Divides

[hbelkins]

Someone posted a photo in another thread of the Mississippi-Missouri divide. That, and the fact that I crossed it Saturday and today, made me think about the Eastern Continental Divide.

Can anyone provide a link or a source for a good map that shows it, and the other major divides? I know that the DeLorme Atlas & Gazetteer shows the Tennessee Valley Divide in one of its state books.

I'm not sure where I crossed the ECD in either location. I traveled I-68 as far east as US 219 north, and I know the ECD used to be signed on I-68, along with a big, long-since-gone "Entering Chesapeake Bay Watershed" sign. Not sure where I crossed going east. I may have crossed on PA 31 between Somerset and Bedford. I came back on WV 90 between US 50 and US 219. WV 90 starts out paralleling the Potomac but I know that the Fairfax Stone and the headwaters of the Potomac are to the right of WV 90 and US 219.

As far as signage of water divides goes, Ohio has "Ohio River" and "Lake Erie" signs on I-75 to mark the divide.

[froggie]

Not aware of any good maps offhand.  That said, I have the data to make such a map in GIS if necessary.

[1995hoo]

Here is where I-68 crosses it: 39°40'58.1"N 79°02'15.7"W
https://goo.gl/maps/sLM13Pajq1x

That location is east of US-219.

My brother has some photos from the tunnel where the Great Allegheny Passage crosses the Divide–for obvious reasons, it's a major milestone for people biking from Pittsburgh to DC. But I don't have a map. The Wikipedia article has some links to various locations that might allow some level of reasonable guesswork, given that, for example, the Turnpike's Allegheny Mountain tunnel passes under the Divide. Based on that, you can reasonably surmise you're correct in your guess about PA-31, though the exact spot would be harder to determine (maybe if you use an online map's satellite view, you could trace the ridge from the Allegheny Tunnel to Route 31?).

Edited to add: Should be roughly around this location:
https://goo.gl/maps/V1AKxf7WCaB2

[davewiecking]

I had thought that the Appalachian Trail followed the Eastern Continental Divide, but that's not entirely the case. As Hoo notes, the ECD crosses I-68 at Green Lantern Road (about 5 miles east of the easternmost US-219 interchange); the brown sign was still in place in September, but no extra sign about the watershed. Wikipedia has incredibly low-resolution maps of the various hydrological divides in North America, and a nice table showing various points in different states-but probably not as detailed as what Froggie has.
If you click on Hoo's second link and switch into Street View, a few hundred yards west near the peak of the hill is a collection of blurred official-looking signs of various colors (on both sides of the road); the right most sign looks like it might include a map depicting a watershed. Or something else entirely...

[coldshoulder]

There used to be a sign on the Ohio Turnpike in Northeastern Ohio notating the divide between the watersheds of the Great Lakes (Lake Erie) and the Mississippi River (Ohio River and smaller tributaries).  The sign may still exist; I recall it being southeast of Cleveland, perhaps somewhere near Streetsboro (Exit 187).

[kphoger]

There used to be a sign on the Ohio Turnpike in Northeastern Ohio notating the divide between the watersheds of the Great Lakes (Lake Erie) and the Mississippi River (Ohio River and smaller tributaries).  The sign may still exist; I recall it being southeast of Cleveland, perhaps somewhere near Streetsboro (Exit 187).

The Portage service area is named after that divide.  Here is the westbound sign.

[J N Winkler]

Wikipedia has a map showing the main watershed divides (Mississippi, Laurentian, etc.).  After a certain point, it depends on how granular you want to get.  A few years ago, when I was seeking to confirm a theory that deer collision risk is highest at locations where a roadway crosses a watershed boundary, I looked up one for Kansas that had creek basins shown as county-sized regions.

[hbelkins]

Best I can tell, after finding a few maps online, the ECD in West Virginia follows county lines. I know it's signed at the Randolph/Pendleton line on US 33. So I would have crossed it at the Mineral/Tucker line on WV 90, which was at the top of a small rise but not as pronounced of a mountain peak as the US 33 crossing. It's not signed there.

The short Pendleton/Pocahontas line also appears to be the ECD, then it follows the state line south to Monroe County. A couple of sections of Monroe are east of the ECD. I remember an almost level crossing, that is marked on WV 3 west of its terminus at WV 311. And the isolated section of Monroe County that's served by CR 17 (accessible from the Pearisburg area and VA SR 635) is also on the east side of the ECD.

I never considered the divide between the Great Lakes and the Atlantic to be one separate from the ECD. I always just regarded the dividing line between draining into the Gulf of Mexico and the Atlantic to be one divide.

[GaryV]

I never considered the divide between the Great Lakes and the Atlantic to be one separate from the ECD. I always just regarded the dividing line between draining into the Gulf of Mexico and the Atlantic to be one divide.

So on this Wikipedia map https://en.wikipedia.org/wiki/Eastern_Continental_Divide#/media/File:NorthAmerica-WaterDivides.png you'd just eliminate the purple line east from New York to Nova Scotia.

[cpzilliacus]

The U.S. Geological Survey has a lot of data, among which are drainage divides.  I suppose that they can be downloaded and used with ESRI ArcGIS or other software, but there are also interactive capabilities. 

From looking, it appears that the most-distant water feature that feeds the Susquehanna River (and thus the Chesapeake Bay) is north of Cooperstown, N.Y.   It is a bog or wetland that drains to Cedar Swamp and then to Summit Lake, which feeds Hayden Creek which in turn  flows into the north end  of Otsego Lake. The south end of Otsego Lake at Cooperstown is where the Susquehanna River begins its long journey to the Susquehanna Flats near the top of the Chesapeake Bay.  According to the watershed boundaries, a small part of southern Herkimer County, N.Y. (normally considered an "Adirondack" county) is in the watershed of the Chesapeake Bay, but there are no discernible streams that I can identify.

You can  look the interactive map here: https://viewer.nationalmap.gov/advanced-viewer/

[Bruce]

The major divides of the North American continent:

[Beltway]

I'm not sure where I crossed the ECD in either location. I traveled I-68 as far east as US 219 north, and I know the ECD used to be signed on I-68, along with a big, long-since-gone "Entering Chesapeake Bay Watershed" sign. Not sure where I crossed going east. I may have crossed on PA 31 between Somerset and Bedford. I came back on WV 90 between US 50 and US 219. WV 90 starts out paralleling the Potomac but I know that the Fairfax Stone and the headwaters of the Potomac are to the right of WV 90 and US 219.

VA I-95 NB -- https://tinyurl.com/ycuks9wo

[Sam]

According to the watershed boundaries, a small part of southern Herkimer County, N.Y. (normally considered an "Adirondack" county) is in the watershed of the Chesapeake Bay, but there are no discernible streams that I can identify.

http://www.oneonta.edu/academics/biofld/documents/OLMP.pdf shows a couple of small streams flowing south out of Herkimer County into a swamp that drains into Shadow Brook. https://goo.gl/maps/ZAN81U3FxdC2

[MNHighwayMan]

Someone posted a photo in another thread of the Mississippi-Missouri divide.

In case anyone is reading the thread and wondering.

[Ga293]

Here's a site showing the ECD in Georgia in more detail. Interesting how it runs through downtown Atlanta.

[NWI_Irish96]

Someone posted a photo in another thread of the Mississippi-Missouri divide. That, and the fact that I crossed it Saturday and today, made me think about the Eastern Continental Divide.

Can anyone provide a link or a source for a good map that shows it, and the other major divides? I know that the DeLorme Atlas & Gazetteer shows the Tennessee Valley Divide in one of its state books.

I'm not sure where I crossed the ECD in either location. I traveled I-68 as far east as US 219 north, and I know the ECD used to be signed on I-68, along with a big, long-since-gone "Entering Chesapeake Bay Watershed" sign. Not sure where I crossed going east. I may have crossed on PA 31 between Somerset and Bedford. I came back on WV 90 between US 50 and US 219. WV 90 starts out paralleling the Potomac but I know that the Fairfax Stone and the headwaters of the Potomac are to the right of WV 90 and US 219.

As far as signage of water divides goes, Ohio has "Ohio River" and "Lake Erie" signs on I-75 to mark the divide.

The divide between Great Lakes and Mississippi watersheds is signed on US 20/31 near South Bend as the "North-South Continental Divide"

[1995hoo]

The one the map above calls the "Laurentian Divide"  is called the "Arctic Watershed"  on signs in Ontario when you cross it.

[ET21]

Based on the map, I've crossed the Eastern and St. Lawrence divides by car

[FrCorySticha]

North Dakota is rather proud of advertising the crossing of the Laurentian Divide by posting signs along I-94. It's a whopping 1490 feet in elevation! From Wikipedia: https://en.wikipedia.org/wiki/Interstate_94_in_North_Dakota#/media/File:Continental_Divide_Sign.jpg

[sparker]

North Dakota is rather proud of advertising the crossing of the Laurentian Divide by posting signs along I-94. It's a whopping 1490 feet in elevation! From Wikipedia: https://en.wikipedia.org/wiki/Interstate_94_in_North_Dakota#/media/File:Continental_Divide_Sign.jpg

And does MN post similar signage where the divide goes right back over I-94 again?

[FrCorySticha]

And does MN post similar signage where the divide goes right back over I-94 again?

I don't recall seeing one on the mainline, but there is a marker just off the highway SE of Fergus Falls. https://www.tripadvisor.com/Attraction_Review-g43066-d15235777-Reviews-Continental_Divide_Marker-Fergus_Falls_Minnesota.html

[MNHighwayMan]

North Dakota is rather proud of advertising the crossing of the Laurentian Divide by posting signs along I-94. It's a whopping 1490 feet in elevation! From Wikipedia: https://en.wikipedia.org/wiki/Interstate_94_in_North_Dakota#/media/File:Continental_Divide_Sign.jpg

And does MN post similar signage where the divide goes right back over I-94 again?

Nope. Would be cool if there was one, though. Perhaps a friendly email suggestion to MnDOT is in order!

[froggie]

^ My hunch is that if MnDOT started posting the Laurentian Divide anywhere besides the historic location on US 53, they'd feel compelled to post it at every state highway crossing.  By my count, that's 33 locations.

Back to the OP, I dug through the data and I-68 actually crosses the Eastern Continental Divide three times, all between US 219 and Frostburg.  There's the crossing at Green Lantern Rd that Hoo posted (the signed location), but it also crosses the divide just east of the Old Frostburg Rd overpass and on the curve just west of Exit 29, roughly where the westbound on-ramp is located.  Neither of these other locations are signed.

On PA 31, the ECD is coincident with the Stonycreek/Allegheny Township line, so just a little west of where Hoo posited.

Where the Great Allegheny Passage crosses the ECD actually isn't in a tunnel.  It's just east of McKenzie Hollow Rd and just south of the Shirley Hollow Rd/Church Ln intersection, at the far end of this view.  The Big Savage Tunnel is a little to the southeast, but is not concurrent with the ECD.

Where the ECD crosses WV 90 is actually the Grant/Tucker County line.  Mineral and Tucker Counties do not share a border...Grant is in between.

It should be noted that, regarding the ECD, the New River is part of the Ohio River watershed and so there's a section of North Carolina near and including Boone that is "west" of the ECD, in addition to the Tennessee River watershed that includes the Smokeys and Asheville, NC.

[1995hoo]

This is why I mentioned the tunnel on the Great Allegheny Passage. My brother's pictures show their group celebrating that they reached the top of the climb; from what I can find online, that seems to be a common theme for photos there. His pictures are from a different angle that make it look like a longer tunnel than it does here.

Based on the map, I've crossed the Eastern and St. Lawrence divides by car

For me, using the names on that map, I've crossed the Eastern, St. Lawrence, Laurentian, and Great Divides by car (or rental SUV in one case, and the Eastern Divide by charter bus at least twice).

[MNHighwayMan]

^ My hunch is that if MnDOT started posting the Laurentian Divide anywhere besides the historic location on US 53, they'd feel compelled to post it at every state highway crossing.  By my count, that's 33 locations.

Well that would be a little excessive, although if they want to do that, I'm not about to stop them. Just signing it on I-94 (and maybe US-10 too) would be enough for me.