Available Water Flow

Meter Size• Typical flow depending on size

– 5/8” = 12 GPM– ¾” = 15 GPM– 1” = 20 GPM

Available Water Flow

Determine available flow with Bucket Test• Water meter: measure at backflow preventer

Available Water Flow

Bucket Test• Pump: measure at pump

Bucket Test

(5 gallons / seconds to fill) X 60 seconds =

Gallons per Minute (GPM)

Available Pressure

Pounds per Square Inch (PSI)• Static PSI

– Pressure when water not moving– Measure with PSI gauge on water spigot (meter)

• Operating PSI– Pressure during operation

High Pressure…..

Low Pressure….

High Pressure

Low Pressure

Low Pressure

Low Pressure

Pressure Measurement

Pressure gaugePressure gauge

Pressure Gauge (Pitot Tube)

• Measure operating pressure

Water Pressure

Created by:Elevation

– Weight of water

Water Pressure

1’ of elevation (head) = 0.433 psiIn irrigation terms, 1’ of elevation

is referred to as 1’ of head

1 in.

1 in.

12 in.

0.433 psi

Water Pressure

2.31’ of elevation = 1 psi

1 psi

2.31 ft.

Pressure and Container Size

What (relatively) will be the pressure at the base of various containers? Same for all (only the height of water column

determines the pressure )

A B C