Driven Wells
Like dug wells, driven wells pull water from the water-saturated zone
above the bedrock. Driven wells can be deeper than dug wells. They are
typically 30 to 50 feet deep and are usually located in areas with thick
sand and gravel deposits where the ground water table is within 15 feet
of the ground’s surface. In the proper geologic setting, driven
wells can be easy and relatively inexpensive to install.
Although deeper than dug wells, driven wells are still relatively shallow
and have a moderate-to-high risk of contamination from nearby land activities.
Driven Well Construction Features
- Assembled lengths of two inches to three inches diameter metal pipes
are driven into the ground. Ascreened “well point” located
at the end of the pipe helps drive the pipe through the sand and gravel.
The screen allows water to enter the well and filters out sediment.
- The pump for the well is in one of two places: on top ofthe well or
in the house. An access pit is usually dug around the well down to the
frost line and a water dis-charge pipe to the house is joined to the
well pipe with a fitting.
- The well and pit are capped with the same kind of large-diameter concrete
tile used for a dug well. The access pit may be cased with pre-cast
concrete.
To minimize this risk, the well cover should be a tight-fitting concrete
curb and cap with no cracks and should sit about a foot above the ground.
Slope the ground away from the well so that surface water will not pond
around the well. If there’s a pit above the well, either to hold
the pump or to access the fitting, you may also be able to pour a grout
sealant along the outside of the well pipe. Protecting the water quality
requires that you maintain proper well construction and monitor your activities
around the well. It is also important to follow the same land use precautions
around the driven well as described under dug wells.
Other types of wells:
The information contained on this page, as well
as the above graphic was provided by The Rhode Island Department of Environmental
Management from their document: Health
Drinking Water for Rhode Islanders: Private Drinking Water Wells
(644KB PDF FILE, 4 pgs)
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