Future water supply uncertain in Mark West Springs area

The long-awaited Kleinfelder report, a pilot study of
groundwater conditions in three water-scarce areas, was released on
Oct. 3.
The report shows the Mark West study area’s two golf courses use
more than twice the water than all its homes.
Peter Dellavalle, with Santa Rosa geology consulting company
Kleinfelder Associates, prepared the report for the county.
The report looks at three water-scarce areas that saw a lot of
growth in recent years: the Joy Road area, Mark West Springs and
Santa Rosa’s Bennett Valley.
Permit and Resource Management will formally present the report
to the Board of Supervisors on Nov. 4, according to 4th District
Supervisor Paul Kelley.
Dellavalle said the ground under Mark West is sediment on top of
volcanic rock that yields highly variable wells of up to 500 feet
deep. The area has an average rainfall of 3.9 billion gallons a
year.
As of 2000, the area had 537 homes using 87 to 175 million
gallons of water a year. The area has 55.2 acres of vineyard using
5.9 million gallons of water a year.
Mark West’s golf courses, Mayacama and Fountain Grove, use some
215 million gallons of well water each year for irrigation.
Kelley said that use is not a problem.
“Those facilities are useful economic engines in the community
that use well water from under their own property,” he said. “It’s
a stretch to say whether that’s affecting the rest of the
area.”
Dellavalle concludes that Mark West probably has enough water
for its planned growth.
“Despite the dramatic increase in residential use of the land
over the last 50 years, there are no recognized areas experiencing
water availability problems,” he wrote. “Such problems may exist,
but unlike the Joy Road and Bennett Valley study areas, the
existence and general location of such problems in the Mark West
Study Area is not common knowledge.”
The report concludes that it is primarily geology that
determines groundwater availability, and that new wells are hitting
water deeper. Dellavalle recommends more study to answer four
questions:
€ What are groundwater conditions now?
€ What are the aquifer’s capabilities?
€ How are conditions changing and what is the significance of
the changes?
€ What is responsible for the change?
With the answers to those, plus a longer list of questions,
Dellavalle said the county can develop groundwater models that will
let the county:
€ Establish groundwater conditions.
€ Understand water consumption rates and patterns.
€ Assess the affect of water conservation measures.
€ Evaluate changes over time.
€ Calculate sustainable extraction rates.
€ Evaluate the impact of proposed extraction increases.
€ Locate undeveloped or underutilized groundwater resources.
Healdsburg forestry hydrologist Fred Euphrat said it is
important to note that many wells draw from the underground flows
of creeks and streams.
“A lot of the people in the environmental groups I speak to are
concerned about people drawing off waterways’ winter flows for
filling reservoirs,” Euphrat said. “They’re concerned both for the
sake of the fish and the replenishment of the water table.”
While residential development is having its impact on
groundwater levels, agriculture concerns him more, he said.
“The real wildcard is the agricultural factor,” he said.
“Agriculture uses so much more water than individuals, and while
individuals can squeak by on deliveries, a vineyard can’t.”
With the possibility of water shortages comes the twin
possibility of water monitoring and groundwater management.
“Everywhere they looked, they found supply problems,” said
Euphrat. “Now they’re recommending more studies. At what point do
you recommend stopping growth?”
Charles Judson, president of Weeks Drilling, said that while the
information gathered from water meters would be extremely valuable,
universal monitoring would be difficult to achieve.
“It’s not that they’re expensive,” he said. “A meter for a
domestic well costs less than $200. But meters require monitoring
and calibration and can be damaged by iron and sand in the water,
both of which are really common.”
Judson said he thought metering would require ongoing
involvement of a government agency and would draw resistance from
water users.
“I spoke to a customer whose well is petering out,” he said. “I
asked him about water meters and he said, ‘I’ll never let them on
my property – it’s just a precursor to making me pay for the
water.'”
Judson said a more practical water monitoring solution might be
to expand the state Department of Water Resources’ limited program
of putting monitoring wells in basins across the state.
West County Supervisor Mike Reilly said the board and Planning
Commission will incorporate the Kleinfelder findings into the
update.
“It’s a tough area to draw firm conclusions around, particularly
in water scarce areas,” he said. Because most of the evidence of
wells drying up is anecdotal, it’s hard to justify managing county
groundwater, he said.
He said the county has created a reporting system for drying
wells through the county Permit and Resource Management Department
and encouraged those with problems to report them.
Download the report at
www.sonoma-county.org/prmd/docs/GW_Pilot/index.htm.