Monday, February 3, 2020

2/3/20 Report - Researching Long Term Coastal Erosion Trends and Various Related Thoughts.


Written by the TreasureGuide for the exclusive use of treaurebeachesreport.blogspot.com.

Scientia potentia est. 

Have you ever tried to stuff a bobcat into a soup can?  Me either, but that is how I feel when I try to create posts on some of my favorite topics.  They just won't fit.

When I don't do a post, it usually isn't because I can't think of anything I want to say.  It is usually because I can't bring it to a conclusion.  I can't get it boiled down to something that I am happy with.

There are topics that would easily make a book, but they won't fit in a post.  I've been trying to stuff one of those bobcats into a can for a couple days now.  Today I'll say just a few words on the topic and have to live with the fact that I left most of the good stuff out.

Knowledge is power.  Information is never isolated or useless.  You just have to discover the connections and applications.

Anymore it seems to me that treasure hunting is more about the information than objects.  Objects  aren't worth anything unless we know something about them.  Adding additional information, what we sometimes call provenance, adds to the value.

We always start with some level of information, even if it is very limited.  If we have any interest in the object at all, we ask more questions and seek answers.  For some the question is simple - what's it worth.  If we don't know much of anything about an object, we discard it and go onto something else - something that seems more intriguing or promising at the time.

I spend a lot of time in this blog keeping you informed about beach conditions.  One way I do that is by posting beach photos.  You know what they say about a picture being worth a thousand words.  Well a picture is worth a lot more if you know how to use it.  I could have said something similar about knowledge.  Knowledge is power, IF you know how to use it.

Instead of stuffed bobcat soup, today I'm just going to give you a little bit of goulash.  It all applies.

I found an article entitled, Air Photo Survey of Coastal Erosion. The author is Donald Stafford of Clemson University.  The article is published on the asprs.org web site. (ASPRS is the American Society for Photogrammetry and Remote Sensing (ASPRS).)  

Here an excerpt to get you started.

The unique characteristics of aerial photographs enable them to serve as an ideal means of collecting coastal erosion data and provide the aerial photographic approach with several advantages over other possible methods. Most importantly, aerial photographs permanently record the location of the beach at the time the aerial photographs were taken. Therefore, where the existing aerial photographic coverage extends over a sufficiently long period of time, studies of long-term coastal erosion trends can be undertaken by comparing the historical records of beach location contained in the aerial photographs. The photographic record is better than a map or chart because the photograph captures an almost infinite amount of ground detail in contrast with maps or charts which graphs to study coastal erosion is that the coastal areas of the United States have been photographed more frequently in the past 30 years than maps or charts have been compiled. The fact that the only field work required in making aerial photographs for pictorial purposes is the photographic mission has permitted frequent photographing of coastal areas without excessive cost. The fact that coastal areas have been photographed by different federal and state governmental agencies for several different purposes insures that aerial photographic coverages exist at frequent intervals. For example, the majority of the North Carolina coast has been photographed at intervals of about five years since 1949 and one 10-year interval between 1938 and 1949 exists for most of the coast. These multiple coverages allow at least four increments of change to be measured over the past 30 years. This is much better than can be accomplished by comparing maps and charts. The four increments of change measured over a period of 30 years cover a sufficiently long time span that long-term erosional trends can be determined and also insure that shorter term trends are likely to be discovered...

I've often wished that I would have periodically taken beach photos of specific spots from the same angle and viewpoint over the past thirty or so years.  If I had, I would be able to compare more precisely how the beaches have changed.  It turns out that there are sources that provide aerial photographs of most beaches over nearly the past hundred years.  That is detailed in the Stafford article.  Furthermore, the Stafford article discusses methods for identifying long term trends.

Here is another excerpt from the same article.

Regarding the data obtained along the North Carolina coast, it was found that considerable variability existed in the rates of change that have been experienced by different sections of coast and also during different time periods within a particular section of coast. The predominant process is erosion although accretion has occurred along some limited sections of the coast. The data also indicate that major storms play an important role in determining the rates of change in beach location.

Here is the link.

http://www.asprs.org/wp-content/uploads/pers/1971journal/jun/1971_jun_565-575.pdf

Those are just a few of the relevant points you can find in the article.  I don't have the space to explore or elaborate on many others.

I've written about long term and short term beach trends in this blog but have never put it altogether in a single place.  And the photos I post are not aerial photographs, but still they document to some extent the beach as it appears at different times.

If you look at one of the charts presented in the article, you'll notice that the long term trend shows a lot of erosion in one area and less erosion or even accretion to both sides of the eroding area.   In this blog I've previously discussed a lot that relates to that, but it would be too much to elaborate on now.

Perhaps most importantly the article lists sources of coastal aerial photographs that that cover extended periods of time.

The article is not recent so I suspect that even more useful aerial photography is now available.  Of course you still have to know how to interpret any changes you are seeing and how those changes relate to what you are looking for.

If you are one guy and metal detecting is just a part time hobby, I can understand why you haven't extensively employed this type of information, but if you are running a serious operation and making big investments, how in the world could you fail to thoroughly and systematically apply this type of information.

  1. Just got the tip of the tail in the can, but I'll put a lid on it now, even though there is much left to discuss. 

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If you ignore the slashes, yesterday's date was not only Super Bowl day, it was also a palindrome (reads the same backward and forward).

02/02/020

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Wouldn't it be better if our heroes were maybe scientists, engineers, or saints or people that do good things, rather than athletes and entertainers?  Its a crazy world.

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Source: MagicSeaWeed.com


Happy hunting,
TreasureGuide@comcast.net