Andy just sent me a couple Google Maps images he thought were bizarre and when I first saw them all my years of schooling (I have a MS in soil chemistry I don’t use) came back in a wave. I may be talking out of my ass here, but here are my best guesses:
This set of pools in Utah look like evaporating pools. You can kind of see a progression in the pools next to each other, as they get clearer. My guess is the whitest pools are precipitating salts. It’s likely agricultural runoff that’s high in salts that they don’t want making the soil saline or sodic or they want to keep the runoff from getting into nearby streams so they let them sit in shallow pools to evaporate the water vapor off, and the salt is recovered and processed or disposed of. I don’t see any nearby irrigated fields so a fish farm or mining operation is also an outside possibility, but I’d put money on evaporating pools.
I mentioned to Andy that when you drive around the Silicon Valley you see shallow areas of the San Francisco bay evaporating down to salts and he showed me this cool section of the bay. Now this is a bit different, the red and green colors appear to be due to algae blooms, and since they appear to be in contained areas, they’re purposefully there in order to help “scrub” fertilizers from agricultural runoff heading into the bay. When runoff high in nitrogen or phosphorus hits these ponds, blooms form and the algae consume the nutrients, leaving cleaner water to pass back into the bay. Without this kind of cheap natural wastewater management, the blooms would happen in the main areas of the bay, choking out oxygen and often leading to fish kills and other problems. Red and green algae bloom in response to varying levels of nutrient load and temperature, so I’m not sure if the green algae blooms are in deeper pools or less nutrient rich ones, but that’s my guess as to why the big colored pools are there.
When I told Andy all this, he said: When I looked at it, all I thought was “purty…”
update: freaky small world moment #2 from Google Maps: Heather’s shot here includes those pools, off to the right, where you see a sliver of silver-blue. Heather says they were evaporation ponds for collecting potash, and that it was a windy high desert pass. Makes perfect sense to accelerate evaporation in a hot, windy place and I wouldn’t doubt someone could create a economically viable business just evaporating runoff and selling the minerals as fertilizer.
A bunch of folks familiar with the area have emailed me saying there’s a nearby mine and they are most likely ponds to capture tailings. That seems more likely the more I drag the map around, since there do seem to be mines nearby but no agriculture. So in this case, the runoff from processes in the mines would produce wastewater filled with all sorts of nasty heavy metals in solution. The tailings would get moved to the ponds to evaporate until the metals precipitate and fall out of solution, and then they probably have to pay an arm and a leg to dispose of it. This way makes it easier to keep their mining waste contained, if they were to simply send the water to the nearby river the metals getting into the ecosystem would have toxic effects to river flora and fauna. A little copper or lead that gets out can cause a lot of harm.