System Inspections
Because irrigation systems typically operate during the early morning or overnight hours, many systems suffer from deferred maintenance. Irrigation equipment may no longer be applying water evenly to the target landscape. Roots, animals, pedestrians, gardeners or plastic fatigue will cause required maintenance to an irrigation system.
Irrigation system checks is the technique of visually inspecting each sprinkler head during operation to verify proper operation and allows for repair or adjustment of equipment in need. System checks should be completed 3 to 4 times per irrigation season, which is March through October. Ideally these checks should be done at least once per month; however, thorough system checks require substantial time to properly complete. It is not cost effective for the client to allocate resources more frequently than 3-4 times per year. Of course, gardeners, residents or other site personnel should be encouraged to report any system malfunctions as a complement to the regular system checks.
System Controller/Timer Adjustments
During the course of the year the weather behaves in patterns that are, for the most part, predictable for any given month. Likewise, these somewhat predictable monthly weather and temperature patterns vary from month to month. This results in an irrigation factor known as EvapoTranspiration (ET). Simply, ET is a weather driven factor used to measure the moisture that has transpired (sweated) from plant tissue and has evaporated from the soil. Thus the inches measured by evapotranspiration are an indication of the inches of water that should be reapplied for a given period. To make matters even more confusing, ET is universally based upon a certain type of plant and therefore should be adjusted for turf or shrub areas. These are called crop co-efficients and typically use 80% of the published ET for turf and 60% for most shrub areas.
ET factors are developed daily and cumulated for weekly and monthly totals. They are typically published in the newspaper or on water department websites. It is most practical to utilize historical monthly ET numbers for programming the irrigation controller. Each area or zone controlled by the controller should be programmed to apply irrigation at a precipitation rate that closely matches the factored monthly ET.
