Understanding soak cycling, Precipitation rates vs. infiltration rates, Precipitation rates for common sprinkler types – Baseline Systems BaseStation 3200 V12 User Manual
Page 16: Estimated infiltration rates for common soil types
BaseStation 3200 Advanced Irrigation Controller Manual
Watering deeply and infrequently on a consistent basis will promote healthier plants with deeper
root structures. As roots grow deeper, the plants are then able to access water in deeper and
typically wetter soil layers, making them even more water efficient. Plants with deeper roots are
also able to draw nutrients and fertilizers from deeper soil layers, making the plants more nutrition
efficient as well.
Understanding Soak Cycling
When you set up your irrigation programs, remember that the rate at which the irrigation
application devices apply water might be very different than the rate at which the soil in your
landscape can take up that water.
Soak cycling breaks the total run time into shorter water “cycles” with “soak” periods in between to
allow time for water to soak into the soil.
Precipitation Rates vs. Infiltration Rates
The precipitation rate, which is the rate at which sprinkler heads or drip emitters apply water to the
soil, is typically measured in inches, like rainfall.
Many soils only allow water infiltration at a rate of .25 inch per hour or less, whereas most head
types put down .50 inch per hour or more (much more in the case of some spray heads).
Also remember that head spacing and overlap directly influence the total precipitation rate for any
specific zone.
Precipitation Rates for Common Sprinkler Types
Spray Heads
1.00 inch to greater than 5.00 inches per hour
Gear Driven Rotors
0.25 inch to 0.65 inch per hour
Multi-stream Rotors
0.40 inch to 0.60 inch per hour
Drip Emitters
Depends on area covered, rarely exceeds infiltration rate
Estimated Infiltration Rates for Common Soil Types
Course Sand
0.75 inch to 1.00 inch per hour
Fine Sand
0.50 inch to 0.75 inch per hour
Find Sandy Loam
0.35 inch to 0.50 inch per hour
Silt Loam
0.15 inch to 0.40 inch per hour
Clay Loam
0.10 inch to 0.20 inch per hour
As you can see from the tables above, most sprinkler heads have higher precipitation rates than the
infiltration rate of most soils.
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