Maximize the longevity of your drip irrigation system

Know More. Grow More.

In 2023, we launched the Rivulis Drip Guide, a comprehensive set of four books that cover everything from product selection, to design, to maintenance of drip irrigation systems. All four books are available for download at the Rivulis Knowledge Hub.

One of the most critical aspects of drip irrigation is maintenance. In Book 4, we delve into maintenance in detail. In this article, I would like to provide an overview of what we call “The Big Nine” topics of maintenance. By mastering these nine areas, you will maximize the life and efficiency of your drip irrigation system.

So with that, let’s get started with the big nine! Note that this article offers a high-level summary only. Therefore, within each section below, we have included a link to the relevant section of the Knowledge Hub for more detailed information.

1. Good Filtration

Why it matters: Filtration is your first line of defense against clogging. If your filters are not maintained, debris can enter and clog the system.

Tips for Maintenance:

Pressure differential is one of the most important areas to monitor. This is the pressure difference between the inlet and the outlet of the filter. By consequence, this measures how clogged the filter is. However, it can also indicate filter problems. E.g. A pressure differential below normal head-loss indicates that the filtration medium is not filtering correctly, and water is passing through unfiltered.

In addition, the type of maintenance undertaken depends on the type of filter. Common maintenance requirements by filter type:

• Hydrocyclone Filters: Regularly open the drain valve to remove collected sand. Do not allow sand to build up more than one-third of the tank.
• Manual and Semi-Automatic Screen and Disc Filters: Pressure wash screens and discs at the beginning and end of each season. Check and lubricate O-rings and gaskets. Disc filters may also require chemical treatment.
• Automatic Screen Filters: Monitor flushing frequency and pressure differentials. Clean the hydraulic motor and recalibrate PD switches annually.
• Media Filters: Check media quantity and quality periodically. Install a flow control valve to manage back-flush flow properly. Consider chlorination treatment at the beginning and end of each season.

Read more: Knowledge Hub – Filtration Maintenance

2. Correct Operation Pressure

Why it matters: The operational pressures for your system will be included in the original hydraulic design. Any variance to these stated pressures normally reflects a problem that needs to be addressed.

Tips for Maintenance:

• Pressure Gauge / Port Installation: Pressure measurements need to be taken, and therefore pressure gauge/port installations need be installed, on the mainline both before and after the filters, and at each submain riser as a minimum.
• Monitoring: Regularly record pressure readings to detect deviations. Variances in pressures can lead to a diagnosis by assessing if the pressure change is gradual or sudden, increasing or decreasing, and where (e.g. across the filter). An explanation of pressure variance diagnoses can be found within the Rivulis Knowledge Hub.
• Pressure Reducing (PR) Valves: Verify that all pressure regulating valves are functioning correctly and adjust them as necessary.

Read more: Knowledge Hub – Correct Operation Pressure

3. Correct Flow Rate

Why it matters: Flow rate is as vital as pressure. If both the flow rate and pressure are within an acceptable range, you can have confidence that your system is functioning well from a hydraulic perspective.

Tips for Maintenance:

• Install Flow Meters: At minimum, you need one flow meter on the mainline to measure total water applied.
• Regular Monitoring: Once your irrigation schedule has been determined, read the flow meter to confirm that the system is applying the amount of water it was designed to apply. Because of the large number of variables at play in an irrigation system, the measured application rate cannot be expected to be exactly the same as the predicted rate. What you are looking for are large differences – either sudden or gradual.

Read more: Knowledge Hub – Correct Flow Rate

4. Flushing Regime

Why it matters: Even with filtration in place, tiny particles like silt and clay can still pass through the system. These usually won’t cause issues unless they accumulate and combine with organic material over time, potentially forming larger, more problematic material. Flushing expels this foreign matter before it becomes a problem.

Tips for Maintenance:

• When to Flush: Flush mainlines and submains at the start of the season and after repairs. Flush drip laterals at the start of the season, after repairs, and periodically during the season based on water quality.
• Velocity Requirements: Ensure submains have a flushing velocity of at least 0.5 m/s (1.5 ft/sec) and drip laterals at least 0.3 m/s (1 ft/ sec).

Read more: Knowledge Hub – Flushing Regime

5. Chemical Treatment

Why it matters: Chemical treatment is necessary to avoid clogging of the drip lines by solids that precipitate and aggregate in the tubing, and organic matter that passes the filter and propagates inside the irrigation system.

There are effectively two types of treatment:

• Acid Treatment: Used to dissolve mineral sediments.  
• Oxidation Treatment (chlorine/peroxide): For oxidizing organic material, iron and manganese, prevention of algae formation, and elimination of sulfur bacteria

Chemical treatment is very important, but it must be done right, and specific safety instructions must be adheared to. Furthermore, there are many considerations including acid types, chlorine vs hydrogen peroxide treatments, material sensitivity, and how to calculate concentrations and how much to inject.

For this reason, it is strongly recommended to read the section on Chemical Treatment in the Knowledge Hub. Not only will it provide the information above, it also provides the calculation formulas you need to determine the concentration and injection required, both in metric and US measurements.

Read more: Knowledge Hub – Chemical Treatment

6. Leakage and Clogging Prevention

Why it matters: Pressure and flow measurement reveal problems after they have occured. Better is to undertake preventative measures to reduce the likelihood of leakage and clogging in the first place.

Tips for Maintenance:

• Leak Monitoring: Regularly inspect for leaks caused by insects, rodents, or physical damage. If there are problems identified, place mitigation methods to reduce further occurrence. Consider Rivulis Defend for additional insect protection.  
• Clog Prevention: Filtration maintenance, flushing and chemical treatments are very important methods of clog prevention. However, part of your maintenance regime should also consider active management to prevent dripper root intrusion, soil ingestion into the dripper (which generally occurs at system shut-off), and precipitation (when dissolved salts combine and become insoluble).

Read more: Knowledge Hub – Leakage and Clogging Prevention

7. Correct Fertigation Regimes

Why it matters: The emphasis of the headline here is “correct”. Using the correct fertigation regime in your irrigation system will yield the incredible benefits and cost savings of drip fertigation. An incorrect fertigation regime can clog your system.

Tips for Maintenance:

• The Bucket Test: A useful test is ‘the bucket test’. Effectively putting the fertilizer mixture that you intend to use with your irrigation water in a bucket, mixing, and seeing the results in an hour. If the mixture is cloudy, or if there is a precipitate in the bucket, do not use the fertilizer in the drip irrigation system. Watch a demonstration – how to conduct a bucket test.
• Fertilizer Compatibility: Only use fertilizers together that are confirmed to not have negative interactions. We have developed a handy fertilizer interaction table that you can use.
• Injection: Calculate injection rates correctly to ensure correct fertilizer dosage. Inject fertilizer during the latter part of the irrigation to reduce the risk of it leaching past the root zone, but ensure that the system is run for sufficient time so that it is completely purged from the system.   

Read more: Knowledge Hub – Correct Fertigation Regimes

8. Maintenance of Pumps and Open Water Sources

Why it matters: Compared to the rest of the irrigation systems, the pump has the most moving parts. Open water sources also need to be maintained to manage the quality of the water.

Tips for Maintenance:

• Pump Maintenance: Regularly inspect and service pumps. Although the maintenance required for an electric motor, internal combustion engine and a centrifugal pump specifically vary. The principal remains the same. Maintain your pump, and you will maximize the lifespan and efficiency of it.
• Water Source Management: Keep reservoirs and other open water sources clean to avoid contamination. This includes management of organic growth, maintaining the boundaries (e.g. planting vegetation on the embankment), and maintaining a clean water inlet and pumping (suction) area.

Read more: Maintenance of Pumps and Open Water Sources

9. Salinity Management

Why it matters: Salts are present in nearly all water sources, and when concentrations are too high, they can harm plants. It’s important to manage salinity to prevent salt buildup around the plants.

Tips for Maintenance:

• Keep the wetted area at or near field capacity at all times.
• Maintain a nearly continuous slow downward movement of water and salts.
• Place drip laterals as close as possible to salt-sensitive plants.
• Leach at the start of the season before the crop water requirement increases.
• Run the drip irrigation system for salt-sensitive crops during light rain fall.
• …and more tips are available on the Knowledge Hub.

Read more: Knowledge Hub – Salinity Management

The Rivulis Knowledge Hub & Drip Guides

For a more detailed dive into each of these maintenance areas, I invite you to explore the full Rivulis Drip Guide series. Visit the Rivulis Knowledge Hub to access a suite of comprehensive resources to ensure your drip irrigation system performs at its best.

Additionally, PDFs of the Rivulis Drip Guides are available for direct download and are available in English, Spanish and Italian:

• English: https://www.rivulis.com/knowledge-hub/
• Spanish: https://es.rivulis.com/knowledge-hub/
• Italian: https://it.rivulis.com/knowledge-hub/

By diligently following drip irrigation maintenance procedures, you can maximize the life of your irrigation investment.

Please note: This article is provided as a high-level overview only. It is important that you verify what is best for your specific application, including for design, installation, operation, and maintenance. For both personal and irrigation system protection and before use, it is important to read the relevant suppliers’ instructions (for non-Rivulis products such as pumps, chemicals, fertilizers, etc), to consult with applicable professionals, and to read the relevant section of the Rivulis Drip Guide/Knowledge Hub, particularly with respect to safety and handling information, and more detailed instructions for use.