Coastal Erosion and Archaeological Sites

By Jenna Tanner

My involvement in the coastal erosion project started in southern Monterey County during the 2012 Cabrillo College Archaeological Field School.  When we surveyed along the steep coastal bluff line of southern Monterey County, it was apparent that coastal erosion was in full effect.   While coastal erosion itself is a normal, natural process, what is abnormal is the rate that it is occurring at.  During field school, I visited six sites along this portion of coastline.    Two of these were very close to the cliff edge and both contained a large amount of artifacts and features (mostly flakes that have been struck off the original rock used to make various stone tools, some bifaces, and a few bed rock mortars) that would soon be lost in the ocean.   The field school survey is part of the Society of California Archaeology (SCA) Climate Change Project.   The project focuses on surveying the coastline for both previously recorded and un-recorded sites in preparation for the impending impacts of climate change.   The project is a non-invasive, intensive pedestrian land survey consisting of walking paralleling transects – this is a systematic way of walking the area to look for archaeological sites.

Climate change is a lasting and significant change in weather patterns over periods of time.   A number of things can cause it: plate tectonics and volcanic eruptions, solar radiation, oceanic processes, and even humans can influence a change.   It has a vast variety of effects on Earth such as the melting of ice caps, rising sea levels, and coastal erosion to name a few.  From an archaeological standpoint, rising sea levels have the potential to destroy archaeological sites found along coastlines around the world.

Months after the field school was over, I was informed that the SCA Climate Change survey project was continuing in Marin County in Point Reyes National Seashore in October.  A few friends from field school and I decided to volunteer.  We met up with Mike Newland, the president of the SCA, and went out to survey a portion of the Marin coastline.  The survey began after an annual data-sharing meeting.  While I was unable to attend the actual meeting, I heard that there were over a hundred volunteers that came forth after the meeting to donate their time.

As we walked along the shoreline, Mike instructed us to pay attention to the cliff area because sometimes artifacts are spotted sticking out of them.  This observation has stuck with me for some time now; this is what makes the destruction of archaeological sites due to coastal erosion real for me.  I knew it was actively happening, but to actually look for it made me want to look even harder for those artifacts that were about to be washed away to sea.  My crew spotted a few obsidian flakes along the shore where a site had been previously recorded.   We were able to use some of the skills we learned in field school to update the site record.  We walked transects to re-establish site boundaries, used a GPS to get the coordinates to map the site electronically and filled out the proper paperwork describing the area as it was that day.  I am unsure about how much damage has been made to the area since the site was originally recorded, but I did see evidence that climate change was definitely actively affecting it.  After a long day, I had to head home due to work the next day, but most of the volunteers camped overnight nearby to continue the survey the next day.

I volunteered my time again at Point Reyes during the last weekend in April, when another survey was planned for the SCA Climate Change project.  This time a new, smaller group of people came together.  The new group was students and professors from Foothill College and UC Santa Cruz.  We were very lucky to have been able to camp at a secluded area near Kule Loklo, which is a re-created village site of the Coast Miwok who were the traditional that lived within Point Reyes.  There were about seven crew chiefs chosen (some were even from my field school!) and the rest of us were paired off with them to make groups of four to five people.  I was lucky enough to get teamed up with all new people and was able to make a great connection with one of the members from Foothill College.

Shortly after pairing off into our crews, we made our way to our assigned area.  We lined up in our transect line and off we went.  We walked slowly through a large area hoping to find some artifacts, but our hopes were soon crushed due to the poor ground visibility caused by dense vegetation.  We must have hiked about five miles at this first site and climbed a 400-foot slope.  The next day, three groups, including mine, merged to take on a large portion Tomales Point.  The signs at the start of the trail indicated that it was a 9.5-mile hike, there and back, reaching a 300-foot elevation.  One of the crews we were with was out there the day before and pointed out an unnatural rock formation that stretched longitudinally across the land.  We continued our journey down the point, lined up strategically so we cover the entirety of the land in hopes of finding more important cultural constituents, but nothing turned up – that is until we went down to a beach area where there was a previously recorded site and found shell midden.  Shell midden is comprised of assorted dietary shellfish and midden soil and sometimes artifacts that indicate previous human activity.  After a long, exhausting day, this was exactly what we needed – we were all so excited! We soon wrapped it up at the beach to make our way back to camp to head home.

The archaeological record is non-renewable and can show us how the people before us may have occupied the area.  Once these artifacts are gone, we lose valuable information that could have potentially opened the doors to the past of the people that once inhabited the area.  It is said that thousands of sites will be wiped off along the coastline during the next century due to a number of social and environmental factors, such as urban development, sea level rise, and global warming.  We volunteer because we understand what we are about to lose and to better understand the effects of and future impacts of climate change on the preservation of archaeological records and I know I can’t wait to get back out there again to do my part.

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