I have a fascination with tunnels. So I like to feature them regularly, including articles such as Superlative Tunnels, Tunnel Under the Border, and Tunnels, Bridges, Lifts and Inclines. Also I’ve fixated on boundaries and watersheds 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. It featured 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. They do this by using police cars as rolling roadblocks. It’s an interesting concept. 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.“
Eisenhower Tunnel
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”. However it’s 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 certainly 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.”
Crossing the Rocky Mountains isn’t a joke. The Eisenhower Tunnel burrows beneath a summit that climbs to 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. They sputtered along 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 people to become light-headed until acclimated. I certainly felt it as someone who lives practically at sea level.
Where the Water Flows
What would happen if a bottle of water happened to fall from one’s vehicle at whatever point in the tunnel marked the divide? It would probably break and evaporate. But for the sake of amusement lets say it happened right on the divide. Let’s assume further that the 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. Straight Creek isn’t nearly as famous and faces a set of environmental issues. Unfortunately, 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. That then washes into the creek as silt.
More Examples
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:
- Moffat Tunnel: a railroad tunnel in Colorado.
- Alpine Tunnel: a narrow-gauge railroad tunnel also in Colorado, now a historic site
- Gallitzin Tunnels: train tunnels on the Eastern Divide in Pennsylvania
- Allegheny Mountain Tunnel: vehicle tunnel on the Pennsylvania Turnpike, also crossing the Eastern Divide
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 noticing that it hasn’t required any great mental adjustments on my part.
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