Quote Originally Posted by surfarcher View Post
Even a very high level ritual caster would chew through a lot of time and components (=money) filling in even a medium gorge and I doubt it'd be perfectly flat afterwards (it'll settle over time). My thought was magic would simply be used for removal of rock and soil that wouldn't be viable by hand (think disintigrate) and to assist in support structure construction like bridges (yeah the Romans built those for their roads+armies too). So basically I've already elected to stay more or less with what the Romans did but to up the grand scale of some select structures to fit in with the scale of a fantasy world.
As someone who has played more Wizards than any other class, I'd have been using a 6ft stack of Rock to Mud spells, not Disintegrate. Mountainside turns to mud, slides into valley, large rocks fall after, wait for spell to end AND REPEAT. It gets you a shorter mountain (which may be useful for garrisons/fortification/defensive position buildings) and gives you a taller valley (for your road).

But then, I also was renowned for trying to solve combats by not actually having the combat... as evidenced by the Rock to Mud trick above...