Yes, absolutely. You are right, the question is very much on point. That is where the main issue lies.
I think we have to see jurisdiction over water as a fluid power. The pun was not intentional, but that is the case. This fluidity is seen at all levels, whether for a regional watershed, for example the Mackenzie River watershed, which covers an enormous area, or the much more localized watershed of a lake. There will be issues relating to fisheries and navigation that will unarguably fall under federal jurisdiction, but of course there will be overlap between those and provincial and municipal or even indigenous jurisdictions.
Given this, it becomes a matter of collaboration. Starting from the principle that whatever the extent of the land affected, we may encounter a strong intergovernmental dimension, I think the role of the federal government, in this scenario, is really to initiate cooperation. Its role is to implement the necessary tools, the safety net, to avoid falling into a situation where we are no longer able to manage water because management is too fragmented and no political agreement can be reached. Certainly, in political terms, there are very strong issues. However, I think the federal government should institute the necessary and sufficient guardrails while respecting regional diversity and richness.