Picture from Rainbir Drip Irrigation Maintenance R. Troy Peters, Ph.D., P.E. WSU Extension Irrigation Engineer
Efficiency Comparison Surface =~ 50% Sprinklers =~ 70% Drip =~ 95%
Drip/Micro Irrigation Higher cost Very clean water required (filtration) Operates at low pressures Most efficient. Very little loss to evaporation High uniformity. Easily automated. Great control over timing and amounts Suitable to all soil types Foliage stays dry Additional heat units to crop.
Drawing from KSU Irrigation Extension Education
Maintenance Tasks Regular System inspection Plugged emitters. Leaks Service filters, Check sand levels in sand media filters, change sand if necessary. Take disc filters apart and soak disks in cleaning solution 10% peroxide for organics, or a 10% hydrochloric acid if iron, manganese or carbonate deposits)
Flushing System Flushing Filters Flushing Lines
Cyclone Sand Separator Disk Filter Drawing from KSU Irrigation Extension Education
Drawing from KSU Irrigation Extension Education
Screen Filters
Disk Filters
Drawing from KSU Irrigation Extension Education
Sand Media Filters
Drawing from KSU Irrigation Extension Education
LAKOS Sand Media Filters Sand Media Filters Filtering Back Flush
Flushing High water velocity required for effective flushing.
Flush more often if your water looks like this!
Flow Meter Data Located at the pump. Comparison with new system shows degree of plugging Kinked lines Broken (open) lines or large leaks Which valves are opened or closed
Pressure Gauge Data Located at key locations throughout the system Plugged filters (high pressure difference) Pump not working right Pressure regulators working properly Valves are open or closed
Prevent Clogging Keep sand particles out of lines when installing and/or fixing. No precipitates Lower water ph if necessary Get an irrigation water chemistry analysis Take this with you when you buy fertilizers No algae or bacteria growth Inject Hydrogen Peroxide or Chlorine to kill it This stuff is caustic!
Prevent Clogging Inject fertilizers before filters if possible Only fertigate with those that are completely water soluble and free of impurities (solubility change with temp.) Water with high alkalinity & phosphate fertilizer often precipitates with calcium and magnesium present in the water. Double check with your fert dealer Chemical interactions. (Jar test)
Root intrusion Only an issue on buried drip, and longterm installations (many have been in > 20 yrs) A problem when roots are very thirsty Prevent by not water stressing the crop Treat by injecting herbicides that will burn the roots back a bit.
Rodent Control Repellents Trap and Remove Encourage predators (hawk nests, owl boxes) Shoot Poison Flood fields
Blow them up!
Google: Netafim Drip Irrigation System Maintenance Handbook It s fabulous.
Soil Moisture Sensors
Soil Moisture Sensors Tensiometers Strengths Soil water tension (same as plant sees) Less expensive Widely used, studied and accepted Not affected by salinity Weaknesses Small sample area Indicates when to irrigate, not how much
Soil Moisture Sensors Resistance type Strengths Inexpensive Usable trends Give soil water potential (same as plant sees) Easy to log data Weaknesses Affected by salinity Imperfect accuracy Samples small
RESISTANCE
Soil Moisture Sensors Resistance type Strengths Inexpensive Usable trends Give soil water potential (same as plant sees) Easy to log data Weaknesses Affected by salinity Imperfect accuracy Samples small
Soil Moisture Sensors Neutron Probe Strengths Accurate Gives soil water content Large soil sample area Unaffected by salinity or temperature Repeatable Easy to sample at different depths Weaknesses Highly regulated (nuclear device) Can t leave in the field Expensive
Soil Moisture Sensors Dielectric constant/capacitance Strengths Usable trends Gives soil water content Easy to log data (real-time) Weaknesses Imperfect accuracy Inconsistent (high variability) Small sample area Can be expensive Proper installation is critical, and difficult to do Affected by salinity and temperature
Soil Moisture Sensors The Look and Feel Method Advantages Cheap Easy Forces you to get out in the field Weaknesses Subjective
Soil Moisture Sensors Summary Neutron Probe is still the best. All others are not as accurate, and are not as repeatable to varying degrees Most sensors will give a trend that is usable for irrigation scheduling. Proper installation of sensors is critical and must be done right or data is worthless Not all sensors are suitable to all soil types
Pod Irrigation
Manufacturers: K-Line, Irripod
K-Line, Irripod Cost is between hand-line and wheel-lines Fast and easy to move. Not suited to large acreages (requires big hose which is too heavy to move) Max of about 10 pods/line. Best on pastures. (Tall crops cause problems moving)
Pumps and Energy
Water and Power Power Flow Pressure Efficiency /100 Pay for power (kw) over time (hrs) = kw-hr (KWH)
Centrifugal Pumps
3 phase vs. Single phase Power is generated in 3 phase 3 phase is ideal for electric induction motors Higher starting torque More efficient Less expensive Smaller motor Simple and reliable (less vibration) 3 phase motors are more efficient at higher hp Necessary for pumps > 10 hp Not typically supplied to residences
Variable Frequency Drives Changes motor spin speed. AC DC AC Solid state. No moving parts. Cost Quality Works with existing motor and pump. Can use a 3-phase motor on single phase power source www.joliettech.com
Variable Frequency Drives Power savings. No burning up pressure across valves. Soft starts longer pump life Produce heat that must be vented. ~ $100/hp installed Possible cost share from power company. (BPA) Cost effective if flows vary widely and for long periods of time.