Drought Leaves Ojai High, Dry

Rainfall year ends Sept. 30 with 7.84 inches, worst total since 1877. Chart at right shows the annual rainfall deviation from average at Matilija Canyon from 1868 to 2007.

By Daryl Kelley
Despite a rare splash of September rain, the Ojai Valley experienced its driest year in recent history as a new rainfall season began this week. Indeed, precipitation for 2006-2007 may have matched the lowest ever.
“It could be the driest year in recorded history,” said Ron Merckling, spokesman for Casitas Municipal Water District. “Matilija Dam received 7.84 inches, which means this year was a virtual tie with the previous record of 7.83 inches set in 1877.”
That compares with an average annual rainfall of about 25 inches at Casitas Dam. The lowest previous rainfall in recent history was in 1960-1961, when 8.77 inches fell. Not even during the drought of 1986-1991 did rainfall drop below 9.46 inches in a year.
As a result, Oak View-based Casitas diverted no water from the Ventura River into its huge reservoir this year, Merkling said.
In just the last two years, and despite an average rainfall year in 2006, water stored behind Casitas Dam has dropped from nearly 251,000 acre-feet to about 211,000, records show. Casitas Reservoir is still about 83 percent full, but that’s down from 90 percent in the spring. And Merckling noted that declines accelerate sharply if dry years repeat.
Lake Casitas was only about half full after the six-year drought.
New data also shows, Merckling said, that the drought and a late-summer heat wave prompted local farmers to buy far more water from Casitas than in the previous year — 42 percent more in August and 40 percent more in September.
That was partly the result of groundwater basins not being refilled with saturating rains, which caused some wells to run dry, forcing the purchase of more reservoir water, he said.
“Groundwater has been depleted much more this year than in normal conditions,” Merckling said.
Such conditions prompted Casitas to begin new water conservation programs in the spring, including a $150 rebate for old, water-wasting washing machines and toilets. That program is still under way, Merckling said, and all Ojai Valley residents qualify, even those who do not buy water from Casitas.
“We could use a lot more requests,” he said.
Another conservation program, a survey of water use by farmers, found startling results.
A survey team from California Polytechnic State University, San Luis Obispo evaluated the irrigation practices of 35 local farmers and found a need for improvement.
The so-called “distribution uniformity”evaluations, found that local farmers’ irrigation by drip and micro-sprinkler systems were only about 66 percent effective, compared with a statewide average of 85 percent effectiveness, Merckling said.
“A low distribution uniformity means that fields were watered unevenly and most likely produced lower crop yields,” Merckling said.
Common problems, he said, were that farmers did not water often enough, and that they watered for too long when they did.
“They often applied more water per cycle than the soil could store,” he said. “And about half watered too infrequently.” Ojai Valley soils are often rocky and shallow, he said.
About three-fourths of the participating farmers made immediate changes as a result of the survey, Merckling said.
Meanwhile, local water agencies have accelerated their efforts to work together on water conservation, he said. They will meet to discuss those plans next Wednesday, he said.
“There’s a lot more coming on water conservation,” he said. “We’re concerned about the potential for a prolonged drought.”