We give a introduction to a few calculating methods on fall velocity of water drops athome and abroad at present.

The load of aircraft after landing was investigated by different vertical velocities,horizontal velocities and landing elevations.

Discussion on fall of level at the down reach of dams;

Influences of stage′s drawdown speed of the Three Gorges Reservoir on embankment;

All research results identify that the mode of the decrease of reservoir level is key mode to control stability of the landslide and must be control mode in harness of the landslide.