Could Tehama County someday be home to more than 300,000 residents?

That question is being asked as the Planning Commission took a key step Thursday in finishing a document that will guide growth and land use decisions for the next two decades or longer.

Commissioners agreed to start an environmental impact report on the update of the county’s general plan, a package of written directions and maps that counties and cities consult to determine what gets built and where.

The EIR’s completion in about eight weeks will trigger a 45-day comment period and public hearing before the commission forwards the plan to the Board of Supervisors for final approval, which could come in October or November, county Planning Director George Robson said.

Last updated in the early 1980s, Tehama County’s revised general plan would stiffen protections of the most fertile agricultural lands while opening large parts of the Interstate 5 corridor north of Red Bluff to development.

“Our primary focus is to conserve and protect agricultural lands in Tehama County,” Robson said.

"However, we do know that growth is something that you accommodate and plan for. You don't ignore the growth that will occur."

However, critics argue that converting large swaths of grazing lands between Cottonwood and Red Bluff to residential and commercial uses would ruin the area's rural atmosphere and overburden roads and public services.

The opponents have seized on a study by the Tehama County Resource Conservation District, which found that the county's population could swell to 316,266 -- more than five times the current population of 58,700 -- if everything allowed in the revised general plan was actually built.

"In time, I think it will happen," said Gary Catlin, a resident of the Country Hills subdivision just south of Cottonwood. "Why on earth is the county preparing a general plan that has the potential of allowing the population of the county to increase by 500 percent?"

Robson responds that many urban areas are a mess because they didn't plan for long-term growth. But he largely dismisses the notion of 300,000 people, saying the county only grows at a rate of 1.5 percent to 2 percent a year.

"The other component is the economic tide, and right now we don't have an economic tide to speak of," he said. "Without really knowing the economy, if we tripled the growth rate ... we wouldn't get to 300,000 for 150 years."

But Catlin points to such communities as Lincoln, which he said "have exploded" once the door was opened. Lincoln had one of the slowest growth rates in the nation until a Sun City was developed there, and now it's one of the fastest growing cities, he said.

"We're concerned that's a possibility here," he said.

The debate has drawn attention outside Tehama County, too. Bruce Waggoner, who chairs the Sierra Club's Shasta Group in Redding, said the Redding area's population is projected to increase to 350,000 by 2050. Similar growth in Tehama County would add to traffic problems, air pollution and sprawl, he said.

"This is something that could affect climate, global warming and the way of life that people enjoy up here," Waggoner said. "Most people who live up here do not want to see the kind of sprawl that's happening in Sacramento."

The back-and-forth shows no sign of subsiding even after six years of discussions over the general plan -- discussions that involved an ad hoc citizens' committee and have consumed the Planning Commission in hearings and study sessions for nearly a year.

The updated general plan calls for boosting the minimum lot sizes on prime agricultural lands -- from 40 to 160 acres in some areas, Robson said. Most areas south of Red Bluff would be left in agriculture, he said.

Residential and commercial development along the northern I-5 corridor would occur in special planning areas. Robson and county Chief Administrator Bill Goodwin said there have to be enough homes to support needed highway improvements, such as a third lane on I-5 and interchange upgrades.

"You can't expect somebody to come up with $23 million and then tell them to keep it at 5 acres" per parcel, Goodwin said. "You've got to spread it (the cost) over several thousand homes.

"Yeah, I think the growth is going to occur," he said. "We can try to put a cap on it, but the market will keep it at a pace. ... We can preserve open spaces, which is what this plan is trying to do."