Hidden Dangers

of

Improperly Abandoned or Constructed Wells

Steve Walker, P.G., Source Water Specialist, Georgia Rural Water Association

Even though approximately 70% of the earth is covered in water, only about 1-2% of that water is considered drinkable. With humans inhabiting almost every corner of the earth, its easy to see how safe drinking water has always been somewhat of a concern.

Here in Georgia, early settlers collected rain water, utilized springs or hand dug wells to obtain drinkable water. Dug wells gradually became more common and allowed people to settle in areas further from drinking water springs. As medical science advanced through the 1800s, people became more aware of the link between unclean drinking water and illness. This knowledge coupled with an ever increasing technical/mechanical ability, fueled the use of machines to drill wells deeper in search of cleaner, more prolific groundwater sources. These steel-cased (or other tubular casing materials) drilled wells are now the standard construction method for both public and private drinking water wells.

Few people spend much time these days thinking about where their drinking water comes from and even fewer are concerned with old wells that are no longer in use. However, from a drinking water standpoint, improperly constructed wells and old, forgotten wells both pose a risk to all individuals that use the well, and under the right circumstances, these old wells could pose a risk to an entire groundwater aquifer.

As the science of hydrogeology has grown over the last few decades, geologists and engineers became more aware of how groundwater moves and interacts in the subsurface and how a bad well or and old well might actually cause a problem. During the same timeframe, more and more contaminating events became known. As a result, The Federal government and The State of Georgia Environmental Protection Division (EPD and predecessor agencies) began generating rules and regulations to protect the groundwater resource.

Portions of the Georgia Safe Drinking Water Act of 1977, as amended (391-3-5), and the Georgia Water Well Standards Act, as amended (O.C.G.A. Title 12-5-3), both require wells to be constructed to standards set forth in order to protect the well from failure and from contamination. Standards include setbacks from septic systems, grouting depth of casing based upon use, thickness of well casing based upon diameter and type, etc. It is easy to envision how surface runoff containing parking lot drainage or pesticides/fertilizers from a yard or nearby agricultural field could flow toward a well and into a drinking water aquifer.

Photo showing annular space between well casing and borehole wall. This should have been filled with neat cement (or in some cases other impervious substances) in a prescribed manner to a certain depth. This is to seal the casing in the borehole and  the seal depth is specified based upon intended use of the well (drinking vs irrigation). The cement seal also prevents casing from contacting the soil, which over time could create pitting from galvanic corrosion. In this case, the casing is PVC and therefore won’t corrode, but surface runoff is flowing directly into the collapsed well bore.

This kind of thing impacts not only the users of the well, but all current and future users of that aquifer may be impacted as well. In most aquifers, groundwater flow is far slower than most people imagine, so contaminated aquifers typically STAY contaminated for very longer periods of time, possibly decades (depending upon aquifer hydraulic conductivity, matrix interaction with contaminant, geochemical makeup of the groundwater, nature of contaminating substance, etc.).

As previously mentioned, the Georgia Water Well Standards Act specifies if, when, and how an unused well is to be “filled, sealed and plugged” by a licensed water well contractor. Unless a person can observe an old, dug well which presents the obvious physical danger of falling into it, these unused drilled wells seem to be totally off the radar of most people, even those that work with groundwater regularly. These forgotten wells sit silently forming a direct conduit into whatever aquifer they were installed in. Note that according to the Water Well Standards Act, a well that has not been used for three years should be plugged and abandoned and the property owner is responsible.

Downhole camera view of an old, unused well with casing that has corroded completely through. Note that shallower groundwater of unknown quality is flowing into the well and down into either a deeper aquifer or deeper zone within the same aquifer.  The annular space around this well casing was either never grouted, the grout was improperly applied, or it simply failed over time.

The former Georgia Geologic Survey (GGS) had a program at one time that properly plugged and abandoned wells on state property and abandoned old municipal wells for small, impoverished townships. However, the GGS and its programs no longer exist and to date there have been no plans to resurrect them.

Abandoned artesian well in the surf zone at St. Simons Island. Its presence indicates encroaching sea level on a former private or public well.

Same well being properly abandoned by Georgia Geologic Survey drill crew in 1999. 

Today, some property owners and most municipalities of all sizes have wells that need to be properly abandoned. Most of these wells will remain unplugged due to lack of knowledge of the law regarding wells, lack of knowledge of the well itself, or lack of funding to properly abandon the well.

An improperly constructed well or a forgotten well sitting unused and open to the elements could pose a direct threat to the general public that might obtain groundwater from the area. It would be prudent for all citizens of Georgia to be aware of these dangers to our subsurface drinking water sources that should be protected from contamination, because once an aquifer is contaminated, it will most likely be exceedingly difficult if not impossible (both in costs and in human timeframes) to clean it up.

 

Steve Walker, P.G.

Source Water Specialist

Georgia Rural Water Association