Research & Science Note 6: Water Well Decommissioning and Groundwater Protection
It is important to maintain unused wells during prolonged periods of non-use. Settling of fine clay particles on infiltration galleries may cement wells in if they are not being regularly pumped.
Background
The Milk River Aquifer is critical in the provision of water for urban and rural residents and in sustaining base flows of the Milk River during low flow periods. In the 1960s, a study showed that the groundwater resource was depleting. In 2004, the status of groundwater wells in the Milk River Aquifer was investigated by the Milk River Aquifer Reclamation and Conservation Program (MRARC). This study found over 1,000 water wells in the Milk River watershed that were either unused or abandoned.
More recently, the Milk River Transboundary Aquifer Project verified the status and location of an additional 266 water wells, of which 45 wells were abandoned. Some of these abandoned wells continue to flow at surface and many others are left uncapped and exposed at the surface. There is a tangible concern that contaminants can enter the aquifer from the surface or mixing of lesser quality unconfined aquifers with the Milk River aquifer in abandoned wells.
Although most well owners indicated the desire to decommission unused and abandoned wells, the work is costprohibitive.
About 101 wells (only 23%) were decommissioned through the MRARC program, while the majority of wells are still abandoned and not properly sealed.
During the summer of 2013 the MRWCC facilitated a workshop to promote awareness on the importance of proper decommissioning
of abandoned wells and also allow watershed residents and extension staff to see the procedures and discuss challenges of decommissioning water wells. This workshop was sponsored by the Shell FuellingChange program and was open to producers, community members, and extension staff working with well owners to protect groundwater resources in Southern Alberta.