Raising Shasta Dam by 18.5 feet appears to be feasible and financially justifiable, according to the findings of a draft feasibility report by the U.S. Bureau of Reclamation.
The report, released along with a preliminary draft environmental impact statement as part of the Bureau's Shasta Lake Water Resources Investigation, examined the potential impacts, costs and benefits of five alternatives for raising the dam. Lake Shasta, at the northern end of the state, is the starting point for the federally run Central Valley Project. The system of 21 reservoirs, canals and aqueducts funnels water to 3.2 million acres of farmland and supplies water to about 2 million Californians.
The report analyzed alternative dam raises ranging from 6.5 feet to 18.5 feet and corresponding increases in reservoir storage from 256,000 acre-feet to 634,000 acre-feet.
According to the report, raising the dam by 18.5 feet would increase the lake's storage by about 14%. The additional storage capacity would be used to improve the reservoir's ability to provide colder water for winter-run Chinook salmon during drought years. Cold water is needed to help salmon that used to migrate to cooler water upstream before the dam blocked their path, according to the U.S. Bureau of Reclamation. It would also increase water supply reliability for agricultural and municipal water users in the state.
The report identifies several unresolved issues associated with raising the dam, including impacts on the McCloud River and Native American and cultural resources.
Bureau officials have been studying a potential dam raise since 1999.
Raising the dam also would mean some businesses and resorts would have to move. And it would cause flooding of lake-side religious sites of the Winnemem Wintu tribe, including two sacred rocks involved in coming-of-age ritual. Some of the ancestral land of the Winnemen Wintu was submerged in 1945, when the federal government built the dam downstream of their ceremonial and prayer grounds.
The current feasibility study has been under way since 2005. The projected cost would likely be less that building a new dam or adding a peripheral canal.