A journey I’ve never made (yet)

I was laying flat on my back on the living room sofa, surfing TV-channels. Two guys appeared on screen, replacing their kayaks with tiny rubber canoes which were better suited to the shallow water of a river. After a while, though, they ended up walking, legs dry above their ankles, searching for a way out to the sea. There was no such … ditch(?). Usually, rivers grow during their journey to the sea, but this one just ceased to be. I never thought this could happen to the mighty Colorado River.

colorado-river
Credit: Klaus Stebani / pixabay

Let’s start at the beginning of the story, which is where the river ends.

Usually, rivers grow while heading for the ocean. Why is the situation almost the opposite when it comes to the mighty Colorado River? Well, I missed the beginning of the TV-programme, so I had to figure out it on my own. Fortunately, that’s possible nowadays.

Sentinel-2_UtloppMiosture_2018-04-08
The Colorado River does not meet the Gulf of California. The amount of water is far too low to say so. This false-colour image, called “Moisture index” band combination (8a-11)/(8a+11), from the ESA Sentinel-2 satellite shows dry land in red and yellow. The blue parts in the picture are water. Well – Do you see any uncut stream of water where the Colorado River is supposed to meet the sea?

So – Where does the river begin? That’s often as hard as telling how long the beam from your flashlight lasts. However, I decided the journey along the river starts at Lake Granby.

Lake Granby didn’t exist until 1950 when the Granby Dam was built. Now it’s home to one of the highest-elevation yacht clubs in the world. It also provides Boulder and Fort Collins with water through the Colorado-Big Thompson project.

Sentinel-2_LakeGranby_2018-04-21
The Colorado River passes through the Lake Granby from north-east to south-west. That’s what it looks like. If you give the image a second glance and think it over, you might find it odd that the great river entering the image leaves like a tiny stream. Image: Sentinel-2, band 4, 3 and 2, meaning Red Green and Blue referring to the colours as we see them with our eyes., pretty much what you know from taking pictures with your camera. That’s called “Natural Color”.

I had never before heard about Lake Granby, nor the dam, nor about the yacht club. The Colorado-Big Thompson project hadn’t crossed my path of interest. Even seeing a part of the Colorado River covered by ice and snow was a, somewhat, new experience of mind.

Any river will follow along any path that takes its water closer to the centre of the Earth. Simply put; The water flows downwards. Furthermore, water is more massive than we usually think. (That’s why a car flipped into water floats. At least initially.) Any river is, therefore, a source of energy. I.e. the mass of the water in it. That’s why power plants are built along rivers paths.

The power plants, however, do not consume water. They just collect the potential energy. Every litre of water has a potential of giving one joule of energy when lowered one metre. Doing so in one second yields an effect of one watt. Every cubic metre falling five metres, which takes approximately one second, is a potential source of 5000 watts, five kilowatts. That’s enough for you to keep a vacuum cleaner and a hairdryer going while frying your egg and bacon at the same time. Still, the water continues its journey to the sea. It just leaves an amount of energy behind.

Sentinel-2_Phoenix_2018-04-08
The wavelengths of EMR around 560 nanometres are reflected from any growing plant on planet Earth. The other visible wavelengths are absorbed. That’s why leaves look green to us. On the other hand – If we could see wavelengths of about 850 nm, that would be the colour of growing plants, a sign of photosynthesis in action. We can’t see wavelengths of about 850 nm. That’s Near InfraRed, NIR. But we have sensors sensible to NIR on satellites. In this image, NIR is shown in red. (Hard to figure out what an invisible colour would look like) So – Where you see red in this image, you are looking at green fields, forests, lawns and so on.

But where does the water disappear? Well – the Colorado-Big Thompson project may explain the missing water higher up by the Lake Granby, but it doesn’t explain the reduced river downstream.

I followed the Colorado River through the “eyes” of the satellite Sentinel-2, using the Sentinel Hub Playground. Googleing downstream, I saw a river giving itself up to give the people around it amusement, food and life itself. That’s what you see in the image above.

In the upper left corner, you see Lake Havasu. The tiny strip you see south of the lake is the Colorado River continuing below the Parker Dam. The red fields to the left are croplands along the river. Down to the right, you see the city of Phoenix. North of Phoenix is an artificial lake with the suitable name of Lake Pleasant.

Canals and pipes bring water that once ran with the Colorado River to every reddish field in the image above. The inhabitants in Phoenix drink water from the river, and Lake Pleasant wouldn’t be big and deep enough for pleasure without additional water from the Colorado River.

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Every time I’ve made a journey, I’ve learned something. Often quite a lot. So I did this time, making an imaginary trip some 800 km above the Earth’s surface on a satellite.

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