By Bernard Cardenas
Ever suspect that some of your neighbors apply too much
water to their lawns? In some cases you might be right. To remediate this
issue, the irrigation industry has developed products to reduce the amount of
water wasted during landscape irrigation.
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| Water waste adds up (via EPA WaterSense) |
Among these technologies are rain sensors and soil moisture sensors (SMS). Rain sensors detect when sufficient rain has fallen and then bypass the irrigation
timer’s schedule. Likewise, SMS can detect if the soil is moist enough (so that
the lawn can withstand some extra days without watering) and then prevent
scheduled irrigation events.
Sensor vs. Sensor
In a recently published study researchers at UF evaluated the
water savings potential of rain sensors and SMS in homes for more than two
years. They compared their results to homes only equipped with irrigation
timers. They also compared those results to homes that were provided both a
rain sensor and educational materials.
To evaluate if the homes in the study were applying the
right amount of water, the researchers also estimated the water applied by the
different technologies compared to a theoretical requirement (calculated using
a daily soil water balance).
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| Palm Harbor, FL - where we lay our scene |
The Location
In the vicinity of Palm Harbor, FL, a total of 64 homes
supplied with reclaimed water for irrigation were selected for this study.
Dedicated irrigation flowmeters were installed in every home to measure the
amount of water applied. The 64 homes were divided in 4 treatments with 16
homes each. Treatments were: MO (monitored only), SMS, rain sensor, and rain
sensor plus educational materials.
The Results
By the end of the study, SMS-equipped homes were the only
group significantly different to the MO homes. This means that the homes
equipped with a rain sensor, or a rain sensor plus educational materials, did
not save a significant amount of water compared to the MO homes.
Further, the homes equipped with a SMS reduced the average
number of irrigation events per week, compared to the MO homes (1.7 vs. 2.7
events/week, respectively), decreased the depth of the weekly irrigation (22
vs. 42 mm, respectively), and applied 44% less water, over the 32 months of
data collection. These savings were achieved with no adverse effects to turf
quality.
These results indicate that the tested SMS can save a
significant amount of reclaimed water, compared to the other
methods/technologies investigated.
This paper is part of a series. Read part one here. And if you are attending the ASABE International Meeting in Orlando this month, the studies will be presented in session 138 on 7/18, 2:30pm - 5pm. Follow all our Orlando coverage on Twitter.
