CSU Hydraulics Lab creates physical model for dam design

Molly O'Shea

The Colorado State University Hydraulics Lab has been working on the Los Vaqueros Reservoir Expansion Project for the last 11 months.

The lab plans on running the model built for the project for at least six more months, according to the lab’s manager Taylor Hogan. 


The expansion project works to improve the Bay Area’s “water supply reliability and water quality while protecting Delta fisheries and providing additional Delta ecosystem benefits,” according to the project’s website

Dam designers contacted the University’s lab to produce a physical design that will have the ability to raise an existing dam’s capacity, Hogan said. 

According to the Hydraulics Laboratory website, this lab is part of CSU’s Engineering Research Center located at the Foothills Research Campus. 

The University has made hydraulic modeling and performance testing a priority, according to the Hydraulics Laboratory website.  

“Physical models act as a level of insurance for design engineers. We are able to observe and measure flow through many pieces of the design and ensure that each piece is working as it should.” -Taylor Hogan, Hydraulics Lab manager

Hogan said that the purpose of the Los Vaqueros Reservoir Expansion Project was to create a physical model of a design to raise the existing dam by 50 feet to allow for additional capacity.

Civil and Environmental Engineering Associate Professor and Director of the Hydraulics Laboratory Christopher Thornton explained that the current dam was built to a height of 192 feet in 1998.

The dam serves to supply drinking water to over 600,000 customers in the region, Thornton said.

“In 2012, the dam was raised to 226 feet whereby increasing holding capacity by 60% (and providing) a 1-3 month supply of emergency water storage,” Thornton said. “Currently, the Contra Costa Water District is commissioning a second renovation to raise the dam 58 feet, expanding holding capacity another 70%.”

The dam is positioned 30 miles outside of San Francisco, California, and currently being operated by the Contra Costa Water District, Hogan said.

Hogan said the dam designers reached out to the University’s lab to conduct the physical model because a computer-generated one cannot accurately predict the complicated flow paths that go into the dam expansion. 


“Physical models act as a level of insurance for design engineers,” Hogan said. “We are able to observe and measure flow through many pieces of the design and ensure that each piece is working as it should. Overall, this improves the safety and resiliency of the design once constructed.”

The purpose of the project being in the lab is to evaluate the performance of the design as well as improve features that weren’t able to be optimized as well with the computer simulations, Hogan said.  

The project began back in January, construction on the physical model started in June and the model began running in October, according to Hogan.

Hogan explained that the model is a 1-to-12 scale that consists of a spillway and an emergency sluice outlet to release water from the reservoir in emergencies.

The sluice and spillway connect at a point in a ski jump-like area where the spillway flow jumps over the sluice outlet and reattaches further down the slope, Hogan said. 

The Los Vaqueros Reservoir Expansion Project is being worked on by one undergraduate student, three full-time tradesmen during the construction, one graduate student and one full-time researcher, according to Hogan. 

The Reservoir Expansion is one of many jobs the lab has undertaken. The Hydraulics Lab contributed and tested many different projects over the year, including an indoor waterfall to help Denver Water raise a dam in October 2019. 

Thornton expressed the importance of the job of the CSU Hydraulics Lab. 

“The results of this study highlight the importance of physical modeling in the design and implementation process of hydraulic infrastructure systems,” Thornton said. “Studies like the Los Vaqueros Project not only provide critical information to engineers and designers but the ability of our students to contribute and gain a working knowledge of this aspect of civil engineering is invaluable.”

Molly O’Shea can be reached at news@collegian.com or on Twitter @Molly_O23.