Sunday, February 24, 2008
State Route 106 winds along the southern shore of the hook of Hood Canal. At the western end, near Union, it probably is all built on fill. At the eastern end, it may follow an old terrace. In many places, it is held in place by a sacrete revetment that may date to the road's construction in the 1920s. (Sacrete is what you get when you stack bags of concrete and let the seawater soak in). The challenge is how to maintain the road and restore a more natural shoreline at the same time. The solution will depend on location, but may include localized nourishment, vegetation and bioengineering, and maybe some clever placement of large wood.
The first two pictures are taken on the road west of Union, where the beach skirts the edge of the Skokomish Delta. The beach (which is mainly under the highway now) consists of gravel supplied by the bluffs and moved along the shore by waves (the gravel was very much in evidence where it had been washed down gullies by the December 3rd storm). But the low tide terrace (under water in these pictures) is basically the low tide extension of the Skok delta, complete with tidal channels and fine grained sediment. Deltas and beaches also overlap at Warm Beach (Stilli), Marietta (Nooksack), and maybe once upon a time, south of Pioneer Square (Duwamish).