Subterranean Continental Divide

On November 20, 2011 · 8 Comments

I have a fascination with tunnels and I’ve featured them before on the Twelve Mile Circle including articles on Superlative Tunnels, Tunnel Under the Border, and Tunnels, Bridges, Lifts and Inclines. I’ve also fixated on boundaries and watersheds previously such as the Hydrological Apex of North America.

It seems odd to me that I hadn’t yet encountered a mashup of the two, yet that’s exactly what occurred when I read an article in Slate a few weeks ago. The article wasn’t about tunnels or watersheds precisely. Rather it focused on traffic efficiency versus driving speeds, including the counterintuitive notion that "sometimes you have to go slower to go faster." Colorado throttles Interstate 70 speeds down to 55 miles per hour west of Denver at certain levels of congestion using police cars as rolling roadblocks. It’s an interesting concept and you can read the article on your own if you prefer because it’s not actually germane to this conversation. I latched onto a single phrase… "a two-mile-long tunnel that dips under the Continental Divide."

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You read that correctly. It’s possible to drive across North America’s continental divide below the surface. Technically this is the Great Divide, one of several "continental divides" albeit the most well-known version and generally the one that’s meant when someone mentions a divide without qualifiers. It’s pretty cool even with the asterisk, don’t you think?

It required a little fact-checking because it sounded almost too good to be true. The Colorado Department of Transportation believes it. They constructed the Eisenhower Tunnel in two phases in the 1970’s, the Eisenhower Memorial Bore for westbound traffic and the Edwin C. Johnson Memorial Bore for eastbound traffic. CDOT throws out a number of superlatives as they describe their engineering achievement:

It is the highest vehicular tunnel in the world, located at an elevation of 11,013 feet at the East Portal and 11,158 feet at the West Portal. The Tunnel traverses through the Continental Divide at an average elevation of 11,112 feet… Annual snow fall in the area averages 315 inches (26 feet) for the months of November through April.

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Crossing the Rocky Mountains isn’t a joke. The Eisenhower Tunnel burrows beneath a summit that climbs 12,500 feet (3,810 metres). An Interstate highway could not possible cross here without a tunnel. Previously vehicles twisted around the southern edge using Loveland Pass at speeds considerably lower than Interstate standards, adding another hour to their passage.

The tunnel entrance at 11,000+ feet is still amazing. I’ve never used this tunnel although I crossed the Great Divide further north during a visit to Rocky Mountain National Park. That’s an elevation high enough to cause one to become light-headed until acclimated, as was the case for myself who lives practically at sea level.

What would happen if a bottle of water happened to fall from one’s vehicle at whatever point in the tunnel marks the divide? It would probably break and evaporate but for the sake of amusement lets say it happened right on the divide and water flowed unobstructed in both directions without soaking into the ground, etc., etc., etc. The eastern water would travel Clear Creek –> South Platte River –> Platte River –> Missouri River –> Mississippi River –> Gulf of Mexico –> Atlantic Ocean. The western water would travel Straight Creek –> Blue River –> Colorado River –> Gulf of California –> Pacific Ocean.

Clear Creek is quite famous as the epicenter of the 1859 Colorado Gold Rush. It also passes through Golden, CO, the home of the Coors brewery. A few molecules of our hypothetically spilled liquid might possibly make its way into the Rocky Mountain Water touted by the brewery (or be contaminated by it). Straight Creek isn’t nearly as famous and faces it own set of issues. The I-70 corridor takes a toll on the surrounding countryside. CDOT dumps huge amounts of sand on the roadway to keep it open during the winter which then washes into the creek as silt.

I became aware of other tunnels under continental divides during my search and perhaps I will elaborate on them someday. Until then, feel free to explore on your own:

Totally Unrelated

I enabled the new MapsGL this morning in Google Maps. It seems like Google is bringing Maps a bit closer to Google Earth (without requiring the plugin). I’m not sure I have any immediate reactions other than to notice that it hasn’t required any great mental adjustments on my part.


Random Canada

On February 8, 2011 · 3 Comments

Many months ago I toyed with an idea that I called the Throw the Dart game. That’s where I’d go into Google Street View, drop the cursor onto some random part of the world and then try to create an article from thin air. It worked pretty well in October 2009 when I hit a spot outside of Piedmont, Alabama, USA. I found similar success when fate delivered my eyes to Chesterfield, Derbyshire, England in March 2010.

Then I stopped.

I still enjoyed the concept so that wasn’t the problem. No, it was this image that put me into a tailspin for nearly a year:

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Yikes! Go ahead and circle that image all the way around. I’ll wait. I can guess that you saw only a ribbon of Ontario 527 stretching to both horizons with a curtain of trees on either side. I should have known I’d hit a bunch of remoteness if I threw a cursor at interior Canada when something like 75% of the population lives within 160 km of the United States border. A gambler wouldn’t place any meaningful bet on the odds of hitting a recognizable settlement by random chance here. That’s closer to Lotto territory. Why would the Google car even drive here?

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So I’d succeeded in capturing an image of some inexplicable stretch of rural Ontario north of Thunder Bay surrounded by forests and lakes. It sat unexplored as a draft in the queue of my WordPress blog software, month after month, reminding me that I’d been stumped. I came close to deleting it. Repeatedly. Psychologically I couldn’t do it though, and it remained lodged there every day confronting me. I’d come back to it from time-to-time, piddle around with it a bit, and still find nothing.

The beauty of the Intertubes is that as long as one searches hard enough and waits long enough then something will turn up eventually. Is today my day? Well, maybe. Let’s see if we can salvage something from this location and exorcise this demon for good.

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I’ll drill in a little closer. Ponds and lakes of various sizes dot the landscape. The largest one, maybe 3 km west of my spot, is called Cheeseman Lake. I tried to determine how it gained it’s unusual name and found nothing. However, I did learn that people fish here. In fact the fishing is supposed to be pretty good according to Internet chatter. Anglers warn that one should bring plenty of extra gasoline along though: the nearest filling station is 100 km further north in Armstrong, it’s expensive, and the pumps have been known to run-out at times.

It’s also not too far away from one of Canada’s continental divides. My random spot drains towards the Great Lakes and St. Lawrence River. A bit further either north or west and the land drains to Hudson Bay.

The last one is best. The Ontario Ministry of Northern Development, Mines and Forestry mentions the Cheeseman Lake area on its Geology Ontario website. It’s also caught the attention of the Ontario Prospectors Association. Early testing has shown anomalous amounts of copper, gold, silver and several rare earth elements. This random spot may be sitting on a gold mine — literally — and that’s not so bad for some unknown place set in the middle of nowhere.

Nonetheless, I think I’m done with the Throw the Dart Game. Canada kicked my butt again.

They Reversed the Chicago River

On November 19, 2008 · 0 Comments

What’s a growing city to do when its water supply is jeopardized by its own filth? If it’s Chicago and it’s the late 19th Century, they reverse the flow of an entire river system and purposely puncture a Continental Divide in the process.

I’m in Chicago this week so I wanted to make sure I got away from work for a few moments to explore a little local geo-history, the great Chicago Sanitary and Ship Canal. Most visitors stop by Grant Park, the Navy Pier, the Magnificent Mile and places like that. I, on the other hand, pay homage to the remnants of an open sewer. The city still dumps treated wastewater into the Chicago River system, but no doubt to the delight of visitors that take those tour boats through its skyscraper canyons, it’s a whole lot cleaner than what got sent through here a century ago (Dave Matthews not withstanding).

Chicago River at State Street
The Chicago River flowing through downtown Chicago from the State Street bridge, looking east

The Chicago River extends 156 miles. It once flowed east through the city and into Lake Michigan, taking raw sewage and whatever else got thrown into it away from a growing population. This caused a dilemma: Chicago also got its drinking water from the lake. Besides the awful visual image this conjures, this had the potential to become a major health issue. So in 1887 the government decided upon a solution: they would simply reverse the direction of the Chicago River and flush their troubles away from the lake, thus separating their toilet from their drinking water. Sewage would be forced to travel in the opposite direction from its natural flow through the marvels of civil engineering. It would drain instead into the Des Plaines River, using a series of locks, canals, dams and pumps where it would travel far, far away. A 28-mile waterway, a massive undertaking known as the Chicago Sanitary and Ship Canal, opened in 1900 to much fanfare and critical acclaim to complete this honorable mission. That is, of course, for the citizens of Chicago. I’m sure the people who lived downstream in the other direction were less thrilled.

Engineering marvel aside, there’s another extremely interesting aspect of the local geography. A low ridge runs parallel to Lake Michigan about a dozen miles west of Chicago’s lakeshore. It’s the remnants of an ancient beach dating back to the end of the last ice age of 12,000 years ago. That’s all that separates two vast drainage areas: the Great Lakes / St. Lawrence basin that empties into the Atlantic Ocean and the Mississippi River basin that flows into the Gulf of Mexico. Nowhere else is it so easy to travel between those two massive waterways. Towns grew here and became prosperous simply because of the easy portage. An early passage, the Illinois and Michigan Canal, replaced the land-based portage. The Chicago Sanitary and Ship Canal took it one step further by actually removing the entire Chicago River watershed from the Great Lakes drainage basin and adding it to the Mississippi basin. In addition to the sanitation it provided to the city of Chicago, it served another vital purpose, the only navigable link between two hugely important commercial waterways.

To understand how little separates the Great Lakes from the Mississippi system, take a look at the Google Street View Image and you may be able to discern the slight rise that separates the two.

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Are you having trouble spotting it? That’s exactly the point. Contrast that with another continental divide I’ve featured previously. It quickly becomes apparent why this area on the southwest corner of Lake Michigan became so vital to trade and transportation.

This spot came to my attention from the Oak Park Tourist website, specifically from their series of pages on the Oak Park Continental Divide.

The terrain in our Village is so flat that the slopes are difficult to perceive. The best place to see a distinct drop off in both directions is at the northwest corner of Taylor Park, at the intersection of Berkshire and Elmwood. There you will be standing on the continental divide. At the time this area was first settled, the land east of Oak Park, being an old lake bottom, was mostly swamp. Our low ridge was the first high land west of the Lake and was a desirable place to build. Thus Oak Park’s first settler, Joseph Kettlestrings, in 1837 chose to build west of Oak Park Avenue, on top of the ridge. The oak trees, growing on the sandy ridge, gave Oak Park its name.

As a final thought, there are pressures to separate to two watersheds and return the Continental Divide to its original condition. This is for a couple of reasons. First, given the finite nature of the Great Lakes, there are concerns about the amount of water being drawn off for purposes other than drinking (i.e., as a giant toilet flush down the Mississippi). Second, there are anxieties that linking the two large systems will hasten the spread of invasive species through even greater territories of the United States.

Satisfied with my tourist excursion up State Street to the river, I returned to work.

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