Hydro:
https://www.google.com/maps/place/Abitibi+Canyon,+ON,+Canada/@49.717424,-81.6017282,16365m/data=!3m1!1e3!4m5!3m4!1s0x4d16327856e495c9:0xb99603fe74e3013c!8m2!3d49.8790539!4d-81.571385
Terrain?
Other than the Canyon it'self, I'm not sure there's more than 10' of topography between Cochrane and Moosonee.
It's aboot as dead flat as you can git.
I could look up the marks on the topo map, but don't want to dig'm out right now.
We're lookin' at a big pc of paper with hardly any lines on it!