Over a decade of Elwha grain size images

 

A grain size image collected on 23 November 2011, from about here on the Elwha River delta, at an elevation of 2.5 m MLLW

Over the past few weeks I've been spending unseemly amounts of time sorting and curating approximately 13000 grain size images, like the one shown above, collected over the past 13 years on the Elwha River delta.  Once I can get them organized and named, the idea is that they will be run through a classification algorithm developed by Dan Buscombe, and we will have in our hands one of the most comprehensive beach grain size data-sets ever assembled.  The idea is to evaluate how grain size on the beach changed before, during and after dam removal dumped thousands of tonnes of dam-trapped sediment at the river mouth.  We've published the papers that describe the topographic change associated with that sediment, and we know that beach substrates fundamentally changed because of dam removal.  As an example, the grain size photo collected at the site of the photo at top just last month (10 years on), looks like this:

Grain size image collected on 4 November 2021, from about here on the Elwha River delta, at an elevation of 2.5 m MLLW

But what we haven't yet done, outside of an early and middling effort in this paper, is quantified the grain sizes from the photos (which you can do using a variety of digital grain size techniques), and really analyzed the data quantitatively through time.  Doing so will allow us to see new patterns, and hopefully connect the grain size changes to topographic change, river sediment delivery, and possibly oceanographic processes (i.e. waves and tides).  

13,000 images...that is insane to think about, and represents a LOT of my time over the past 13 years.  What does that look like?  Mapping the photos doesn't really do it justice, as they are collected on transects...so they sort of stack on top of each through time...but there is a go:

Recent aerial image of the Elwha River delta, overlaid with locations of photos collected during ~50 grain size surveys over 10 years.  Each color represents a different day.