Module 9 — Plugging Abandoned Wells
Plugging Abandoned Wells
When a well is no longer being used or maintained for future use, it is considered
abandoned. Abandoned wells pose a serious threat to the preservation of groundwater
quality. They are also a serious safety hazard for children and animals.
There are approximately 59,000 farmsteads in Alberta and most of these have at least
one well. In addition there are a great number of non-farming rural residents that rely on
water wells. The exact number of abandoned wells in Alberta is unknown but is estimated
to be in the tens of thousands. Plugging an abandoned well prevents:
Downward movement of water in the well or well annulus
Surface contamination from reaching aquifers
Intermixing of water between aquifers of different water quality
Serious accidents from happening.
Unfortunately, groundwater contamination and its effects are usually not recognized
until groundwater quality is seriously affected and nearby wells have been contaminated.
Surface contaminants can enter a well several ways:
Directly through the surface opening if the cap is loose, cracked or missing
Through unsealed spaces along the outside of the casing (see Figure 1,
Well Contamination).
When the steel casing of an abandoned well starts to corrode, holes will develop. When
this takes place, surface contaminants or poor quality water from shallow aquifers may
migrate into the deeper aquifers of nearby operating wells (see Figure 2, Contamination
From an Abandoned Well).
For more information refer to
the Water Wells That Last video (Part II —
Managing and Maintaining).
Wells that are no longer being used should be
plugged. They are a serious public safety and
environmental hazard.
Figure 1 Well Contamination
Figure 2
Contamination From an Abandoned Well