Thursday, February 16, 2006

Natomas Flood Protection, Less Than Thought?

From tragedy comes opportunity, and from the tragedy of New Orleans has come the renewed and focused look at the flood situation in Sacramento, from which this story from today’s Bee has emerged, that Natomas may have less flood protection than thought, and that we have the opportunity, and hopefully the time, to fix it.

Here is an excerpt.

Natomas flood safety disputed
New studies suggest area lacks minimal level of protection.
By Deb Kollars and Carrie Peyton Dahlberg -- Bee Staff WritersPublished 2:15 am PST Thursday, February 16, 2006

New engineering studies indicate Natomas may not have the minimal 100-year level of flood protection that marked the safety threshold for opening the area to widespread development less than a decade ago.

The sobering news, which will be publicly discussed at a meeting this afternoon of the Sacramento Area Flood Control Agency, has been quietly circulating among local politicians and flood control experts.

Some were stunned. For years, the levees surrounding Natomas have been touted as among the city's sturdiest, with new home buyers routinely assured they faced minimal flooding risks.

"It's a combination of disbelief, dismay, frustration and a little bit of anger," said Sacramento Mayor Heather Fargo, who sits on the flood control agency board. "We may not have the 100-year level of protection that we had thought, that we had been told."

Having 100-year protection means the flood control system can be expected to withstand severe storms with a one in a 100 chance of occurring every year. The Federal Emergency Management Agency considers this the minimal level of protection that communities must have to avoid building restrictions, mandatory flood insurance for mortgage holders and higher insurance rates.

Flood control leaders had known Natomas levees were likely to need more work under changing federal standards, as well as a growing realization that "underseepage" was occurring far below the levees that hold back the Sacramento and American rivers.

But the extent of the problem and what it will take to fix it - Fargo and others said estimates are in the $100 million vicinity - emerged recently as SAFCA directors received private briefings about engineering studies the agency conducted last year.

"It's looking like there's going to be a substantial cost to stabilize the levees to reconfirm our 100-year protection," Sacramento City Councilman and SAFCA board member Steve Cohn said.

Earlier suggestions that Natomas could be fortified by altering just a couple of miles of levees now appear to be "wishful thinking," he said. Instead, major stretches of waterways will need slurry reinforcement poured deep into the levee core, or new levees set farther away from the river, or some combination of the two, Cohn said.

Fargo said the news is disappointing for a city that had hoped to turn its attention to getting 200-year protection, and now has to retrace steps. She and Cohn said it may be necessary to increase assessments on property owners to help cover the costs, as well as seeking federal and state assistance.