FEMA Tripling Calif. San Joaquin River Flood Plain

The federal government will triple the size of California’s San Joaquin River flood plain on maps, which could limit development and force more homeowners to buy flood insurance.

The Federal Emergency Management Agency plans to carry out the project next year using improved technology and more accurate storm information to make flood maps more precise, said Gregor Blackburn, a hazards program specialist with FEMA.

“Communities use it to help guide development decisions, insurance companies use it to determine premiums, so it behooves us to make the most accurate maps that we can and use those maps to guide development away from high-risk areas,” Blackburn said. “It’s a life and safety issue.”

The agency proposed expanding the flood plain after the San Joaquin and other rivers crested their banks and flooded parts of the Central Valley in 1997. Under FEMA’s plan, more valley residents would have to buy flood insurance and developers could be forced to build higher foundations.

The new flood plain, which could extend as much as 11 miles from the San Joaquin River in some areas, was called excessive by some local officials.

Fresno and Madera counties have twice proposed narrower expansions of the flood plain that have been rejected by FEMA.

A flood like the 1997 deluge was unlikely to occur more than once in 125 years, said Tony Buelna, chief of operations for the Bureau of Reclamation at Friant Dam.