Oct. 31, 2018 — During last week’s Florence City Council meeting, the council voted to amend chapters of the Florence City Code to update the tsunami code. Councilors approved the Beat the Wave Code Amendments with the approval of Ordinance No. 13, Series 2018, which amended Chapters 2 and 7 of Florence City Code Title 10, concerning tsunami and earthquake amendments.
Florence Associate Planner Glen Southerland gave the presentation during the public hearing.
“The intent of this code, first and foremost, is to reduce loss of life during a tsunami event; reduce the damage to public and private property; reduce social, emotional and economic obstructions; and increase the resilience of the community,” he said.
He talked about the timeline for this process, including the initiation of the amendments in August, the Planning Committee work session and evidentiary hearing and the sending of 1,200 notices to area residents about the possible amendments. The city received 200 responses through people coming to the counter, sending in emails or calling on the phone, along with 50 people who attended the Planning Commission hearing on Oct. 9.
“Hopefully all the fears were assuaged,” Southerland said.
According to the staff report, Florence was able to complete these changes thanks to grant funding from the 2015 National Oceanic and Atmospheric Administration (NOAA) Coastal Program, which assisted in the development and drafting of a comprehensive plan and development code provisions. These utilized scientific information from the Oregon Coastal Management Program Tsunami Land Use planning guide and Oregon Department of Geology and Mineral Industries (DOGAMI) modeling.
“The proposed local comprehensive plans and development codes are designed to significantly reduce risk and enhance community resilience to a Cascadia Subduction Zone or distant tsunami,” the report read.
Southerland said, “What this did was take Tsunami Inundation Maps and paved routes, such as trails, streets, sidewalks and the like, and overlay those with high ground safety destinations. … Taking the time for the arrival of the wave, and the distance at any given point to the safety destination at any given speed … at what speed would you have to travel from any given point to reach safety?”
The maps provide three rates that people tend to travel — a slow walk, at two feet per second; a regular walk at four feet per second; and a fast walk at six feet per second — and overlay those rates over maps of the area.
He added later that DOGAMI included the “slow walk” rate in Florence’s maps reluctantly.
“They had to make a separate calculation, a separate category, for Florence, which is the slow walk category,” Southerland said. “They didn’t even want to put that in there, but they did for Florence.”
He also said much of Florence “looks pretty good” for evacuation times.
“You would only have to walk at a slow walk pace to get to any point of safety from anywhere in Old Town,” Southerland said. “At two feet per second, you could make it from these furthest points in Old Town to the safety destinations. … It’s no more than four blocks to safety in any direction.”
Some areas will require the faster speed, such as northern subdivisions of Heceta Beach, but Southerland said communities could add trails, paths and even vertical evacuation structures to help resolve that.
“In seeing other communities’ results, ours are enviable,” he said. “Ours are very, very good compared to other cities like Seaside, where there are sections of the city — assuming that the bridges did not survive the earthquake — where it is hard to survive a tsunami event.”
He said one place in the area that could have difficulties during a tsunami hazard would be at the South Jetty of the Siuslaw River, since the road’s surface would likely be disrupted and car access would not be guaranteed.
“At the very tip of the jetty … it would be hard to survive that event without some sort of evacuation structure built towards the tip of the South Jetty,” Southerland said.
The Beat the Wave code also includes development of tsunami evacuation routes, with increased signage and walking paths; discouraging high-density and lodging development within the tsunami zone; and requiring, where feasible, tsunami resilient construction methods in infrastructure development.
The code’s other purpose is to “put less people in harm’s way, but also particular groups of people, where it would be difficult to evacuate a large number of them and get them a good distance away,” Southerland said. “This is a tool to get people to recognize that there is a risk of tsunamis and to consider evacuation route improvements, but not to prohibit any type of development.”
For more information and to view the area’s tsunami maps, visit www.ci.florence.or.us/planning and go to “Hazard Planning.”
DOGAMI also has Beat the Wave Maps and further information available for download at www.oregongeology.org/tsuclearinghouse/beatthewave.htm.
There is also information specifically for Dunes City and the areas outside Florence.