Worth Our Salt: Tightening constraints on water supplies

 

Worth Our Salt: Tightening constraints on water supplies call into question the legal line drawn between saline and pure sources

7/3/2009

Published in Alberta Oil Magazine Summer 2009
By Jason Unger

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.

 

This regime has recently changed in Alberta with the closures of most of the South Saskatchewan River Basin to further water allocations from surface water. With continued growth, groundwater allocations will likely also become more restricted through time. If this occurs, it is reasonable to conclude that the Alberta government will put increased reliance on the trading of water licences.

 

In the event that watersheds are closed to both ground and surface water allocations, water will only be obtained through the transfer of an already licenced allocation. It is through this transfer system that a market value for water allocations has begun to evolve in the South Saskatchewan basin.

 

Another option under the Water Act is to have a licence holder temporarily assign its allocation. The ability to assign a licensed allocation is limited by the fact that only two licence holders can take part in an assignment (along with other restrictions).

 

But saline water diversions are not licensed under the Water Act. This regulatory reality effectively bars the transfer or assignment of saline water and therefore stands in the way of taking advantage of the economic incentives to treat, reuse and conserve water.In this way, the 4,000 mg/L total dissolved solids dividing line also separates water into two groups: one that is subject to the price signals of the market and one that is not.

 

Admittedly, current and future use of saline water (whether treated or not) will depend on much more than this legal context. It will depend on the quantity of water produced and the costs of transferring and storing this water for other uses.

 

Although the amount of produced saline water is tracked and reported, there is little public information available about the cumulative or average quantity of the water involved. Nevertheless, it is clear that this issue is on the radar of Alberta regulators. A cost benefit analysis of treating saline water was conducted by Alberta Environment in 2007.

 

While minimizing Alberta Environment’s regulatory oversight for saline water made sense in the past, a constrained water supply is likely to continue to be a reality for parts of the province in the future. If we are to take advantage of market forces in relation to water allocations, there is a need to consider changing the dividing line between saline and non-saline water.

 

This need means considering options for treatment and reuse of produced saline water and altering the level of salinity at which an aquifer is deemed appropriate for receiving waste.

 

Promoting the economical reuse and conservation of saline water has the added environmental benefit of alleviating pressures on surface water bodies and other potable sources. Just as the world’s commerce has evolved from being centered on salt, the world has evolved in saline water treatment technologies and the value we place on “usable” water.

 

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