Effective Rainfall; Plant Available Water - Rain Bird ESP-SMT Installation & Operation Manual

In this example the daily water losses due to ET are as follows:
Day
1
2
3
4
5
Total

Effective Rainfall

Not all rainfall is usable by the plant. If the rainfall intensity
is high, the rain may not percolate completely to the plant
root zone before running off the clay soils or in sandy soils,
the water may go below the plant root zone. The integral
tipping rain bucket measures both the total amount and
intensity of the rainfall and determines how much of it
should be considered "effective" rainfall.
In this example the daily water losses due to ET are as follows:
Day Total Rain
1 0.00"
2 0.00"
3 0.46"
4 0.00"
5 0.00"
Total 0.46
ESP-SMT Smart Modular Control System
77
ET/Day
0.18"
0.16"
0.16"
0.18"
0.14"
0.81
Effective Rain
0.00"
0.00"
0.16"
0.00"
0.00"
0.16

Plant Available Water

In the attached example, the plants roots are 12 inches
deep. The soil class is Loam. Looking at the adjacent Soil
Water Holding Capacity Table, the AW is 0.17 inches of
water per inch of soil. The Plant Available Water (PAW) in
this example would be 0.17 inch/inch X 6 inch root depth
= 1.02 inches of potentially available water in the soil
reservoir for the plant material.
Soil Available Water (AW) Table MAD Table
Soil Type or Class
Clay
Silty Clay
Clay Loam
Loam
Sandy Loam
Loamy Sand
Sand
Available Water (AW)
(in of water per in of soil)
0.17
0.17
0.18
0.17
0.12
0.08
0.06