Talk about erosion!

[florida girl]

There's a old 1700 map of the Florida panhandle going around the internet, and I was curious to see how it compared with a current map. Did a little work on Photoshop, and this is what I came up with. Probably not completely accurate, but a general idea. Soil erosion has been devastating through the years, much less the past 300 years! From the old map, I don't think the Choctawhatchee Bay existed back then. It is very shallow, and probably occurred filling a shallow area.

 

[sunspotbaby]

Well, maybe by the time my children are grown, our lot will be gulf-front.

That's cool....love seeing the way things used to be. Not to mention how wondrous and mighty this planet is...shifting sand and water.

 

[DuneAHH]

FG - I'm intrigued but not really sure what I'm looking at / how to read the map. Any way to include a "color" legend of the coastline then/now... and perhaps a couple more degrees of zoom for those of us with diminished eyesight? Thanks

 

[AndrewG]

The erosion was caused by humans through swimming. We're going to have to regulate swimming by taxing it to reduce global erosion. According to satellite imagery by 2100 we're expected to lose 90% of the Worlds land mass.

Insert pictures of [STRIKE]polar bears [/STRIKE] humans on rapidly eroding islands along the coast that are clinging to life while sunbathing

 

[florida girl]

Here's another attempt.

 

[BeachSiO2]

FG:

I am curious as to your methodology as the figure you produced doesn't match up with the scientific literature. Below is a link to a report produced by the FDEP in which they compared shoreline change rates over a variety of time periods. One of those periods was between 1872-1997/98 where they found shoreline change rates varied between -0.5 feet/year and +0.5 feet/year. This means the shoreline has fluctuated between 60 feet wider or narrower than it is now during that time period.

ftp://ftp.dep.state.fl.us/pub/water/beaches/HSSD/reports/walsre.pdf

Additionally, geologists have posited that the shoreline may have been about 50 miles south of it's current location at the end of the last ice age but that was over 14,000 years ago. In the last 8,000 years, sea level has slowed dramatically with sea level increasing from ?10 to ?3 m below present from 8000 cal B.P. to 4000 cal B.P. Here is a link to an abstract from 2008.

A new composite Holocene sea-level curve for the northern Gulf of Mexico ? GSA Special Papers

Generally speaking, experts believe that a one-foot rise in sea level in Florida will lead to a shoreline erosion loss of about 50-100 feet (per Walton, T.L. Jr. (2007). Projected sea level rise in Florida. Ocean Engineering. Doi:
10.1016/j.oceaneg.2007.02.003.)

Thus, we would expect that the three meter rise between 4,000 years ago and present would lead to shoreline erosion of somewhere between 500 and a 1000 feet, much less than your figure suggests. This number would also fall within the range of measurements when compared with the FDEP report.

 

[Kurt]

A fun photoshop idea. Good info sand man. No satellites in the old days meant maps weren't very accurate - rivers, inlets and bays in particular were way off, except for the northeast US where they were well traveled.

 

[BeachSiO2]

A fun photoshop idea. Good info sand man. No satellites in the old days meant maps weren't very accurate - rivers, inlets and bays in particular were way off, except for the northeast US where they were well traveled.

Did you know that the first major effort to map the southeast and gulf areas by the United States was led by A.D. Bache, Benjamin Franklin's grandson (or maybe great-grandson)? There were some small efforts to map the ports before the Civil War when the government knew that the South was planning to secede but the majority of the work was after the war.

By the way, I re-read my first response and my intent was only to inform, not be rude so please don't take it that way.

 

[scooterbug44]

FG, that was a cool idea, but that isn't erosion, it's an inaccurate map.

It's cool to look at really old maps and see what they thought some places looked like - and amazing how accurate well traveled places were.

 

[florida girl]

I'm sure that the old 1700 map is probably not accurate, but given the lack of data from that time period, it's still interesting. In the last 100 years, there has been quite a lot of erosion in certain places here. It's still shifting sand!