Friday, July 04, 2008
Seward - another case study in geological hazards. Most of the town is built on the alluvial fan at the base of Lowell Creek. That's good because at least some of the town is out of reach of tsunamis. That's bad because there is no reason to think that the alluvial fan stopped growing when they built the town. As matter of fact, in 1917, Lowell Creek washed out pretty much everything in a big swath along Jefferson Street. But in the 1930s, the clever engineers solved the problem. They put the creek in a tunnel and diverted it to one end of town. I looked at the hole the creek goes down. It's not very big. A debris slide or a gully washer with a few big rocks and trees, and the hole is plugged. The overflow will go right down Jefferson Street, just like in 1917... (okay, so I'm being alarmist, I'm sure those clever engineers anticipated this back in 1930 and planned accordingly).
In 1964, most of Seward's shoreline slid into Resurrection Bay - carrying rail yards, fuel tanks, trains, you name it. The tsunami cleaned up some of the mess. Subsidence repositioned the shoreline. Now there's a strange beach with old piles and debris sticking out of it. The shoreline is now a two mile long RV park and a nice public trail and lots of tsunami warning signs. The Kenai Peninsula is one big study in how quickly beaches can re-establish after mother nature cleans the slate.