The three-year drought had little effect on California's overall farm production, though some locales were hit harder than others, a new study concludes.

Despite the arguments of tea party-backed activists and their supporters in Congress, the drought and new environmental restrictions in the Delta did not cause widespread economic damage, even in areas dependent on Delta water, the report states.

"Indeed, there were high levels of suffering and unemployment in the region, but this report suggests the causes of the high rate of unemployment and sustained high levels of poverty are more complex and do not appear to be directly related to water supplies," said Juliet Christian-Smith, lead author and a researcher at the Oakland-based Pacific Institute, an environmental research group.

Several thousand farm jobs were lost during the drought, but those losses were dwarfed by the loss of construction, sales and other kinds of jobs, the report says.

The report shows that statewide, revenue from California's farms actually increased during the drought and even increased in Fresno County, the state's richest farm county and the epicenter of staged protests in which the region's woes were blamed on Delta smelt, a 2-inch fish that was protected under additional restrictions on Delta pumping beginning in 2007.

Farm revenues did decline in a couple of neighboring counties, Kings and Kern, and all three of those counties fallowed more land than they had before the drought. But only about 25 percent of the shortages were due to new environmental restrictions, according to the group's research.

A spokesman for a farm group said the impacts were severe in some areas and on some families.

"Attempts now by others to give a broad brush to say the agriculture economy is doing fine is a disservice," said Mike Henry, spokesman for the California Farm Water Coalition. "It's very unfair to characterize individuals losing their jobs and unemployment going up as moderate."

In Fresno County, the nation's largest irrigation district -- the politically powerful Westlands Water District, which serves about 600 large farms -- was able to partially make up for the loss of Delta water by buying water and increasing groundwater pumping nearly twentyfold.

Those strategies are more expensive than buying Delta water -- meaning they cut into profits -- and can only carry farmers so far in a long drought, but the study showed that in the past few years farmers appeared to generate nearly as much in sales as in previous years.

The report noted that many other farms got normal supplies and that water shortages fell particularly hard on Westlands and similar water districts. That is because Westlands is a relatively young district and when the federal government built dams and installed Delta pumps, it promised existing water users their supplies would not be cut. As a result, shortages are not shared equally -- older districts have rights and contracts that trump those of younger ones such as Westlands.

"(The economic impact) is significant, but in the big picture it's relatively small, given the reduction in water supply and the rhetoric surrounding the issue," said Jeff Michael, an economist and director of the Business Forecasting Center at the University of the Pacific who has closely tracked the effect of drought and Delta regulations.

A spokeswoman for Westlands declined to comment because the district has not seen the report, called "Impacts of the 2007-2009 California Drought: What Really Happened?"

During protests and in recent congressional hearings, an oft-cited statistic was that environmental restrictions in the Delta have contributed to 40 percent unemployment in Mendota, a poverty-stricken farm town in a region dependent on Delta water.

While no one disputes the misery in some farm towns such as Mendota, that figure is unreliable, economists say. It is an official state figure but it comes from a U.S. Census Bureau measure in 2000, when water supplies were ample and Mendota had an unemployment rate of 32 percent, California's highest, Michael said. That number was then adjusted upward to account for employment trends in Fresno County.

The increase in unemployment in that county was mostly due to the collapse of the housing market and the recession, Michael said.

Because the economy is still languishing there, it shows unemployment in Mendota continuing to climb last year even though much more Delta water was available than in the previous year.

Henry, who grew up in Mendota, said he believes that there is a connection, because the unemployment figures rose at the same time water supplies were cut.

"How do you not connect the dots?" he said.

The Pacific Institute study noted that Mendota has had chronic unemployment for decades, but that it worsened beginning about the time Delta water started flowing to the area in 1968.

That is because once farms started irrigating in the area, farm workers arrived looking for seasonal work. And since the census workers are in the field in April, many workers have not yet started work for the growing season, said Dave Runsten, an agricultural economist at the Community Alliance for Family Farmers in Davis.

"A lot of farmworkers, people in those towns are unemployed that time of year," Runsten said.