All and all it is easier to move people than water. The steep slopes of BC would need to be terraced if high production is a goal. Alberta would need to increase the farmland in the north by draining some of the muskeg and the extra peat shipped south to be mixed into the current soil that is too sandy for production today. If they want to keep the irrigated south stop the evaporation by delivering water underground rather than spraying. The desert is cold at night that is the only time water should be fed to the plants. They don't need to import they need to conserve what they have already. You can also make water my mixing two gases together, the goal there would be water with price having no limit.
Lightweight sail-cloth would last 20 years and then no water is needed above the initial filling an resupply of what open doors would cause. That could be installed between the arrays of solar panels replace the water now being lost to making power. Using the right solar angels the white cloth could also enhance the light reaching the solar cells upping their out-put just a tad.
The bigger projects might need some real capital (honey-comb Baffin Islands high cliffs with sunlight being piped in via fiber optics which allows for fresh plants like tomatoes and humans would need the Vit D that suntanning provides today). Can you imagine what the hallways (streets actually) would look like while collecting all the shifting light patterns of the Northern Lights?
The only real concern I have over water diversion is in how it is diverted. If they open Lake Michigan to the Mississippi at Chicago, how long will it be before boaters on the Trent and Rideau canals are going to be dodging flying carp?
"flying carp" is that the name of a new freight hauling company that uses the canal for big loads of cargo. The Red River could be reversed just with a strong north wind and Lake Winnipeg could be refilled from the north via many small dams.
