Driven wells can be deeper than dug wells
Like dug wells, driven wells pull water from the water-saturated zone above
the bedrock. 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.
There are land activities around a driven well can also contaminate it. (see activites that may contaminate a drinking water well)
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: