Monday, June 24, 2013

Beaches: Change is a Constant!

Beach 3-33 (FMR) Tide 0.5' Feb 2, 2012
I volunteer for FMSA (Farallones Marine Sanctuary Association) part of NOAA (National Oceanic Atmospheric Administration) in a program called Beach Watch (BW). I'm part of a team that surveys beaches in the Sanctuary area from Point Reyes to Ano Nuevo on a bi-monthly basis. My main beach is a series of 4 contiguous beaches that make up Fitzgerald Marine Reserve (FMR) in Moss Beach, California. Part of the duties of a BW volunteer is to count and identify all live bird species and marine mammals as well as any other animal found on the beach. Also all dead birds, marine mammals and other species are identified and documented. If there is an unusual find or observation the appropriate organizations are notified such as The California Academy of Sciences and the Marine Mammal Center (MMC). BW volunteers most importantly are on a vigilant look out for signs of oil from natural seeps as well as oil spills. This is critical in bringing action against the responsible parties.

Beach 3-33 (FMR) Tide 2.2' June 1, 2008

A common observation by BW volunteers is how their particular beach dramatically changes from month to month. Of course tide effects are an obvious force for change as beaches range from wide expanses at low tide to impassible sections during high tides. The deposition of sand is another factor that is constantly changing and sculpting the beaches. Other factors are rock slides, erosion and beach retreat. To illustrate this point I've chosen beach 3-33 in the FMR located about 1 mile south of The Moss Beach Distillery restaurant. The photo dated Feb 2, 2012 shows the south boundary of 3-33 looking north. The tide is fairly low and there are only small rocks present on this beach so traversing it is fairly easy. I should note that about 3/4 of a mile further north is Distillery Point. There are large boulders in this area and it is very difficult to maneuver thru this section. So to see 3-33 as above is a relief, knowing there is some easy going before the difficult Distillery Point area.
Beach 3-33, Tide 1.4' October 12, 2012

The photo dated June 1, 2008 shows the same beach after much sand has disappeared exposing many rocks and boulders. It's not an easy trek thru this kind of rock field as one has to be constantly aware of  ones footing. This makes the survey more difficult but it's not as bad as it can get. Adding algae to the mix makes this down right treacherous. Algae appears the time of year that sand is minimal July-October and the rocks and boulders are exposed.  Now  rocks are covered in slippery algae in some cases just coating the rocks and in others algae is several feet deep above the rocks.
Beach 3-33 Tide 2.2' Sept 14, 2011

As can be seen in the distance are some very high cliffs that are continuously retreating, which is a nice word for crumbling onto the beach. Often time in this area due to rocks, boulders, and the tide line, we are forced to traverse closer toward the cliff face. The cliffs are constantly sloughing and sometimes significant rock falls occur. Needless to say it's a hazardous area and we try not to dally there but pass by as quickly as possible. Did I mention this is a volunteer job?

Beach 3-33 Tide -1.3' May 17, 2010
Photo dated May 17, 2010 shows the beach at a low tide of -1.3 feet. Plenty of sand is apparent and off to the left is northern outer portions of Frenchman's Reef. To the right can be seen a recent rock-fall.

The final photo Feb 4, 2010 shows a very large recent slide that nearly blocked the whole beach. BW volunteers in the foreground are Jack Sutton and Melissa Dubose. Further in the back ground is BW volunteer Peter White.
Beach 3-33 Tide 0.8' Feb 4, 2010