Working with Jertberg, Strawberry Hills project leader Bruce Eisenman of the Soil Conservation Service designed a system that Jertberg said he at first rejected as more than his fields needed. But the severe winter of 1982-83 convinced Jertberg otherwise: Not only did he lose a lot of good soil, but property owners downhill from him also complained about the sediment. Then, too, there was the erosion-control ordinance.
"It was a real nightmare," Jertberg recalled. "There were no two ways about it: It was not a question of cost, but of whether I wanted to grow strawberries."
Under the project, a graded "diversion road" along the top of the field diverts runoff toward drains leading to a 24-inch pipe buried beneath the grassy access roads running vertically down the slope. Below the road, each row and furrow is graded in a 1% slope toward the drainage lines. Where each furrow meets the access road, a "pickup pipe"--6-inch buried corrugated plastic with a hole cut in the top at ground level--drains runoff from the field into the 24-inch pipe, which connects with the main drain at the base of the field.
Soil Filtered Out
The main drain flows into a basin, where any soil coming off the hill is filtered out for recovery at the end of the harvest, and the clear water passes on down a grassy water way to county-maintained culverts and ditches that carry it harmlessly to the Elkhorn estuary on Monterey Bay.
"I didn't lose any sediment last year," Jertberg said.
The Soil Conservation Service estimates that the Strawberry Hills project saved 2,787 tons of soil last year on 54 acres. All the same, Eisenman said, growers have been slow to invest the $1,500 an acre needed to install a comprehensive drainage system, even though the fields to be protected range in value from $2,000 to $10,000 an acre. Once installed, annual upkeep costs less than $375 an acre, he estimated. (Some of the worst-eroded fields are worked by sharecroppers who may be reluctant to invest in someone else's property.)
"We're at the stage now where we want to build up the confidence of the land users that something can be done," said Jay Collins, head conservationist for the Soil Conservation Service's nine-county central coastal area. So far, 10 pilot projects have been completed, Collins said, and another dozen systems are expected to go in after picking ends this fall.
Jertberg said many of his neighbors consider his installation "overkill"--designed as it was to cope with a once-in-25-years storm--especially since the last two winters have been mild. "In the back of my mind," he confessed, "I'd sort of like to see a real heavy winter to see how it works."
Eisenman agreed: "The test would be to have the same intensity and duration of rains (as in 1982-83), and compare."