Good luck watering your fields with a 1m diam pipeline...

Or, to expand on this, a gallon of oil makes a car go dozens of miles, while a gallon of water won't even flush a toilet; volumetrically, the US uses about 50 times as much water as oil.

I would suggest two 1m diameter pipelines, but I feel like one 1.4m diameter pipeline would be even cheaper.

There's no limit on how long you can make an aqueduct. We don't have long aqueducts because water isn't very valuable.