For the past two years, the U.S. Bureau of Reclamation Technical Service Center in Denver, Colo., has been conducting tests of its 1:12-scale model of St. Mary Diversion Dam facilities in Montana.
In a recent exclusive interview with Hydro Review, Technical Service Center hydraulic engineer, Kit Shupe, provided detail on what the center is currently doing to rehabilitate the St. Mary Diversion Dam facility and at the site, increase bull trout passage.
In 1903, the newly formed U.S. Bureau of Reclamation authorized its first irrigation project, the Milk River project, located in north-central Montana on the Blackfeet Reservation in Glacier County.
The project includes the non-powered St. Mary Diversion Dam and attenuating facilities, which were authorized in 1905.
According to the Montana Department of Natural Resources and Conservation, the St. Mary Diversion Dam and associated infrastructure have been in operation since 1915, receiving only minor repairs and improvements. Many of the structures, it says, have exceeded their design life by several decades and are in critical need of repair or replacement.
Additionally, Reclamation says studies it conducted indicate the St. Mary Diversion facilities are having a negative impact on bull trout (Salvelinus confluentus), which are listed as a threatened species under the Endangered Species Act
In the past few years, a partnership formed between basin stakeholders that includes: users; tribal, state and federal government – all of whom developed a course of action for pursuing the system’s rehabilitation. The most recent plan was approved in May and on July 12, several stakeholders toured the St. Mary facilities.