In the May 26th issue of the Sacramento Business Journal is a very good overview of the levee issue and development impacts in Natomas.
Here is an excerpt.
New Natomas levee angst
Army Corps of Engineers declaration adds heft to reports of risky protection
Sacramento Business Journal - May 26, 2006 by Mike McCarthy / Celia Lamb Staff Writers
The U.S. Army Corps of Engineers is adding its weight to findings that the Natomas Basin's flood-control levees are not very flood-proof after all -- a pronouncement that could temporarily squelch development in one of the region's largest planned-growth areas.
Plans for Natomas include about 75,000 homes and more than 50 million square feet of offices, stores and warehouses. The population of future workers, shoppers and residents combined would likely surpass 200,000.
The Corps' confirmation that the levees are defective in a basin that could experience 15-foot-deep floods may prompt building moratoriums or other restrictions by Sacramento city and county and Sutter County.
The levees were retrofitted in 1998 and the Army Corps of Engineers certified them as being able to withstand a 100-year flood -- a deluge of such severity that statistically there is only a 1 percent chance of it happening each year.
However, the Sacramento Area Flood Control Agency in March published an analysis concluding that the levees in Natomas and elsewhere "may be subject to unacceptable risk of failure due to deep underseepage and continuing erosion."
SAFCA asked the Corps and the state's Water Resources Department to review the study. Corps spokesman Jeff Hawk said the agency "basically concurs" with SAFCA that the levees are defective. An official announcement is expected soon.
Further putting the status of the levees in doubt, this month the Federal Emergency Management Agency announced that levees nationwide, including those in Natomas, will have to be recertified at the 100-year level.
That's the level of protection the Federal Emergency Management Agency regards as safe enough to build without flood insurance. And municipalities regard that level of protection as safe enough to allow construction without requiring expensive flood-proofing for individual buildings.
Complicating matters for development in the basin, John Bassett, a director of engineering for SAFCA, estimated that it will take three to four years -- until at least 2009 -- to return the levees to 100-year flood protection.
More spoilers on horizon
The 55,000-acre Natomas basin runs northward along the Sacramento River from the American River to the Natomas Cross Canal in Sutter County. The basin is encircled by levees that were thought to offer protection against a 100-year flood.
If the Natomas' levees are believed to be less than safe, FEMA could issue new flood maps showing Natomas as a flood-prone area, kicking in the need for flood insurance and, possibly, for flood-proofing new buildings. FEMA estimates a first draft of the maps could be out next year.
Sacramento Mayor Heather Fargo said that should the levees be found defective, she would favor stopping annexation proceedings in Natomas for the time being. She is less sure whether entitled infill projects should be stopped. That will require more study and discussion, she said.
"We don't want to put more people in harm's way," she added.
Other potential development spoilers on the horizon are two state Assembly bills. Assembly Bill 1988, introduced by Lois Wolk, a Yolo County Democrat, calls for a halt to building in areas that can't provide 200-year flood protection within five years. However, Wolk is considering an amendment to allow development in areas with 100-year protection if they could increase to 200-year protection within 10 years.
Sacramento County's Dave Jones, a Democrat, has introduced Assembly Bill 3050 requiring municipalities to jointly accept with the state liability for the results of bad flood-control decisions in new-growth areas. Currently, the law makes the state fully liable, leaving local governments to allow development with impunity, despite the existence of questionable flood protection. In other words, local officials who make land-use decisions may soon be on the hook for litigation.
"Cities and counties need to think twice about land-use decisions in floodplains," Jones said. "They've got to make darn sure they're not putting people in harm's way and that the levees are strong enough to protect them."
Money could also be a problem. But Gov. Arnold Schwarzenegger signed two bills last week that can help. Assembly Bill 142 allows $500 million to be spent immediately for emergency work on erosion of levees statewide. SAFCA's Bassett, however, said the bill is probably not going to route enough money to the agency to bring the levees to the 100-year level.
A more likely source for that is Assembly Bill 140. It would raise $4.09 billion for flood protection from bonds. But the bonds need public approval on the November ballot. Basset estimated the state bond could supply up to 70 percent of the $140 million to $240 million needed to bring the levees to 100-year status.
SAFCA's goal is to build the barriers to the 200-year-level. That would put the full cost at $300 million. The agency's March analysis also suggested it might be wise to build a secondary levee, running behind the Sacramento River levee, that could push the total to $432 million.