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10 Things You Didn’t Know About the Yampa River

By Kim Cassels   •   June 21, 2023

10 Things You Didn’t Know About the Yampa River

Guide standing in raft while rowing through the Yampa River in Dinosaur National Monument - Mild to Wild

If if there’s one thing that people know about the Yampa River, it’s usually that it holds the mighty title as the last free-flowing tributary in the Colorado River system.

For a little context on this wild waterway— The Yampa River starts in the mountains above Steamboat Springs, Colorado, and flows 250 miles to the meet the Green River in Echo Park. Much of its journey sees a lot of little Colorado towns to start, before meandering into wide valleys, and eventually into narrow, isolated chasms of Earth’s oldest sandstones.

Read on to know more about the Yampa River, and how incredibly special it is.

#1 Mapped by Ferdinand Hayden

John Welsey Powell wasn’t the only hotshot surveyor to conquer the uncharted rivers of the West. In fact, Ferdinand Hayden was the main man to map the entire state of Colorado for the U.S Geological Survey in the 19th century. He surveyed everything from the territory’s fourteeners, fossils, and every stream in between. 

As one might imagine from a guy who surveyed one of the most dramatic landscapes in North America, Hayden was a bit of an understated badass with the portfolio to match. He began his rambles through the Rockies in 1859, but had to stop momentarily to serve as a surgeon in the Civil War. After 1865, he taught geology for a year before becoming the head of the U.S. Geological and Geographical Survey of the Territories, per Britannica. He also helped establish Yellowstone National Park. So yeah, hats off to Hayden!

Morning shot of the Yampa River in Dinosaur National Monument - Mild to Wild

#2 The Yampa Was Originally Misnamed 

The Yampa River was named in 1855 by colonizers who misinterpreted the Ute word “Yampah” for bear. They named the river as such for English speakers, and probably eager beavers (fur trappers) prospecting Colorado’s western slope, per Craig Daily Press. But “Yampah” is actually the name of a sweet root plant that Yamparika Utes and their related tribes ate. 

There was a back and forth for decades over whether to call the river Yampa or Bear, and in 1915, communities voted to have Yampa as the name for originality points, and its indigenous connection before whites came along. The “Bear” section of the Yampa that remains is one of its many contributing creeks near the Flat Tops wilderness. 

Yampa River - Ariel view of river and rock formation

#3 Geologic Beginnings of the Yampa Canyon are Still Unknown

Unlike the dramatic carvings of the Grand Canyon or Royal Gorge, where no-nonsense erosion has been making gains for millions of years, the origins of the Yampa River Canyon, and much of the Colorado River Basin at large, still have geologists in a tizz.  

The archaic layers exposed in Dinosaur National Monument don’t really line up with the typical course rivers tend to take— the path of least resistance. In fact, the canyon’s Weber sandstone is proudly dense, and super hard for water to make a scratch at. 

The Weber most likely trapped the Yampa River for quite some time before meeting the Green in Echo Park. However it still doesn’t explain the age of the exposed layers in conjunction with the course of the Green and Yampa Rivers through DNM. Geologists seem to agree (at least for now) that the landscape started rising after the rivers had already chosen their course. 

Yampa River Rafting-Colorado White Water-Mild to Wild Rafting

#4 Mantle’s Cave is a Top Archeological Site in Colorado 

According to Dinosaur National Monument, people have been living in the Yampa Canyon for at least 14,000 years based on projectile points of other cultures. 

The most special archaeological site along the Yampa River is Mantles Cave. This dramatic alcove and its countless artifacts was re-discovered in the early 20th century by homesteaders who settled right by the site. 

Over the next 20 years, archaeologists returned for multiple excavations of this growing treasure trove. Chip after chisel, they uncovered 1,000 year old relics, including feathered headdresses, wrenches from the horns of Big Horns, pieces of games, and plenty more, per Colorado Encyclopedia. The makers in question are known as the Fremont People.    

The Fremont culture is understood to be more sedentary, and is known for their beautiful basket weaves and geometric artwork. They also left behind super sweet moccasins, which left the claws on the animal hide for traction— like cleats, per NPS

Yampa River - Guest kissing Tiger Wall - Mild to WIld

#5 The Yampa Helped Ignite the Environmental Movement and Wilderness Act

In 1938, Dinosaur National Monument’s 80 protected acres expanded to 200,000 to encompass the extraordinary canyons of the Green and Yampa Rivers, per NPS. But oddly, the National Monument had no official restrictions from modern development. 

So when every river became seemingly eligible for monetization in the 1950s, these astoundingly beautiful canyons became not-so-special after all, particularly to the Bureau of Reclamation. Their plan was to put a dam smack dab in the middle of the monument, where the Green and Yampa Rivers converge in the epically rare landscape of Echo Park.

Early conservationists from the Wilderness Society and Sierra Club understandably thought it was deeply illogical, an obvious insult to the meaning of National Monuments, as well as completely illegal due to the National Park Service Act of 1916, per Britannica. The organizations fought for years to eradicate the projects until they arose victorious.

But the battle had just begun. Dinosaur National Monument was traded for the Glen Canyon Dam, a beloved and arcane crevice carved by the Colorado now swamped by Lake Powell. Conservationists would have to double down to keep a hydropower-hungry government at bay.  

Howard Zahniser from the Wilderness Society went on to propose a bill that would actually protect areas where “the earth and its community of life are untrammeled by man,” Wilderness Act. After years of pushing against Congress, the Wilderness Act was passed into law in 1964.

#6 The Yampa Feeds over 15 Water Projects 

While the Yampa is the last tributary to keep its natural hydrograph of the Colorado River System, plenty of its water goes towards diversions and reservoirs. 

The Yampa helps make snow for Steamboat Springs Ski Resort, fuel small-town power plants like Craig and Hayden, and feeds crops in the northern valleys of the Western Slope, per AECOM. Despite the diversions and small dams along the Yampa River, most of its water manages to flow through uninhibited.  

Yampa river - Scenic shot of Warm Springs rapid

#7 Warm Springs Rapid Formed in 1965

The largest rapid on the Yampa River is a Class IV spitter, frothing in the depths of Dinosaur National Monument. Before 1965, Warm Springs was hardly a blip over the boat. But a torrential downpour that spring season dramatically changed its topography forever, per Rig to Flip

Warm Springs rapid thunders in a narrow corridor with a precipice on river left, and a steep rugged slope to the right. After days of rain pouring its weight across the crumbling cliffs of the Yampa, shear stress gave way to gravity, and sent boulders upon boulders plummeting down to the water. 

This small but intimidating section continues to change, as the cliff on the left has also dropped rocks— the most recent being in 2012, per NPS.   

Yampa River - Close up of woman kissing Grasshopper

#8 The Yampa Still Has 90% of Its Natural Insect Populations

Let us tell you how to feel about this fact: Overwhelmed with joy. Why? Because as you definitely already know— bugs are a big deal. HUGE. Especially in riparian environments where fish, amphibians, reptiles and flora equally depend on them for survival. 

For comparison, the dam-controlled Green River only has around 50% of its natural insect populations, according to our friends at Dinosaur National Monument. But after the confluence in Echo Park, the population immediately increases, thanks to the Yampa’s contributions of creepy-crawlies.  

The Yampa River’s natural flows allow for the distribution of wood debris and sediments needed for native insect habitats, which also discourages the invasive tamarisk to invade on their turf. If you’ve floated along other western rivers like the Colorado or Green, it’s evident that tamarisks hardly struggle to survive. But thanks to the every-changing water levels of the Yampa, these thirsty invasives shrivel. 

Peregrine Falcon Flying - Mild to Wild

#9 Home to One of the Last Viable Populations of Peregrine Falcons 

After WWII, a perilous pesticide known as DDT began infiltrating American crop fields, and subsequently wrecking the vulnerable environments of our beloved wilderness areas. Peregrine falcons in particular transitioned from taking literal nose-dives for prey to figurative ones in reproduction. 

DDT was originally used for soldiers to combat malaria and other pesky, live-threatening diseases caused by bugs, before going to commercial use. Whilst annihilating insect populations, DDT simultaneously began wrecking bird populations, and thus dismantling entire ecosystems, per the United State Environmental Protection Agency

But thanks to the book Silent Spring, published in 1962, which detailed these pitfalls of DDT and chemical controllers introduced to the natural world, people started getting concerned, even downright mad, and demanded Congress to clean up its mess.  

Luckily, Peregrine falcons were doing just fine in Dinosaur National Monument thanks to its isolation from agricultural hubs. Starting in the 1970s, their eggs were captured from Yampa Canyon to re-establish populations in other areas. In 1999, the fastest animal on Earth was removed from the endangered species list, per NPS

Yampa River - Scenic boat shot with rocks and trees in the background

#10 The Yampa River Doesn’t Have Wilderness Area Designation

An act of Congress is needed to create a designated Wilderness Area, which falls into the National Wilderness Preservation System to receive the highest level of protections, per the Wilderness Society. So despite the Yampa being protected under the Antiquities Act in Dinosaur National Monument, it’s still, somehow, vulnerable to possible development.

According to our friends at DNM, National Parks are required to receive more preservation management than National Monuments, however they tend to be managed the same. There have been multiple proposals to turn the monument into a National Park, as well as give the Yampa River Wilderness Area designation.

We hope that someday this spectacular landscape is granted the laws of preservation it deserves, and that the astounding stretches of the Yampa River remain just as beautiful and wild for future generations to enjoy. 


More Reading

History and Geology of the Yampa River — A Past of Keeping it Wild 

Why is the Yampa River Such a Big Deal?

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