A Sad Day for Coastal Communities

Dr. Abby Sallenger passed away today. You may not know his name, but for those of us that live in coastal communities you certainly know his legacy...and we are better prepared as a result of it. Abby was (and still is) one of the country's premier investigators of coastal hazards and has done more than pretty much anyone to help us understand the importance of, and plan for the sometimes destructive interactions between the ocean and human society. As a scientist he was a role model...extraordinarily productive in scientific circles, vocal in the realm of policy and government, and willing and able to communicate his thinking to a wider audience. Abby's legacy for me, as a coastal scientist, is as an inspiration, a role model, and a reminder that we have much work to do to adapt to coastal hazards. That won't change. But he will be missed...

Data Love: A Visit by NOAA CO-OPs

NOAA's Mark Bailey describing how the Port Angeles water level measurement station works to students from my Fall quarter Intro to Oceanography course.

I love time-series of data. It hasn't always been like this, but there are some things that graduate school in the sciences will teach you...and one is how useful data time series are for helping us work out how the ocean works. And in my humble opinion, one of the champion data collecting organizations in the world is NOAA's Center for Oceanographic Products and Services, part of the National Ocean Service. These are the folks that collect water level data at hundreds of sites around the country. What makes that so special? They've been doing it well for well over a hundred years, and they are incredible at getting out high quality data from hundreds of sites out to the public, via their Tides and Currents website, only seconds after it is collected. So yes, if it isn't yet obvious, I have something of a science crush on CO-OPs.

I use data from water level station's on the Strait of Juan de Fuca almost every day, both for work and for play. Lately I've been having quite a bit of fun tracking the "non-tidal residuals" that are part of the winter season in this part of the world (see Jeff Adams' blog post on December's coincidence of a perigean high tide with a large non-tidal residual here).

Here, for example, is the standard plot for "preliminary" water level data from the Port Angeles water level station. There are three curves shown here. In blue is the predicted tide, or the water level that would be expected based on the large-scale, mostly astronomical, forces that "generate" tides. The red line is the actual measured water level, and then the green line...ohh, the green line how I love thee...is the difference between the two. And in this case that green line shows the transition from the very storm December that we had into a very cold and clear January...can you see it? That green line essentially shows the "non-tidal residual", or the component of the water level not predicted by the long-term average water level measured at this site over decades. In December we had consistent elevated water levels...in some case an extra two feet of water on top of already high tides. By January though, water levels were consistently LOWER than predicted. This is also called "storm surge", though in our case it isn't always associated with a "storm" proper. The thing that I love about this, is how closely the water level of the Strait of Juan de Fuca tracks the weather. Really, this is largely driven by pressure:

Here are measurements of pressure at sea level from the Port Angeles water level station. Low pressure equals, in general, stormier, while high pressure equals, in general in the winter, cold and clear. And, of course, that pressure also dramatically influences water level - higher pressure equals lower water levels, and vice versa.

I could go on...and I think I will. How about sea level trends? Much in the news these days, changing sea level is one of the threats facing coastal communities these days. And, because NOAA has been collecting water level data at some sites for well over 100 years, they are at the forefront of helping us to understand the relative risk of sea level rise around the country. Here, for example, is Seattle's relative sea level trend (relative because tide stations measure the level of the water against the land):

Seattle has a nice long water level record...over a hundred years at this point, and suggests a rising sea and something to think about. However, its useful to put things into context. Here is the same from Atlantic City, New Jersey:

here the rate of relative sea level rise over about the same time period is nearly twice as fast. This is probably due primarily to tectonic influences, possibly with a bit of help from "isostatic rebound" - more on that later. The point is - how lucky are we to have this sort of perspective on the places we live!

Okay, enough on that for now, and time to get into the real reason for this post. Prior to December 3 I had never actually seen an actual water level station, despite using the data produced from them all of the time. Well that changed, thanks to NOAA's Mark Bailey. Mark very kindly offered to come out to Port Angeles from headquarters in Seattle and provide a tour of the Port Angeles water level station for the students of my Intro to Oceanography class. He then stuck around to participate in a ocean science and technology career panel I put together for the class. The field trip was awesome! The water level station itself is non-descript, stuck in between boxes and crates on the very active Port of Port Angeles commercial pier. Really its just a small locker packed with electronics, cabled to a few instruments under the pier. But I was still impressed thinking about how useful and special these long data time-series really are (and I actually think a few of the students' were as well).

A student standing next to the "stilling well" that holds the instruments used to measure water level in Port Angeles.

Watch a coastal arch turn to beach sand

This is very cool...its obvious that this sort of erosion happens, but it is rarely caught on "film".

The Dock

A few weeks back I wrote this blog post about how difficult and anxiety-provoking trying to manage the potential risk associated with marine debris from the Tohoku tsunami has been. Well, that post, as well as some of my other work in this area, was focused on what we sort of consider the "garden variety" debris... the small, mostly untrackable, items that we worry will end up piled on beaches. Thus far there haven't really been any reports of huge amounts of debris finding its way to Washington shore's (I will be presenting more on this on Tuesday).

However, what has definitely turned out to be a real concern are invasive species associated with large items that were in the water at the time of the tsunami in Japan. While landfall of this particular class of large item is relatively rare, it has emerged as a key risk associated with the tsunami debris. Today I had the chance to assist a multi-agency team responding to a large section of dock that made landfall on a remote beach in Olympic National Park. The focus today, as it has been in the days since the dock turned up, was on assessing and neutralizing the threat of invasive species from Japan recruiting to local waters. For a variety of reasons it appears that the risk associated with this dock section is less than from the identical section that washed up in Oregon in June 2012...but a full effort is still being made to deal with those species that hitched a ride across the ocean. A few pictures from today:

today's crew at the tail end of the ~2 mile bushwhack to get down to the beach

finally on the beach...1.5 miles to go

on the final approach...the dock in the distance

a pano of the dock and adjacent shoreline and off-shore. Getting this thing off the beach is going to be a CHORE...the coastal zone is choked with reefs.

and finally, even though no distinguishing markings were found on this section, my take after checking out the video below is that it sure does look a whole lot like the section that washed up in Oregon, and the one that was spotted off of Hawaii...

Stories in the bluffs

To understand the coast, at least in this part of the world, is to understand the soft, easily eroded bluffs that back much of the shoreline. I had the chance to stop by Port williams in Sequim Bay the day before Christmas Eve and, as is often the case while wandering beaches around here, i found myself awestruck by the bluffs. Two things in particular struck me about this site...first, the incredibly complex stratigraphy that given the interpretation of a better observer would have told stories that, I suspect, would go back at least a few million years. Second, this was one of the few places that I've actually seen "erosion notches" recorded in the base of the bluff...these notches are produced by high water and wave action eating away at the base of the bluff and are one of the hypothesized mechanisms of bluff failure...but I haven't really seen them anywhere else. So here are a few pictures from the walk:

A view looking along the bluff back (south) towards the Port Williams boat ramp

Look at that stratigraphy! McHenry for scale.

Notches cut into the base of the bluff...likely a product of the persistent high water of winter combined with wave action generated by the east wind we've been seeing a a bit of lately.

Okay, someone help me with this one. In places where there were pockets of well-sorted sand in the bluffs there were these things...clearly organic, parchment consistency...what are they?

Here they are in situ

a view seaward towards Protection Island from the site.

The latest sand deluge hits the beach

While the sand that hit the beach of the Elwha delta this summer was exciting, things really slowed down during the fall, and by October most of it had transported away (for more on this check out our poster from AGU 2012). The autumn beach, at least at my monitoring sites, was almost as cobbly as it had been at the beginning of the year. But perhaps due to the higher flows over the past few weeks (noting, though, that there still hasn't been a flow over 10,000 cfs this winter) and perhaps due in some way to the release of sand and gravel from the lowering of the Glines Canyon dam, the spigot has turned back on. Starting in mid-November a new pulse of sand arrived at the river mouth, this one easily larger, in both area and volumetric extent, than the one associated with Aldwell that flowed to the mouth of the river between April and July of this year. More to come on this, but here are a few panoramic views of the shoreline taken on the east side of the river.

This first shot was taken yesterday, 10 December 2012 at 4:40pm, looking shoreward from a point on my Line 164, about 300 meters east of the river mouth. This is a site I monitor routinely. The photo was taken from just above Mean Lower Low Water.

There was very little sand retained at this site just two weeks ago.

This next shot was taken from atop the berm on the east shore of the river, just upstream from the mouth, at about 4:30 pm.

Its not stunningly obvious given the perspective, but if you look close in the far field of this pano, to the right, you can see the two long shore-perpindicular bars that have built out from the river mouth. Both extend ~100+ meters or more at this point. Both weren't there a month ago, at least anywhere near that length or extent.

And finally, here is a view of the bar built on the west side of the mouth...couldn't pano this one, but this shot was taken at sunset on 10 December, at a water level of about -0.25 m MLLW. I walked out about 100m on to this brand new sand bar and shot this view back towards Place Road

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The Vexing problem of "tsunami debris"

The debris associated with the March 2011 Tohoku tsunami in Japan continues to turn our attention to the dynamics of the great ocean to our west. It must be the first time in history that the world's attention has been riveted by reports of single debris items (like last month's report of Hawaii's first confirmed item from the tsunami) washing up around an ocean basin. Its striking to watch this issue unfold and in particular how the uncertain science and modelling of wind- and current-driven transport across the ocean interacts with the concerns of communities. Above all it seems that communities, already struggling to wrap their arms around a host of crises, are wrestling with how much attention to pay this issue. Some sense of certainty would be nice...that is clear.

But for all of the oceanographic advances of the last few decades, the dynamics of the ocean still hold some mystery. As a result, most of the planning at the community and state level that I've been exposed to has adopted a very reasonable adaptive response capacity...the response will depend on what happens and given the huge number of scenarios that one can imagine its hard to outline one specific response plan. This approach may start to look like the wrong one IF we suddenly get a massive influx of debris that strains our capacity to mobilize resources quickly and effectively...but in the face of uncertainty it is difficult to justify doing otherwise.

At this point, a year and a half after an estimated 1.5 million tons of debris floated away from the coast of Japan, the uncertainty remains as large as ever. Debris will make landfall - that is a certainty if only because it already has. But the real questions are, "How Much?", "Where?" and "Will it cause damage, especially immediate damage?". This last question is not at all clear - the ecological effects of debris accumulation on beaches are not well researched or established. This leads to the fourth question, "Will the debris be of a kind (i.e. toxic or large) or volume that will overwhelm the capacity of existing systems to deal with it?".

So where is it all? What prompted me to sit down and write this blog was Dr. Curtis Ebbesmeyer's recent statements in the Peninsula Daily News. Dr. Ebbesmeyer is a noted debris-tracker who tracks and analyzes interesting flotsam from around the world, and he correctly surmised the approximate timing of landfall of the first items from the Japanese tsunami to make landfall in Washington State. Last week Dr. Ebbesmeyer was quoted in the Peninsula Daily News as saying, "the first big field of tsunami debris is about 400 miles off the Washington coast and probably will land on beaches next month". Dr. Ebbesmeyer suggested that this statement was based on reports from off-shore fishermen combined with results from an OSCURS ocean model. The Pensinsula Daily News then added that "Ebbesmeyer speculated that the main debris field, which is 2,000 miles long and 500 miles wide, could include items as large as buses, cars and parts of houses."

I think that what struck me about this is what an ominous picture it painted - a field of debris 2000 miles long by 500 miles wide is only 400 miles off-shore and headed for our coast. The implication, at least to me, was that we should expect all of this to come ashore shortly. The image conjured is of an overwhelming volume of debris pasted to the beach up and down the coast. However, other oceanographic modelling efforts suggest that we may need to paint a more nuanced picture to help us prepare. More and more I've been turning to the SCUD model results produced by the International Pacific Research Center (IPRC) at the University of Hawaii, and particularly some of their more recent analyses that integrate what was learned from some of the early landfalls of wind-blown debris. The video at the top of this post, for example, is a model hindcast of debris dispersion for debris items with various exposure to the wind (the sizing is odd - just click on the part you see and a full screen version will pop up).

I could stare at this animation for a long time, but I found that looking at model results for the various levels of windage in isolation was interesting and instructive. For example, the animation below shows only the modeled trajectories of particles with lots of wind exposure, and is consistent with the first arrival of the lightest items (floats, etc.) that were found in November of 2011 on Washington's coast. This animation also suggests, however, that most of this high-windage material had already moved away from the Washington coast by last summer:

Looking at items with slightly less windage we find a similar pattern, but see that we could have expected that most of this material might have come ashore in the late spring or early summer of 2012...exactly when a small bump in the quantity of debris on Washington's beaches was anecdotally reported by a variety of observers.

The no-windage category suggests that items that are not directly exposed to wind are moving much more slowly across the Pacific and are likely still well away from the coast:

But it is the mid-range windage items that may be the next big thing on our coast, and it is this debris that I assume Dr. Ebbemeyer was referring to. The model results for the 2% windage category (what exactly this means isn't entirely clear to me - but I will assume that it is items that are somewhat less buoyant than a plastic float, and somewhat more buoyant than something that is floating at or below the water's surface) suggest that some portion of this material is still making its way westward, even as most of it has already entrained in the broad southward moving California Current and is heading southward on its way to eventual entrainment in the North Pacific Sub-tropical Convergence Zone:

It seems quite plausible to expect, based on these results, that some of this debris may come ashore...but again we are really interested in how much, and there is no way to really predict that with much certainty based on any of the data sources that I am familiar with. For starters, its not at all clear what fraction of the total debris out there falls within this windage category (and therefore might be lingering just off-shore). Its also not clear exactly how windage affects how efficiently debris can be moved on to the beach from locations just offshore - it is thought, for example, that local coastal winds may play a big role in driving material on shore. If debris windage is reduced, therefore, it may not be blown on to the beach as easily. Couple all of this uncertainty with inherent model uncertainty and its easy to throw your hands up and walk away from the whole thing. However, if we make the assumption that the model tells us SOMETHING, than what is suggested by these model results is a small fraction of the total debris in this category should be expected to near the Pacific Northwest coast, and that some fraction of it could make landfall on Washington beaches associated with our typical winter "downwelling" winds.

But what these model results do not seem to support is that the entire field will come ashore, much less in Washington. Will we see more "tsunami" debris items...almost certainly. Will we see individual large items (i.e. cars or buses)? I have no idea, but it seems like it is still within the realm of possibility. Will we see huge quantities of debris? Well, that depends in large part on your definition of "huge", but these IPRC models, as well an analysis that I published a few months back, both suggest that the lions share of this debris will still end up in the Sub-tropical convergence zone and not on Washington's shores.

So now its time, as winter ramps up and the southwest winds blow, to test all of these model results against observations. Since I am spending far too much time inside these days, please, PLEASE, let me know what you are seeing on the beach...