Permafrost and Artesian Water
Most people are greatly pleased when they strike artesian water, but recent events on Farmers Loop Road near Fairbanks show that an artesian well can constitute a geologic hazard instead of being beneficial. A well driven there yields an artesian flow that, so far, cannot be stopped. The result is unwanted flooding and icing of nearby property.
Artesian wells are common in some parts of the country, especially in the midwestern states. Artesian wells there result from drilling through an impervious capping layer into a water-bearing layer which is sloping. Water enters the aquifer layer at higher elevation than the top of the well and thereby creates a pressure head to drive water up the well.
The situation on Farmers Loop Road is much the same. Water enters the soil on the hills above the road and is trapped under the permafrost layer at the foot of the hills. Since the permafrost extends uphill above the wellhead, a pressure head is created, and so water flows up the well.
A normal artesian well can be stopped by simply capping the pipe. Apparently, water flowing upward through the well on Farmers Loop Road has thawed the surrounding permafrost and made the soil around the well permeable to water. To stop the flow it probably will be necessary to either refreeze the soil around the pipe or in some other way make it impervious to water pressure.
