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Mammoth Dam collapse in center of controversy

A large water intake tower still stands behind where the Mammoth Dam once held back water over 90 years ago.
The spillway of the Gooseberry Dam that sits just above where the Mammoth Dam was located on Gooseberry Creek. The small lake behind this dam was formed after this dam was built in 1939. It was later remodeled in the the 1960s.

Sun Advocate publisher

In June, 1917, workers in the Gooseberry Narrows, about 12 miles east of Fairview, noticed water leaking from the base of Mammoth Dam that was filling just a few months after the structure was completed.

The warning about the leaking dam traveled down the canyon, while employees of the Price Irrigation Company, which owned the dam, tried to release water from the newly-constructed reservoir and, at the same time, tried to plug the leak.

But the crews could not halt the effects of poor design and inadequate engineering safeguards and the dam collapsed during the afternoon of June 25. Approximately 3.6 billion gallons ran down Gooseberry Creek into Fish Creek, then into the Price River, where the water wreaked havoc in Castle Gate and Helper on the way to the Green River.

The damage was extensive, with coal operations curtailed in Castle Gate due to an inoperable Denver & Rio Grande track system damaged by water. The time that passed between the leaks being detected and the dam breakage was more than 24 hours.

Many people residing along the course of the river had been warned and the damage was somewhat diminished. However, the incident was cited for causing one death, which occurred after a woman backed a car into the river, after examining the flood's path.

Following the disaster, some people claimed the collapse was sabotage. They accused everyone from jealous Sanpete County residents, who thought the water should be theirs, to German saboteurs. Coincidentally, the United States had entered World War I against Germany two months before the dam collapsed and the railroad through Price Canyon was considered an important supply line for the war effort.

In the end, however, an inquiry into the dam's demise, through a commission set up by Utah Gov. Simon Bamberger, determined the failure was due to an engineering problem.

The dam was never rebuilt, but the structure's design, construction and demise are part of the struggle of western water users, and, particularly, that of the Gooseberry Narrows controversy. The Mammoth Dam concept and disaster play a role in the conflict that has raged for more than 100 years between Sanpete and Carbon County regarding water from that part of the Wasatch Plateau drainage.

The history of the ongoing struggle is a difficult story to compile, primarily because accounts vary and many records have been lost.

The two sides of the conflict have disagreed for so long that the history of what happened has almost become legend. Reports in newspapers from the two areas lean toward the chosen sides.

In basic terms, many Sanpete residents believe that all water and snowfall in their county belongs to them. The fact that all water on the eastern slope of mountains that edge the Sanpete Valley has a natural drainage into the Price River system simply doesn't matter.

On the other side, Carbon (and, to a certain extent, Emery) residents see the natural drainage as part of their right, because that is the way the water has flowed, literally forever, in terms of human lives.

But the idea of building a dam on Gooseberry, or above it, came about long before the Mammoth Dam was constructed, back before settlers came to the Price River's banks.

The first recorded documentation of work toward a project at the Narrows themselves was filed with the Sanpete County Recorder's Office in 1895.

The document was a survey for a right-of-way submitted by Charles S. Stevenson.

The hydraulic and irrigation engineer had completed the survey for a group of interested parties, including eight Sanpete residents and one man from Carbon County, George Frandsen.

Stevenson's survey started on June 23 and ended July 3, 1895. The document was filed with the recorder's office on Aug. 7, 1895. The engineering study identified an area of approximately "926 acres on unimproved land" where the reservoir could be constructed.

Construction on the reservoir project would eventually proceed, but not under the tutelage of the originators, although they filed on the water in 1896 under the name of the Mammoth Reservoir Company.

In 1900, little work had been done toward the construction of the dam. Several Sanpete farmers gained rights to the future reservoir.

The agricultural producers from Sanpete County intended to divert water through the mountain into the Fairview-Mount Pleasant area, but lacked adequate financing to tackle the endeavor.

The project was subsequently presented to the Irrigated Land Company. But that company had no desire to build a canal or tunnel through the mountain side to supply water to the Sanpete Valley. Instead, they wanted to build a dam so water could be stored to irrigate 25,000 acres in Carbon County.

The company started to plan for the actual dam and construction began in 1908. But financial difficulties surfaced a second time. In 1911, the project manager reorganized to form the Price Irrigation Company. Construction at the site moved forward.

But, even with backing from the state of Utah, progress was slow due to financial problems and the lack of demand for water in Carbon County. However, as the money came on line, portions of the project were completed.

Finally, the reservoir was allowed to start filling around 1915, although the structure was not completely finished.

Estimates indicated that the reservoir, when completed, would contain approximately 37,000 acre feet of water. The total water volume stored in the reservoir behind the dam never reached the intended size, because the project was not completed. Instead, the reservoir's peak level before the dam broke registered at 11,000 acre feet. That was probably lucky for those downstream.

The remnants of the Mammoth Dam can be viewed by people visiting the area, located less than one-half mile downstream from the present Lower Gooseberry Reservoir.

That reservoir was created with the construction of a small dam in 1939 which was reconstructed in 1990.

At the Mammoth Dam site, one significant landmark is the 30- to 40-foot tall concrete water intake tower. The tower allowed water to be released to locations downstream as needed.

The hills surrounding the Mammoth Dam site continue to bear scars from being torn up to provide fill for the dam. Two concrete walls continue to stand alongside Gooseberry Creek.

Although Mammoth Dam was never rebuilt, the ongoing conflict regarding the Gooseberry-Narrows reservoir project has resulted in several lawsuits being filed in the courts.

But the collapse of the Mammoth Dam also didn't dampen the spirit of water storage for Carbon County.

Following the 1917 failure, the concept of constructing of a dam in Pleasant Valley emerged as a way to store water in what later became known as the Scofield Reservoir.

That concept became the first dam at Scofield.

It was constructed in 1926 under the direction of the Price River Water Conservancy District and the U.S. Bureau of Reclamation, and that changed thing along the streams for good.

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