Pick up the incorrect statement from the following :

• The net amount of water which joins the surface streams in a catchment, is known as surface run-off
• The amount of water which joins the stream from the underground water, is called base flow
• The yearly run off in cm depth over the catchment, is termed as the yield of the drainage basin
• The yield of drainage in cm depth multiplied by the area of the catchment gives the annual volume of water
• None of these.