Bright-blue ‘potash ponds’ shine alongside a dark-green river in Utah — Earth from space
QUICK FACTS
Where is he? Moab, Utah [38.47920940, -109.68412599]
What’s in the photo? Dozens of dynamic solar evaporation ponds along the Colorado River
Who took the photo? An anonymous astronaut aboard the International Space Station
When was it taken? June 26, 2017
This eye-catching astronaut photo shows a series of bright blue “potash ponds” near the dark green meanders of the Colorado River, as the waterway winds through the rocky plateaus of southeastern Utah.
The multi-colored bands are solar evaporation pools, located about eight miles southwest of the city of Moab in the heart of the Colorado Plateau, an elevated region of about 130,000 square miles (340,000 square kilometers) covering parts of Colorado, Utah, New Mexico and Arizona.
The photo shows 23 ponds, grouped into two larger structures, which cover a total area of about 400 acres (160 hectares), according to NASA Earth Observatory. The ponds are used to refine potassium chloride, also known as potash, which is mined at a site just out of view (under the ponds in the image).
THE potash is extracted by pumping boiling water into the ground to create a mineral-rich brine that is extracted and transported to solar evaporation ponds, where it is reduced to tiny brown crystals. The distinct colors of the ponds mean that they are at different stages of the evaporation process.
When the ponds are initially filled, workers add a dark blue dye to the water to help it absorb more sunlight, speeding up the rate of evaporation. However, this dye also evaporates, so as the water level drops, the intensity of the blue decreases. Eventually, the ponds turn white and then turn brown when only a layer of dried potash remains.
Solar evaporation pools near Moab change color depending on the amount of water, and then turn color if left there.
(Image credit: Halbergman via Getty Images)
Potassium sulfide is primarily used as an agricultural fertilizer, but has various other industrial applications, including in the production of medicines, cement, fire extinguishers, textiles and beer.
The term “potash” is derived from “pot ash”, which is the name of a pre-industrial fertilizer made by combining wood ash with water and evaporating the mixture in a pot. The element potassium was later named after pot ash when it was discovered to be the secret main ingredient in this mixture.
In addition to the usual environmental effects of mining, which include habitat destruction and noise pollution, potash mining produces high levels of waste, such as sodium chloride and clay, which can cause environmental damage.
This salty sludge is often piled into large mounds or dumped into tailings ponds. A 2017 study found that the sludge is sometimes washed into nearby waterways. This can “significantly alter biological communities” and trigger harmful algal blooms. However, it is not yet clear what effect, if any, potash mining has on the Colorado River.
The Colorado River is the sixth longest river in the United States and extends approximately 1,450 miles (2,330 km) from its source in the Rocky Mountains of northern Colorado to the Gulf of California in northern Mexico. The long waterway, which played a role role in the formation of the Grand Canyonappears green from above due to high levels of suspended sediment, much like in the aptly named Green River, a tributary of the Colorado River which also crosses Utah.
A satellite photo from 2024 shows suspended sediments crisscrossing the mouth of the Rokan River, thanks in part to a particularly high tide caused by a full “Strawberry Moon.”
A 2022 satellite photo shows a thick carpet of blooming algae and invasive aquatic plants spreading across the surface of the Hartebeespoort Dam reservoir in South Africa.
An astronaut photo from 2011 shows a series of colorful mini-lakes that appeared at the edge of a giant salt flat, known as Etosha Pan, following a major flood.
