Why Is My Irrigation Well Losing Pressure or Flow Rate?
A drop in pressure or flow rate from an irrigation well can bring agricultural operations to a halt. These systems are critical to maintaining consistent crop yields, and any reduction in performance must be addressed quickly to avoid long-term damage. When your irrigation well no longer delivers water with the same strength or volume as before, it may indicate underlying mechanical issues or natural changes in the well’s environment.
By understanding the possible causes of reduced performance, you can take steps toward effective irrigation well troubleshooting and timely repairs. This article will walk through the most common reasons behind pressure loss or declining well yield and guide you through the signs, causes, and potential solutions.
Natural Decline in Aquifer Levels and Well Yield
The first area to examine when facing a pressure or flow issue is the water source itself. A well relies on an aquifer to supply water, and when water levels drop, the available yield decreases. This scenario is common in regions experiencing prolonged drought or increased water demand from nearby users. If an aquifer becomes overdrawn, it might not replenish quickly enough to support all connected wells.
Declining well yield caused by aquifer depletion is not always reversible. In some cases, the well may need to be deepened or a new location considered. Seasonal variation can also affect water availability. During dry months, the water table may naturally fall, reducing the overall pressure available for pumping. Regular monitoring of the static and pumping water levels can help determine if the decline is due to natural causes or if something more mechanical is occurring.
Mechanical Issues: Pump Bowl Wear and Submersible Pump Failures
Mechanical components inside the well system wear out over time, especially in high-demand agricultural settings. One common issue is pump bowl wear. The pump bowl is part of the vertical turbine pump that helps lift water to the surface. Over time, friction from sand, grit, or debris in the water wears down the impellers and bowls, reducing their efficiency. This can lead to a noticeable drop in pressure and flow rate.
Similarly, problems with submersible pumps can also affect performance. Submersible pump repair is often needed when internal seals fail, impellers break, or the motor loses power. Vibration, voltage irregularities, or prolonged dry running can cause internal components to degrade faster than expected. Identifying these signs early through pressure monitoring or pump performance tests can help prevent complete system failure.
If the pump begins cycling frequently or struggles to reach the target pressure, it may be a signal that the pump is either undersized, failing, or facing resistance due to blockage or buildup. Replacing worn pump components or upgrading to a more suitable pump model may restore pressure and flow.
Encrustation and Biofouling Within the Well
Another significant factor that can limit water movement through a well is encrustation. Over time, minerals in the water can accumulate on the well screen, casing, and pump components. This mineral scale (commonly calcium or iron deposits) narrows the openings where water flows, resulting in reduced discharge and pressure.
Encrustation in wells is often gradual and goes unnoticed until a substantial decrease in performance occurs. In addition to mineral scale, biological fouling can occur when bacteria grow inside the well. These microbial colonies form slimes that clog screens and create biofilms, adding to the flow restriction.
To address encrustation, chemical cleaning treatments may be necessary. Acidic cleaners are often used to dissolve mineral buildup, while shock chlorination may be applied to kill bacteria and clear biofilms. Periodic well cleaning should be considered part of routine irrigation well troubleshooting to prevent significant long-term damage.
Pipe Leaks and System Design Flaws
Sometimes the issue lies not in the well or pump itself, but in the distribution system. A leak in the underground piping or connectors can cause pressure to drop significantly, even if the well and pump are operating normally. These leaks are often hard to detect, especially if the piping is buried or runs under large fields.
Another common issue is incorrect or outdated system design. As farm operations grow, the irrigation system may be expanded without upgrading the pump or well capacity. This results in a system that struggles to meet demand, especially during peak irrigation times.
A flow rate test can help determine how much water is being delivered at various points in the system. Comparing this to the expected output of the pump and well will reveal if losses are occurring due to leaks or undersized components. In some cases, modernizing the system layout, adding pressure regulation valves, or replacing aging lines may be necessary to restore efficient water delivery.
Clogging from Sand, Silt, or Sediment
Lastly, clogging from natural materials like sand or silt can reduce well efficiency over time. If the well screen is not properly sized or begins to degrade, fine sediment can enter the system. This material builds up in the pump, pipes, and filters, creating blockages that lower the flow rate and strain mechanical parts.
This problem is particularly common in wells located in sandy or unconsolidated formations. Over time, abrasive particles can damage pump impellers and wear out internal surfaces, requiring more frequent submersible pump repair or replacement.
To address this, a sand separator or improved filtration system may be added to the wellhead. In severe cases, the well may need redevelopment, a process that involves surging, airlifting, or jetting to remove accumulated debris and restore flow paths within the aquifer.
Routine inspection of pump components and sediment levels can help detect these issues early. If the water becomes visibly dirty or filters clog quickly, sediment intrusion should be suspected and addressed promptly.
Conclusion
When an irrigation well begins to show signs of reduced pressure or flow, it’s rarely a simple fix. The cause may be linked to natural aquifer decline, mechanical wear like pump bowl degradation, clogging due to encrustation in wells, or damage within the distribution system. Submersible pump repair may be necessary, but without a full diagnostic approach, the underlying issue could persist.
Effective irrigation well troubleshooting involves a combination of flow testing, physical inspection, water quality analysis, and historical performance comparisons. Proactive maintenance, including regular cleaning, monitoring, and upgrades, will help ensure that your irrigation system continues to deliver consistent performance for years to come. Keeping your system efficient not only conserves water and energy but also supports the productivity of your agricultural operations.
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Welcome to B&M Pump Irrigation Sales & Service, Inc.! We are your professional irrigation specialist! Our typical services include complete pump service, water well service, system design, and pivot systems. We deliver personal service and reliability to our customers in Texas, Oklahoma, New Mexico, and Arizona. No matter where you are in the southwest, B&M Pump Irrigation Sales & Service, Inc., is a name you can trust. We strive to educate owners and operators on making pumps and motors last longer and work more efficiently. We sell good quality products at a fair price and stand behind the products we sell. Give us a call today to speak with one of our service experts today!
Categorised in: Irrigation