US Rivers Don't Just Roll On

A study of satellite images of major US rivers, taken between 1984 and 2018, have found that around a third have changed their colour in less than 40 years (https://www.theguardian.com/environment/2021/jan/22/one-third-us-rivers-changed-color-recent-decades). Some rivers (e.g. the Mississippi) show seasonal colour change but alterations elsewhere seem related to climate and/or human intervention. For example, Lake Mead (part of the Colorado river) has changed from blue-green to yellow in colour as a result of declining water levels. The Double Mountain Fork Brazos river in Texas, has done the reverse after the creation of a dam in that region. This kind of analysis is helpful, in terms of tracking what is happening to the environment. It could also be applied to other geographical features.