Drip Irrigation Design Guide-Calculating Total Flow & Creating Watering Zones
Designing & Planning Your System
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Calculating Total Flow & Creating Watering Zones
When planning your drip system, it’s important not to exceed your drip zones water source capacity. To determine a flow zones capacity, add up the total number of drip emitters and their flows. This same method applies for micro sprays and jets.
Example: Your drip irrigation plan calls for using a total of 80 drip emitters and 40 ft of soaker hose dripline. The emitters consist of 25 – 2 GPH, 15 – 1 GPH, 40 - 1/2 GPH drip emitters and 40 ft of soaker hose dripline with 6" spacing with 1/2 GPH emitters. The plan also includes using 4 micro sprayers for ground cover at 10 GPH each.
To calculate the overall flow rate:
25 – 2 GPH Emitters (25 x 2) = 50 Gallons per hour
15 – 1 GPH Emitters (15 x 1) = 15 Gallons per hour
40 – 1/2 GPH Emitters (40 x .5) = 20 Gallons per hour
40 Ft soaker hose drip line (40 / .5) x .5) = 40 Gallons per hour
4 – 10 GPH Micro Sprayers (4 x 10) = 40 Gallons per hour
Total flow rate = 165 GPH or 2.75 GPM. If the max capacity of 1/2" drip tubing is 240 GPH, you will have a flow reserve of 75 GPH or 1.25 GPM.
If your drip systems flow demand exceeds its water source capacity, you will need to create a new water zone. Installing a hose splitter will give you extra water source connections for additional drip zones.
QUICK TIP: When planning a drip zone, be sure to leave enough flow for future system expansions or when plants mature and require more water.
QUICK TIP: Install flow control valves on both 1/2" & 1/4" drip tubing to isolate and control water to various sections of your drip system.