Drip Irrigation Management

Transcription

1 Drip Irrigation Management

2 Layout and Design Professional irrigation designers develop design layouts and assist in system component selection. Designer provides: Hydraulic design System layout Importance Pressure and flow rates differences Pipe hydraulics - correct product selection Spacing (drippers, sprinklers) Filter system selection Key locations for maintenance Grower Benefit Efficient and economical choice optimal velocity for flushing Ease of maintenance of system with least amount of labor

3 Influencing Factors Professional irrigation designers evaluate additional information that will influence their decision in equipment selection and placement. Influencing Factors Pest pressure Root intrusion Clogging Design Decisions - Wall thickness - Location in the soil - Crops - SDI (Sub-surface drip irrigation) - Chemigation Option - Water analysis - Filtration selection - Dripper selection - Chemigation Options

4 Influencing Factors Water Source Treatment Leakage Prevention Filtration Flow Rate Follow-Up Operating Pressure Chemical Treatment Flushing

5 Drip Irrigation System Management Part II: Maintenance, Monitoring and Troubleshooting Part I: Overview Part II: Maintenance, Monitoring and Troubleshooting Part III: Practical Examples

6 Maintenance Part II Outline: Pump Main Filters Main Lines and Manifolds Air Valves and Backup Filters Drip Lines

7 Pump - Overview

8 Pump Role in the System Pump Role in the System: Heart of the system Provides water supply Delivers pressure and flow rate Can be submersible, turbine or centrifugal

9 Pump - Maintenance Pump Check List Start-up specs Visual inspection Indicators of changes Influencing Factors - RPM (revolutions per minute) - Pressure - Flow rate - Pressure gages - Flow meter - Oil levels - High or low flows - High or low pressures - Excessive power consumption

10 Pump - Troubleshooting Pump Indicator Pump Problems or Other? High or low flows Maybe Wear of impellers Indicators of changes High or low pressures Excessive power consumption Maybe Yes Blockage of inlet Possible short in motor No water Yes Loss of prime

11 Main Filters - Overview

12 Main Filters Role in the System Main Filters Role in the System Kidneys of the system Remove impurities that may plug the drip lines Require pressure and flow rate to operate Can be media, automatic screen, Hydrocyclone, gravity and manual screen

13 Main Filters - Maintenance Main Filters Check List Influencing Factors Start-up specs Visual inspection Indicators of changes - Pressure (inlet, outlet, differential) - Flow rate - Pressure gages - Flow meter - Control filter - Screen or media - High or low flows - High or low pressures - Debris in back-up filters - Continuous back-flush

14 Main Filters - Troubleshooting Main Filters Indicator Main Filters Problems or Other? High or low flows Unlikely Check pump Indicators of changes High or low pressures Debris in back-up filters Maybe Yes Plugged filtration area Damaged screens or missing under drains Continuous back-flush Yes Excessive debris in the water

15 Main Line and Manifold - Overview

16 Main Line and Manifold Role in the System Main Line and Manifold Role in the system Veins of the system Deliver water from the pump station to the field Most often buried and permanent Can be PVC, HDPE and sometimes metal

17 Main Lines and Manifolds - Maintenance Main Lines and Manifolds Check List Influencing Factors Start-up specs Visual inspection Indicators of changes - Pressure - Flow rate - Pressure gages - Flow meter - Flush valves - Low flows - High or low pressures - Water accumulation

18 Main Line and Manifold - Troubleshooting Main Line and Manifold Indicator Main Line and Manifold Problems or Other? Low flows Yes Damaged pipe Indicators of changes High or low pressures Yes Trapped air or debris Water accumulation Yes Damaged pipe

19 Air Relieve Valve and Backup Filter - Overview

20 Air Valves and Backup Filters Role in the System Air Valves and Backup Filters Role in the System Remove air from the water Prevent water surge and allow vacuum relief Protects drip lines from contamination from breaks in mainline and sub-main Can be screen or disc filter Element

21 Air Valves and Backup Filters - Maintenance Check List Start-up specs Visual inspection Indicators of changes Influencing Factors - High elevation locations - Pressure - Flow rate - Backup filter located near the field - Pressure gages - Sounds - Flush valves - Water accumulation - High or low pressures - Low flow rate - No water condition

22 Air Valve and Backup Filter - Troubleshooting Change Indicator Air Valve/Backup Filter Problems or Other? Water accumulation Yes Damaged or plugged air valve Indicators of changes High or low pressures Low flow rate Yes Yes Trapped air or debris Plugged filter or trapped air No water condition Maybe Closed valve

23 Drip Lines - Overview

24 Drip Lines Role in the System Drip Lines Role in the System Provides uniform water and chemicals to each plant Maximizes inputs to produce yields Can be installed above ground hanging, or buried Can be drip lines, online drippers, sprinklers and sprays

25 Drip Lines - Maintenance Drip Lines Check List Start-up specs Visual inspection Indicators of changes Influencing Factors - Pressure - Flow rate - Wetted area - Pressure gages - Flow test - Water accumulation - Water run-off - Low flow rate - Low pressures

26 Drip Lines - Troubleshooting Drip Lines Indicator Drip Line Problems or Other? Water accumulation Yes Damage from pests Indicators of changes High or low pressures Low flow rate Yes Yes Trapped air or debris Plugged filter or trapped air, root intrusion No water condition Maybe Closed valve

27 Drip Irrigation System Management Part III: Practical Examples Part I: Overview Part II: Maintenance, Monitoring and Troubleshooting Part III: Practical Examples

28 Practical Examples Part III Outline: Design Influencing Factors Monitoring Troubleshooting

29 Design Influencing Factors Grower Question: Where my farm is located, we have freezing conditions. Are there special design factors that I need to pay attention to during the construction of my irrigation system?

30 Design Influencing Factors Grower Question: Where my farm is located, we have freezing conditions. Are there special design factors that I need to pay attention to during the construction of my irrigation system? Response and Possible Solution: All of the water in the irrigation system must be removed before the temperature drops below freezing. This will require additional flush locations and drains to remove the water or the use of a compressor.

31 Design Influencing Factors Grower Question: Do I need flush-outs for my main lines and manifolds?

32 Design Influencing Factors Grower Question: Do I need flush-outs for my main lines and manifolds? Response and Possible Solution: Yes, to keep the velocity in the main line high enough to move the dirt out of the pipeline. Manifolds are designed to balance the pressure loss and are much smaller than the mainline, and moving water through the manifold can expose the driplines to dirt. Place the flush out at the end of a pipe line.

33 Management Grower Question: The local government agency told me that all water applied to my field must remain on my field, If I can t drain water from my field, how do I still flush my pipelines?

34 Management Grower Question: The local government agency told me that all water applied to my field must remain on my field, If I can t drain water from my field, how do I still flush my pipelines? Response and Possible Solution: The water can be flushed into a holding tank or a water truck tank and spread around the field on the roads. Flush it into a tail water system or drainage system that recirculates it back to the source

35 Monitoring Grower Question: My filters have an automatic flushing system, How often do I need to manually clean my filters?

36 Monitoring Grower Question: My filters have an automatic flushing system, How often do I need to manually clean my filters? Response and Possible Solution: Filter elements need to be cleaned when the pressure difference reaches 0.5 bar or at least once a week. When using automated filters use pressure differential (pd) on 5.0m and or 6 hours. Manually flush once a month to check the operation of the filter.

37 Monitoring Grower Question: Other growers have warned me to check on my drippers, How do I find out that my drippers are working properly?

38 Monitoring Grower Question: Other growers have warned me to check on my drippers, How do I find out that my drippers are working properly? Response and Possible Solution: There are two ways to tell that your drippers are working properly. First are your plants healthy or show signs of stress. The second compare the flow meter rate to the recorded rate when the system first operated. If you can see a reduction in flow rate the drippers might be blocked.

39 Monitoring Grower Question: What type of devices should be installed to help me monitor my system?

40 Monitoring Grower Question: What type of devices should be installed to help me monitor my system? Response and Possible Solution: A properly designed and installed system should include an accurate flow meter to monitor the system flow rate. The system will also require pressure gages located at the pump and control filter to monitor the pressure changes. Also pressure gauges should be installed at the manifolds to ensure the driplines are operating at the proper pressure.

41 Troubleshooting Grower Question: I monitored my flow rate from the beginning of the year and now I notice I have a 10% reduction in flow rate. What happened?

42 Troubleshooting Grower Question: I monitored my flow rate from the beginning of the year and now I notice I have a 10% reduction in flow rate. What happened? Possible Response: Always remember that changes in flow rates should accompany a change in pressure. If the pressure is increased, and you have a reduction in flow rate it is often associated with plugged or clogged drippers. If there is a decrease in pressure and a drop in flow rate the water table may have dropped.

43 Troubleshooting Grower Question: I noticed a lot of water around my pressure relief valve. Why does my pressure relief valve go on all the time?

44 Troubleshooting Grower Question: I noticed a lot of water around my pressure relief valve, Why does my pressure relief valve go on all the time? Response: The pressure relief valve goes on when the pressure in the system increases above the pre-set value that the valve was originally set. This is often due to plugging in the filters, closed valves, pressure surges and plugging in the emission devices.

45 Troubleshooting Grower Question: My pipelines were buried in the road and I noticed I have wet areas in my field along my pipelines. Do I need to replace my pipes?

46 Troubleshooting Grower Question: My pipelines were buried in the road and I noticed I have wet areas in my field along my pipelines. Do I need to replace my pipes? Response and Possible Solution: It depends. Wet spots along the pipeline can indicate cracked pipelines or damages pipes underground and a thorough investigation needs to occur to determine the problem and possible cause.

47 Drip Irrigation System Management Course Summary You have now gained insights to: Drip irrigation systems Preventive and on-going system management Maintenance, monitoring and troubleshooting practices Please note all recommendations are general in nature. We recommend you contact a Rivulis Irrigation technical representative for specific recommendations and advice.