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<br />Drought
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<br />even though you might not
<br />detect any problem now, you
<br />could have a real problem later
<br />in the year. It's much better to
<br />take steps now to reduce that
<br />risk."
<br />Air gurgling from the faucet,
<br />s] ower flow, or no water are
<br />signs the well may be going dry,
<br />he said.
<br />Wells work by pumping water
<br />to the surface from aquifers,
<br />which are layers -of fractured
<br />rock, sand or gravel, usually
<br />deep underground, that are per-
<br />meated by water. Rainwater fil-
<br />ters down through the soil to
<br />the aquifer — a process that can
<br />take anywhere from days to mil-
<br />lennia, depending on geologic
<br />conditions— and fills in the
<br />cracks and spaces between the
<br />rock and soil particles.
<br />When rainfall decreases for
<br />long periods, as it has during
<br />the current drought, the water
<br />table — the upper limit of the
<br />saturated layer — begins to.fall.
<br />"The water table is drop-
<br />ping," said Nat Wilson, a hydro -
<br />geologist with the N.C. Division
<br />of Water Resources. "It's look-
<br />ing for recharge, which comes
<br />from rainfall, and it isn't getting
<br />any That's why stream flow is
<br />so reduced; streams get most of
<br />their water from groundwater
<br />discharge, and when the water
<br />table drops too low you don't get
<br />that." .
<br />In periods of prolonged
<br />drought, the water table can
<br />drop below the intake of shal-
<br />low wells. When that happens,
<br />the tap runs dry.
<br />As a general rule, the deeper
<br />the well, the less susceptible it
<br />is to drought. Like a straw in a
<br />drinking glass, the amount of
<br />water a well can draw depends
<br />on how deeply it reaches down
<br />into the aquifer.
<br />Most newly drilled wells are
<br />some 200 feet deep, Holdway
<br />said. Older bored wells — or
<br />lower, and therefore more prob-
<br />lematic.
<br />"If you have a relatively
<br />recent drilled well, you're prob-
<br />ably going to be in good shape,"
<br />Wilson said. "The caveat to that,
<br />of course, is that we don't know
<br />how much longer this drought
<br />will go on. It could be years. But
<br />what we're seeing so far are
<br />problems with old bored wells,
<br />of which there are still a lot
<br />around.
<br />"In those few cases where we
<br />do have problems with drilled
<br />wells, it's usually because
<br />there's. some specific circum-
<br />stance, like several wells com-
<br />peting for limited water in a
<br />localized area."
<br />Homeowners should be able
<br />to tell what type well they have
<br />by a simple examination, Wil-
<br />son said. Drilled wells typically
<br />have a 6 -inch diameter pipe
<br />with a steel casing, he said,
<br />while bored wells are often two
<br />to three feet in diameter with a
<br />concrete casing.
<br />In Orange County, the effect
<br />of the drought on wells depends
<br />on depth, age, location and
<br />other variables, Holdway said.
<br />The aquifer is not uniform.
<br />throughout the county, and dif-
<br />ferent . tracts; even adjacent
<br />ones, may have very different
<br />levels of access to groundwater.
<br />"There are places where you
<br />can have two wells 40 or 50 feet
<br />apart, and you have completely
<br />different flows," Holdway said.
<br />"It's extremely variable. But the
<br />bottom line is that the shallower
<br />the well, the more impact the
<br />drought is going to have."
<br />Holdway said the county is in
<br />the process of implementing a
<br />new computer program that
<br />will track wells throughout the
<br />county, identify those that go
<br />dry and look for patterns in the
<br />groundwater supply.
<br />Residents with concerns or
<br />questions about their well sys-
<br />tems, Holdway said, should call
<br />Orange County Environmental
<br />Health Services at 245 -2360.
<br />even, .in some cases, hand -dug Dave Hart can be reached at
<br />wells — are considerably shal- 932 -8744 or dhart @nando.com
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