Irrigation in the Pacific Northwest

Percent Timer Setting

Older pivots only have a percent timer. Use this form to calculate a timer setting to apply a particular depth. For partial pivots use the numbers for a 360 degree, full rotation. Use the full rotation calculator to find the approximate amount of time it will take for a pivot to make a full rotation. Calculate the time for a 1" application.

To see the equations used in these calculators click here.


Learn more about the units used on this page.


Percent Setting By Depth

Percent setting at known application depth:
%
Depth of water applied at above setting:
Desired new depth to apply:
New percent timer setting:
%

 

 

Percent Setting by Desired Completion Time

Percent timer setting at known completion time
%
Known completion time
New desired completion time:
New percent timer setting for new completion time:
%

 

 

Percent Setting By 1" Application

Time for Full Rotation at 100%:
Time for 1" Application:
Application Required:
Percent Timer Setting:
%

 

 

The Equations

These calculators use these formulas to determine the percent timer setting to achieve a specified application depth or completion time.

 

Percent Setting By Depth


Where:

= The new pivot percent timer setting to achieve desired depth (as a %)

= The pivot percent timer setting to achieve known application depth (as a %)

= Known application depth (in)

= Desired new application depth (in)

 

Percent Setting By Desired Completion Time


Where:

= The new pivot percent timer setting to achieve desired completion time (as a %)

= The pivot percent timer setting to at known completion time (as a %)

= Known completion time (hrs)

= Desired completion time (hrs)

 

Percent Setting By 1" Application


Where:

= The new pivot percent setting to achieve desired depth (as a %)

= Pivot full rotation time at 100% (hrs)

= Pivot full rotation time to apply 1 inch (hrs)

= Desired application depth (in)

 

WSU Prosser - IAREC, 24106 N Bunn Rd, Prosser WA 99350-8694, 509-786-2226,