The Colorado River is about 1,450 miles in length and runs through Colorado, Utah, Arizona, Nevada, and California (specifically Baja California and Sonora), and ending in Mexico. It begins at La Poudre Pass Lake in Rocky Mountain National Park, and continues into various reservoirs and tributaries, and finally ending in its delta in Mexico.

http://insightsdels.nas.edu/?p=43

Area map of Colorado River

http://wwwpaztcn.wr.usgs.gov/fscc/stanton-repeat-photography/repeat-photos.php?mode=photo&PID=489

1890 photo of the upper Colorado River

The Colorado River: Then and Now

It is constantly changing—the river carves through the Earth, constantly changing both the land and the river’s path. There is evidence of native people (most likely the Mohave, Chemehuevi, Hopi, and Navajo tribes) surviving off the river through fishing, floodwater farming, and possible ditch irrigation systems. Since the 19^th century however, the river has been dammed, changing its natural progression and diverting water from the lower region. 

What the Colorado River delta is supposed to look like:

http://sonoran.org/blogs/index.php/colorado-river-delta-blog/7-welcome

What is looks like now:

http://www.wbur.org/npr/155777834/as-colorado-river-dries-up-the-west-feels-the-pain

The water level of the Colorado River has greatly decreased due to overuse of water. The white block of rock shows where the water level used to be.

http://www.msnbc.msn.com/id/32012701/ns/us_news-environment/t/warming-warning-colorado-river-water/#.ULUVq6RSTWY

Human Impact

The human impact is ugly. The river provides water for more than 30 million people, and irrigation for 3.5 million acres of crops. People in the U.S. and Mexico are both using up more water than is sustainable, even after the Colorado River Compact, which was a state treaty limiting the amount of water use. The river is so dammed, diverted and overused, that it dries up before it reaches the delta. Many species, especially fish species, in the Colorado River are on the brink of extinction (due to dams interrupting the flow of nutrients and water temperature), and invasive species are coming in more. Mineral resources are also being explored, leading to more disruption in the river. The Colorado River doesn’t have any specific areas with protection. Although there are national parks, the operation of dams still degrade even those. 

Conservation status of fish species in the Colorado River:

FE = Federally Endangered

FT = Federally Threatened

SE = State Endangered

ST = State Threatened

SC = State Special Concern

http://wildlife.state.co.us/WildlifeSpecies/SpeciesOfConcern/ThreatenedEndangeredList/Pages/ListOfThreatenedAndEndangeredSpecies.aspx

Benefits of the Colorado River

The main benefit people get from the Colorado River is water. The river runs through states that have a very dry climate, and require substantial water to support human existence and agriculture. States have taken more than what is sustainable, however, and are now facing the consequences. There is a small benefit people get from tourism, like rafting, on the river, which brings money to the state economies, but that pales in the comparison of the necessity of water.