The Disappearing Rivers of the American West

Humankind has had a huge impact on the rivers of the American West. Nearly half of all river miles in the West are no longer in their natural state. Disappearing Rivers allows you to explore how humans have impacted on rivers in the West and how far they have been unnaturally altered.

Disappearing Rivers is an interactive map which shows the degree to which all the rivers in the American West have been altered by humankind. All the rivers on the map are color-coded to reflect the percentage that each river has been altered. This is the combined percentage of floodplain and river flow which has been altered by human beings. A drop-down menu allows you to change the map layer to show river & stream flow restriction or altered floodplains instead.

If you select the 'Threats' option you can view dams, major human diversions, culverts and bridges on the map. If you select the option to view dams then scaled markers are added to the map. These markers show the locations and the sizes of river dams in the West.

Disappearing Rivers includes a detailed look at one river to highlight the kind of alteration that rivers have suffered in the American West. Over half the Colorado River is dammed, diverted or otherwise altered from its natural state. Disappearing Rivers uses a story map format to travel along the Colorado River, showing how agriculture, irrigation runoff, nearby mines, dams and diversions have combined to change the natural state of the river.