I'll take a stab at it.
CEMA is, as you said, a multi-stakeholder organization set up to advise, as I've been told, the Alberta government in its decision-making process. It's a discussion forum to see whether they can reach consensus on how to manage the issues related to the oil sands. In cases where consensus cannot be reached, and I'll give the example of the water management framework, it was the two decision-making authorities--the provincial government and the federal government--that actually decided what the water management framework should be.
On the basis of that example, I don't think we could say that any authority has been devolved to CEMA. The governments still retain the decision-making authority and are exercising that authority where CEMA cannot help.