Transcript Research & Scholarship UI College of Engineering

The Turf-Tech Water Watchertm
for Soil-Based Automation of
Residential Sprinkler Systems
Turf-Tech Inc., Logan, Utah
Presented at the 2000 National Irrigation
Symposium in Phoenix Arizona
Objectives of Presentation
Discuss the advantages of and best
approach for a soil-based control
system
Describe the Turf-Tech Water
Watchertm system as an application
example
Why listening to the soil is best
Soil keeps track of the water going out
(ET) and the water coming in
(Irrigation + Rain)


As ET increases or decreases, the soil knows it
As irrigation and rain increase or decrease, the soil
knows it.
Soil keeps track of ET needs and root
extraction for the specific local
vegetation
“ET is half the
story.”
“How much rain
did you say we
got?”
“Only my ROOTS
know for sure!!!!”
Why only a single sensor is needed
Generally, differences in ET for vegetation
types float up and down proportionately
(with weather)
o
o
i.e. we can assume that the Kc ETo approach is
applicable
even zones in shade or full sun generally float
together
Other zones are adjusted by adjusting
the minutes of on-time for each zone

to account for differences in application rates,
exposure, and vegetation type of the zone
Why only a single sensor is needed
When on-times of zones are adjusted for
differences in application rates and ET, all
zones will dry to the target point at the
same time
Therefore, only a single sensor is needed
“Hey, we’re cool
with each other!!!!”
Why only a single sensor is needed
The sensor does need to be placed:
o
o
away from areas of runoff
away from external additions of water
(swimming pools, kiddie pools, car-washing
areas).
The best spot is usually in sunlit turf
o
(this will be the quickest to dry in hot
weather)
Why only a single sensor is needed
Sensor can be placed in any zone, when
the control unit uses a “latch” to lock
the watering system on for all zones,
once the decision has been made to
water
“Hey! We plants
stick together.
You water me, you
water him!!”
What keeps the system
from over-watering?
Set clock to provide enough water during
mid-summer using daily or each two day
waterings
At each watering, add less than the
capacity of the soil to hold the water.
No “deep percolation” of moisture occurs from the root
zone
“It’s so neat.
When I’m a little
thirsty, just the
right amount of
water comes!!”
“Pulse” nature of waterings
Twin Falls, Idaho - Turf
8
7
50
6
40
5
30
4
3
20
2
10
1
0
0
4
5
6
7
8
9
10
Month
Rain
Watering
ET
ET, mm/day
Watering or Rain, mm
60
(simulated)
Soil water stays between limits
Watering or Rain, mm
80
10
70
60
50
0
-10
Buffer to capture rain
-20
40
-30
30
-40
20
-50
10
-60
0
-70
7
8
9
Month
Rain
Full
Watering
Set Point
Depletion
Depletion in Soil, mm
Twin Falls, Idaho - Turf
(simulated)
What turns the water off?
Once the clock is allowed to activate
valves (using its own schedule), all zones
progress as programmed in the clock
Water is in effect added in daily "doses,”
but only if needed
“Can you say
‘Optimum’ ?”
What keeps the system
from underwatering?
A moisture control dial on the control
unit, when set to the optimum point, will
allow the system to come on when the
clock is programmed to come on
(provided the soil water level is drier than
the setting of the dial)
“Tweak the dial
just a little. I’ve
been feeling a
little dry lately”
Makers following these concepts
Irrometer WaterMark systems
Rainbird AquaMiser (discontinued?)
Turf-Tech Water Watchertm
A few others
Turf-Tech Water Watchertm
Turf-Tech Water Watchertm
Turf-Tech Water Watchertm
Turf-Tech Water Watchertm
Turf-Tech Water Watchertm
Turf-Tech Water Watchertm
Turf-Tech Water Watchertm
Why does the Water Watcher
eliminate the need for “ET”
information?
The WW “listens” to the soil
o
As weather gets hot, ET increases, and the
soil dries more quickly
• The WW allows the system to turn on
more frequently
o
As the weather cools, ET decreases, and
the soil dries more slowly
• The WW precludes the system from
turning on the valves as often.
o
(WW “knows” ET)
What makes the WW so automatic?
By listening to the soil, the WW feels
the “pulse” of the entire system
It feels the effect of rainfall and
irrigation amounts
It feels the effect of extraction of water
by roots (the ET process)
Why is the WW so simple to use?
Once individual zones are set for
minutes on:
o
the wet/dry dial on the WW can be
adjusted to raise or lower the target soil
moisture levels for the whole landscape.
Most of the time, the WW needs no
adjustment and is left unattended for
months at a time.
It feels the effect of rainfall and
irrigation amounts
Why is the WW so simple to install?
It can be used with virtually all
automatic clocks
o
o
o
It mounts next to the watering clock and
requires only a few connecting wires
It obtains its power from the watering
clock
The sensor can be attached to any valve
box in the lawn at any location
Benefits of the Water Watchertm
Information free (no ET information or
rain sensing is needed)
The WW follows the seasonal ET curve,
but without input of external
information
User does not need to adjust the on-
times or watering frequency as weather
changes
Benefits of the Water Watchertm
The WW system “knows” how much
water has been applied or rainfall
received
The WW conserves water by preventing
over-watering, but can keep the
landscape green
The WW can be used to conserve water
by keeping the landscape in a “thirsty”,
but sustained mode
Benefits of the Water Watchertm
The WW keeps the watering system
“tuned” and optimized even while the
owner is on vacation
The built in “latching” technique
guarantees that all zones get watered,
even if sensor becomes saturated by
watering in progress
Summary
Soil based monitoring of soil water
provides the near “perfect” feed back of
water in and ET out
The WW system interfaces with nearly
all types of 24 VAC water controllers
(clocks)
Summary
The WW system conserves water by
following the ET-Rain curve
automatically
o
with stress reduction of ET as desired
The WW is simple to use
o
o
no resetting of zone times is needed
little “intimidation” factor for the user