hydraulics terms and definitions

absorption rate

rate at which a soil will accept water. rate decreases as soil “capacity” is reached

percolation rate

application rate

rate at which water is applied by the irrigation system. it is usually measured in inches/ hr or GPH

arc

the surface area of the landscape that the head will provide water. usually described in degrees or part of a circle

as built-plan

a corrected/redrawn plan showing the actual location of all major components of the system and other information the property owner might require

contour lines

line of equal elevation drawn on a plan

cycle

refers to one complete operation of a controller through a program

design

act of determining various elements of a landscape irrigation system that will include site specific info, defining scope of the project, defining plant watering needs, selecting and laying out emission devices, etc.

distribution uniformity

measure of the uniformity of irrigation water over an area. how uniformly water is made available to the plants over an area.

flow restrictions

physical restrictions in component parts of an irrigation system that affect the flow of water thus causing a pressure loss

head spacing

spacing between sprinkler heads

head-to-head spacing

spacing of spray or rotary heads equal to the manufacturers published radius of the head

irrigation plan

scaled drawing of a landscape irrigation system which lists required information, the scope of the project, and represents the changes made in the installation of the irrigation system

record drawing

drawing of installed irrigation system showing the location of major components either scaled on the drawing or shown by dimension not to scale

seasonal watering schedule

recommended adjustment of the watering schedule to conform to seasonal conditions. different watering requirements may be due to temperature, day length, humidity, and plant life cycle. schedules should be checked periodically for plant stress and adjusted as the plants needs dictate

section of heads

section of sprinklers controlled by one valve

slope

measure of the rate of change of elevation over a prescribed distance. may be expressed as a ratio, grade, or percent

static water pressure

measured pressure of water when it is not moving

water schedule

procedure of establishing and implementing the time, frequency, and amount of irrigation water to apply to landscape

water window

allotted time available for operating an irrigation system in a 24-hr period

gallons per zone

no more than 75% of meter, K max

go with lowest number of the 2

AH=

S - L

DP=

DH + L