The W Line began in the mountains at Golden and ends in downtown Denver at Union Station. Along the way, I've seen ancient lava flows, art, antique toys, and miniature houses, and heard people's stories.
Not much of a spectator, I look and pass by.
Denver should be a Mecca for people who like bridge architecture. There are bridges everywhere illustrating many styles. These truss bridges over Cherry Creek are foot bridges connecting the Auraria neighborhoods to Denver proper. They don't span much distance so the simple truss structure works well. It works like a board across a creek.
If you built bridges as a kid, you probably remember that your plank was, well...fun? As you walked across, it sagged in the middle and bobbed up and down.
All bridges are a road or trail bed supported by some kind of structure to carry the weight of the "plank" and lead the force of the weight down into the earth. Here, sturdy steel girders form a lattice work that lays across from one bank of Cherry Creek to the other. The road bed rests on a platform of girders like the slats under your mattress. The trapezoids on either side keep it from sagging and bobbing. The trapezoids are reinforced by diagonal girders that form triangles. In a triangle, any joint is braced by the opposite side. A triangle is the most stable plane shape.
Cherry Creek and the South Platte River define major regions of Denver. West Denver is west of the river. The original settlement of Auraria where settlers of European heritage joined Chief Little Raven's tribe of Arapahoe was nestled between the two streams, and Denver proper developed across Cherry Creek. The streams have never been navigable to large river traffic but was the original draw to the area as gold was panned from them and their tributaries. Then they served as open sewers. Although they have been cleaned up considerably, they still carry an invisible load of diverse toxic metals from mining operations upstream and enteric bacteria like Escherichia coli from ongoing sewage contamination. Swim at your own risk.
Nevertheless, water fowl find the streams inviting, and I occasionally see fish there. Denver used to be on the migration routes for many birds but as the climate has warmed, more and more are staying put year round. Also, further south they get shot.
The South Platte River and Cherry Creek merge in downtown Denver at Confluence Park. This area has been extensively landscaped not only for aesthetic reasons but also to manage erosion. A lot of energy is expended here and the valley shape can change quickly (over geologic time) if allowed.
Confluences are often a good place to look for heavy metals like gold. Industrial placers are troughs fitted with slats or ridges in the beds. Water is sent down under pressure (often by gravity flow). Light particles of dirt, sand, or crushed rock wash on by while the heavier partials are caught behind the slats. In a confluence, the trough is the natural stream bed and the slats are rocks and boulders that slow the flow of the water. The Sand that collects there is enriched with heavy materials and can be panned to find heavy particles.
Confluence Park is a popular place for kayaking and tubing because the water gets a big boost there. There's actual white water around the boulders that have been washed down from upstream (but keep an eye on the pollution reports if you're interested!) It's no surprised that this was the first place prospectors decided to look for gold in the area.
Why is Denver where it is?
That's why.
Geology not only changes geography. It changes us.
But they didn't find gold at the Confluence of the South Platte and Cherry Creek. Bragging rights for the first gold panned in the area goes to the confluence of Clear and Ralston Creeks further to the west. Then they found placer gold three miles south at the confluence of the South Platte and Little Dry Creek, and the rush was on.
Many of the bridges in the Denver area are arch suspension bridges. The road bed is suspended by cables from an arch. Of course, arches were used extensively by the Romans for their strength and stability. In the case of the pedestrian bridge at Confluence Park, each cable holds only a section of the weight of the road bed. The downward pull of the cables threaten to push the ends of the arch outward but, if you look at them, they're braced so that the force of the weight is conducted up the cables into the arch and down into the Earth.
This is a typical confluence. Two streams rarely, if ever, join at right angles. There is a stagnation zone in a larger stream just before a smaller tributary joins it. That allows particles to precipitate out of the water to form a delta pushing the junction of the two stream further downstream.
Near Confluence Park are three suspension bridges of innovative design. They're featured prominently in the January 13, 2019 blog, Terminus: Union Station (http://adventuringbcc.blogspot.com/2019/01/terminus-union-station-gold-drew-people.html). Here, the road bed is supported by cables attached to one or more masts. These two masts are curved outward to counteract the tendency of the weight they're carrying to pull them together. They're also springy (remember the old saying, a flexible tree doesn't break in the wind"), so you might have a little more bounce in your step as you cross the South Platte River pedestrian bridge.
All three bridges are in line and visible from each other.
This striking building, at the edge of downtown Denver, is a condominium called "the Riverfront Tower". It was built in 2002 and if you want to live there, be ready to shell out the $$$, because it's right in the middle of everything. At this writing, space goes for over $700 per square foot per month. You can sit in Commons Park and gaze at it for free. (I also like to watch humans and dogs play catch there.)
This hike (and the W Line) ended at Union Station light rail pavilion. The Millennium Bridge is just to the west (trains pass under it as they pull into the station). The big concrete barrels shown in the photograph above are works of art but, primarily, they are the ventilation shafts for Union Station's underground bus terminal.
Union Station sits directly on the 105th meridian west. It is one of 24 meridians on which time zones are based. Running north and south, the meridians are imaginary lines of longitude used to describe positions and time zones on the globe. This one is seven hours west of the prime meridian. That means that, when it's noon at Union Station, it's 7:00 pm in Greenwich, England.
How does the topography of your area alter your weather. If it's hilly or mountainous, it might impede winds and air masses as they move across. If you live on the plains, they may crash through with impunity.
If you pay attention, the more you walk in an area, the more you become aware of migration patterns of animals. Have you noticed that habits of animals in your area have shifted? Are new species appearing or old ones disappearing?
Are there any places near you where two streams join? Is there a delta there? If so, what does it look like? Is the water in the streams different colors? Do they mix immediately or can you see the different colored waters further downstream as though there are two streams flowing down the same stream bed?
Bridges are cool! There's likely one near you. Visit it and see if you can tell how the road bed is supported. How does the force from that weight flow from the road bed to the ground. Most energy, to be useful, has to flow from a source to a sink. For instance, in an electrical circuit, electrical force is produced by a battery or generator, some of the force is lost to heat in a load, and the rest travels into a ground. In a microscope, light is reflected from a small object, magnified by lenses, and collected by your eyes' retinas. If most of the force of a road's weight was not directed through a bridge's structure into the ground, it would strain the bridge's structural members and eventually break them.
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