Developments on the Colorado River: A Crash-Course

Blake Boles
23 min readApr 22, 2021

In Spring 2021, I road-tripped the Southwest to better understand the Colorado River: the dams, the diversions, and the different populations it serves.

My goal was to grasp this mind-boggling system well enough to explain every major development along the river to a fifth grader. This article shares what I learned.

Two excellent books informed my journey—Cadillac Desert (1993) and Where the Water Goes (2017)—with plenty of help from Wikipedia. If I’ve gotten something wrong, or you think I’ve missed an important piece of the puzzle, please reach out: Photographs, unless otherwise noted, are my own.

First things first: an orientation.

While we call it the “Colorado”—and it officially begins in Colorado’s Rocky Mountain National Park—the Colorado River owes its existence to a bivy of tributaries that originate in Wyoming, Utah, Arizona, and to a much smaller extent, New Mexico and Nevada.

credit: Shannon1 / Wikimedia

Those six states—plus California—created the Colorado River Compact in 1922, which determined who can take from the river and who cannot. (In 1944, Mexico also gained some rights.)

The Compact divided the river into Upper and Lower Basins. Arizona sits awkwardly in both basins, but most consider it a Lower Basin member.

credit: USGS

The dividing line between the basins is Lee’s Ferry, just south of the Arizona-Utah border. This is where John Doyle Lee, a Mormon pioneer and leader of the Mountain Meadows Massacre, operated a river-crossing ferry while hiding from federal authorities. Today, Lee’s Ferry is a popular put-in spot for Grand Canyon rafting trips.

According to the Compact, each basin is entitled to divert 7.5 million acre-feet of water each year. An “acre foot” is 326,000 gallons, roughly what 2.5 single-family households use each year.

An acre-foot, explained. (Now multiply by 7.5 million.) credit: Catalina Islander
Blake Boles

Author: Why Are You Still Sending Your Kids to School? / Founder: Unschool Adventures /