Dams, whether raising Shasta Dam on the Sacramento River the extra 200 feet it was originally engineered for, or a major new dam on the American River, might appear cost-effective once all of the costs, including levee repairs, water meters, flood insurance, (not to mention the $16 billion in damage estimated in Sacramento from a major flood) from floods beyond the 200 year protection now being called for, which could become redundant by having the 500 year flood protection major dams can give.
Though given the time element, it is probably a moot discussion, it is still one whose elements should be considered when being presented various flood protection plans.
Here is an excerpt.Levee price tag startles Natomas
Residents could see hefty tax hikes to pay for repairs.
By Deb Kollars and Matt Weiser -- Bee Staff Writers Published 2:15 am PST Friday, February 17, 2006
Fixing weak levees in the Natomas basin will take at least $270 million and may require a new tax assessment on homeowners, local flood control leaders announced Thursday.
Property owners in Natomas could see their tax bills rise to $300 a year to cover the levee work, which will cover seepage repairs far more extensive than previously known.
The grim news was delivered during an afternoon meeting Thursday of the Sacramento Area Flood Control Agency. The full board attended, as well as more than 100 observers from the public and a bank of television crews. It was more attention than the board had seen in a long time.
During the hearing, Stein Buer, executive director of the agency, described preliminary results of geological testing of Natomas levees. The tests found the levees, because of seepage, don't even meet a minimal 100-year level of flood protection.
The news hit SAFCA board members hard.
"The findings in the report are staggering, especially in the context that we are so much more urbanized now," said Ray Tretheway, a Sacramento city councilman and member of the SAFCA board. "The risk is extraordinary."
Buer told his board that 20 out of 26 levee miles in Natomas need major repairs to control deep seepage that could cause levees to fail when rivers are high. In addition, two miles of levees have severe erosion.
These problems must be repaired just to attain a 100-year level of protection for the area, meaning the levees could withstand major storms with a 1 percent chance of striking in any given year.
SAFCA's goal is to reach 200-year protection for the entire Sacramento region. To do that in Natomas will require 16 miles of levees to be raised: 11 miles along the Sacramento River and five miles along the Natomas Cross Canal.
Together, this work is estimated to cost $270 million, Buer said. If Natomas residents are to cover the bill themselves, the work could require homeowners to approve a tripling of the property tax assessment they pay now for levees, from about $100 a year to $300, he said.