Most towns are already built on flood plains because historically it was good farmland. Look at the Fraser Valley in BC. Nearly two million people all living on one big flood plain.

Look at the towns around you. Are they built in a wide, flat bottom valley? That's probably a flood plain. Every town I can think of around me is built in the valley bottom first, then only goes up the hills as development grows over time.

Maybe, but certainly does help the unfortunate souls who already live in areas where the provincial governments have purposefully diverted flood waters, who wouldn't otherwise have been flooded.

They're fine taking the bullet to save hundreds or thousands more homes. They're not fine footing the recovery bill.