(1) The decrease in total head caused by friction (2) The effect of obstructions, such as narrow bridge openings or buildings, that limit the area through which water must flow, raising the surface of the water upstream from the obstruction
1) The loss of energy experienced due to a reduction in head For example, when a given volume of water released from Mica Dam in British Columbia results in low energy production because non-Treaty storage space is not full 2) The amount of the reduction
The loss of pressure in a flow system measured using a length parameter (i e , inches of water, inches of mercury)
The pressure of water as measured at a stated point; it may be measured in feet or in pounds per square inch (PSI)
in farm channels, if the channel cross-section and the speed of water flow remain fairly uniform, head loss can be taken to be the difference in water level between any two points
The head, pressure or energy (they are the same) lost by water flowing in a pipe or channel as a result of turbulence caused by the velocity of the flowing water and the roughness of the pipe, channel walls or restrictions caused by fittings Water flowing in a pipe loses head, pressure or energy as a result of friction losses Also see friction losses