Subsurface Drip Irrigation Guide - Page 6

The following is a simple way to determine the correct soil. There is another faster method at the end of this guide - please click here for more information.

SUPPLIES YOU NEED:

WHAT TO DO:

WHAT TO DO NEXT:

This will be remarkably easy because Netafim USA has developed a series of charts that answer virtually all product selection, flow rate, spacing and run length questions.

The General Guidelines Chart above tells you what type of Techline CV to use. The specific dripperline chosen is based on the answers you provide and what is being irrigated and its soil type. For instance, if you are irrigating turf and with clay soil, the chart tells you to use:

• Drippers with 0.26 GPH flow rates
• Drippers spaced 18" apart in the dripperline
• Rows spaced anywhere from 18" - 22" apart

The type of plant and its soil are two questions that need to be answered regardless of what type of irrigation system you are designing. The important thing is, even if you have never used dripperline before, you have just been steered to the proper product. In this case, you would ask your Netafim Landscape & Turf Distributor for 0.26/18" (0.26 GPH flow rate per dripper with drippers spaced every 18") Techline CV dripperline.

As we continue down the column there is more information available for us. The chart indicates that you can bury the dripperline down to 6", as well as what the application rate is in inches per hour. Going one step further, we have translated application rates into how long it will take to apply 1/4 inch of water.

Now that we know what flow rate and dripper interval to use, (0.26 GPH and 18" dripper interval in this example) we can move to the Maximum Length of a Single Lateral Chart on the next page. Here we'll learn how far a single dripperline lateral can run.

Note: We are often asked how many feet of dripperline you can put in a zone. We normally answer the question by asking, "How many rotors or sprays can you put on a line?" The answer to that question comes fast. "It all depends on how much water you have, and the pressure." It's no different with dripperline. The amount of dripperline you can put on a zone is a function of the pressure and the amount of water available.

The Techline CV Maximum Length of a Single Lateral chart takes the information we learned from the General Guidelines Chart and expands on it. In our example, we are using 0.26/18" Techline CV for our turfgrass in clay zone. This chart tells us that if we have 45 psi available at the beginning of the dripperline lateral, we could run a single lateral 877 feet. If the pressure is 35 psi, the length of a single lateral could be 763 feet.

The science behind this number is simple. We have taken the friction loss over distance and the amount of water it can flow at velocities at or below 5 feet per second and determined for you the point that the dripperline would no longer work properly. In short, this is a friction loss chart with all the heavy lifting done.

As to the number of rows needed, each of them extending as far as 877 feet, that is a function of how much water you have. Just like the number of rotors you have depends on available water, pressure, and piping, so does dripperline.

The last of the three charts designed to speed the selection process is the Techline CV Flow per 100' chart. This chart simply translates the gallons per hour world of low volume into gallons per minute. Because Techline CV and Techline dripperlines are pressure compensating, we can accurately determine the flow. In the case of 0.26/18" Techline CV, every 100 feet would use 17.58 gallons per hour, or 0.29 GPM. For example, a lateral that is 800 feet long would use 2.32 GPM (8 x 0.29).

Armed with what you are trying to grow and what type of soil you have, we have answered many questions with our easy-to-use charts.

• Dripperline flow rate
• Dripperline interval
• Dripperline row spacing
• How deep to bury the dripperline
• Application rate
• How much time to apply 1/4" of water
• The potential maximum length of a lateral (once we know the psi available to us)
• The flow per 100 feet in GPM and GPH

There is another piece of information that would be nice to know. That is, how many feet of dripperline do we need for the zone?

Subsurface Drip Irrigation Guide - Page 6