The reconstruction of a 1906 dam that serves Yuba Reservoir won a national award from the Association of State Dam Safety Officials earlier this year, deemed the project of the year across the country.
The goal of the organization is to improve dam safety across the nation, region by region.
Its goals include:
- Advance and expand the technical expertise of dam owners and dam and levee safety practitioners
- Increase public awareness of the role of dams in society, the risks they present and the importance of both dam safety and preparedness for dam failures
- Increase the interest and awareness by federal and state lawmakers and administrators so that laws, policies, funding, and programs that serve to improve the safety of dams and levees and reduce the risk to the public are carried out.
The Utah Division of Water Rights has identified more than 100 dams classified as “high hazard” and not meeting safety standards.
Sevier Bridge Dam, the one built in 1906 and upgraded in 2016, and DMAD (named after four communities Delta, Melville, Abraham and Deseret) in Millard County, are two examples of high hazard dams that were under active construction.
It is important to note that hazard constitutes the consequences of the dams, not necessarily their condition. What it really means is there are risks to people and communities downstream from the dam should it fail.
Because of this, the division is in a constant watchful and inspection mode. With 6,500 dams in Utah that are state or privately owned, it is a monumental challenge.
A recent project was the Sevier Bridge Dam that impounds Yuba Lake.
The dam is owned by the Consolidated Sevier Bridge Reservoir Company. The dam was first constructed in 1906, enlarged in 1916 and had some upgrades performed in 2004. It went through an overhaul that included seismic upgrades.
At 92-feet tall and stretching 1,340-feet long, the earthen dam creates a 227,000 acre-foot reservoir, making Yuba the largest privately owned reservoir in the state of Utah.
With a 5,160 square-mile drainage basin, the Sevier Bridge Dam is required to pass a probable maximum flood (PMF) of 53,200 cubic-feet per second, significantly higher than the old spillway’s approximate 17,000 cfs capacity.
A dam good project
To accommodate the full operational storage and PMF requirements, a full spillway replacement was necessary.
The rehabilitation effort to replace the spillway and address the geotechnical deficiencies began in the summer of 2022 and was completed in the spring of 2024.
Matt Call, the assistant state engineer for dam safety and stream alteration, said the national award recognizes the degree of collaboration that went into the rehabilitation.
“It was a really great award and recognition for the project,” he said. “The project was a really great success. There were a lot of new features typically not used in new projects.”
It is a very significant dam because it is privately owned and how much water it holds, he added.
“It was interesting to see some of these old historic structures.”
A lesson learned and reemphasized was the importance of creating and implementing a reservoir management and emergency action plan during construction.
The construction began during drought, but the weather changed.
“Utah then experienced its wettest winter on record, placing the dam in a vulnerable position with the spring runoff season approaching. Execution of the reservoir management and emergency action plan helped fine tune inflow forecasts and the final cofferdam configuration,” the association said.
“The extreme weather during construction highlighted both the strengths and weaknesses of the Sevier River forecasting system and can serve as a template for other reservoir and river systems needing similar improvements.
The total cost of the project was nearly $28 million, but due to law passed by the state Legislature, 90% of the costs were picked up by the state.