In 2017, USGS released 72.57 kg of red dye into Idaho’s Kootenai River in 90 seconds; aircraft 1,000 metres above mapped the plume in 0.5-metre pixels to study river dispersion

In September 2017, the US Geological Survey (USGS) carried out an unusual experiment on Idaho’s Kootenai River. Researchers released 72.57 kg (160 pounds) of Rhodamine WT dye into the river and then followed its movement through the water.

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