Introduction To Irrigation System Design 101

Submitted by: John Hoffman

It is my opinion there are two types of irrigation systems, landscapes and gardens with the same goals in mind, to have water for plant growth and conservation. Regardless the purpose of you reading this introduction, I am presenting a few basic principles of irrigation system design to, hopefully, answer some questions that you have regarding this topic.

There are two basic items required to operate a sprinkler, water flow and pressure. A lot of us think in terms of water flow. How much water do I need for my system. It is an important consideration; however, an equally important question is, how much pressure will I have at the sprinkler? This is critical! Why? For illustrative purposes, let us hook up a sprinkler to a short piece of garden hose and at the other end insert a funnel.. Now pour a five gallon bucket of down the hose to the sprinkler. What is happening? Nothing! Why didn’t it work? There was plenty of water, 5 gals; well, the water poured down the hose had insufficient pressure to make the sprinkler function. Water pressure is the energy that allows the sprinkler to do what it was designed for, spread water.

In an ideal world, when one turns on the water at the source, the water pressure at the destination would be the same. Wrong! Some of pressure is lost when the water goes through the water meter. More is lost as it moves through the various pipes in your yard and home. Squeezing through valves eats up more pressure. Simply put, everything that the water encounters in its travel from the source to the final destination, the sprinkler uses up a small amount of water pressure.

Alas, we have the key to a good sprinkler system design. There must be sufficient pressure left to permit the sprinkler to function for what it was designed to do. Employing the correct sizes of pipes, valves, etc, one can control the amount water pressure loss in the irrigation system, and that, my dear reader, is what sprinkler system design is all about.

There you have it in a nutshell. Easy. All you have to do is control the pressure throughout the system.

There are 5 basic steps to sprinkler system design.

1. Measure your yard. Accurately measure your yard and then sketch out the area to be irrigated. After that some information needs to be obtained. What is gallons per minute (GPM) and water pressure which is measured in pounds per square inch (PSI).

2. Exam the things that can reduce your water pressure as the water moves to the sprinkler.

3. Start drawing the sprinkler system on paper.

4. Divide your sprinkler system into zones and layout the piping routes. This is where we are going to make the right decisions to create a sprinkler system that uses less water than most and gives one healthier plants. A major cause of turf disease and wasted water is poor sprinkler design.

5. Determine the size of each pipe and clean up a few small details. Examine the practicality of automating the sprinkler system.

Essentially, this is a basic concept for irrigation system design. Below I have a few reminders and additional notes:

Automatic controllers: For automatic systems you will need a controller (often called a “timer”) with one “station” for each valve.

Isolation valves: It’s a good idea to install a manual shut-off valve at the point where your irrigation system connects to the water supply.

Wires for valves: For wires going to the automatic valves use wire made specially to be buried. Most people use a special direct burial cable made for irrigation systems. The cable contains 3, or more, separate, 18 gauge wires. On commercial systems the standard wire used is “#14-1 AWG-UF” which is a single strand, direct burial type wire. One white color “common” wire goes from the controller to every valve, and one individual “lead” wire of a color other than white goes to each valve from the controller.

About the Author: I am a retired aerospace engineer that over the years has acquired a rewarding hobby of gardening and landscapes. Within the scope of my new hobby, I have been fortunate enough to further my freelance writing career under contract to

tnnursery.net

whose expertise has been invaluable.

Source:

isnare.com

Permanent Link:

isnare.com/?aid=1006663&ca=Education