"October 28, 2011—The White Salmon River in Washington state is flowing again as the nearly 100-year-old Condit Dam was disabled with explosives Wednesday. The reservoir draining took about 2 hours. Further demolition is scheduled in 2012."
Don't have a water table to demonstate fluvial geomorphology? This Time Lapse video demonstates deposition and erosion powerfully. This is also a useful discussion started for human and environmental interactions.