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

“Only my ROOTS know for sure!!!!”

“ET is half the story.”

“How much rain did you say we

got?”

Why only a single sensor is neededGenerally, differences in ET for vegetation

types float up and down proportionately (with weather)o i.e. we can assume that the Kc ETo approach is

applicableo 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 away from areas of runoffo 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

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Rain Watering ET

Twin Falls, Idaho - Turf(simulated)

Soil water stays between limits

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Rain Watering DepletionFull Set Point

Twin Falls, Idaho - Turf

Buffer to capture rain

(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 clockso It mounts next to the watering clock and

requires only a few connecting wires

o It obtains its power from the watering clock

o 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 useo no resetting of zone times is neededo little “intimidation” factor for the user