Weather Based Technologies for

Residential Irrigation Scheduling

Technical Review Report 

Prepared for Municipal Water

District of Orange County

U.S. Department of the Interior

Bureau of Reclamation

Lower Colorado Region

Southern California Area Office

May 2004
TABLE OF CONTENTS

Introduction 3

Weather Based Irrigation Principles 3

Product Features and Comparison Criteria 5

Installation 5

Replacement Controller Versus Receiver Add-on 5

Automatic Run Time Calculation and Adjustment 5

Application and Distribution or Efficiency Rates 5

Irrigation Run-Soak Cycles 6

Rain Sensors and Gages 6

Other Sensors 6

Station Circuit Rating and Terminal Wire Sizes 6

Clock Mode Operation 6

Non-volatile Memory 6

Product Descriptions 6

Aqua Conserve 7

Weathermatic 10

WeatherSet 14

AccuWater 16

ET Water Systems 20

HydroPoint 23

Irrisoft 25

Product Features Matrix 29

Summary of Product Features 30

2
Introduction

Water agencies implementing water use

efficiency programs have long struggled

to achieve quantifiable and reliable water

savings in residential landscapes.

Historically, programs targeting residential

landscape savings have focused on education including irrigation system maintenance, irrigation scheduling and climate

appropriate plantings. Although these

efforts have garnered savings, these savings are usually short lived as newly

acquired techniques are readily forgotten.

In the late 1990's, the Irvine Ranch Water

District, Municipal Water District of

Orange County and Metropolitan Water

District of Southern California learned

about an emerging irrigation management technology now dubbed "Smart

Irrigation Controllers" or "Weather-based

Irrigation Timers". This technology

removes the need for homeowners to

make regular scheduling adjustments

because the controller or timer adjusts

the schedule automatically as weather

changes. A water savings evaluation was

implemented known as the "Residential

Weather-Based Irrigation Scheduling ñ

The Irvine ET Controller Study". This

evaluation identified single-family home

savings rate of 37 gallons per day. Alas,

an opportunity for quantifiable and reliable residential landscape water savings

had materialized.

As this study was concluding, cities and

counties throughout the State were

establishing new educational programs to

increase public awareness to reduce nonpoint source pollution. This awareness

brought about a second study to evaluate

the linkage between improved residential

irrigation management and reduced dryweather runoff. The "Residential Runoff

Reduction Study" found comparable

water savings of 42 gallons per day per

single-family home and also quantified a

reduction in runoff ranging from 64 to 71

percent. With this change in runoff volume, concentrations of pollutants did not

change therefore reducing pollution by a

like amount.

Water agencies throughout the country

recognize weather-based irrigation timers

as an emerging tool to achieve landscape

water savings and reduce non-point

source pollution. When the first study

began, the study team was aware of only

two automated controller technologies.

Today, several different smart or weatherbased irrigation controller manufacturers

exist and others are quickly emerging into

the marketplace.

In 2003, the Municipal Water District of

Orange County approached the U.S.

Bureau of Reclamation, Southern

California Area Office to provide an objective evaluation of all the residential irrigation controller technologies that was

available to consumers. The purpose of

this evaluation is to document the overall

status of residential technologies along

with a general description of how each

technology operates. From this information, water agencies can quickly gain

knowledge about the technology for use

in their incentive programs.

Weather Based

Irrigation Principles

All of the products reviewed operate

based on the principle of scheduling irrigation, based on evapotranspiration (ET),

which is a function of weather conditions

and plant type. ET is the quantity of

moisture which is both transpired by the

3
plant and evaporated from the soil and

plant surfaces. 

Each of the irrigation scheduling systems

evaluated utilize micro-processing

devices which calculate irrigation schedules based on weather conditions, plant

type, and site conditions. A significant

factor in comparing the various products

is the location at which the weather conditions are measured to calculate ET and

monitor rainfall. Since it is cost prohibitive to install and maintain a complete

weather station at every site, two techniques are being used to collect weather

data and calculate ET. Specifically, ET is

calculated either using limited on-site

measurements, or using multiple sensors

to collect data on each of the daily weather parameters necessary to calculate theoretical ET based on accepted equations,

such as the Penman-Monteith Equation.

The daily weather parameters required to

be input into the Penman-Monteith

Equation to calculate reference ET are:

maximum and minimum temperatures,

maximum and minimum relative humidity,

solar radiation, mean air pressure and

mean wind speed. The latitude and elevation of the site for which ET is being

estimated must also be known. 

Three of the products reviewed use onsite weather measurements to calculate

ET utilizing either on-site temperature or

solar radiation sensors. Two of these

also use historic ET data in the ET calculation. The historic ET data used for both

products are a function of the site location. This technique is based on the relationship between these two weather factors (temperature and solar radiation) and

ET. An obvious consideration with this

technique is the accuracy of the historic

data relative to a specific site. 

Four of the products reviewed calculate

ET using a full set of data from local

weather stations or a network of weather

sensors. The weather station data are

collected from public or private weather

stations. The weather station and sensor

network data are processed by a centralized computer server, and transmitted to

the irrigation sites. There are ongoing

service provider costs associated with the

operation of the weather stations, sensor

networks, computers, and information

transmission systems associated with

these products. These costs are either

absorbed by water entities or are paid by

the users.

In some cases, compelling data were

submitted for this review showing accurate ET calculation and or significant

water savings associated with a product.

However, given the overall lack of data, it

is difficult to draw conclusions about the

overall performance of one technique

over the other. Both techniques provide

potentially effective methods for developing weather based irrigation schedules.

Bench test type studies are being conducted by the Metropolitan Water District

of Southern California and the University

of California at Riverside Cooperative

Extension in an effort to better understand the overall advantages and disadvantages associated with these techniques. The findings of these studies

should be available during 2004.

Additionally, the Center for Irrigation

Technology at California State University,

Fresno will initiate bench test type product evaluations of most of the products

included in this technical review during

2004. 

4
Product Features and Comparison

Criteria

Significant product components and irrigation features are discussed below. The

discussions identify different methods

used to achieve similar results by the various products, and associated advantages and disadvantages. 

Installation

Although most of the manufacturers recommend professional installation and

programming of their products, several

indicate installation and programming can

be done by the typical homeowner. Most

of the individuals associated with demonstration programs and pilot studies which

were interviewed during this review

expressed concerns about homeowner

installation and programming. It appears

the percentage of homeowners actually

capable of installing and programming

most of these products may be relatively

small.

Replacement Controller Versus

Receiver Add-on

The primary component of most of the

products reviewed is an automatic irrigation controller which would replace an

existing clock type controller.

Alternatively, two of the products include

a receiver or scheduler which is connected to the existing controller. In the case

of one of these receivers, cost is a significant attraction. Regardless of cost, the

quality of an existing controller should be

a factor when considering replacement.

If the consumer's existing controller is a

high quality unit with adequate features,

consideration of an add-on receiver may

be warranted. However, the level of

automation is limited with these units relative to some of the replacement controller systems. Specifically, the receivers

do not automatically calculate run times.

The user must manually calculate run

times based on experience and guidelines provided by the manufacturer.

Automatic Run Time Calculation

and Adjustment

Most of the products reviewed will automatically generate irrigation schedules for

various hydrozones as a function of application rate, plant and soil types, slope

and sun/shade conditions, and distribution uniformity. The ability of the controller to accurately generate an efficient

and satisfactory schedule is a primary

consideration relative to maintaining the

health of the plants as well as reducing

runoff. As stated above, the manual

alternative is inexact and may be difficult

to calculate. Regardless of automatic or

manual run times, all of the products

reviewed have a feature which allows

adjustment of station run times by a percentage factor or by minutes. This function gives the user the ability to compensate for inaccurate programming inputs,

design/sprinkler inefficiencies, and

sun/shade areas. Also, this input serves

to ease the mind of the property owner

that they have control to slightly regulate

watering, thus negating the fear of

over/under watering and losing expensive

landscape.

Application and Distribution or

Efficiency Rates

Some of the products reviewed allow the

user to enter actual application rates versus preprogrammed rates based on irrigation type (spray, rotor, drip, etc.), and

to enter distribution or efficiency factors.

These features provide the user more

ability to accurately program the controller to actual site conditions.

5
Irrigation Run-Soak Cycles

When conditions require multiple runsoak cycles, the soak times should not be

more than the maximum needed for efficient irrigation and minimal runoff. In the

case that soak times are excessive, the

overall irrigation run time could be unacceptable. 

Rain Sensors and Gages

With one exception, all of the products

reviewed offer a rain sensor or gage with

the system or as an optional add-on

accessory. In the case of the exception

(HydroPoint), the receiver will accept

commercially available rain sensors. All

of the products have a rain delay feature

which is triggered by the rain sensor or

gage. Some of the products' rain delay

only interrupts ongoing irrigation when

significant rainfall is detected. Other systems adjust the irrigation schedule based

on the amount of rainfall measured by a

gage, or the duration of the rainfall

detected by the sensor. No documentation was provided for this review on the

accuracy of the sensor based schedule

adjustment, and it is assumed the use of

a gage for this purpose is a significantly

more accurate method. Although some of

the systems have the ability to initiate a

rain delay or adjust the irrigation schedule based on rainfall measured at a local

weather station, the advantage of an onsite rain sensor for interrupting irrigation

is obvious.

Other Sensors

Some of the products reviewed include

standard or optional wind and temperature sensors. These sensors interrupt or

delay irrigation when programmed wind

and or temperature conditions are

adverse to irrigation. Alternatively, some

of the systems delay irrigation based on

wind and temperature conditions measured at a local weather station.

Station Circuit Rating and Terminal

Wire Sizes

The compatibility of the existing electrical

circuits (wiring from the controller to the

station valves) should be considered in

the selection a new irrigation controller.

The station wire terminals on some of the

products reviewed will not accept wire

sizes larger than 18 gage. In which case,

adapters must be used. Also, the circuit

current capacity required for an existing

system should be checked prior to

installing a new unit. Reports from

demonstration studies indicate previous

installation problems associated with

insufficient circuit capacity to operate

some irrigation valves with high circuit

resistance.

Clock Mode Operation

Some of the products reviewed will not

operate in a standard clock mode. So, if

a user elected to discontinue receiving

the automatic scheduling service, installation of a new controller would be

required. 

Non-volatile Memory

Most of the controllers and receivers

reviewed have non-volatile memory to

protect them during power outages. This

provides that the device is not totally

dependent on batteries, and the microprocessor programming is saved and

reinstated when power returns. 

Product Descriptions

The following product descriptions

address operational characteristics and

features, and include discussions of available information from demonstration and

6
pilot studies, relative to documented

water savings and ET calculation accuracy. Each of the manufacturers were provided copies of the product descriptions,

for their input, prior to being incorporated

into this report.

Aqua Conserve

Aqua Conserve Incorporated, located in

Riverside, California, has been in business since 1996 and is a subsidiary of AG Sod Farms, which has been in business for over 30 years.

The company manufactures 7 residential ET controller models and an ET

based irrigation scheduler,

which is used in combination with most existing

conventional controllers.

All of the controllers, and

the scheduler, operate

based on adjusted historic

ET data; with the adjustment made as a function

of on-site temperature

sensor readings. An

optional rainfall sensor is

available as an add-on

component to all of the

controllers and the scheduler. 

Aqua Conserve's residential controllers have been on the market

for approximately 4 years, and the irrigation scheduler became available late in

2003. Their commercial controllers have

been on the market for approximately 6

years. Information regarding the number

of controllers sold is not available from

Aqua Conserve.

Four indoor residential models are available which accommodate up to 6, 9 or 14

stations (models ET-6, ET-6M, ET-9 and

ET-14). The ET-6M differs from the ET-6

in that it does not have a non-volatile

memory. The remaining residential models also are designed for outdoor installation, and will accommodate up to 8 and

12 stations (models ET-8b and ET-12b).

Each controller includes one station terminal which may run concurrently with all

the other stations, and may be used to

control a master valve or drip system.

Other than this, the Aqua Conserve controllers will not run multiple stations concurrently. The controllers and the scheduler include a wired

temperature sensor,

and optional combined

temperature and rain

sensor devices are

available. All products

are available directly

from Aqua Conserve

by mail and internet

order, and through a

limited number of local

distributors. The retail

prices for the controllers, the scheduler,

and the temperature

and rainfall sensors

are summarized in the

table below. There are

no ongoing service

costs associated with

these controllers.

Aqua Conserve's ET controllers and irrigation scheduler are preprogrammed with

16 individual historic (10-year) ET curves,

each representing certain geographic

regions within the states of Arizona,

California, Oregon, Washington, Nevada,

New Mexico, Colorado and Texas.

Refinement of water demands within

each of the regions is accomplished by

programming month of July total run

times specified by Aqua Conserve for

certain areas within each region. The

7
total run times are specific to plant types

and for either spray or rotor type sprinkler

heads. As an example, the California

coastal/desert ET curve region for

Orange County includes 3 of these irrigation scheduling (run time) areas. These

areas coincide with CIMIS reference ET

zones. Refined run times may be programmed based on the prescribed total

run times and soil and slope conditions,

per Aqua Conserve's guidelines. Four

programs are available with all of the

controller models except for the ET-6M,

which has 3 programs. The multiple programs allow the user to specify different

watering days for different stations. Four

run times (3 for the ET-6M) are available

for each program to refine the prescribed

total run times due to soil and slope conditions. The minimum irrigation frequency for low water requirement or native

plants is once per week.

The actual irrigation run times for a given

day are dependant on the programming

described above and an automatic

adjustment made by the controller, based

on the measured on-site average temperature. The average temperature for the

latest 24-hour period (midnight to midnight) is compared to the preprogrammed

historic data, and an adjustment to the

next scheduled irrigation is made if the

average temperature measurement

varies from the historic data. The run

times may also be decreased manually in

one percent increments up to 20 percent.

The units' accumulation feature eliminates cool period run times which are too

short for plant benefit by storing programmed run times, until 50 percent of

the July run time has been accumulated

before irrigating. 

The findings of a 2002 study by the East

Bay Municipal Water District (Oakland,

California) indicate installation and programming of the Aqua Conserve residential controllers is relatively simple and can

be performed by most homeowners.

Aqua Conserve provides toll free telephone technical support and provides significant technical information on their

internet site. Aqua Conserve will arrange

for professional installation and service

anywhere in the U.S., upon request. The

estimated cost for this service, according

to Aqua Conserve, is $50 to $100. Aqua

Conserve's support system appears to be

adequate, and the installation and programming instructions appear to be complete and easy to understand. The only

apparent major programming instructions

related deficiency concerns programming

8

Component Type Model No. Price

6-Station Indoor Controller ET-6M $129

6-Station Indoor Controller ET-6 $169

9-Station Indoor Controller ET-9 $235

14-Station Indoor Controller ET-14 $325

8-Station Outdoor Controller ET-8b $369

12-Station Outdoor Controller ET-12b $459

Irrigation Scheduler IS-1 $99

Wired Temperature/Rainfall Sensor RTS-2 $69

Wireless Temperature/Rainfall Sensor RTS-1 $129

Aqua Conserve Component Retail Prices
for drip irrigation. The instruction manual

does not provide information regarding

programming the controllers for drip systems.

The Aqua Conserve controller and scheduler units do not come equipped with a

rain sensor or rain gage. The optional

rain sensor (shut-off) signals the controller once every 20 minutes, initiating

the rain delay function when significant

rainfall is detected and continues the

delay until rainfall ends. In rain delay

mode, the controller will not re-initiate irrigation demand calculation for 24-hours

once significant rainfall has ceased.

Depending on the duration of the rain

event, the rain delay may cause the controller to interrupt irrigation for several

days. Without the rain sensor, the user

has the ability to trip the controller's rain

delay feature manually. 

The indoor controllers are constructed of

plastic, and the outdoor controllers are

housed in lockable stainless steel boxes.

The indoor models' dimensions are

8.25"6"2” and the outdoor models' dimensions are 9"8.75"3.25”. The controller

panel includes a dial and push button

type controls and a 2-line LED display.

All of the controller models and the

scheduler include a 24VAC power transformer. The station circuit current capacity 1.0 amperes and the terminals will

accept wire sizes of 18 gage or smaller.

The controller programming is saved in a

non-volatile memory (except for ET-6M),

and a back-up battery powers the controller clock in the event of a power outage. In the event of a power outage

combined with a dead clock battery, the

date and time would have to be reset

after replacing the battery, but all station

programming would remain stored in

memory. The ET-6M must be totally

reprogrammed following a power outage.

All Aqua Conserve products come with a

limited 3 year warranty. 

Based on reports from various pilot studies conducted with Aqua Conserve controllers, it appears significant water savings can be achieved for a relatively low

initial cost and no ongoing costs.

Significant savings have been reported

even when the controllers were used

without the temperature and rainfall sensors. Reported outdoor water use savings for pilot studies performed by the

City of Denver, Colorado, Sonoma,

California, and the Valley of the Moon

Water District in Northern California were

21%, 23%, and 28%, respectively. 

Currently, the Aqua Conserve internet site

includes irrigation scheduling guidelines

for certain locations in Arizona, California,

Oregon, Washington, Nevada, New

Mexico, Colorado and Texas. Aqua

Conserve plans to expand this database

in the near future, and they will assist

users with irrigation scheduling information for other areas, upon request. Even

with the prescribed irrigation schedules,

some trial and error could be involved in

programming these controllers.

Depending on site conditions, it appears

the potential exists for a relatively high

level of user monitoring and manual

adjustment of run times could be required

of the user to improve on the basic

scheduling guidance provided by Aqua

Conserve. For example, based on the

significant variance in the run times specified for given plant types in the 3 different areas within Orange County, the

specified run times may not fit for a user

located on the border of two of these

areas, or in a microclimate area not representative of the overall area. In which

case, the user would be required to moni9
tor operation and make manual adjustments, as recommended by Aqua

Conserve.

Although the 16 run times available with

these controllers (4 per program) should

be adequate to prevent run off and inadequate irrigation, when properly programmed, the programming process for

numerous multiple start times could be

difficult for some users. The user must

manually calculate the start times using

irrigation scheduling guidelines provided

on the company's internet site, and enter

them into the multiple programs. It

appears professional installation could be

warranted in such cases.

The Aqua Conserve products offer a

proven and competitively priced alternative to limited areas in the western U.S.,

and the company plans to increase service areas as market growth dictates.

Participants in demonstration studies

report the Aqua Conserve controllers tend

to over-irrigate, but that this can be compensated by using the manual adjustment

feature. 

Weathermatic

Weathermatic, established in 1945, is a

worldwide manufacturing company of a

full line of irrigation products. The company, headquartered in Dallas, Texas,

began developing water conserving products in the 1950's when it used soil moisture sensors which were later followed by

its innovation of the industry's first rain

sensor shut off device in the 1970's. 

The Weathermatic ET controller technology patent was filed in 1998 and granted

in 2000. The unit accepts user inputs by

zone for sprinkler type, plant type, soil

type, slope, and a zone fine-tune adjustment factor. The unit then incorporates a

ZIP code input (for solar radiation) and an

onsite weather station (sensing temperature and rainfall) to perform real time ET

measurements that are used with user

inputs to calculate proper zone run times,

including cycle/soak, at user selected

start times and watering days. No historical weather information is used in the

unit's calculations and no offsite weather

information is gathered so there are no

ongoing costs associated with operation.

After 8 years of development, testing,

and field trials, the ET controller line is

scheduled for worldwide release in

November of 2004 with capacity in

excess of 100,000 units for the first year

of production. 

The Weathermatic residential controller

platform is built around a programming

module that is incorporated in a residential housing (4 - 16 zones). Four zone

modules allow expandability for varying

landscape sizes. All residential units are

suitable for either indoor or outdoor

installation and are shipped standard with

a pre-wired plug-in line cord and mounting bracket for easy installation. The unit

is powered with an internal transformer

accepting 120 or 240 volts with 24 VAC

output (1.5 amps) to zones capable of

running 4 zone valves concurrently or 3

10
zone valves with a master valve. Wire

sizes accepted range from 14 to 18

gauge and the unit is 10î tall by 9î wide. 

The unit has advanced functions including zone-to-zone and master valve timing

delays as well as a unique diagnostic

function that displays the electrical current by zone for troubleshooting.

Additionally, the user can omit specific

calendar event dates, days of the week,

and times of the day when no watering is

allowed. The remote control option

allows the programming module to be

used as a remote (range 600 feet line of

sight) and also enables the programming

module to be mounted independent of

the base housing in a user-friendly location (e.g. kitchen or utility room). 

The onsite weather station includes a

temperature sensor and rain sensor. The

unit has a microprocessor to record and

process measurements. The temperature-sensing unit, designed for a very

precise measurement of ambient air temperature, is encased in a solar shield and

white in color to avoid strict mounting

location requirements. Both wired and

wireless weather station units are offered.

The planned list prices for the controllers

range from approximately $135 for the 4-

station model to $240 for the 16-station

model. The weather station will have a

list price in the $250 range.

Weathermatic plans to partner with its

wholesale distributor and contractor network to offer an installed package price of

$349 for select markets, which will be

lessened by any local market subsidies

and may include a free system audit for

further potential water savings (system

upgrade costs additional). The controllers will not be available to the consumer directly from Weathermatic, but

will be distributed through their established wholesale suppliers (specialty irrigation suppliers) and installation professionals. The Weathermatic

controller/weather station package operates stand-alone and does not require

communication with remote servers to

obtain weather data or irrigation schedules and no ongoing service costs are

associated with the unit. 

Installation and programming of the unit

is designed to be simple and intuitive for

both the novice homeowner and the

advanced professional who is familiar

with the unit's industry standard programming dial. Advanced user functions are

located in an "Advanced Functions" position on the programming dial so as to not

complicate the set up for novice users.

While programming the unit is simple,

Weathermatic recommends installation by

a professional who will give the site the

highest rate of success for not only controller programming, but also complete

system operations with an emphasis on

water conservation. Based on

Weathermatic's solid reputation and wellestablished support network, it is reasonable to assume their ET controller technical support system will be adequate.

Installation and programming instructions

were not available for this review, however, a programming video and DVD will be

available to accommodate the standard

user manual. 

Programming of the "Auto Adjust" ET portion of the controller requires inputs by

zone for sprinkler type, plant type, soil

type, and slope. Sprinkler type can be

entered on a basic level by the user

selecting the type of sprinkler in zone ñ

SPRAY, ROTOR, or DRIP. A more

advanced user can scroll past these

basic inputs with default precipitation

11
rates and prescribe an exact numerical

precipitation rate for the zone from .2î/hr

to 3.0î/hr. Plant type works similarly to

the sprinkler type input in that the user

can simply select the type of plant life in

the zone ñ COOL TURF, WARM TURF,

ANNUALS, SHRUBS, NATIVE, or

TREES. Again, a more advanced user

can scroll past these basic inputs with

default percentages and prescribe an

exact numerical percentage for the zone

from 10 to 300% based on the plant life

in the zone and sun/shade consideration.

The soil type ñ CLAY, SAND, LOAM -

and slope (numerical degree of slope 1 ñ

25+ degrees) are used to automatically

calculate the cycle/soak function by zone. 

In addition to these inputs by zone, the

user programs the ZIP CODE of the site

or, primarily for locations outside the

United States, the latitude of the site.

This input and the calendar day of the

year is used to determine the solar radiation at the site, which is a variable in ET

calculation. These static inputs are combined with the dynamic onsite weather

station inputs to perform the overall equation that determines proper zone run

times. No historical ET information is

necessary for the real time ET calculation.

The user will have the ability to fine tune

the zone run times by zone through a

MORE/LESS function. This allows the

user to increase watering by zone up to

25% or decrease watering by up to 50%. 

The controller's irrigation schedule is

based on the user prescribed irrigation

days, start times, and omit times (dates,

days, and times of day) so as to conform

to local watering restrictions and also

accommodate site-specific hydraulic

issues, which vary by time of day. Once

programmed, the controller calculates ET

for the period beginning at the end of the

last irrigation cycle, or measurable rainfall, and ending at the next prescribed irrigation day. Irrigation will occur if the calculated run time is sufficient for an effective irrigation watering. If insufficient

demand has not been reached, irrigation

will not occur and the controller will carryover the accumulated ET to the next prescribed irrigation day and time. This

accumulation threshold, which prevents

ineffective irrigation, is calculated based

on a default accumulation factor.

Weathermatic has tested its ET calculation algorithm and controller functionality

extensively over the past 8 years. For

comparing ET calculations, CIMIS weather station ET calculations were compared

to those using the Weathermatic controller/weather station methodology at 10

geographically diverse sites over a 7-year

period for 70 years of combined data.

The ET results at each site show a very

high correlation between the CIMIS

weather station ET results and the

Weathermatic ET results using the relatively inexpensive onsite weather station.

The graph is one example that is representative of the study:

Beyond comparing the ET calculation, the

Weathermatic unit has been part of a

field study performed by the Northern

Colorado Water Conservancy District.

This three-year study of the unit analyzes

the Weathermatic controller's accumulated water output in comparison to ET (as

measured by a lysimeter and onsite

weather station) and the plant water

requirement of the zone. The results

show the Weathermatic unit waters consistently with the varying needs of the

plant life as is shown below in the 2003

study:

12
The Weathermatic unit is also part of a

field pilot program conducted by the

Marin Municipal Water District. In this

study, 13 controllers were installed at 7

sites to compare water usage in 2002

and 2003 to the base year usage in

2001. In 2002, sites installed with the

Weathermatic ET controller saved 26%.

In 2003, the water savings climbed to

32%. Based on available documentation

from this program and the other studies,

it appears the Weathermatic controller

performs well and yields significant water

savings. 

Weathermatic’s test center is conducting

ongoing testing on the controller and

weather station in the following areas

affecting reliability: mechanical stress

testing, environmental testing, software

testing, and functional/characterization

testing. Additionally, Weathermatic will

ensure user friendliness and perform further reliability test during the summer of

2004 at 500 sites in the United States

and a number of international countries. 

Once the Weathermatic controller

becomes available in November, it looks 

13

ETo

ET Controller

2003 Irrigation Applied

5/ to 10/17

PWR WM Lysim.

30

25

20

15

10

5

0

5/75/8

5/155/225/29

6/5

6/126/196/26

7/3

7/107/177/247/31

8/7

8/148/218/28

9/4

9/11

9/189/25

10/0210/0910/16

-5

inches of water
to be an economical and effective unit

with the benefits of real time, onsite ET

measurements and inputs by zone for

key programming parameters. 

WeatherSet 

The WeatherSet Company is located in

Winnetka,. WeatherSet has manufactured commercial weather based irrigation controllers for landscapes, golf courses and greenhouses since 1979. The

company began development of the first

residential controller prototypes in 2000,

and began marketing the residential controllers in September 2001. Their controllers utilize a WeatherSet designed and

custom fabricated solar sensor to approximate on-site ET, and these solar measurements are combined with an on-site

rain sensor to automatically adjust irrigation schedules. 

The WeatherSet residential controller utilizes the same solar

radiation sensor

used with the company's greenhouse

and commercial irrigation controllers.

This solar sensor

has reportedly functioned reliably in

demanding environmental conditions

from Wisconsin to

Florida to control

greenhouse misting

systems both

indoors and outdoors since the early

1990's. 

Two indoor residential controller models,

and five outdoor models are available.

Models and low volume prices are summarized in the table below. The prices

include the solar and rain sensors. The

WeatherSet controller is a stand-alone

controller and does not require communication with remote servers to obtain

weather data or irrigation schedules, and

there are no ongoing service costs associated with the controller unit. The controller units are available directly from

WeatherSet or from their internet site,

and the company plans to also distribute

the product through select specialty irrigation contractors. 

The WeatherSet controller calculates a

daily ET estimate based on solar sensor

SunFall TM measurements which are

logged by the controller on a 2-minute

frequency. The sensor must be installed

in a mostly sunny location in order to

function accurately. From their work with

commercial controllers, WeatherSet

reports that "SunFallTM" reduces by

about two-thirds from a clear day in summer to a clear day in winter, and that their

5 self-adjusting programs follow these

changes.

The calculated ET information is com14
bined with rain sensor data and user programmed information to adjust schedule

irrigations. To program the controller for

automatic adjustments, the user assigns

each station to one of three programs,

which are labeled LawnsTM FlowersTM,

and ShrubsTM, and designates irrigation

type as either rotor or spray for each station. A runoff factor may also be entered

each station to stop runoff. Alternately,

the user may program custom run times

for each station in one-minute increments

from 0 up to 255 minutes.

The controller also includes two low

water plant programs (LWU1 and LWU2)

for drip systems and native plants. The

LWU programs allow the user to manually

enter a "Days-Between-Waterings" interval for the hottest time of the year and

run times up to 255 minutes. As the solar

measurements indicate the ET is falling,

the LWU programs automatically increase

the "Days-Between-Watering"while holding the run times constant. For example,

10 and 18 day summertime frequencies

will automatically increase as solar sensor data measurements a fall in ET. The

run times remain constant for valves in

the LWU programs. The 2 LWU programs

and the LawnsTM, FlowersTM, and

ShrubsTM give WeatherSet controllers 5

self-adjusting programs.

The controller has a manual start function, and an optional irrigation history

review function. With the H-option, the

controller keeps a running tab of total run

time for each station like a water meter

records total gallons. The controller's

rain sensor is a Hunter Mini-Clik® unit.

The sensor signals the controller to interrupt irrigation in its rain shut-off mode,

and the rain sensor signals are also used

by the controller for irrigation scheduling.

The WeatherSet controller is preprogrammed to account for the duration that

the rain shut-off circuit has been interrupted when scheduling irrigations. 

The WeatherSet irrigation controller provides 7 different runoff factors which are

set for each station. A maximum cycle

run time of 2, 4, 6, 8, 11, 15, 20 and

unlimited minutes per hour is associated

with the respective factor. The default

cycle limit factor (number 6) is four 4 minutes per hour. As an example, if the controller calculates a total 12 minute run

time for a station, this station will be irrigated in three 4-minute increments over

a 3-hour period, with the default setting.

For stations which generate runoff,

WeatherSet recommends the user measure the time required to cause runoff

(using the manual run mode), divide the

15

Controller Type Model No. Price

8-Station Indoor WSR8 $170

12-Station Indoor WSR12 $195

8-Station Outdoor WSC8 $210

12-Station Outdoor WSC12 $235

16-Station Outdoor WSC16 $320

20-Station Outdoor WSC20 $380

24-Station Outdoor WSC24 $440

Irrigation History Function H-option $35

WeatherSet Controller Retail Prices
time by two and use that time to choose

the runoff factor for the station. The runoff

factor may be shut off to allow continuous

watering when required. For example,

valves controlling drip systems in LWU

programs may best be watered with

runoff limit shut off.

The indoor controller cabinets are constructed of aluminum and the indoor

power transformer is an external plug-in

type unit. The lockable outdoor cabinets

are constructed of zinc plated steel with

powder coating and stainless steel

hinges. The outdoor models include

internal power transformers. The station

circuit current rating for the indoor units is

0.75 amperes and it is 1.5 amperes for

the outdoor units. All models' station circuit terminals will accommodate wiring

sizes from 12 to 20 gage. The controller's program memory is non-volatile,

and the time-keeping microprocessor

chip uses a 3.3V coin-type battery which

has a reported life of ten years if no

power is applied. When the controller is

powered, then the energy of the 10-year

battery is not used. WeatherSet provides

a standard 3-year warranty with their controllers.

WeatherSet has provided data showing

the close correlation between ET estimate calculation by their controller and

that calculated by an AZMET (Phoenix,

Arizona ET network) weather station.

WeatherSet controllers have not been

used in any formal demonstration studies

and no water savings data was evaluated

for this review. It is estimated that

approximately 180 commercial units have

been installed since 1995, and that most

of these controllers remain in use.

Approximately 100 residential controllers

have been installed since they became

available in September 2001.

WeatherSet reports current production

capacity is approximately 25,000 per

year, and delivery time is about 8 weeks,

depending on volume. WeatherSet has

contracted with a major irrigation manufacturer to provide assembly operations,

and the above production capacity is

based on this recent business arrangement.

WeatherSet reports that most homeowners should be capable of installing the

residential controller. WeatherSet

believes that programming the residential

controllers by the typical homeowner is

easy because of FlowersTM, LawnTM and

ShrubTM program labeling. Technical

support is available by toll free telephone

and also through the company's internet

site. Service by factory trained contractors is limited to California, Oregon,

Washington, and Colorado at this time

and will grow as the market expands.

The installation and programming instructions, which include directions for locating

the solar sensor, appear to be adequate

and easy to follow. 

The WeatherSet controller appears to be

simple stand-alone alternative that should

function adequately at most locations.

Although WeatherSet reports the technology used in their controllers is proven,

water savings data is not available and

the track record for their residential unit is

limited. 

AccuWater

AccuWater, Inc. was incorporated in

October 2002 and is based in Austin,

Texas. The company is currently in the

final stages of developing a centralized

weather-based irrigation management

system. Their first prototype controller

was developed in 2002 and pilot testing

has been ongoing since late 2002.

16
AccuWater plans to begin actively marketing their system within Texas beginning in May 2004. For the rest of 2004,

sales outside of Texas will be limited to

formal pilot programs sponsored by water

authorities.

The AccuWater system schedules irrigation based on ET

calculated from

local weather data

collected through a

private network of

weather stations

and or sensors.

Communication and

data transfer to the

controllers and sensors is accomplished through

Internet connection

to a centralized

computer server

operated by

AccuWater.

The residential

model of the AccuWater controller is an

indoor unit with a 16-station capacity,

including one station terminal that may

run concurrently with all the other stations

to control a master valve or drip system.

The controller includes a wired tipping

bucket type rainfall gage. The planned

retail price for the controller will be

between $400 and $600. The annual

service fee will start at $180 for up to a

quarter acre of irrigation landscaping and

increase by $1 per additional thousand

square feet of irrigated landscaping, with

a cap at $600 (1.05 acres of irrigated

landscaping).

The controller housing is constructed of

injection-molded plastic, and the transformer is external to the controller. The

rain gage is commercial grade and is

constructed of UV-resistant heavy-gage

nylon. The station circuit terminals will

accept all common wire sizes and the

station circuit current rating is 0.3

amperes. AccuWater plans to provide at

least a one-year limited warranty with the

controllers and weather stations.

Initially,

AccuWater

products will

only be available directly

from the

company or

AccuWatercertified irrigation contractors. The

AccuWater

controller

requires an

"always on"

Internet connection (e.g.

DSL or cable

modem). In a typical implementation, the

controller will piggyback over the homeowner's high-speed Internet connection

via a wired or wireless network router.

The system does not involve loading any

software on the homeowner's computer,

nor does the computer need to remain on

for the system to operate. 

The controller is configured and managed

by the end user using a web browser.

Because all configuration occurs on the

server, configuration and management

can be performed from anywhere that the

end user can get access to a web browser. Also, since all configuration data is

stored on the server, no battery backup is

required on the controller.

17
Information for each controller includes

site location (latitude, longitude and elevation), environmental limits (temperature, wind speed), ET lookback period

(days), irrigation start time, daily station

run limit (number of stations per day),

and other operating parameters.

Information programmed for each station

includes plant type/coefficient, replacement factor, application rate, irrigated

area, maximum run time, minimum delay

(soak) time. 

Installation of the AccuWater system

involves (1) installing the AccuWater controller in place of the existing controller;

(2) installing weather instrument(s) and

connecting to the new controller; (3) performing an initial site survey to determine

flow rates and areas; and (4) configuring

the stations and performing a test run of

all stations.

Guidelines will be provided with the programming instructions for adjusting the

replacement factor to compensate for

shade areas and other special needs,

and for determining maximum run and

delay times for sloped areas.

Adjustments, based on post installation

monitoring, are accomplished by changing the replacement factor. AccuWater

reports that most users are able to make

these adjustments, with technical assistance provided upon request.

The AccuWater controller tightly integrates a weather station and an irrigation

controller. It relies on weather monitoring

instruments attached to each irrigation

controller, and can share weather data

between nearby units via the server. The

AccuWater controllers send weather data

to the server every minute, and the server backfills missing data elements from

nearby sites by searching a pre-defined

hierarchy. The server then replies to the

controller with a complete weather sample for that locale containing temperature,

humidity, barometric pressure, wind

speed, rainfall and solar radiation. The

controller calculates dew point and wind

chill for each incoming sample. As a

result, the AccuWater controller always

knows the current weather conditions and

can make decisions (adjust, delay or

abandon).

Once a day, the server calculates a

schedule for each client based on stored

weather data, irrigation history, on-site

rainfall history, and the National Weather

Service local forecast. The schedule is

sent to and stored on the controller until

time to execute each record of the schedule. Controller clocks are synchronized

with the server to ensure that the entire

system remains in synchronization. If a

controller is restarted following a power

failure, history and schedules will be

reloaded from the server on the first connection.

Within an irrigation schedule, one schedule record represents a complete station

18
activation for that day. If necessary, the

controller will break down a schedule

record into multiple intervals to meet the

"maximum run time" and "minimum

delay" criteria (commonly used in situations where runoff is a problem). The controller will wait until the specified start

time for each record, and will then analyze the current (real-time) weather conditions. If conditions are appropriate (no

rain or high wind and temperature within

limits), the system will open the valve and

irrigate the specified zone. When it completes each irrigation segment, the controller will generate an irrigation history

record and send it to the centralized server for storage. When the schedule for the

next day is generated, the stored irrigation history is used to tabulate previous

irrigation amounts.

If the controller determines

weather conditions are not

appropriate for irrigation, it will

wait for conditions to improve. If

conditions do not improve

before the record expires, no

irrigation will occur and a null

history record will be generated.

If the weather forecast includes

a high probability of rain, irrigation may (based on a probabilistic model) be delayed for 24

hours. The unit also has the

capability to provide manual irrigation for individual or collections of stations by minutes or

inches. Manual irrigation history

records are taken into account during

normal scheduling, so it is not possible to

manipulate the system by occasionally

performing manual irrigation.

Since the AccuWater System relies on

having a sufficient density of weather stations within their service areas, the company anticipates the need to locate

AccuWater-owned weather stations and

weather sensors at selected user sites.

All weather stations and sensors will be

monitored automatically for suspicious

data, and maintenance will be managed

by AccuWater. As service areas are

developed in other areas of the country,

AccuWater may locate additional computer servers within these areas (e.g. West

Coast or East Coast) for redundancy and

load balancing. At present, all sites are

serviced from AccuWater's server facility

in Austin, Texas.

By storing all operating data on the server, AccuWater makes it possible to evaluate the effectiveness of controllers (individually or collectively) very easily. The

following chart illustrates the effectiveness of one controller and was created in

Microsoft Excel by accessing the

AccuWater database.

The above chart is representative of ten

similar pilot study data sets, and it should

be noted that there was a problem with

the ET algorithm that was not recognized

and fixed until late May 2003. (The 

19

Inches per Month

10504 San Souci Place (Najvar Residence in Great Hills)

0

1

2

3

4

5

6

7

8

Jan-03Feb-03Mar-03Apr-03May-03Jun-03Jul-03Aug-03Sep-03Oct-03Nov-03Dec-03Jan-03Feb-03

Rain

Irrigation

TAMU ET

Adj. ET

1.50

Jan-03 Feb-03 Mar-03 Apr-03 May-03 Jun-03 Jul-03 Aug-03 Sep-03 Oct-03 Nov-03 Dec-03 Jan-03 Feb-03

 0.55 0.45 0.29 1.54 2.93 1.16 1.10 1.88 1.26 0.84 0.61 4.55 3.59

0.00 2.41 3.39 4.49 3.72 3.92 2.34 1.03 1.06 0.95 0.14 0.00 0.90 1.80

2.21 5.90 6.33 6.52 6.72 4.36 3.65 2.61 2.52 1.64 1.84 1.92 3.56 5.32

1.84 4.92 5.27 5.43 5.60 3.63 3.04 2.17 2.10 1.37 1.53 1.60 2.97 4.43
acronym TAMU is for Texas A&M

University.)

AccuWater has implemented the waterrationing algorithm for Austin, Texas, and

can add algorithms for any other city (by

zip code). This is a user-selectable

option. AccuWater plans to make water

usage information available to local water

authorities (subject to the provisions of its

privacy policy) for analysis and to even

build in the capability to adjust water

usage (if allowed by the end user) during

periods of peak usage or water shortage.

AccuWater reports that most homeowners will be capable of installing and configuring the controller. An installation and

programming manual was not available at

the time of this review. The company

plans to make arrangements for local

technical service representatives for service calls, and technical support will be

available by toll free telephone and

through the company's Internet site.

Because of its Internet-centric design and

web-based controls, the AccuWater system integrates easily into most home

automation systems.

AccuWater installed twelve controllers at

residential sites in the Austin, Texas area

during the winter of 2002/2003, and has

monitored these sites as a pilot program.

Based on documentation from this program, which has been provided by the

company, it appears the system functions

well and that it has the potential to yield

significant water savings as well as

reducing runoff. 

Assuming sufficient and accurate weather

monitoring data is available within adequate proximity to the user, this system

should provide accurate ET-based irrigation scheduling and require minimal monitoring and adjustment. The computer

interface provides an easy and effective

method for monitoring irrigation information and weather conditions. Given the

limited track record for this system, long

term reliability and operation and maintenance is a concern. The AccuWater

System could potentially satisfy the more

demanding and affluent portions of the

ET irrigation controller market.

ET Water Systems

ET Water Systems (ETWS), based out of

Mill Valley, California, is a new manufacturer of weather based irrigation controllers for the residential and commercial

markets. The company is currently in the

final stages of developing a centralized

weather based irrigation management

system. ETWS was incorporated in 2002

and their first prototype controller was

developed in 2003. The company plans

to begin marketing their system in the

California, Nevada and Colorado markets

beginning in July 2004.

The ETWS system schedules irrigations

based on ET data received from existing

weather stations and user programmed

20
information associated with specific landscape features. Currently the ETWS system uses publicly available weather data.

The option to install a weather station is

also available. A 12-station indoor residential controller is planned for distribution by September 2004, which should

retail for approximately $199. The controller will accommodate an optional rain

sensor shut-off or tipping bucket type rain

gage, and an outdoor installation enclosure will also be available. An annual

service fee will be charged, and it is estimated the fee will be $48 or less. 

ET and precipitation data is automatically

retrieved from the Internet each day by

the ETWS host server. This data is

planned to be obtained from existing

weather station networks in the cities

where ETWS will market its product. If

necessary, ETWS plans to install or use

other non-public weather stations to collect ET and precipitation data in locations

where sufficient quality data is not available. The server automatically processes

the ET data in combination with the user

programmed landscape information, to

develop irrigation scheduling. The user

enters the landscape information from

any computer with an Internet connection

via the ETWS Internet site. However, a

personal computer is not required at the

site residence for the system to function.

Communication between the user's controller and the server may be by cellular

telephone or land-based telephone link.

(It is anticipated most residential users

will use land lines.) The ETWS central

server communicates with each field controller on a daily basis. During each daily

call the ETWS server receives a log of all

watering activity since the last call and

sends any required scheduling adjustments. The controller will be able to

operate independently if communication

to the server is temporarily interrupted.

In which case, the controller functions

using the latest schedule received from

the server, then revises the schedule

once reconnected to the server. The

ETWS controller can accommodate

schedules of any duration and frequency,

including schedules that require watering

on a very infrequent basis (i.e. every 30

days).

To enter landscape information, a user

goes to the ETWS Internet site and logs

into their account with a user name and

password. The program interface to

enter the site specific landscape information is set up with WindowsÆ based pull

down menus and appears to be intuitive

and easy to use. The program is well

organized and covers a comprehensive

set of landscape factors including; plant

type, irrigation type and optional application rate, soil type, slope, root depth, sun

exposure and distribution uniformity.

User-defined sprinkler precipitation rate

(PR) and sprinkler uniformity (DU) may

be entered or default measures may be

selected in the absence of precise PR

and DU information. A wide selection of

plant types are available to select from

and multiple plant types may be selected

for one station. The program will automatically set the watering schedule based

on the plants with the highest water

requirement. Irrigation types available

include spray, rotor, impact, stream spray,

drip emitter, and bubbler. The default distribution uniformity factor is 70 percent.

All default settings can be changed at

any time by ETWS and each water

agency can select the default settings it

wishes to use for its customers. The

user may also enter non-irrigation days,

adjust the total station run times by a percentage factor, and initiate manual irriga21
tions by station. The user will also be

able to review system and irrigation history information on ETWS's Internet site

from any Internet accessible computer.

The ETWS setup program includes help

screens to answer questions common to

first time users. Once the user becomes

familiar with the program, an advanced

setup mode may be used which offers a

more efficient means of programming.

Adjustments to specific site factors may

be made at any time via the ETWS

Internet site. Site factor changes will

generate new irrigation schedules. 

The ETWS controller also has an offline

programming feature in which users can

manually set a watering schedule for

each station. This feature is intended to

be used during periods when phone service is temporarily unavailable (i.e. newly

constructed home prior to sale). Offline

programming may be performed at the

controller using the keypad and the 2-line

LCD display. The manual start mode

may also be initiated at the controller.

ETWS' objective is for the system to

automatically generate, download and

execute irrigation schedules. The need

for program modification in the field is

expected to be very limited.

ETWS reports the irrigation scheduling

algorithms used in their system are

based on current state-of-the-art horticulture science. The program incorporates

all landscape factors needed to accurately determine soil moisture depletion, and

irrigation scheduling. ETWS uses a different algorithm for scheduling sprinkler

and drip irrigation stations. The company's proprietary algorithms automatically

generate daily schedules with station run

and soak times based on the station

application rate, soil intake rates and

slope conditions.. The station run/soak

cycles for each irrigation period remain

constant, based on replenishment of a 50

percent plant root zone moisture depletion level. Irrigations are delayed until a

soil moisture depletion level of 50 percent

is calculated, based on the measured

daily ET and rainfall.

ETWS' initial residential controller will use

a fabricated metal enclosure. Starting in

early 2005, ETWS will manufacture all of

its residential controllers with an injection

molded plastic enclosure. In addition to

the 12 station circuits, the controller is

expected to provide a master valve/pump

start circuit. Information on the controller's power transformers and station

circuit current capacity was not available

at the time of this review. The station circuit terminals will accept 12 to 20 gauge

size wiring. The controller memory is

non-volatile and it includes 9-volt back-up

battery for the clock. An optional powder

coated lockable steel cabinet for outdoor

installation will be available. 

Other options will include a rain sensor

and a tipping bucket type rain gauge.

The rain sensor will cause circuit interruption and simply suspend irrigations when

significant rainfall occurs. The rain gauge

data would be transmitted to the server

for use in irrigation scheduling. 

Since telephone communication allows

two-way information transfer, ETWS will

be able to manage the information

received from the individual controllers.

This may be beneficial to water agencies

by allowing analysis of customer water

use data. ETWS plans to provide this

information through their Internet site.

Also, ETWS may sell their software program to water agencies that would maintain the server and provide the service for

their water users. In this case, the water

22
agency could absorb the ongoing service

cost.

The controller will not require professional

installation, although the company recommends professional installation and plans

to provide factory trained individuals or

irrigation contractors to install all units. It

is estimated a typical professional commercial installation should take 1 - 3

hours, including a site assessment and

discussing the assessment with the user.

Typical residential installations will be

completed in less time. The professional

installation/consultation cost is estimated

to be $75 - $225 depending on location,

size, and other site conditions. Technical

support will be available by toll free telephone, in addition to the support provided

on the company's Internet site.

The ETWS System has not been included in any demonstration programs and

no water savings data were available at

the time of this product review. However,

ETWS reports about 20 commercial prototype units that were installed during

2003 are functioning well. ETWS plans

to provide a 3-year limited warranty with

the controller. 

The ETWS System appears to be a well

designed real-time approach to weather

based irrigation scheduling. Depending

on the conditions at a given site relative

to those measured at the weather station

used, the ETWS controllers should function well. Post-installation monitoring and

adjustments may be required to address

any problems. The controller cost is

competitive and ETWS will offer several

pricing options for service. Users will

have the option of purchasing a one-time

service plan for the lifetime of the product

(this will be in lieu of annual service fees)

in addition to the option of purchasing a

multi-year service plan. The computer

interface method of programming and

monitoring the system is outstanding.

The water use monitoring option should

also be attractive to progressive water

agencies interested in quantifying water

savings.

HydroPoint

WeatherTRAK is the "smart" irrigation

controller product of HydroPoint Data

Systems of Petaluma, CA. WeatherTRAK

provides a wireless, real-time ET data

service combined with a "scheduling

engine" that updates irrigation schedules

for each valve in a landscape daily.

Network Services, which developed the

patents on the broadcasting of ET data,

began business in 1997. HydroPoint was

incorporated in 2002 and now has 1,000

units currently in use.

The WeatherTRAK system uses data

from existing ET stations and the National

Oceanographic Atmospheric

Administration's system of 12,000 nation

wide weather stations to deliver ET to

any area in the US. The WeatherTRAK

23
system uses advanced climatologic modeling techniques, developed at Penn

State University. This proprietary system

is called ET Everywhere, and has proven

accuracy to a standard deviation of .01

inch of daily ET down to one square kilometer. The WeatherTRAK ET

Everywhere data service provides local

ET (microzone) without the need for

weather station on site. The HydroPoint

Data Center validates the weather data

and transmits calculated ET through

three satellite servers to each controller

everyday. The three satellite services provide over-lapping coverage of the U.S. to

ensure signal reception to WeatherTRAK

controllers located anywhere. 

The WeatherTRAK controller calculates

irrigation schedules for each independent

valve on a site. The controller does not

use pre-set irrigation schedules input by

the user. Instead, it asks a series of

questions to "understand" the site variables that influence water need. The controller is programmed by entering the following station specific information: sprinkler type or precipitation rate, plant type,

soil type, microclimate (sun or shade),

slope (including if the valve is at the top,

middle or bottom of the slope, and system efficiency (percentage). The schedule for each station is adjusted daily

according to the local weather data

received via the ET Everywhere Service.

With these inputs, the WeatherTRAK calculates an efficient irrigation schedule for

each irrigation valve. Soil moisture depletion tracking, triggered at a 50% depletion

level, along with daily ET updates allows

the controller to adjust schedules as the

weather changes. The number of water

days, minutes and cycles (with appropriate soak times between cycles) are generated automatically and change as

weather and water need fluctuates. The

WeatherTRAK has an eight week scheduling window. This allows for infrequent

watering of low water use or native

plants.

The WeatherTRAK has a manual feature

providing any amount of time setting to

check the irrigation system on a valve by

valve basis. An adjust feature provides

percentage (in 5% increments) increase

or decrease to any independent valve. A

rain pause mode allows the user to shutoff irrigation for up to 14 days during or

after rain. HydroPoint can also be contacted to automatically "rain pause" controllers and groups of controllers using

the wireless data service. Non-water days

can be selected. A "help" mode alerts the

user to the HydroPoint customer service

center toll free telephone number to

answer questions and walk users through

any situation occurring on the site.

The currently available WeatherTRAK

model is an indoor unit which accommodates up to 12 stations. The retail price of

the 12 station unit is $480 and this

includes two years of scheduling service.

Afte the initial two years of service an

annual fee of $48 is charged.

WeatherTRAK 6 station, 9 station and 12

station models will be available in April

2004. The Toro Company will be selling a

full line of residential and commercial

models with full WeatherTRAK enabled

features available during the summer of

2004. Custom inputs for crop coefficient

values, community water restrictions

(odd/even or selected watering days) will

also be available with the spring 2004

models. The controller is available directly from HydroPoint or through local

HydroPoint, Irritrol, and Toro distributors.

The WeatherTRAK residential controller

24
is a small (7î X 6î X 2î) metal and plastic

unit for indoor installation. It features a 3

knob interface with 2-line LED display.

The power transformer is a 24VAC external plug-in type. Spring models will have

hard-wire and 110 volt wiring options. The

station circuit current capacity is 1.0

amperes, and the terminals will accept 12

to 20 gage size wiring. Stations run

sequentially. WeatherTRAK can accommodate rain shut-off devices, master or

pump valves. The WeatherTRAK has a

non-volatile memory and does not require

a back-up battery. 

The WeatherTRAK controller does not

require professional installation, although

"trained" installation is recommended.

Typical installation times, as seen in public agency studies and distribution programs, range from 1 hour to 2.5 hours,

depending upon the size of the landscape covered and mounting issues.

Installation should include a site assessment and discussing the site irrigation

system, how the controller operates with

the user. Technical support is available

from HydroPoint by a toll free number, on

the company internet site and through

field "certified" contractors.

The WeatherTRAK controller has been

tested (or testing is in progress) in at

least 15 public agency settings in the

West since 1998. The overall results from

these tests indicate sufficient water savings (16% - 58%) and significant reduction in runoff (64% - 71%) have been

achieved. Tests locations information is

summarized in the table above.

The WeatherTRAK controller has a

proven track record, and has been on the

market longer than any other real-time

weather based controller. The

WeatherTRAK has added and updated

features as public agencies have 

requested, such as adding the ability to

irrigate native and low water use plants in

the proper way.

Irrisoft

Irrisoft Incorporated manufactures the

Weather Reach Receiver (WR-7). The

WR-7 is a weather data receiver which is

used in combination with a user's existing

irrigation controller to schedule irrigation

based on ET demand. Irrisoft has been

in business since 1999, and became a

subsidiary of Campbell Scientific

Company during 2001. The WR-7 has

been on the market since July 2002, and

25

Test Sponsor No. of Test Sites

Irvine, California 180

Los Angeles Dept. of Water and Power 540

Boulder, Colorado 10

Colorado State University, Ft. Collins 3

University of Las Vegas, Nevada 15

Santa Barbara, California 200

Lake Arrowhead, California 78

Victor Valley, California 12

Marin, California 8

Park City, Utah 24

Santa Clara Valley Water District, California 125

Summary of WeatherTRAK Demonstration Projects
approximately 600 units are currently in

use.

The Weather Reach System works in

conjunction with local Campbell Scientific

weather stations and centralized computer servers using Irrisoft software to calculate local ET based on real-time climatic

data. Weather data is transmitted from

the computer server through a pager network to the receivers hourly. Data

includes temperature, wind speed, relative humidity, and solar radiation data.

The WR-7 uses this information to estimate ET accumulation on an hourly

cycle, and processes it into a running ET

balance. 

The WR-7 does not include on-site sensors or gages. A tipping bucket type rain

gauge is available as an optional add-on

component to the receiver. With or without the gauge, the receiver accounts for

local rainfall which affects the root zone

soil moisture balance. In addition, the

receiver includes a wind factor adjustment which may be set to compensate

for significant variance in on-site wind

conditions versus the conditions measured at the weather station. The current

retail price for the WR-7 is $485, and

accessory prices are summarized in the

table below. The existence of an ongoing

service fee is dependant on the service

provider, as discussed later.

A growing network of Weather Reach

System Providers exists throughout the

U.S., covering areas in several northeastern, southwestern and Rocky Mountain

states. For a covered area, data from

multiple weather stations are received,

processed, and then transmitted by a single provider. The WR-7 receivers are

programmed to receive data from the

appropriate weather station based on a

weather region code. The data are transmitted by the provider using a Motorola®

Flex® paging system. 

Once the WR-7 receives the data and

calculates ET, one of four modes are

available for the receiver to communicate

with the irrigation controller. These

include: ET Enable, ET Trigger, ET

Pulse, and RS-232. Selection of the

appropriate mode is dependant on the

irrigation controller being used.

26

Component Model No. Price

Plug-in Transformer WR-PS $25

External Antenna WR-ANT $32

Outdoor Enclosure WR-OE $98

Pronamic Rain Gage WR-PRG $85

WR-7 Accessories Prices
Residential irrigation controllers typically

require use of either the ET Enable or the

ET Trigger modes. The ET Pulse and

RS-232 modes are compatible with commercial type controllers, and their communication processes are not discussed

herein. 

The ET Enable mode functions by interrupting the common wire circuit from the

irrigation controller to the automatic irrigation control valves. The WR-7 allows for

irrigation by closing this circuit. This

mode is used to control most irrigation

controllers that use a common circuit to

provide power to the system.

In the ET Trigger mode, the WR-7 closes

a switch contact to trigger irrigation when

ET accumulates to the programmed

threshold. The switch duration is programmable to accommodate the controller. The controller recognizes the

momentary switch closure as a signal to

irrigate. For this mode, the controller

should also have day and time condition

settings that must also be met to start an

irrigation cycle.

Regardless of the receiver to controller

mode used, the controller is programmed

based on a plant root zone moisture

depletion and ET threshold balance concept. This balance is maintained based

on ET minus effective rainfall. The user

programs one of four settings to define

effective rainfall. Effective rain is based

on the soil moisture intake rate and soil

moisture holding capacities.

The controller schedule is set to irrigate

every day, unless certain days are to be

excluded for a variety of reasons. The

receiver then signals the controller when

the ET threshold is reached, and the prescribed irrigation amounts are applied to

replenish the root zone depletion. The

receiver includes two programs so that

two ET thresholds and landscape adjustment percentages may be used. This

provides for different stations to be

scheduled separately to meet the needs

associated with varying plant types and

conditions. There are user-defined settings to define effective rainfall. 

As discussed above, the WR-7 simply

turns the irrigation controller on when a

specified demand is reached which coincides with a specified depletion. The irrigation controller's features allow for programming to satisfy the demands dictated

by the landscape features. Specifically,

the controller schedule should be developed based on application rates and

plant types, and soil, slope, and shade

conditions. Hence, the ability of the system to irrigate all stations efficiently and

minimize run off is very much dependent

on the controller used. 

The WR-7 is a small (4.8"X5.25"X1.5”)

plastic cabinet designed for indoor installation. A lockable fiberglass outdoor

enclosure is available as an accessory.

In the event a power supply is not available from the existing controller, an

optional power transformer is available.

Irrisoft requires installation by a professional irrigation system specialist, and

they market their products through specialty irrigation product suppliers.

As mentioned above, potential ongoing

costs are dependent on the service

provider for a given area. Irrisoft reports

that the split between existing public and

private providers is approximately 50 percent. Public providers typically absorb

the cost of the weather stations, computer server and software, and paging system, and there is no ongoing user cost.

Private providers pass on these costs to

their users, and the two providers inter27
viewed for this review reported typical

residential rates in the range of $100 to

$350. Existing public providers include

the City of Denver, Colorado Water

Department, the Northern Colorado

Water Conservancy District, Southern

Nevada Water Authority, the Utah

Division of Water Resources, and Irvine

Ranch Water District, in Orange County,

California.

During recent years, numerous demonstration projects using the Irrisoft System

have been initiated. The overall results

from these ongoing projects indicate sufficient water savings can be achieved with

the system and that the system functions

well in many areas.

A sampling of these projects is provided

in the table below. In addition, Irrisoft has

provided a list of about 25 municipal and

institutional entities currently using their

product in residential and commercial

applications.

Depending on the variance between onsite conditions and those measured at

the weather station being used, the use

of a rain gage, and the accuracy of the

controller programming; the WR-7 should

provide most users with relatively accurate real-time weather based irrigation

scheduling system. 

28

Sponsor No. of Test sites

Denver Water Department 12

Utah Division of Water Resources 8

Northern Colorado Water Conservancy District 10 

Southern Nevada Water Authority 10

Terra Weather Broadcasting, Houston, Texas 25

Summary of Irrisoft Demonstration Projects
29

Manufacturer Advantages Disadvantages

Aqua Conserve Documented track record 

Low controller cost

No ongoing service cost

Stand alone - Not dependant 

on communication network

Weathermatic Documented pilot testing

Fully automatic scheduling

Moderate controller cost 

Rain sensor included

Stand alone - Not dependant 

on communication network

WeatherSet Fully automatic or manual

scheduling

Low controller cost

No ongoing service cost

Rain sensor included

Stand alone - Not dependant 

on communication network 

AccuWater Fully automatic scheduling

Includes rain gauge

Computer interface

Water use info available to 

others via internet

ET Water Systems Fully automatic scheduling

Computer interface

Low controller cost (Planned)

Water use info available to 

others via internet

Can suspend irrigation due to 

wind or temperature

HydroPoint Documented track record

Fully automatic scheduling

Irrisoft Documented track record

Ability to control unlimited

number of stations

Can suspend irrigation due to 

wind or temperature

Product Features Matrix

Schedules must be programmed manually 

Runoff may result if runtime and soak cycles

are not programmed correctly

Rain sensor extra

Adequacy of 16 historical ET curves

unknown

Uses limited amount of weather data to estimate plant irrigation needs

Does not account for amount of local rainfall

in irrigation schedule adjustment

Instructions do not account for drip or native

plants

Not available yet

Uses limited amount of weather data to estimate plant irrigation need

Does not account for amount of local rainfall

in irrigation schedule adjustment

Limited track record

Solar sensor needs to be cleaned 

periodically.

Limited ability to select application rate.

Total runtime may be excessive for locations where multiple cycle and soak is

required

Not available yet

Limited Track Record and planned availability in US locations limited

High controller cost

Ongoing service cost

Requires high speed internet

Not available yet

Limited track record

Ongoing service cost

Rain sensor extra

High controller cost 

Ongoing service cost

Rain sensor extra

Does not account for amount of local rainfall

in irrigation schedule adjustment

Rain sensor extra

High receiver cost

Potential ongoing service cost 
30

Weather Based Residential Irrigation Technologies - Summary of Features

PhoneContact PersonWeb PageNumber of Residential ModelsDate of Product AvailabilityBasis for ScheduleWReplacement Controller or Add-on to ExistingNumber of Station TerminalsOne Station Operates Master Valve or PumpUser Review of Irrigation HistoryNon-volatile MemoryStation Circuit Current Rating (Amperes)Accepts All Common Wire SizesOutdoor InstallationOn-site Rain SensorOn-site Rain GageRain Shut-offHigh Wind Shut-offFreeze Shut-off

eather Data Source

Historical DataOn-Site Sensor(s) (1) (1) (1)

Remote Weather Station(s)Modeling Software

Product FeaturesUser Defined Non-Irrigation DaysOperable in "Clock" modeVariable Run TimesScheduling FeaturesProvides Review of Recent Irrigation InformationProvides Review of Current Weather InformationBase Irrigation Schedule RequiredAdjusts for Multiple Starts AutomaticallyRuns Concurrent StationsNumber of Multiple Starts Per Station+/- Percent Irrigation Adjust FeatureApplication Rate SettingRoot Depth SettingPlant Type SettingSoil Type SettingSlope Factor SettingShade Factor SettingIrrigation Uniformity or Efficiency SettingProfessional Installation & Programming RequiredOngoing Maintenance RequiredClock Battery Replacement Required

Stand-alone units which utilize preprogrammed historic ET data and or on-site weather sensors to automate irrigation schedulingUnits which automate irrigation scheduling based on data from local weather stations

Product Support and WarrantyWInstallation and Maintenance RequirementsCostProduct Cost (Listed Retail Prices)Annual Service Cost1 - Optional add-on feature not included in base controller price2 - Rate prescribed by spray or rotor irrigation type only (no flow rate or drip setting)

arranty

Support Service Technicians

TelephoneInternet SiteLocal Distributors

Company Name

(909) 352-3891

Gary Bailey

www.aquaconserve.com

7

New Model-July 2003

Both

6-14

1.0

16

(ET-8b & 12b)(1)

(1) (1) (1)

(1)

(1)

24

(1)

(1)

4-16 (by 4 Sta modules)

Unlimited2 Years

$349 (includes installation) $170-230

None None

$400-$600

$180

$299 (includes 1 year of service)

$48

$485

None or $100-$350

$480 (includes 2 years of service)

$48

1.5

8-24

0.75 and 1.5

160.3 1.0

At Personal Computer

Unlimited Unlimited

12 plus masterNot Reported

12 Dependent on Controller

Dependent on ControllerDependent on ControllerDependent on ControllerDependent on ControllerDependent on ControllerDependent on ControllerDependent on ControllerDependent on Controller

Not ApplicableNot Applicable

Replacement Replacement Replacement Replacement Replacement

Up to 64 cycles

Add-on

16 preprogrammed ET curves

with on-site temperature sensor

On-site temperature sensor and solar 

radiation estimated based on 

geographic location

Solar sensor Accuwater & user owned weather

station data managed by

centralized computer server

Public & ETWS weather station

data managed by centralized

computer server

Public weather station data 

managed by centralized computer

server

Public & private weather 

station data managed by 

centralized computer server

Aqua Conserve

(972) 278-6131

Brodie Bruner

www.weathermatic.com

1

Planned November 2004

Weathermatic

(818) 993-1449

Andrew Davis

www.weatherset.com

7

W

New Model-September 2003

eatherSet Company

(512) 231-8696

Tom Watson

www.accuwater.com

4

Planned May 2004

AccuWater

(415) 388-4887

Bruce Cardinal

www.etwater.com

1

Planned September 2004

ET Water Systems

(707) 769-9696

Chris Manchuck

www.hydropoint.com

1

New Model-June 2004

HydroPoint Data Systems

(435) 755-0400

Steven Moore

www.weatherreach.com

1

July 2002

Irrisoft Inc.

Method of Operation

3 years$99-$459

None

(2)

3 Years 3 Years 3 Years 1 Year 1 Year

Pending

Recommended

Clean Solar Sensor

Recommended

Clean Rain Gage & Calibrate Sensors

Recommended Recommended

(2)

(1)(1)(1)(1)

(1)(1)

(1)(1)

30