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About Keith Patton
Expertise
I can answer questions concerning physical and historical geology, environmental geology/hydrology, environmental consulting, remote sensing/aerial photo interpretation, G&G computer applications, petroleum exploration, drilling, geochemistry, geochemical and microbiological prospecting, 3D reservoir modeling, computer mapping and drilling.I am not a geophysicist.

Experience
I have 24 years experience split between the petroleum and environmental industries. I have served as an expert witness in remote sensing, developmental geologist, exploration geologist, enviromental project manager, and subject matter expert in geology and geophysical software development.

Organizations
American Association of Petroleum Geologists
American Association of Photogrammetrists and Remote Sensing

Education/Credentials
Bachelor and Master of Science
Registered Geologist in State of Texas

You are here: Experts > Science > Geology > Geology > why is the Colarado River green?

Geology - why is the Colarado River green?

Expert: Keith Patton - 10/19/2009

Question
why is the Colorado River green?

Answer
It is probably due to algae. Not sure what part of the river you are speaking about, but most green opaque coloration is due to algae growth. Blue-green algae blooms occur when water temperature gets higher. Water coming out of the base of a dam will be colder and hence you might not see the green color until it gets farther down stream and the water warms up.

Also, water carries a sediment load at higher energy states. When it slows down or enters a placid pool, like behind a dam, the sediment load drops out. So if you think about it, a man made dam is esentially a water fall in the making. It is only a matter of time before the area behind the damn sediments up, and turns into a marsh, then when enough sediment has filled in, the river will flow over the sediment and down over the dam forming a water fall. Engineers of course will try to prevent this.

When the sediment free water is released from the dam through the hydroelectric generating system, it is once again moving vigorously and guess what? It picks up more sediment causing erosion down stream of the dam. The high sediment load can cause the river to look muddy. We call that turbidity and it can mask the green color of any algae until the river slows again and the sediment drops out. But chances that the water is green coming out of the dam is slight since the water at the base of the dam or at lower levels is much colder than the surface water due to what we call a thermocline.

As the water slows and moves down river, it will warm up and the algae can once again grow.

If the water is clear and green it can be due to high levels of copper from such things as acid drainage from mines which at high levels is toxic and essentially makes the water sterile to organic live. Copper plates and copper compound paints were used on the hulls of ships top prevent barnacles and algae from growing on them. The copper compounds absorb all the colors but green so that our eyes see the water as green, just as chlorine compounds due to the water in a swimming pool.

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