How to Use and Maintain Drip Irrigation Systems

How to maintain your drip irrigation system in top shape?

Reducing irrigation operational costs and preventing crop damage with periodical maintenance schedule.

Drip irrigation maintenance pays back.

We would like to address the importance of proper maintenance of the drip irrigation system and its end result benefit. The best policy is prevention: long-term system operation depends on inspecting the whole system periodically and systematically in addition to correct design and installation. A good drip irrigation system implies a professional hydraulic design, proper installation and maintenance. For optimal performance, drip irrigation systems require simple routine check-ups. If periodical maintenance is not performed, the risk of damage to the irrigation system increases.

The first step to check that the drip system is still operating correctly is to verify the main head flow rate and pressure. This is done by simply reading the water meter and pressure gauge. Any deviation from the designed flow rate and pressure is a sign that there are problems in the system.

If we notice an increased value for the flow rate, this can indicate a possible rupture in mainlines, submain or drip laterals. A decreased flow rate might possibly indicate clogging of one or more system components.

The second step is to check the pressure at the main head and field valves and make sure that the pressure values match the original hydraulic design pressure values. Pressure regulating valves are based on spring resistance and hydraulic equilibrium. The springs can be weakened after prolonged operation. Therefore, they should be inspected and recalibrated every season at system start-up.

 

Weekly maintenance

Check that the water reaches the end of the line by spot checking that the drippers at the end of the row are emitting;

Check the pressure differential across the filters. If the pressure differential exceeds 0.8 bar, this could indicate a filter or controller malfunction;

Check the flow rate and pressure for each irrigation shift after the system has been active for 30 – 45 min and the pressure has stabilized;

 

 

Monthly maintenance

Check the pump maintenance instruction provided by the manufacturer. Special care should be provided to ensure that the suction screen is clear of any debris, and that the lubricating bearings and lubrication oil are at the appropriate level and quality;

Initiate a filter manual flushing sequence and make sure the filters are backflushing correctly and pressure differential drops to 0 bar after flushing;

Connect a pressure gauge to the field valves outlet and make sure that the value is still as per the hydraulic design;

Flush drip lines until the water coming out is clean and clear. Note: The required interval between the flushing regime will depend on the water quality. A general rule of thumb during the season is weekly for very dirty water, once every two weeks for dirty water, and once a month for clean water.

There are six main components of a drip irrigation system.

1. Valve: A drip kit irrigation valve controls the flow of water. You can equip a water valve with an automatic timer and pre-program your watering times.

2. Filter: The filter on a drip irrigation kit prevents debris from clogging the tubing.

3. Pressure regulator: The water pressure of the typical home water supply is too high for a drip irrigation system. The pressure regulator both decreases the water pressure and provides a constant low-pressure flow, even if your home water supply's pressure fluctuates.

4. Backflow preventer: This device prevents water in your irrigation system—which may become filled with dirt and bacteria from the soil—from getting sucked back into your drinking water supply when your drip system is turned off.

5. Dripline: This flexible drip tubing transports water from the valve to your plants. Also known as a distribution line, the dripline connects to the pressure regulator via a tubing adapter. Black or brown drip line is common, as it blends in with soil and mulch.

6. Emitters: Also known as drippers, drip irrigation emitters are small plastic devices that connect to the tubing to discharge water into the soil. Emitters are rated based on their gallons per hour (GPH) flow rate and the maximum water pressure they can handle in pounds per square inch (PSI). As a general rule, most plants require one or two emitters to receive the proper amount of water.

7. End cap: Also known as a flush valve, an end cap prevents water from running out the end of a drip line. Remove the end cap at least once a year to flush out any sediment or algae that has built up inside the tubing. Once the water runs clear, the tubing has been properly flushed, and you can reapply the cap.

Conclusion

Farmers are always working to save water, produce crops of the highest quality, and most importantly, realizing a return on their investment. A drip irrigation system is a major investment that incorporates different components which need to work together to deliver the best results. Much like the cars we drive, regular maintenance is the guarantee that we will reach our destination safely.

Disclaimer: The above is provided as general advice only. Every applications is different, and the maintenance regime you require for your drip irrigation system should be developed in consultation with an irrigation professional or your Rivulis representative.