BLUE MESA RESERVOIR — On a chilly April day, David Primus walked down to where the edge of the largest reservoir in Colorado normally laps against the shore — and then kept walking. His shoes left shallow footprints in the wet sand as he headed toward a rectangle of stones revealed by the receding waters.
“That’s a foundation there,” said Primus, a technology professional turned local historian and author of the book “Beneath Blue Mesa.” “That’s going to be some sort of structure that’s associated with a little ranch right outside of town.”
At first glance, Blue Mesa looks like an enormous lake that’s always been there. But it, like many other reservoirs in Colorado and the West, was created by the federal government and provides water storage, generates power and supports farms and endangered fish. And, as it had done with other Western dam projects, the federal government bought, burned and removed small communities to make way for the reservoir.
These lost cities and towns, located alongside centuries of Ute history, are a contentious part of Colorado’s history. Houses were moved to other parts of the state. Graves were unearthed and remains reburied as cemeteries relocated. Some families left the state. Many refused to watch the water fill the land where they went to school, ran businesses and built lives. A few still gather annually.
Over the 20th century, scores of new dams tamed the Colorado River and paced its irregular flows to provide a reliable water supply for the growing West. Water utilities and federal agencies, like the Bureau of Reclamation, constructed the dams, which can only be placed where the terrain, water sources and geology allow. Communities from Denver to Colorado’s borders still benefit from them.
But they have a cost, Primus said, talking over the wind whipping across the reservoir. For a long time, he had decided he couldn’t say whether these projects did more to help or harm. Creating hydropower, controlling floods, providing recreation and water storage — these make life and growth in Colorado safer and more feasible.
He’s also spoken to descendants and experts, and read personal anecdotes and memoirs. He flipped through his published book on the history of the area, showing photos of ranches, resorts, bridges and schools that used to sit in the valley. When it comes to Blue Mesa, he’s made up his mind.
“Think of what was lost. This wonderful stretch of river and beautiful bottomlands. I’ll tell you what, I think I’ve really changed my mind,” he said. “This reservoir was a mistake.”
The question echoes at five large reservoirs in Colorado: Progress or blunder? Some clues to the answers have remained. A road map to the sites where water didn’t quite wash away what came before might help curious visitors decide for themselves.
Blue Mesa Reservoir, western Colorado
What to explore: Check out the dam overlook on Colorado 92, Sapinero Village Campground and the remnants of Iola, mostly old cement foundations, located along Colorado 149 on the south side of the lake.
Congress authorized Blue Mesa Dam in 1956 as part of the Colorado Storage Project Act. The dam generates hydropower, then released water goes on to support farms in western Colorado and bolster flows for endangered fish and the Gunnison River through the Black Canyon of the Gunnison National Park.
The reservoir, however, has dropped to about a quarter of its capacity, mostly because of this season’s record-low snowpack, the warming climate and ongoing releases. That means if you walked down to the edge of the water Friday, your toes would have been nearly 90 feet below the surface of the lake when it’s completely full.
Before the Bureau of Reclamation constructed the dam in the 1960s, the valleys in between canyons held the small, but growing communities of Cebolla, Sapinero and Iola, which was fictionalized in the bestselling 2023 novel “Go as a River” by Western Slope writer Shelley Read.
The first homesteads in the 1870s were ranches, and kids often spent their childhoods riding horses to school and helping on the ranch. The railroad came in the 1880s, and as a popular flyfishing destination for Denverites, ranch resorts soon became popular.
LEFT: The Big Little Store in Iola, Colorado, prior to the construction of Blue Mesa Dam in the 1960s. (Courtesy of the Bureau of Reclamation) RIGHT: Blue Mesa Reservoir’s receding waters revealed more remnants of Iola, Colorado, August 4, 2026. (Dean Krakel, Special to The Colorado Sun)
The Bureau of Reclamation told residents they could sell their homes before the reservoir filled, as long as they were relocated, Primus said. The government offered a fair-market price for the properties. But those prices were already low, tanked decades before when plans for the reservoir were made public.
Anything left, the government burned.
Primus recalled reading the memoir of Mildred Goodwin, a resort owner. She didn’t move her home out the valley. Instead, when the federal agency came to burn it down, she sat on a hill and watched.
“She sat there, probably alone. I just can’t even imagine it,” Primus said.
The valley was home to the highest highway span in the nation, known locally as the “high bridge” built in 1924. That steel bridge still spans the canyon roughly 150 feet below the surface when the reservoir is full, Primus said.
When the reservoir recedes, visitors can see the cement base of a flagpole inscribed with the initials of school children, old pottery and glass, and the concrete foundations of buildings. (Primus emphasized that it’s illegal to remove any items, like old glass bottles, from the national recreation area.)
Blue Mesa is now a popular recreation destination for paddleboarding, boating and fishing. Primus wondered if it could possibly have had a greater economic impact if the resorts had been allowed to grow near Black Canyon of the Gunnison National Park.
“Many of the people that lost their land, businesses, houses left the Gunnison country and even left Colorado, they were so pissed off,” he said.
Navajo Reservoir, southwestern Colorado
What to explore: Our Lady of Guadalupe Church, a mile west of Navajo Dam on New Mexico 511, has served as an annual gathering place for descendants of the former towns. Its interior is closed except for certain Catholic holidays but the property is open to visitation.
The federal government authorized Navajo Dam (and Blue Mesa Reservoir) in the Colorado River Storage Project Act of 1956. By 1957, construction started. Eventually, Navajo Reservoir filled and now straddles the Colorado-New Mexico border near the Southern Ute Reservation, Durango and Pagosa Springs.
The dam on the San Juan River was meant to generate hydropower, help with flood control, deliver water to farms and communities, and help control the flow of water to the immense Colorado River reservoir downstream, Lake Powell. Along the way, it became a popular destination for fishing, boating, hiking and hunting.
It was also a death blow to the communities of Rosa and Los Arboles and other nearby hamlets in New Mexico.
The communities date back to the 1870s, when primarily Hispanic settlers took up farming, growing fruit and sheepherding along the San Juan River in New Mexico. They eventually held clusters of homes, stores, churches, schools, cemeteries and post offices. Rosa was the most developed, according to a Colorado-commissioned historical study in 2021.
Once plans for Navajo Dam were made public, the federal government started buying or condemning residents’ land. Grave sites were moved. Rosa was abandoned and flooded. Los Arboles was partially relocated to the northern area of the reservoir. The small community is known by locals as “new Arboles.”
Former residents and descendents have continued to gather for a service at Our Lady of Guadalupe Church. At low lake levels and in dry years, like 2026, the spire on a flooded church in Rosa and parts of Los Arboles are visible.
Dillon Reservoir, central Colorado
What to explore: Visit the Summit Historical Society, read “Dillon, Denver, and the Dam” by Sandra F. Mather, or take a historical boat tour (when available).
Dillon was the town that couldn’t stand still, said Ken Raggio, a volunteer and tour guide with the Summit Historical Society. It was first settled with mining in mind, but in 1882, it moved to be near the new Denver and Rio Grande Railroad. When a second railroad line arrived, it moved again to be close to both lines.
The last time the town moved was to get out of the way of a new reservoir, Dillon Reservoir. Now, it is a popular tourist and ski town located just up the hill from its former site.
“Back in the day, it was a lot easier to do condemnation than it would be now in the 21st century,” Raggio said. “Reservoirs like this don’t happen hardly anywhere in America anymore.”
The Denver Water Board began purchasing land around what is now Dillon Reservoir starting in the 1910s. The water managers knew growing Front Range communities would need a more consistent water supply, and the best place to look was on the Western Slope. (Colorado has a long-standing tension over water between the eastern and western halves of the state.)
They built the dam to divert water from the Blue River Basin through the Harold D. Roberts Tunnel under the Continental Divide and into the South Platte River Basin, where modern Denverites and Front Range communities still drink it and use it to water their lawns. The scenic reservoir is a popular site for fishing, hiking, sailing and more.
By the 1950s, when the expansive water project was underway, Dillon was the largest town, with around 1,000 residents, and the nexus of Summit County, Raggio said. The town’s main street featured a general store, saloons, hotels and other businesses.
People knew the reservoir was coming — Denver Water started digging the Roberts Tunnel during World War II. When it was time to clear out the land that would be filled with water, wealthier residents were able to relocate their homes and businesses. They had to exhume, relocate and rebury over 300 bodies to move the cemetery. The rest was bulldozed and burned, and by 1961, the last residents moved away.
“A lot of these graves were made when people had unknown diseases and the Spanish flu,” Raggio said. “They hired some high school kids and put them in hazmat suits to dig up the remains to do the transportation, so there was no chance of infection.”
Pueblo Reservoir, southeastern Colorado
What to explore: The Swallows Cemetery, at the end of Swallows Road south of U.S. 50, includes remains that were relocated in order to fill the reservoir.
The town of Swallows, located west of Pueblo, began as an active homestead community, faded after a devastating flood and ultimately ended with the creation of Pueblo Reservoir.
Before settlers started building the community, the Ute bands built dwellings and left tools and a pictograph site in the area, discovered during an excavation ordered before Pueblo Reservoir was filled.
In the 1870s, settlers built up the community of Swallows, which included farmers, railroad workers, families, a post office, school and railroad station. The Great Pueblo Flood of June 1921 washed out the town, leaving only a few residents until the 1940s when the post office closed.
The one-room stone schoolhouse held Christmas plays and was incorporated into Pueblo County School District 70 before eventually closing. As of 1970, when construction of Pueblo Reservoir began, all that was left of the Swallows School were stone ruins, according to the Pueblo Chieftain.
The train station, which served the Denver and Rio Grande Railroad, closed and the Swallows Cemetery was relocated to make way for the reservoir, now part of Lake Pueblo State Park.
The few remaining buildings were bulldozed away to make way for the construction of Pueblo Dam and the Pueblo Reservoir, which are part of the federal Fryingpan-Arkansas Project approved in 1962 to bring irrigation and drinking water from the Western Slope to water-short areas of eastern Colorado. (The project has yet to be completed.)
The Bureau of Reclamation constructed Pueblo Reservoir’s distinctive buttress dam between 1970 and 1975 to help with flood control and provide water storage. The Swallows Cemetery, located near Pueblo West, is the most visible remnant of the former town of Swallows.
(Trinidad Lake is another option for exploring the history of lost cities. The town of Sopris, a small mining town plagued by flash flooding, lies beneath its waters.)
Horsetooth Reservoir, northern Colorado
What to explore: Check out the population sign reading “Stout, Colo. pop 47 1/2,” see the sandstone deposits around the reservoir, or walk its shores at low water levels to see old foundations.
Horsetooth Reservoir west of Fort Collins, like many in Colorado, is beloved for its camping, boating, fishing, swimming and hiking opportunities.
Far below its surface lie the remains of the former town of Stout. Both have roots that date back to the start of the Colorado territory.
In the 1870s, European-American settlers in northeastern Colorado started digging ditches to bring the water from nearby rivers where they needed it. By the 1890s, people realized the region needed more access to reliable water quickly, and Colorado lawmakers wanted to bring it over the mountains from the Western Slope.
LEFT: Quarriers pose at a stone lodging house in 1893 in Stout, Colorado, a former quarry town flooded by Horsetooth Reservoir. (Courtesy of Denver Public Library Special Collections) RIGHT: A sign welcomes visitors to Stout, which is south of Horsetooth Reservoir in Larimer County, on Aug. 15, 2026. (David Krause, The Colorado Sun)
Then came the studies and investigations that formed the foundation of one of the most complex projects undertaken by the federal government, the Colorado-Big Thompson project, which was completed in 1959.
Communities and farms in northeastern Colorado benefit from this complicated series of reservoirs, tunnels, canals and hydropower facilities today. And Horsetooth Reservoir is part of this project.
While the federal project grew, so did Stout. The town, which dates back to the 1860s, became famous for its sandstone. It soon had a community of quarry workers and families, homes, boxing matches and saloons, a general store, and a post office.
Stone from the town paved streets across Colorado until the rise of asphalt undercut its growing industry. An economic depression, the Panic of 1893, was another blow.
News of plans for Horsetooth Reservoir, constructed in the 1940s, further crippled the town’s growth. Residents were relocated; buildings were removed. Occasionally, when the lake’s water levels drop, the remnants of the town become visible.