Anchor Dam: After A Decade And Millions Spent, It Literally Never Held Water

Wyoming has its own money pit. It’s called Anchor Dam, and it lies in the southwest corner of the Bighorn Basin.

The valley where the dam was built looks picture perfect for a dam. There’s that narrow gap between two rock walls that are part of what’s known as the Ten Sleep Formation.

Then there’s a lovely oval-shaped valley, just waiting to be filled with water from Owl Creek.

The only trouble is, no matter how picture-perfect it seems, and no matter how many scientific studies were done, there turned out to be too many hidden problems. The dam has never held any the water it was designed for, and water has never topped its spillway.

That’s despite $7 million spent over a 10-year period, and Herculean efforts — including 10,000 pounds of dynamite to try and settle all the hidden sinkholes and fill them up with rubble.

In the end, engineers couldn’t build a reservoir that would hold water.

More Than A Boondoggle

The dam has long been held up as an obvious government boondoggle, an example of wasted tax money.

Residents at the time warned geologists and engineers that water had a tricky way of disappearing in this valley, and they just didn’t listen.

But the real story behind Anchor Dam is more complicated than that. It’s a story about dreams in a thirsty, arid West.

That’s something John Vietti, a geology student at University of Wyoming at the time, watched unfold in 1962.

“It’s not quite accurate to say that geologists told the engineers don’t do it,” he told participants on the 70th annual History Trek in and around Thermopolis last weekend. “They raised quite a few red flags, but never actually said don’t do it.”

Yes, there were locals who raised questions, Vietti said. Because of that, numerous studies were done to figure out whether a dam could work at the location.

At the time, America’s engineers had already built many other successful dams, around 200 in all in the 1950s when Anchor Dam was put on the drawing board.

“They had a pretty good track record,” Vietti said. “And the Bureau of Reclamation did listen to (local concerns). Because they had eight studies to decide whether to build a dam or not.”

Settlers Had Big Dreams

The thing about this area is that it looks like cattle heaven.

It’s beautiful, it’s green. There’s this lovely little creek winding through it all, and beautiful mountains that cradle and shelter the valley with a postcard pretty backdrop.

Those elements are more than just postcard perfect. The creek ensures cattle have water and future green grass. The mountains shelter the cattle and forage crops from blasts of winter wind.

But looks here are not just deceiving when it comes to the geology for building a dam.

“It looks like it’s pretty and green, but there’s not enough water to go around,” Vietti said.

Because there were few passes leading into the area, settlers didn’t find the area until much later.

Once they did, however, its popularity quickly exceeded its capacity.

“These big ranches came in and claimed all the water,” Vietti said. “And then smaller guys came in, and the water was soon over-appropriated.

That’s still a problem today, he added.

“There’s a saying that whiskey’s for drinking and water’s for fighting,” Vietti said. “And you could say that about this area.”

Ranchers paid no heed to the limited water, as they settled the valley. They felt like water seemed plentiful enough. They built irrigation ditches to bring water for thirsty crops like alfalfa.

Drought Hits

Droughts are not uncommon for the area where Anchor dam is located, 35 miles west of Thermopolis.

In fact, members of the Arapaho Nation, also located in the area, last year told Cowboy State Daily they have experienced a multi-decade drought. That’s affected their efforts to grow their cattle operation at the Arapaho Ranch.

In the early 1900s, prompted by drought, a group of ranchers sought to bring Bighorn River water to Owl Creek, or, failing that, to build a dam. There were no funds for such a project at the time, though so they gave up.

The Bureau of Reclamation, created to look after the water needs of the 17 states that lie in the thirsty West, evaluated the site in the 1930s, but didn’t have any money to build a dam yet.

Money didn’t come along until 1944, when Congress approved the federal Flood Control Act. Many water projects which have brought water to arid areas of the West were approved after that as part of what was called the Pick-Sloan Missouri Basin Program.

Getting things to that point, though, took an all-out political war.

The main figures in this war were Lewis A. Pick, director of the Missouri River Office of the U.S. Army Corps of Engineers and William Glenn Sloan, director of the Billings Montana Office of the U.S. Bureau of Reclamation.

There was a saying at the time, Vietti said, that the Bureau of Reclamation and the Army Corps of Engineers “overlapped everywhere and agreed nowhere.”

They were always sharpshooting each others’ plans. That was making it difficult for Western states to progress on plans to bring water to arid areas.

When frustrated critics started pushing the idea of an alternate authority — a Missouri Valley Authority patterned after the highly successful Tennessee Valley Authority — leaders at both agencies realized this would be their own Waterloo if they did not make peace.

They had to work together and forge an agreement, or they’d lose control of the federal programs that have defined water in the American landscape for decades since.

It was against that backdrop that the Anchor Dam proposal came to be.

The Politics Of Water

Anchor Dam had both proponents and opponents, each spinning their own narrative, and cherry picking the facts that supported their view.

U.S. Army Reserve Capt. Sig Harrison, for example, wrote in the January 1944 issue of the Hot Springs County News, that “our farmers and ranchers are, as a whole, in a healthy condition, with prospects of greater improvement come the building of the Embar reservoir on Owl Creek.”

The dam’s official name came from the ranch that was to be flooded, owned by C.E. Blonde, whose brand was an anchor. Before that, though it was referred to as the Embar Dam by many newspapers of the day.

At first, a significant number of farmers in the area didn’t want to join an irrigation district.

Those who had first claim to the area’s limited water didn’t particularly feel they needed the project. They were going to get water regardless, and their businesses would suffer if they were on the hook for repayment costs of the irrigation project.

Those with later-dated water rights, however, needed the proposal to survive.

Once all those issues were ironed out, there were other wrinkles.

For example, the Bureau of Reclamation had a rule limiting projects to no more than 160 acres, or 320 if a landowner was married.

That didn’t account for the realities of ranching in the arid West, where ranches needed to be much larger to be economic.

That led to a number of lawsuits leading up to 1954, when Wyoming’s U.S. Senator Frank Barrett finally succeeded in having Anchor Dam exempted from acreage limits.

Chugwater Formation

One thing that the Anchor Dam proposal seemed to have going for it was all the red rock in the area.

That red rock is part of the Chugwater formation. It’s mainly red sandstone that doesn’t typically leak.

And that’s a large part of the reason engineers believed, after eight studies, that they could make a dam work in the area and bring water to a thirsty land that needed it.

But some area farmers still had questions, particularly Henry Freudenthal, who was working the old anchor ranch property at the time.

He had noticed water disappearing, Vietti said, and other farmers and ranchers had seen large sink holes in the area as well.

Locals always said that was why there weren’t any beavers working to dam things up.

But, ultimately, most of the studies concluded that while there were some obstacles, things could work — if positioned correctly.

Cracks could be dealt with by grouting, a process where concrete is pumped into a sink hole to fill it. That’s commonly used today to prevent the underground chambers of old coal mines from collapsing.

Fatal Flaws

The thing that made the red Chugwater formation different in the Anchor Dam area were hidden faultlines, Vietti said. That and the Chugwqter formation proved too thin at the area where the dam was eventually moved.

Water, at some point, flooded the area as well, eating out dolomite and gypsum that were also hidden in the Tensleep, Phosphoria and Chugwater formations. That meant there were lots of hidden sink holes that couldn’t readily be detected.

Scrambling To Fix

There were, as the construction proceeded in 1957, signs that things were just not quite right, Vietti said.

Foley Brothers, a Minnesota firm that had the contract, found the rock unsuitable for the dam as designed. So, they just moved the location a distance upstream, even though that would change the engineering significantly.

Sinkholes kept opening up on site, too. Sinkholes that didn’t want to fill, no matter how much grout was pumped into them.

One sinkhole — which was actually an open fissure in the Tensleep formation — the company just diverted the entire flow of Owl Creek into.

It still wouldn’t fill, even after nine days.

So, they covered it with some wooden planks instead, plugging the hole, and poured grout on top of the plug before moving on, Vietti said.

The engineering plans had also called for drilling a series of holes along the foot of the dam, then filling them with grout.

Several of those holes, too, never filled up, Vietti said.

By then, the dam was already $1 million over budget.

The Giant Sucking Sound

Three years later, Anchor Dam was finally completed.

It looked beautiful. It was an engineering marvel that stretched between a narrow gap, with that beautiful spoon of a valley that everyone hoped would feed future dreams of prosperity.

It didn’t take long for that dream to become a nightmare.

One morning the caretaker came out of his cabin and saw that the reservoir had dropped 5 feet. He reported a giant whirlpool, as well as a giant sucking sound. It was similar, he told newspapers of the day, to the sound a straw makes when it’s pulling the last few drops of water from a cup.

Though much, much louder.

Around 10,000 pounds of dynamite was then used to try and settle all the sinkholes that had drained the dam of water.That didn’t work.

A system of dikes was constructed to keep the water away from the sinkholes.

That didn’t work either.

In all, 54 sinkholes would appear and be plugged up through the 1970s, when the Bureau of Reclamation finally stopped spending any more money on the dam.

Late Season Irrigation

There is a small amount of water stored by the dam each year, which gets used for late-season irrigation.

But the structure has never, and likely will never, reach the full potential envisioned for it, Vietti said.

“The reservoir looks good right now,” he said. “It’s been a good flow year. And maybe, more and more sediment is starting to close things off. But I doubt it will ever be what it was meant to become.”

The failure of the dam to hold water was an embarrassing boondoggle for the Bureau of Reclamation. But it was also the death of a dream for a prosperous economy in the region.

Today, the area remains remote and isolated, with few visitors, held back by its pervasive lack of water.

It’s a very beautiful area, however, and well worth a day trip. The dam is a nice spot for a little picnic between visits to the nearby Hamilton Dome Oil Field and Legend Rock petroglyphs.

Four rugged camping sites are available on site as well, for those who want to spend the night. You’ll need to bring your own source of water, however.

Though some water glimmers behind anchor dam’s wet feet, there’s never been, nor likely ever will be, any drinkable water on site.

Renée Jean can be reached at renee@cowboystatedaily.com.