New federal flood plain maps would shrink the flood hazard zones in Cannon Beach, Gearhart and Seaside and lower the estimated flood elevation level at a key levee in Warrenton.
Property owners will have a chance to see the impact of the Federal Emergency Management Agency’s draft flood plain maps on Clatsop County communities at an open house next week.
The event — scheduled for 6 p.m. Monday at the Seaside Civic and Convention Center — will focus on FEMA’s latest revisions to flood maps in Gearhart, Seaside, Cannon Beach, Clatsop County and Warrenton Levee System No. 1.
The product of a multiyear countywide study, the maps — plotted with Lidar, a surveying technology that uses laser — will help residents and officials determine flood hazards in certain areas. When adopted, the maps will influence development, flood insurance rates and land use decisions on the North Coast for years to come.
“There were generally decreases in the flood hazard zones, even though elevations were about the same or may have increased in some locations,” said David Ratté, regional engineer with FEMA Region X, who will be presenting at the open house along with other experts.
Gearhart will see a roughly 8 percent reduction in the mapped 100-year flood plain, where the flood risk in any given year is 1 in 100, according to statistics from the Oregon Department of Geology and Mineral Industries. Seaside’s decrease is less than 8 percent. Meanwhile, Cannon Beach will see an overall decrease of about 27 percent.
In addition, FEMA has lowered the estimated flood elevation level of Warrenton Levee System No. 1. Recently, the agency provisionally deemed the levees large enough to protect properties behind it, a decision that Collin Stelzig, a city engineer, called a “huge win for the city of Warrenton.”
The county said it has mailed letters and draft maps to people in unincorporated areas who will see some of their land added to the flood hazard area.
These preliminary maps are separate from the flood plain maps under dispute by the cities of Astoria and Warrenton, Clatsop County, Port of Astoria and Diking District No. 9.
The five parties are currently splitting the cost of an outside analysis and technical review of FEMA’s draft maps, which they believe overstate the flood risk and would lock locals into paying thousands of extra dollars in flood insurance every year. The results of the review may affect the provisional accreditation status of Warrenton Levee System No. 1.
After the open house, a 90-day appeal period will soon begin, most likely in late September or early October, Ratté said. From there, the time frame for adopting the maps will depend on how many appeals and comments are submitted.
“If there are significant comments we need to address, or an appeal, that could add some time to our processing,” Ratté said. Once that stage is completed, FEMA will issue a letter of final determination to the communities, which will happen early next year at the earliest.
From there, communities will have six months to update their flood plain management ordinances. The maps will then go into effect.
Ratté encourages locals to bring their comments and concerns to the open house so that they leave better educated about the maps that will shape the lives and livelihoods of many coastal residents.
“Hopefully, what’s occurring is, as people learn about the changes, they’re reaching out to their cities and counties and asking questions, gathering information,” he said.
Click on “Map Layers” tab and select “Draft FEMA Revisions 2016.”