FLOOD PLAIN BOUNDARIES UPDATED OFFICIALS FINISH SURVEY OF SANTA CLARA RIVER AS PART OF NATIONAL PLAN.

Byline: Eugene Tong Staff Writer

SANTA CLARITA - The county Department of Public Works has completed surveying the Santa Clara River, part of a yearlong effort by the federal government to update flood maps along Southern California's largest watershed.

The county, working with counterparts in Ventura County and the city of Santa Clarita and the Federal Emergency Management Agency met last week in Los Angeles for a status update.

Congress granted the federal agency $1 billion over five years for updated flood plain boundary maps of the nation's waterways. Existing maps were last compiled in 1989 - well out of date for an area that has seen tremendous growth in the past 17 years.

"It's better information," said Ray Lenaburg, a FEMA senior engineer. "It's new hydrology, new topographical information - a lot better information than what's currently on the map."

The Santa Clara River begins in the San Gabriel Mountains, running 84 miles through the city of Santa Clarita and Los Angeles and Ventura counties before draining into the Pacific Ocean.

The maps are important in determining flood insurance rates and eligibility, levy certification, planning and zoning, Lenaburg said.

"It will help with planning and zoning, and for flood insurance purchases," he said. "If you have a flood area, you should elevate. Some areas, you shouldn't develop at all."

The county has completed air and land surveys of the river and its tributaries from Acton in the east to San Francisquito Creek and Newhall Creek in the west. Ventura County will oversee sections of the waterway in that jurisdiction.

Since 1989, Santa Clarita's population has grown from 110,000 to more than 170,000 in 2006, according to California Employment Development Department figures.

"It's good they're doing it," said Ron Bottorff, chairman of Friends of the Santa Clara River, a Newbury Park-based environmental group. "It should've been done earlier. ... Our organization has always been against developing along the river. It may show areas where the flood plain is larger than they actually thought."

Geoffrey Owu, flood plain manager at the county Department of Public Works, said builders are closely watching the results of the study.

"Most of the developments are fully aware of the flood insurance requirements by FEMA," Owu said. "They don't want all of the sudden be told `you made a mistake."'

A draft is expected to be ready later this year, Lenaburg said.

Meanwhile, the U.S. Army Corps of Engineers, which oversees planning along the river, is in the second year of a four-year look at flood control, erosion, water quality and natural habitats along the river's watershed.

But environmental groups sued the Army Corps in February, alleging that the agency has been lax in its approvals of building permits without thorough study.

eugene.tong(at)dailynews.com

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