program in 2010. The new draft maps provide updated modeling for areas between Hammond and Tongue Point, including new Special Flood Hazard Areas, or areas with a 1% annual chance of flooding in any given year.

Based on changes to the Special Flood Hazard Areas, FEMA anticipates adding an estimated net total of three structures to the flood plain in Astoria, four structures to the flood plain in the unincorporated county and 1,026 structures to the flood plain in Warrenton. Structures include homes, sheds and gazebos.

FEMA Region 10 engineer Dale Meck said one reason for the update is that risk naturally changes over time, especially along rivers. Another is that FEMA now has more accurate tools and data for geospatial modeling.

The draft maps are about a year out from preliminary release, and even further out from adoption — but presentations to community leaders provide an initial opportunity for feedback based on their knowledge of the area and history of natural hazard risks.

“We use it as a really good local gut check of the models,” Meck said. “Let’s get input, let’s make sure community leaders buy in before we gear up for a full public outreach.”

Warrenton looks to certify levees

If the draft maps are adopted, they could affect building codes and flood insurance requirements in newly designated Special Flood Hazard Areas. County and Astoria leaders have said that changes in their jurisdictions will likely be minimal — but Warrenton feels differently.

“The city is extremely concerned by the mapping that is projected out,” Warrenton City Manager Esther Moberg said. “We do understand it is not being adopted immediately, and it is … a chance for the community to look at it and possibly try to work with it.”

Moberg said flood insurance is a chief concern.

“One of our major concerns is suddenly now 1,000 homes are needing this flood insurance that they didn’t need before,” she said.

Changes won’t be implemented until the draft maps are finalized, and the maps themselves won’t change premium rates.

Part of the change is connected to the city’s levee system. For a levee to be included in FEMA’s flood risk map analysis, it must be accredited, and to be accredited, it must first undergo a rigorous certification process by the U.S. Army Corps of Engineers or another licensed engineering consultant.

Warrenton has been working toward levee certification for several years, but none of its levees are certified. As a result, the draft maps essentially show risk as if they weren’t there, mapping the still water elevation behind them instead.

Mapping a levee in a Special Flood Hazard Area doesn’t automatically mean it has a 1% chance of failing, though.

Shane Cline, levee safety program manager for the Army Corps’ Portland District, said the agency can evaluate levees as a precursor for FEMA accreditations, but they also do separate, routine checks every five years. Those inspections are intended to look at risk drivers to determine whether a levee should be eligible for rehabilitation. If a levee passes an inspection, it doesn’t necessarily mean it’s perfect — but it does mean there aren’t any major issues that would cause the Army Corps to doubt its ability to work as intended during a high-water event.

The last routine check of the Warrenton levee system was in 2018.

“The city was actively working on them, and they’ve since progressed to the point that we were comfortable with the trajectory that the levee system was on and so we felt that the system should be eligible for rehabilitation and inspection program funds in the future,” Cline said.

The city just wrapped up a multiyear interior drainage project as a first step toward certification. Completing the process, however, would likely take several more years and hundreds of thousands of dollars, with any improvements coming with an additional price tag, Moberg said. She anticipates some areas of the levees will need to be raised by at least a foot.

“Our levees have never failed. We’ve never had permeation through them. So we do believe they’re fairly steady,” Moberg said. “I mean, they were built by Army Corps of Engineers but they’re well over 80 years old, some of them. So do we think, ‘Yes, they need to be looked at?’ Absolutely. But we want the time to do that.”

Next steps

To Cline, partnerships play an important role in levee safety and certification.

“I view FEMA as a partner, I view the city of Warrenton very much as a partner,” he said. “You know, at the end of the day, we’re all on the same side of levee safety, and we want those levees to be not only as reliable and as good a shape as possible, but we want the community to understand that there is inherent risks living behind them, even if they’ve never had a problem before.”

Meck said FEMA recently met with staff from the city, county, Army Corps and several state agencies to talk more specifically about one of Warrenton’s previously accredited levees that is included on current maps. The conversation focused on opportunities to leverage the draft mapping results to support continued efforts toward certification.

Although the draft map might look like bad news for a city like Warrenton, he said the data can paint a clearer picture of impacts, making a more competitive case for grants aimed at mitigation.

There are also things the maps don’t show, though, like sea level rise, pluvial risks and projections for future flooding.

“I always tell people, ‘Look at the map as a tool,’” he said. “It is not the be-all and end-all. There’s a lot of other data sources and things to think about. This is a tool that you can use at the local level for resilience planning purposes.”

The initial presentation of the draft maps is the beginning of a conversation. Meck said FEMA will be incorporating feedback from the presentation as it prepares a preliminary release of the maps for next March. From there, they’ll work with community leaders to launch public outreach for local residents to see how the maps will affect their individual properties. Even after the appeal and adoption process, the maps can be updated through a letter of map change process.

The study is funded through the preliminary release phase, which means the timeline for next steps is still uncertain. As FEMA moves through the process, however, the overarching goal will be to help communities be prepared.

“We really want the community to focus on long-term resilience and mitigation planning, and not that kind of short-term, knee-jerk gut reaction to the map itself,” Meck said. “The map shows new risk that hasn’t been on the map before. That risk is real, and it’s there today. But we know it’s going to change. So the future steps, the future phases of this project after that preliminary release are to be determined.”