Fluvial geomorphology
http://www.youtube.com/user/gravelbar
Geomorphology
http://serc.carleton.edu/NAGTWorkshops/geomoph/emriver/index.html
Sedimentology
http://www.youtube.com/user/sumnerd
The Earth Chronicles (geomorphology)
http://www.youtube.com/user/bapyou
Geological Society of America
http://www.youtube.com/geosociety