Inflation adjusted… those canals cost $50 billion to construct and the project took decades. It would cost far more now, since getting access to the land rights would be a nightmare.
They’re already not providing enough water, so if building more canals is your proposed solution then you needed to start construction 20 years ago.
Upgrading the canals can potentially double the amount of water they provide. It’s far cheaper, and quicker, than building more canals.
Solar panels alone wouldn’t get you to 2x efficiency but it’ll help a lot, and unlike other upgrades it also provides ongoing revenue. It’s an absolute no brainer to start with this and do other canal upgrades later, when every inch of the canals are already covered in panels.