As a food preservative, salt has been essential to civilization. It is no accident that the word “salary” derives from the same linguistic root. Water is also essential to civilization. Combine the two materials, however, and the resulting substance has diminished value for human use. Nevertheless, a water-constrained future may force us to look at using saline water. Few industries in Alberta deal with saline water more than oil and gas production.

The line between saline and non-saline is relevant to several aspects of oil and gas operations. They include the use of non-saline water for the purpose of enhanced recovery, regulations related to casing and fracturing, the use of saline aquifers for waste disposal, and in the aquifer dewatering process. Alberta regulations distinguish between saline and non-saline water in all of these areas. The focus of this article is on water produced through the dewatering of an aquifer and the deposit of waste in saline aquifers.

The Water Act requires that a licence be obtained prior to diverting water, including the dewatering of an aquifer. The Water (Ministerial) Regulation exempts “saline groundwater” from this licence requirement and defines saline groundwater as “water that has total dissolved solids exceeding 4,000 milligrams per litre” (mg/L). This creates a regulatory dividing line between management of non-saline water and saline water, and between the jurisdictions of Alberta Environment and the Energy Resources Conservation Board, respectively.

Saline water produced through the dewatering process and the subsequent disposal of this water is regulated by the ERCB, whereas non-saline water is regulated by Alberta Environment.

Non-saline water is either disposed of in aquifers of a similar character or to the surface with the approval of Alberta Environment. For surface releases, a federal approval under the Fisheries Act may also be required. In contrast, saline water often remains untreated and is injected into deep aquifers.

For waste disposal purposes the dividing line of 4,000 mg/L total dissolved solids is also relevant. The ERCB regulates the disposal of operational waste in saline aquifers. Waste disposal into non-saline aquifers is prohibited.

In this way the future use of saline water is being compromised in the province. Reuse of produced saline water and future use of saline water in “waste” aquifers is a topic of debate. Currently, the dividing line between saline and non-saline water divides what regulators consider usable and what is unusable or waste water.

Should this dividing line shift? Many people, including the Rosenburg International Forum on Water Policy, think so. Groundwater with total dissolved solids between 4,000 and 10,000 mg/L has been treated and used for various purposes in other jurisdictions.

Up to this point in time there has been little motivation to look to treating saline water for reuse in Alberta. Water licenses have been historically handed out for a minimal cost.

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