Census Says County Up to 650,880 : Population: The early figures reflect a 23% increase over the past 10 years. A financial windfall is predicted for Oxnard.

Despite passage of a series of slow-growth ordinances, the population of Ventura County grew by 23% to 650,880 residents during the 1980s, according to preliminary figures released Monday by the U.S. Census Bureau.

The early count, which has been sent to local officials for review, reflects a surge of 122,000 over the past 10 years. And that total is almost sure to increase when the final count is released in December, federal and local officials say.

“These are preliminary and partial figures,” census spokesman Larry Bryant said. “The census is not over. If local government units find we have missed some, we’ll just add them on.”

While the figures cannot yet be used for reapportionment of legislative districts, it is clear they will mean a financial windfall for at least one city.

The census says Oxnard had 137,468 residents on Jan. 1, nearly 7,600 more than estimated by the state. California cities receive vehicle fees, gas and cigarette taxes and other revenue in proportion to their populations.

“It’s going to be worth a few dollars, that’s for sure,” City Manager Vernon G. Hazen said. He estimated that the federal count will mean at least an extra $363,000 annually for Oxnard.

For months, county officials have credited Oxnard, the county’s largest and poorest city, with a strong effort to make sure that all its residents were counted. Its Censusmobile was a familiar sight in neighborhoods.

Many Latino migrant workers were missed in the 1980 census and in subsequent state estimates, Hazen said. And the city was determined to correct the costly problem, he said.

“We felt we had a lot of people who were not documented previously,” he said. “Our demographics justified a more thorough effort. We counted a lot of second families in homes and the homeless. And we did a lot of going back to homes and checking again.”

While Oxnard stands to benefit, preliminary census figures for other area cities will almost surely prompt an aggressive review by local officials.

For example, the early count for Thousand Oaks is 102,795--up from 77,072 in 1980 but about 3,600 residents fewer than estimated by the state Department of Finance in January.

Thousand Oaks planners could not be reached for comment late Monday. But county planner Steve Wood said the federal count probably will be revised upward for Thousand Oaks and for the county as a whole.

“It looks like a low number right now,” Wood said. “The Department of Finance estimates have been kind of tracking right along each year, so it seems to me that these census numbers should be higher. There may still be some gaps in the areas they’ve counted.”

State estimates placed Ventura County’s population at 668,000 in January, or 18,000 above the preliminary census figure.

Wood said Thousand Oaks, probably the county’s most affluent city, should have lent itself to an accurate count because of its stability.

“The census should have been pretty much right on the button there,” Wood said. “I would anticipate that there’s less doubling up in homes and fewer homeless in Thousand Oaks.”

Though experiencing sharp growth during the 1980s, Simi Valley’s census estimate of 99,316 was about 2,200 under the state figure. Port Hueneme’s early federal count was about 1,300 below the state estimate. State and federal figures were within a few hundred residents in other cities in the county.

State Department of Finance estimates are determined by using 1980 census figures and adjusting them annually after a review of such factors as new housing units, public school figures and utility bills.

A 1980 test of the state’s accuracy found that its figures were within 2.9% of census findings for counties and within 5% for cities.

The Census Bureau will release its final figures to President Bush on Dec. 31 and that information will be available in detail in April for states, cities and counties.

Any changes in preliminary figures will occur between now and December as census takers return to cities to double-check new information from local officials.

Some increase is assured because population increases from new construction during the first four months of this year are not included in the totals released Monday, Bryant said.

New figures for the state as a whole showed a growth rate of 24%, close to the county’s 23% increase.

COUNTY POPULATION

1980 1990* Camarillo 37,797 49,766 Fillmore 9,602 11,686 Moorpark** 8,054 24,912 Ojai 6,816 7,501 Oxnard 108,195 137,468 Port 17,803 19,932 Hueneme Santa Paula 20,552 24,443 Simi Valley 77,500 99,316 Thousand 77,072 102,795 Oaks Ventura 74,393 91,744 Countywide 529,174 650,880

* Preliminary figure. Final figure will not be released until Dec. 31, 1990

** Estimate of population prior to its incorporation in 1983