Regarding the marketing of water resources, I would simply add that exporting water in bulk to the United States could conceivably be a cost-effective move, as the distances involved are not too great. However, exporting water in this manner elsewhere is absolutely not cost-effective. Indeed, it would be more cost-effective to build a new filtration plant in Africa than it would be to ship water to the continent.
The same is true in Canada. Shipping water is an extremely costly undertaking. Water is heavy, cannot be compressed and cannot be dehydrated. Therefore, marketing water is not very useful, unless it is done on site. In that case, it's not really a question of selling water, but rather a matter of withdrawal and usage rights. It's not easy to find a way to make water a profitable commodity, especially in Canada.