Is the Colorado River Always Brown? Not Quite

How Sediment, Storms, and Dams Shape the Colorado River’s Color

If you’ve ever seen photos of Grand Canyon in travel magazines or from a chic travel account on Instagram, you’ve probably seen the Colorado River looking more like something you’d see in Costa Rica rather than in the middle of a Southwestern desert. So it’s no wonder that when some folks show up for their Grand Canyon rafting trip and see a river that resembles chocolate milk more than Caribbean waters, they’re surprised, and maybe even a little disappointed.

To take the mystery out of the color of the Colorado—including when and where you might find clear water—here’s some insight into six commonly asked questions regarding the hue and clarity of this iconic river.

1) I thought the river would be clear. Why is the Colorado River brown?

Short answer? Turbidity. While many travelers expect the deep blue-green water they’ve seen in pictures, the river’s color can change dramatically and quickly due to the introduction of sediment from several different factors, including rainfall, the erosion of river banks, and runoff from side canyons and major tributaries like the Paria and Little Colorado Rivers. All that sediment muddies up the water, creating the reddish-brown hue that’s closer to the Colorado River’s natural state.

2) What causes the river’s reddish-brown color? 

The Colorado River earned its name from Spanish explorers in 1605, who dubbed it Río Colorado (“colored river”) because of its rich reddish-brown tone. That signature color comes from the erosion of sedimentary rocks rich in clay, silt, and minerals like oxidized iron as the river and its tributaries carve through Red Rock Country. 

3) Is the Colorado River always brown?  

Below Glen Canyon Dam in Grand Canyon, the Colorado River can run clear and take on a striking blue-green hue, thanks to the dam trapping sediment in Lake Powell and the introduction of algae from the reservoir. But this clarity isn’t guaranteed, especially during monsoon season. Storms anywhere in the general vicinity of the vast Colorado River Basin will flush sediment into the river and can turn it muddy brown in no time. The farther downstream you go, the more side canyons and tributaries contribute silt and debris, gradually darkening the water as it flows toward Lake Mead.

On stretches of the Colorado that aren’t dam-controlled, such as through Cataract and Westwater Canyons, the river never runs clear. Without a dam to hold back sediment, it flows in its natural, silty state year-round, though clarity can improve outside the monsoon window and before spring runoff really starts gushing.

4) When are the best chances for clear or clearer water in Grand Canyon?

There are no guarantees, but early spring and late fall are your best bets to see the classic blue-green river that has captured the hearts and wanderlust of millions of people worldwide. April, May, and late October typically fall outside the monsoon season (mid-June through September), which means fewer rainstorms stirring up sediment. Just know that any rain in the vicinity, even if not a monsoon, could change the color of the river in a matter of hours.

5) Is it safe to swim, bathe, and wash dishes in the Colorado River’s silty water?

Yes, it is perfectly safe to swim, bathe, and even wash your dishes in the river when it’s running muddy. On river trips, water for dishes is treated to follow proper food handling procedures to combat backcountry illness. And because the river is rich in natural minerals, you can think of a Colorado River bath as a kind of high-desert spa treatment.

6) Does the silty water affect the rapids?

While sediment-heavy water does not impact the rapids directly, it can make it more challenging to read submerged obstacles, such as rocks and boulders. Fortunately, experienced guides are trained to read even turbid water and know how to anticipate and navigate around these hidden obstacles.

Whether the river is running clear and green-blue or rich and silty, know that each hue tells a story about the landscape it’s traveled through. It’s all part of the Colorado’s wild and unpredictable charm. And no matter the color, the Colorado River always delivers an unforgettable adventure.