As this article from KCRA 3 notes, Shasta Dam is near capacity, a sad reminder that had the initial plans for Shasta and the entire California water project been approved—Shasta at 200 feet higher and Auburn Dam built—there would be little worries about flooding right now.
Excerpt from Wikipedia about Shasta:
In the 1990s, with skyrocketing water shortages in the Central Valley and some of California’s largest agricultural coalitions including the Westlands Irrigation District calling for a more dependable water supply, the Bureau of Reclamation suggested the expansion of Shasta Dam.  The expansion is considered feasible because the dam’s foundations were originally built to carry the weight of a 800-foot (240 m) structure, but resources shortages at the onset of World War II prevented completing it to its final height.
Reclamation has suggested three options for the dam raise, ranging from less than 20 feet (6.1 m) to more than 200 feet (61 m). The “low option”, which simply comprises adding a vertical concrete dike to the top of the dam, would provide maximum additional storage while minimizing requirements for reconstruction of buildings and facilities around Shasta Lake. The “intermediate option” would require adding more than 100 feet (30 m) to the crest and replacing the elevator towers on the front of the dam, and the Pit River Bridge and small towns around the lake, if not modified or moved, would be inundated. Finally, the “high option” would raise the dam over 200 feet (61 m), tripling the volume and doubling the surface area of the reservoir. Both the intermediate and high options would require saddle dams constructed at key points along the lake to keep it from overflowing.
The intermediate and high dam raises would allow for increased generation of hydropower. Each would require the construction of a new powerhouse to accommodate five new turbines; for the intermediate expansion, five 215-MW generators would be added for a total capacity of 1,751 MW, while for the high one, there would be five new 260-MW units for a maximum capacity of 1,976 MW. Downstream Keswick Dam would also be raised and its power station retrofitted to accommodate the greater peaking releases from Shasta.
Excerpt from KCRA 3:
SHASTA COUNTY, Calif. (KCRA) —
Water releases from Shasta Lake are at the highest they’ve been in 20 years as the lake nears full capacity Monday.
The lake stood at 96 percent of capacity and 137 percent of the historical average, as of midnight Monday, according to the California Department of Water Resources.
Water officials are releasing 70,000 cubic feet per second (cfs) from Shasta Dam as the lake stands just 5 feet from the top of the reservoir, the Shasta County Sheriff’s Office said.
“This is higher than it should be for this point in time,” the sheriff’s office said. “The release is necessary for space to allow future storms and to prevent uncontrolled release and flooding.”
The reservoir holds 4,552,000 acre-feet and added nearly 4,400,000 acre-feet in Shasta Lake, as of early Monday morning, DWR records show.
We wrote about this in much more detail in our 2006 Report: THE AMERICAN RIVER PARKWAY: PROTECTING ITS INTEGRITY AND PROVIDING WATER FOR THE RIVER RUNNING THROUGH IT: A REPORT ON THE AUBURN DAM POLICY ENVIRONMENT