Towne Road tsunami evacuation

A common sense look at the safest route

There have been discussion threads about designation of the Towne Road Levee as a tsunami evacuation route, here’s an entire post about the topic.

The attached map shows the tsunami hazard zone (yellow) and designated evacuation routes (red arrows). In thick black, I have drawn in the approximate footprint of the newly constructed Towne Road Levee.

When this map was created, the “old” Towne Road was not designated as a tsunami evacuation route due to its narrow width, low elevation, and meandering path. The “new” Towne Road has not been designated as an evacuation route because closed roads are ineligible for such designation. During an October 19th budget meeting, County leaders expected a determination of Towne Road as an evacuation route to be made sometime early next year.

If you haven’t studied the map before, you’ll see that the entire community north of Anderson/Sequim-Dungeness Way is in the hazard zone. Westward escape, via Anderson, takes evacuees over the Dungeness River Bridge which could collapse during a seismic event or be compromised as the bridge is also in the tsunami hazard area. Evacuation eastward, along Sequim-Dungeness Way, closely parallels the tsunami hazard area for 1.3 miles (the entire length to Jamestown Road). Ideal tsunami evacuation routes are designed to move traffic away from an inundation event via every possible route, not parallel the perimeter of an approaching disaster.

The new levee is elevated and fortified "to withstand a 10,000-year flooding event – an amount of water equal to a 100-year flood in the Dungeness River, times four.” This is according to Randy Johnson, the Jamestown S’Klallam Tribe’s Habitat Manager. "It is also 5,000 feet long and beefy enough to withstand a river as big as the Mississippi", he said (see link to article).

Given the elevation and durability of the levee, I see why some residents speculate that Towne Road is the closest route to safety upon reaching the Anderson/Sequim-Dungeness Way intersection. For those concerned that the new levee could liquify during a seismic event, it’s important to remember that a tsunami-triggering earthquake could occur thousands of miles away but not be felt locally. Reopening this vital link to through, two-lane traffic may be a key factor in saving hundreds of lives.

https://nwtreatytribes.org/jamestown-sklallam-tribe-builds-new-levee-for-dungeness-river/