Sunday, November 10, 2013

Wading For Geology

Sometimes its a bit of a challenge to time shoreline bluff visits with the tides and other projects. Wednesday I had a breakfast talk to give and then headed to couple of shore projects on the Olympic Peninsula side of the Salish Sea. The second shore site was a little short on beach sediment.

The lack of beach material was the result of a couple factors. First, the high eroding bluffs at this shore reach are predominantly clays which are readily transported off. The lag of cobbles is not enough to build a beach. Secondly, a reach of low bank has been heavily armored with rock bulk heads for many years cutting off a significant sediment source. Low banks are often overlooked as beach sediment sources, but they do erode and do supply sediment. Indeed a low eroding shoreline bank will recede much faster than a high steep bluff simply because the volume of erosion to cause recession of the shore is so much less.

Combine a sediment starved shore reach and throw in the landslides with trees and brush there is nothing more to it - time to get wet.

All in all a good work out with the added resistance to walking and weight of wet pants and boots. And really not so bad this early in the fall as the water is still not too cold.

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