withdraw water from an aquifer. Although some people believe that groundwater flows in
underground rivers, it’s actually found in saturated pore spaces of rocks. An aquifer is an
underground layer of water-bearing permeable rock or unconsolidated materials like
gravel, sand, silt, or clay from which groundwater can be extracted using a water well. An
artesian aquifer is a confined aquifer whose water is pressurized.
The study of water flow in aquifers is called hydrogeology. Hydrogeologists confirm that
in southwestern Oregon groundwater is found frequently in random bedrock fractures.
Although there is no comprehensive map of water sources there are records of existing
water wells in a central database. We often consult these resources and weigh our own
experience to help you choose the best site to drill for water. Although there is no
guarantee that any particular site will produce potable water, we have had great success
in meeting our clients’ needs.
Drilling a well: If you’ve ever used a bench top drill press, you understand the basic
principles of a well drilling rig. Our press weighs nearly 25 tons with a drill that is 30 feet
high. When we arrive on site, we’ll bring the drill rig and a tender vehicle. That utility
vehicle carries all of the material required to support the drilling effort, including lengths of
pipe and water. Water helps lubricate and cool the drill bit and helps move drilled
material out of the hole.
We build our drill bits by attaching different 6” thick cutting tips to 20’ long hollow pipe
stems to match the hardness of material we’re penetrating. After drilling the first ten feet
of the hole, we insert a 6” diameter steel pipe and surround it with an absorbent material
called bentonite to form an impermeable water barrier. The barrier keeps foreign
material, including loose soil, from falling back into the hole. As the hole gets deeper we
continue to monitor the kind of material we’re penetrating and add more 20’ sections of
drill stem. Knowing how hard and how long to push the drill and making adjustments to
bore through different underground materials is a skill learned through years of
experience.
When the drill bit hits water we make a rough estimate of flow rate and an initial
assessment of water quality. Impurities like salt and sulfur in the water will be quickly
apparent. If you’re satisfied with the results we’ll begin the process of making the hole
permanent and send water samples to a laboratory for analysis. With the analysis we
can recommend a pumping and purification system then return to the site and install a
complete water delivery system. While the drilling may take a day or two, the entire
process may take several weeks.
Water requirements: In America, an average adult uses a little more than 100
gallons of water per day; a family of four needs about 400. Landscaping, irrigation,
livestock, or other rural uses require even more water. To estimate your family’s needs,
this link provides an easy-to-use online calculator: Water use calculator
A well that flows at 2 gallons per minute can produce 2800 gallons over a twenty-four
hour period. As you determine your current needs, you might also plan ahead for
potential resale of your rural property. Many local lenders require a minimum flow rate of
5 gallons per minute during a four-hour flow test. Some will accept 2-3 gallons per
minute when stored in an external tank of 1200-1800 gallon capacity. You may also
check into the boundaries of the nearest fire district. If you’re outside, the county may ask
you to provide a storage system to aid in fire fighting. A well producing as little as 2
gallons per minute with a large external holding tank should meet your basic daily
requirements.
www.wrightsartesian.com * CCB #85085 * License #1736
