Showing posts with label Hadrian's Wall. Show all posts
Showing posts with label Hadrian's Wall. Show all posts

Thursday, May 3, 2012

Fighting the Tide

The first half of this week found my daughter and me in southern New Jersey. One day we rode down to Ocean City, a lovely coastal resort town with a 2 1/2 mile boardwalk and bustling tourist industry.

Ocean City is actually a barrier island. An ephemeral sand mound that forms in front of mainlands, and shifts in and out of existence within a few centuries -- the blink of a geological eye. But, as at many barrier islands, Ocean City's charms quickly drew settlers, investments, and infrastructure. And they now want to stay put.

Cue the eternal fight between nature and man, with the boardwalk and beach as the front line. This town is no stranger to nature's wrath.
1962 Ash Wednesday storm
Source
1991 October "Perfect Storm"
Source
Over the past century engineers have dumped countless tons of imported sand onto her beaches, only to watch it wash away again. 22 times from 1952 to 1995 to a tune of $83 million (p.3 of the PDF), a $21 million effort in 2010, and $7 million more in 2012. Here is the latest effort -- an artificial dune system, staked off from foot traffic and heavily planted with dune grass and beach plums.
Taken by the author, May 1, 2012
The hope is that this manufactured dune will absorb storm surges and help maintain the beach -- so tourists will continue to come, frolic, and spend money. It may, or may not, for a while. But sea level is rising...
Remarkable NOAA Website on sea-level trends:
http://tidesandcurrents.noaa.gov/sltrends/sltrends.shtml
...and will continue to rise. It's a losing battle, getting more expensive as the waves strengthen. Eventually the annual funds will run dry. Then? Then comes a choice between a few options, all bad.

Which makes Ocean City just one of thousands of such spots around the world here in the 21st Century.

The archaeologist in me has seen this before. This is Ostia, for centuries imperial Rome's proud port town:
Source
But by the time St. Augustine visited it around AD 400, parts of the city were a swamp, and rubble had been dumped along the Tiber to hold it back. A few generations later the city was a ruin of hovels. It became so infested with swamp disease and malaria that later scavengers largely left it alone. In a way, a slow-death Pompeii, only rediscovered in the 20th Century.

And it's not just oceans and seas that change with time. Here's Hadrian's Wall in Cumbria, northern England,  running east to west (top to bottom), approaching what was once the eastern abutment to the Roman bridge over the River Irthing (bottom of picture).
Source
Except... where's the river? It's moved, about 100 feet west, over the past 1800 years. A raging flood or two changed its course, undercut the western abutment, and brought low this engineering marvel. One of many Hadrian's Wall bridges that met similar fates.

Bridges. Cities. Monuments to man's ingenuity. Laid to waste.

So what does all this have to do with the Flotsam Diaries? Everything. Today we build condos & business districts at the edge of shifting sands. We build whole cities in flood plains. We fill them with plastic. And then we're shocked when Mother Nature does what Mother Nature does.
New Orleans, 9th Ward, post-Hurricane Katrina 2005
Source
Back at Ocean City, nature is again going to do what she does. Sooner or later. Regardless of a man-made sand dune. And when she does, there will just be that much more persistent plastic wreckage in the ocean for my daughter's grandchildren to deal with. Because of the choices that we make today.

So maybe we could make better choices?

Friday, May 13, 2011

Throwing Stones Across a Pond

A quick touch-in to say I haven't left the blogosphere. I've just left Maine, for a week! The past week I've been rummaging through another era's flotsam. Doing archaeological excavation at Vindolanda, a Roman fort set just behind Hadrian's Wall in northern England. It's a brilliant place where, across 300+ years, a succession of forts was built one on top of the other. The result is that, today, in some places the archaeology goes down 18-20 feet!

Because of the burial of earlier forts, much "stuff" is preserved in anaerobic conditions. Without oxygen, nothing rots. (The same is true at modern landfills.) So Vindolanda has been a treasure trove of the kinds of wooden, leather, cloth, hair, bone, and uncorroded metal artifacts that just don't survive anywhere else. It's a brilliant site. (Check out the Vindolanda writing tablets and prepare to have your socks knocked off.)

But what's fascinating about Vindolanda is that it all comes back to trash. Most of what is brought up today was just Roman trash back in AD 100-400 or so. A delicate hair moss wig that had gotten threadbare and was left behind when one garrison shipped out. Half of a wooden bread-oven spatula that broke in use, and was tossed into a ditch when nobody was looking. A worn-out sandal tossed into another ditch by a lazy soldier.
Hobnailed sole of a Roman leather sandal
I dug up in summer 2005
On and on. Thousands of such items have been uncovered at Vindolanda so far. Litter is not a new thing.

Trash from the ancient world helps us tell something of the lives of forgotten societies. It's a gold mine. And it's a gold mine precisely because it is so rare. If the world was awash in Vindolandas, where most of their garbage didn't rot, didn't break down, didn't go away -- well, that wouldn't be very special. In fact, that would be today.
Plastic bag caught in a tree.
Vindolanda, May 11, 2011
By the way, the whole Tynedale region of Northumberland is bursting with history & natural beauty. Small villages, vast open rolling fields, industrial heritage, what-have-you. An amazing place to spend a week. Or as much time as you can. I'll be back again, looking for more ancient trash, some day.
Field of oilseed rape, Haydon Bridge, May 7, 2011
Caught ray of sunlight, un-Photoshopped