'Green monster' in Doyle Park conceals a well
24-foot-high sound walls put up in effort to limit noise from drilling 1,000-foot-deep hole
Dennis Silva of Santa Rosa, carrying his snake, walks past the 24-foot-high green sound walls in Doyle Park that encircle Santa Rosa’s test well.
KENT PORTER / PDPublished: Friday, July 3, 2009 at 3:00 a.m.
Last Modified: Friday, July 3, 2009 at 10:50 p.m.
The daily inhabitants of Santa Rosa’s Doyle Park — the early morning homeless, the midday legions of dog walkers and occasional late-night troublemakers — are about to be joined by a 24-hour presence.
Well drillers have erected a huge wall of plywood, 24 feet tall and 100 feet long, that surround a planned 1,000-foot-deep test hole to be drilled in about two weeks.
The massive green walls have drawn inquiries from nearby residents and park walkers wondering what it’s for and what it’s hiding.
“It’s a sound wall,” explained Pete Dellavalle, a geologist with ECON, a Sebastopol company heading up a comprehensive study of Santa Rosa’s groundwater table.
The wall is an attempt to muffle the noise of around-the-clock drilling scheduled to begin July 13.
The anticipated five days of drilling will be followed by extensive geological and hydrological testing. The results will be combined with other test borings throughout the city “to help determine the best places to put wells,” he explained.
While Doyle Park is being used as a test site to study that particular geological area of the city, it’s likely the hole will be turned into a small irrigation well for park use rather than a major source of city water.
“This is all exploratory,” Dellavalle said, noting Doyle Park is the fourth test site drilled in the last three years, with the goal of determining how much water might be available underneath the city for emergency use and to map where the most productive wells might be placed.
City supervising engineer Mike Prinz said an additional five to 10 test holes may be drilled over the next few years to complete the study.
Glen Wright, the city’s deputy water resources director, said tests so far have not produced promising results.
“Some have been failures, and some have been marginal,” he said. “We’ve found no real winners yet.”
Prinz said results of the first three borings at A Place to Play, Northwest Community Park and near Jack London School have each produced less than 500 gallons per minute, far below the 750 to 1,000 gallons per minute that emergency wells need to produce when the city’s primary source of water — the Russian River — is unavailable.
The testing is the product of years of discussion among city leaders to develop a backup supply to protect the city should water from the river, its main source pumped through the Sonoma County Water Agency’s pipeline and aqueduct system, be shut off.
That has happened at least three times. In 1982, a formaldehyde spill into the river near Cloverdale resulted in a temporary shutdown. Years later, an electrical problem briefly affected the delivery system.
In 1997, a third shutdown lasting 30 hours was caused when a powdery substance believed to be sulphur was spotted floating on the river’s surface above the agency’s intake system.
That generated a scare among agency customers, including a number of cities, which rely on the river to supply 600,000 residents of Sonoma and Marin counties with water.
For more than a half century, Santa Rosa relied almost entirely on wells for its water, but then shifted to the Russian River water system, leaving the wells to deteriorate.
Some of those wells have since been renovated, including three near Farmers Lane that combined can produce up to 2,800 gallons a minute, or about 4 million gallons a day.
Prinz said those emergency wells, which by state law can only be used up to 15 days a year, are not sufficient to provide the 15 million gallons the city needs daily to satisfy the minimum daily drinking and sanitation needs of the city’s 160,000 residents, as well as fire protection.
Eventual plans are to develop a 15-well system, including the seven older wells that have been rehabilitated, Prinz said.
Wright said it likely will be 10 years before such a system could be completed, particularly at the cost of around $1 million per well.
Prinz said each test boring costs $350,000 to $500,000. While the test holes have fallen short of production levels, Prinz said most will be turned into small wells that can be used to irrigate surrounding parkland.
That likely will include Doyle Park, he said.
The cost of the test borings, along with any costs to develop a production well, would be financed through rates paid by the city’s more than 45,000 water customers.
Dellavalle said Santa Rosa’s test holes also are providing valuable groundwater information to the U.S. Geological Survey, which is conducting groundwater monitoring studies in the Sonoma Valley and Santa Rosa Plain areas.
He said the Doyle Park drilling also will provide other valuable geological information since “the Rogers Creek Fault runs through the middle of it.”
You can reach Staff Writer Mike McCoy at 521-5276 or mike.mccoy@pressdemocrat.com.
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