Historical ET

Historical ET is the estimated ET for an average year. In California's Central Valley, ET does not vary greatly from year to year, especially when ET is collected across a number of days.
Historical ET tables for mature:

Almonds
Walnuts
Pistachios
Stone Fruit
Prunes
Olives
Citrus
Apples
Pears

Immature Trees do not use as much water as mature orchards, so the ET information must be adapted.

For more information on using Historical ET for irrigation scheduling, see the following:

"Scheduling Irrigations: When and How Much"- ANR Pub 3396

Click here to download a free copy of the complete document:
"Reducing Runoff from Irrigated Lands: Understanding Your Orchard's Water . . ."- ANR Pub 8212