Saturday, May 21, 2011
Small, sheltered beaches often seem much more complicated than big, high energy ones. High energy ocean beaches with abundant sediment are just a simple (hah!) balance of wave energy and sediment mobility - the math is hard, but the geology is straightforward, almost absent. But these protected systems are a messy combination of an inherited landscape, a complex geologic framework, a spatially variable wave environment, the role of mixed grain size, often sediment-limited beaches, and the persistence of past human modifications.
Port Hadlock is located at the south end of Port Townsend Bay - where northerly waves dominate and Tertiary bedrock makes one of its rare Puget Sound appearances. Hadlock Spit extends southward from the boat building school, approaching but missing rocky Skunk Island down near the old alcohol plant (as usual, click on the title of the post for the aerial/map view). The beach beneath the boat yard appears to have built seaward, maybe as a lingering result of more than a century of piers and moored ships (and maybe an abundance of sand from the huge fill up at Irondale?). But this sandy beach narrows rapidly just north, with the tide lines swinging landward as if at the end of a spit (starved by the updrift accretion?). But the gravelly beach continues south. The boat ramp is built below the current beach grade, so sandy gravel constantly accumulates and is removed and put in a pile that then gradually erodes. But despite this miniature bypass operation, the shoreline another hundred yards south is eroding, undermining the road out to the private property on the spit itself.
I have few answers, only ideas and questions. Someday I would love to get together with the regular readers of the blog (all 3 of them?) at the Ajax Cafe to figure this all out (funny hats are optional)!