Thursday, May 28, 2020

Low tide on Tongue Point

I wanted to try to visit Tongue Point during a low tide this spring.  This basalt outcrop (part of the Crescent Formation) is generally a pretty popular and heavily impacted tide-pooling area, but I figured that since the adjacent campground has been shut down, it might have reduced some of the pressure on the intertidal community.  I made the trip with McHenry and Theo as an alternative to the usual at-home schooling we are doing, and we ended up spending most of our time here.  This is a bit of what we were able to see in an hour or so of rooting around. 

Carnivorous Nucella sp. (Dog Whelk) and eggs

Adult Pisaster ochraceous, the only one we observed

Halosaccion grandiforme (Sea Sac!), a super widely distributed red algae

A rosette of Pollicipes polymerus (Goose barnacles)

Anthopleura xanthogrammica (Giant Green Sea Anenome)

Tectura scutum (most likely; Plate Limpet), grazing an encrusting coralline algae (maybe Lithothamnion sp.?)

A Mopalia sp. (probably muscosa; Hairy Chiton)

A pot of gold!  Egregia menziesii (Feather Boa kelp) and Hedophyllum sessile (I think; Sea Cabbage kelp)

Anthopleura sp., likely Anthopleura sola.  My field team does a lot of "feeding" of anemones on these trips, but this one came by this meal all on its own.  Cool to see.

Acanthodoris nanaimoensis, the Nanaimo dorid.  Our only nudi on this trip.  

Eudystilia sp., probably vancoverii.  A Pacific coast feather duster worm.  One of my favorites 

Haliclona sp. I think (This one doesn't appear to have a common name...but it needs one).  Super cool sponge
 
Diodora aspera (Keyhole Limpet).  This one was in a group of maybe six individuals.  Haven't seen a congregation like that before


Juvenile Henricia sp. (Mottled Henricia; probably sanguinolenta?)  I can't keep track of the Henricia's :)

Thursday, May 14, 2020

Diving into the Oligocene ocean

A few weeks back we headed out for a hike along the shoreline near the West Twin River, on a beautiful night just before Washington's stay at home order kicked in.  As we were poking along, we came upon some of the usual bivalve fossils that are quite common in the area:

but also ran into some quite nice examples of fossils of a type I'd seen before, but less frequently...and I'd never quite been able to figure out what I was looking at.  To me they look sort of kelpy:

But as I understand it kelp fossils are pretty rare.  Also, if you look closely, many of these fossils have a lot of internal structure going on, in a way that kelp don't:
So I reached out to Liz Nesbitt at the University of Washington, who I had the good fortune to meet doing some field work at Discovery Bay a few years ago.  Liz has to be the foremost expert on the paleontology of Washington's coast, and so I was very delighted that she replied to my email quickly, and not at all surprised that she could explain what I had seen.  

Turns out that these are teredolites (here is a nice example of some similar fossils from Wyoming) or fossilized wood that has been bored by clams of the genus Teredinidae, commonly known as shipworms.  

Liz Nesbitt is also an expert on the chronology of the strata that these fossils are associated with, and she places these in the Oligocene, a time in which what are now the Olympic Mountains were just emerging from the ocean fringing the North American continent.  Where I found these fossils was presumably a warm (the Oligocene was substantially warmer than today's world) fringing sea.  In fact, one of the oldest known whale fossils emerged from the rock near where we found these teredolites.  



Wednesday, May 6, 2020

Dive below the surface near the Elwha River delta



I am incredibly fortunate to be one of the few people that actually got to observe, with my own eyes, the incredible changes to the marine ecosystem that happened as a result of the Elwha dam removals.  Every year for 10 years I spent 30 to 40 hours underwater visiting the same sites, getting to know (and counting/measuring) their residents and their contours.  Of course we did what scientists do, and published our findings as a scientific paper.  However, some of the changes we observed are much more viscerally relatable when you can, well, see them.  So last year we put the finishing touches on a new website and interactive map that is designed to tell the story of the Elwha underwater.  In particular it features videos that we collected at all of our sites, that allow you to watch our sites change as we did, year after year.  Click on the map and enjoy!




Thursday, April 30, 2020

A blog about my new blog

Its been a while!  I'm not sure why really...other stuff going on I suppose.  This will be a short one...but I wanted to use this platform to announce the launch of a new blog, Washington Shorelines Now and Then.  This is a partnership blog, started with Rob Casey of Salmon Bay Paddle and Shanon Dell, in Sequim.  Both of these characters spend lots of time on the water, are excellent photographers and communicators, and share an interest with me in the history of Washington's shoreline.  Rob and I, in fact, have been talking about doing this project for years...so its immensely satisfying to see it come to something.

 

The idea is really simple.  We try to collect and replicate historic views of Washington's shoreline, in order to provide a visual summary for the how Washington's shorelines have changed through time...either due to natural or anthropogenic forces.  The key feature is a side-by-side comparison of the two photos - the historic and the modern:

Check out the post with this photo, and the photo credits, here.
And then we add just a bit of text wrapping.

Enjoy!



Monday, December 2, 2019

Storm impacts on the beach: 27 November 2019



I had a chance to poke around Ediz Hook and Port Angeles Harbor a bit around high tide on 27 November 2019, during a strong northeast wind that coincided with high tide.  Waves were breaking over the coastal defenses on Ediz Hook (video above shot from the Coho ferry), as well as on to the Olympic Discovery Trail:



and not surprisingly, led to a bit of damage along the trail:



Beaches exposed to the northeast were also impacted.  I just happened to collected a few beach profiles on the east side of the Elwha River delta the day before this storm, so went back out afterwards to re-occupy those transects, one collected about here:

 and another a bit further east here:

Both of these beach profiles definitely show the impact of that event on the beach.  In both cases the upper beach eroded landward by anywhere between a fraction of a meter (a few feet), and up to roughly 3 meters (~10 feet).  I don't typically have the opportunity to capture this kind of event-driven change, and in fact these sorts of quantitative characterizations of event-driven change on the shorelines of Puget Sound and the Strait of Juan de Fuca are pretty rare...so I'm glad the opportunity came up. 

The anatomy of this particular storm was interesting to me.  The tide itself wasn't particularly high.  The tide gauge in Port Angeles maxed out at about 0.3 m (~ 1 foot) above MHHW:

and there was no storm surge associated with this event.  In fact, the high tide was suppressed a little bit, probably by the outward flow of air in the Strait (since the air pressure was low-ish during the high tide).  A water level of 0.3 m (~1 foot) above MHHW is nothing - we typically hit 0.3 m above MHHW multiple times a year.  What really made this event tick was wind, and in particular the strong flow of air out of the Strait, that led to sustained winds measured in Port Angeles harbor of 20 to 25 knots from the northeast.  The wind kicked up waves with significant wave heights exceeding 1.5 meters at the NOAA buoy in the Strait of Juan de Fuca, which is big, but not huge, for the Strait in November.  And this is really where we get to what made this event so interesting...it was the direction of the wind and waves...from the northeast...directed straight into Port Angeles Harbor, and straight at the end of Ediz Hook and the east side of the Elwha.

The waves breaking over the rip-rap on Ediz Hook (in the video at the start at this post) also provide an important bit of context.  I know from my survey work out there that the crest of the rip-rap sits at an elevation of roughly 2.5 meters (~8 feet) to 3.0 meters (~9.5 feet)  above MHHW.  Since we know that the water level at the time, as measured at the tide gauge, was 0.3 meters (~1 foot), we also know that water was being pushed 7 feet or more above the water level at the time, up and over the crest of the rip-rap.  So wave-related process, like wave run-up and set-up, were really important in making this event exciting.  Furthermore, we can actually use the event to characterize the magnitudes of those processes during an extreme event...and those sorts of observations are also relatively rare in Puget Sound and the Salish Sea.

Monday, October 7, 2019

Elwha sand hits Ediz Hook (maybe)

Looking at Ediz Hook from the west, September 2013
When I present about Elwha I frequently get asked about if, and how much, Elwha River sediment has made it to Ediz Hook.  I've also addressed this question in a previous blog arguing at the time (summer of 2016) that I didn't see evidence for any Elwha influence on Ediz Hook.  This year, though, I started answering that question with a bit more confidence - I think it is likely that Elwha sediment has made it to Ediz Hook in quantities adequate to lead to measurable changes on the beach.  I'm going to lay out some preliminary evidence for an influence on the beach of Ediz Hook in this blog.

First off, what is the shoreline response that I'm looking for?  I've framed the expected response to dam removal on the shoreline along the Elwha littoral cell as the "X-hypothesis".  Essentially I am measuring two things - the location of the beach profile, and the grain size of the beach.  When the dams came down we expected to see something like this:
in which a previously coarse eroding beach becomes finer and starts to move seaward.  We definitely saw this pattern on the Elwha delta, and in fact just published a paper focused in particular on the beach profile position part of the story (the red line in the conceptual model above).

We also expect this response to move alongshore, driven by alongshore transport processes.  So, essentially, the profile response and grain size response should sort of propagate alongshore with time, something like:


One of the most interesting insights from that paper is that we took a crack at estimating the RATE that the dam removal response moved alongshore, at least on the Elwha River delta nearest to the river mouth...and came up with an estimate of 1 meter per day.  If we extrapolated that rate to Ediz Hook, which is 8.5 km from the Elwha River mouth, we wouldn't expect a response there for quite some time...around 2033.  The evidence I'm going to lay out below suggests the possibility that Ediz Hook is seeing a response now.  Other evidence suggests faster response rates than our paper came up with as well.  The Coastal Watershed Institute, for example, published this account of beach accretion east of the delta in 2014...suggesting early slugs of sediment propagating along that shoreline that may have influenced Ediz Hook in some way.

So what is the evidence on Ediz Hook?  I'm going to show summer annual beach profiles dating back to 2012, and oblique photos of the beach from three locations dating back to 2014, the first being the transect that I survey at the very base of Ediz Hook.  So here, the evidence that I see is in the beach profiles:
So what I think I see here is a fairly stable beach between 2012 and 2016, but then a period of accretion between 2016 and 2018.  Its not huge...the beach moved seaward by a handful of meters...but it is out of character for this beach at least based on the limited data we have.  The grain size story at this site isn't quite as compelling.  Here is an oblique from 2014:
and 2016:
and then 2017, in which if you focus on some of the rip rap material in the far field you can really see the beach accretion
and 2018 in which we seem to see a finer beach face:
and finally this year (2019), in which overall we continue to see a relatively finer shoreline:
So lets turn our attention a bit further east, and further out on Ediz Hook.  This site sits just past the mill, and just about a kilometer from the site above.  The story once you get to the mill and beyond is complicated, and the evidence isn't strong.  But it may be there.  Here are the profile data:
Erosion from 2012 to 2016, then a big bump seaward by the summer of 2017 associated with a cobble nourishment project (more on that below), erosion again between 2017 and 2019, but then, critically, a movement seaward between 2018 and 2019.  Lets look at the oblique photos, starting in 2014:
then 2016:
2017...this is the cobble nourishment:
2018...amazing how quickly that cobble is eroded from the site:
and 2019:
The story at this site is complicated by cobble nourishment, placed very 5 years or so under contract with the Army Corps of Engineers.  Ediz Hook was nourished in this way, and at this site, in 2011 and again in 2017.  However, one of the things that seems clear to me looking at these photos and profiles though is that the nourish material erodes very rapidly after it is placed, and the beach probably continues to erode until the next nourishment.  The summer of 2017 photo above, for example, is a very visual example of what this beach looks like just before nourishment - coarse and heavily eroded.  So the evidence that I see here for an Elwha influence is that between 2018 and 2019 the beach didn't erode...it grew, apparently (based on the photos), because of an influx of sand and gravel.  Scant, I know...but something.

The final site is right around the middle of Ediz Hook.  Here are the profile data:

Its hard to see in this profile view, and the MHHW time-series plot isn't really working here, but you can see the influence of the 2011 nourishment in this profile, and then erosion through 2018 (interesting that there is no obvious influence of the 2017 nourishment in this profile, though there might be in the grain size)...but then a little accretion between 2018 and 2019.  Here are the photos, starting with 2014:
then 2016:
2017:
2018:
and 2019:
So here the summer of 2017 stands out for how coarse the beach substrate was, perhaps reflecting alongshore transport of cobble that was placed near the mill in early 2017.  That nourishment, though, based on the profile data, didn't really add too much volume to the beach.  However, between 2018 and 2019, as at the last location, we see an increase in beach volume driven by sand and gravel (based on the photos).

So is there an Elwha influence on Ediz Hook?  I think so.  I think the profile and grain size data support it, and while its conceivable that there is another source of sediment at play here (bluff erosion for example), I don't think that the rate of erosion on the Elwha bluffs accounts for what we see in these profiles.  As always, looking forward to next year's survey data.


Wednesday, September 11, 2019

Beach dynamics make the West End Natural Resources News



The North Pacific Coast Marine Resources Committee publishes a great annual newsletter highlighting natural resources issues and projects in the "West End" of the Olympic Peninsula.  I was given the opportunity to write up a little summary of my year-long shoreline dynamics study that I pulled off with MRC funding (along with support from Olympic National Park and Peninsula College), which is available here in the July 2019 edition.  But I'm going to reproduce the article here...enjoy:

The Olympic Coast is an extraordinary place - one needs to only try to find a trailhead parking spot on a summer weekend to find visceral proof of that. People travel from around the world to visit.  Drill down further though, and focus only on the narrow boundary between the land and sea, and the shoreline of the Olympic Coast becomes even more extraordinary still.  Most people who visit the coast with this sort of focus tend to dwell on the diverse and colorful intertidal marine community of the rocky shorelines.  But, through the support of the North Pacific Coast MRC and my employer, Washington Sea Grant, I’ve had the opportunity to study the dynamics and behavior of Olympic Coast beaches for the last year, and will describe a bit of what I’ve found.

The broad sandy beach at Kalaloch, one of two study sites for this project.  Photo from April 2018
 My study focuses on two beaches – Rialto and Kalaloch – though it is likely that the lessons I’ve learned are the same up and down the stretch of the Olympic Coast from Pt. Grenville to the south to Cape Flattery in the north.  The beaches along this stretch of coast are alive and dynamic, molding themselves each day to the changing behavior of the unruly North Pacific Ocean, and the geologically-tortured lands of the western fringe of the Olympic Peninsula.  Sandwiched between these two restless bodies, Olympic Coast shorelines literally shape-shift in an effort to hold a line.
Map of the Olympic Coast, which I define as stretching from Cape Flattery to the north, and Point Grenville to the south.  My two study sites, Rialto and Kalaloch Beaches, are marked on the map.

Let me start first by describing what I do on the beach.  I use survey equipment to measure, with great accuracy, location and elevation on the beach.  Collected along transects that cut across the beach, the raw GPS data can be converted into what are called beach profiles.  The figure below is an example from a single transect at Rialto Beach.  You learn something from a profile from a single day – you can easily calculate, for example, the slope of the beach, the width of the beach, or the elevation of the berm at the top of the beach.  All are useful for understanding what sort of habitat a shoreline may provide. 

Three beach profiles, from three different days, collected at Rialto Beach, Olympic National Park.  Beach profiles represent a slice through the intertidal beach
But for me, the really interesting stories emerge by looking at these profiles over time, which is exactly what this project focused on.  I visited Rialto and Kalaloch every other month, developing a picture of the seasonal behavior of both beaches over the course of a year, and was able to calculate and plot a time-series of the position of the beach.  My take-away?  Both beaches are alive, never standing still.  Rialto over that time period moved almost 60 feet seaward between March 2018 and January 2019, and then promptly retreated 45 feet back in just the two months following January 2019.  Kalalaloch followed a similar pattern, except its back and forth movement, first landward and then seaward, exceeded 150 feet, and it ended the year with a final yo-yo back seaward of over 100 feet. 

Time-series of beach position at both Rialto and Kalaloch beaches from approximately Spring 2018 to Spring 2019.  Where the slope of the time-series line is positive the beach is accreting.  Where the slope is negative the beach is eroding.

What makes beaches dance this way?  If we imagine these beaches dancing to music, it is a complex composition.  Different factors like the range of tides, the source and supply of beach-building sediment, the presence or absence of large wood, and even the movement of groundwater certainly play a role in the behavior of beaches.  From a sediment stand-point, for example, both of these beaches are quite different; Kalaloch is a broad sandy beach along a relatively straight stretch of coast, while Rialto is a narrow mixed sand and gravel beach, positioned near a large river mouth.  If I had to guess, though, these beaches are mostly moving according to the seasonal tempo set by ocean waves.  At a basic level, beaches are controlled by the energy delivered to the shoreline by waves, which indeed does vary dramatically over a typical season on the Olympic Coast.

Surveying Rialto Beach during a winter storm, February 2018

I was also able to fit the beach profiles collected over the year into a larger study focused on long-term trends at both beaches; in essence I’m trying to determine if the beaches of the Olympic Coast are eroding over many years, accreting, or just staying put.  The reasons for doing this may not be obvious, but they are important.  Beaches often serve as barriers that protect human infrastructure from the astonishing energy of the ocean.  Indeed, both Kalaloch and Rialto serve this function for things that we’ve built behind them.  Erosion of beaches in and of itself is a natural process, but if that erosion compromises things that we value it becomes a hazard.  The outlook for damaging erosion of shorelines all over the globe isn’t great; a rising average sea level can prompt beach erosion, as can a change in the energy carried by waves across the ocean’s surface, and both are observed to be happening all over the world. 

Example summer profiles from Kalaloch Beach from 2014 and 2018, and a time-series of summer beach position (bottom panel), also from Kalaloch Beach.
Profiles collected every year in the summer, limited though they are to the last 5-6 years, start to paint a picture of a possible long-term erosion trend at both beaches.  It is difficult to conclude too much from the erosion trends that are emerging from my data…it is simply too short of a record to evince a great deal of confidence.  But perhaps these data are a reminder that we live in a time of change, and these beaches that we enjoy may be increasingly stressed by changes in the North Pacific Ocean.  We, as a society, may have some hard decisions to make regarding how to respond to that in the future.