Work has begun on the raising of Shasta Dam, as reprote4d by the Redding Record Searchlight though only for 18 feet when it could go as high as 200 feet-which it was originally engineered for—as Wikipedia notes: “The strained supplies and labor forced Reclamation to cut the final height of the dam from 800 feet (240 m) to 602 feet (183 m).” Retrieved September 28, 2018 from https://en.wikipedia.org/wiki/Shasta_Dam quote from the section entitled : Concrete placement and river diversion.
An excerpt from the Redding Record Searchlight.
Nathan Morgan has been hanging over the side of side of Shasta Dam recently — sometimes upside down — making marks on the side of the dam.
Morgan is part of a U.S. Bureau of Reclamation crew drilling holes in the side and on the top of the dam to test the strength of the concrete.
The drilling is part of the prep work to raise the height of the dam 18½ feet.
The bureau plans to drill about 70 holes in the dam over the next few weeks, said Don Bader, the bureau’s area manager. The crew will also be drilling into the bedrock beneath the dam, he said.
They need to drill the holes to test the concrete to determine whether it is strong enough to bear the weight of the 18½-foot cap on the dam.
“They’re finding out the concrete is very hard,” Bader said.
The concrete includes 8-inch to 10-inch chunks of rock mined from the Sacramento River. The rocks were hauled by conveyer belt from Turtle Bay to the dam construction site where they were mixed with the cement.
Crews are drilling nearly 50 holes on top of the dam and numerous holes on both sides of the dam.
On Thursday, Morgan wore a harness and hung by a rope over the side of the dam as he and the rest of the crew determined where the rebar was in the concrete. After locating the rebar they marked a drill spot to avoid hitting the metal rebar, said Henry Garcia, construction manager for the bureau.
Earlier this year Congress set aside about $20 million for pre-construction work and design on the dam raise.
Raising the height of the dam 18½ feet will allow the bureau to store an additional 630,000 acre-feet of water in Shasta Lake. The dam currently holds about 4.5 million acre-feet, so the raise would add 14 percent to the lake’s capacity.
Retrieved September 28, 2018 from https://www.redding.com/story/news/2018/09/27/work-begins-raising-height-shasta-dam/1449293002/?from=new-cookie