Jamestown

[CWSmith]

Skip, my wife and I have been reading about the rising water level at Jamestown. It seems it's being blamed on climate change, but I'm finding that a bit difficult to understand since it isn't as bad elsewhere yet.

Can you fill us in? What is happening there?

[Ian McColgin]

As with the different times and ranges of tides, topography makes for complexity.

[SKIP KILPATRICK]

Skip, my wife and I have been reading about the rising water level at Jamestown. It seems it's being blamed on climate change, but I'm finding that a bit difficult to understand since it isn't as bad elsewhere yet.

Can you fill us in? What is happening there?

Yes, the Chesapeake region is sinking. This has been known for a long time. I remember hearing about it while I was at Old Dominion University back in the early 1980's.

"Across Maryland and Virginia, the land is gradually sinking, a process that scientists call subsidence. These changes are caused by long-term geological shifts occurring across the Mid-Atlantic region. New research also suggests that human activities may be making the situation worse.Subsidence adds to what is known as relative sea level rise, a term that describes the combined effects of rising oceans and the sinking of land surfaces. "

"This subsidence results from natural processes thousands of years old whose effects resemble a game of teeter-totter.
During the last ice age, a massive glacier called the Laurentide Ice Sheet stretched from Canada down into Pennsylvania and New Jersey. The ice was so heavy that it pushed down the land underneath it. At the same time, the land just outside of the glacier's edge — what we now call the Mid-Atlantic coast — reacted like the other end of a playground seesaw: it was forced up into what's called a glacial forebulge.
Then, around 18,000 years ago, all that ice started to melt, and the seesaw started to flip back. "Now that the ice has been removed, there's a rebound" in the land to the north of the Mid-Atlantic, says John Boon, an oceanographer and professor emeritus at the Virginia Institute of Marine Science in Gloucester. Similarly, "the forebulge that we have here is ... going back down."


https://www.chesapeakequarterly.net/sealevel/main2/

[Peerie Maa]

It is also called Isostatic rebound.
It is happening to us as well, but is now slowing.


This is the world view

https://en.wikipedia.org/wiki/Post-glacial_rebound

[CWSmith]

Yes, the Chesapeake region is sinking.

This actually makes more sense to me. The other thing I've read about is heavy rains which means a rising river due to flow from upstream.

https://www.washingtonpost.com/histo...ds-endangered/

[SKIP KILPATRICK]

https://www.earthisland.org/journal/.../washing_away/

[Hugh MacD]

Interesting! I knew about the land being depressed beneath the glaciers and moving vertically due to rebound, but knew noting of the "glacial forebulge".