DC

Don Cooper

With the attention being paid to water conservation in today’s society, on-site landscape and irrigation water conservation is rapidly being brought to the attention of the general public. California’s AB1881 was signed into law last September by the Governor of California. This bill requires that all water districts have in place a water conservation program by 2010 equal to or better than that dictated by AB1881. By the year 2012 no irrigation controller can be sold in California that is not a weather based (or ET) controller. Additionally at the AWWA conference in San Antonio, Texas this fall the EPA announced WaterSense, a voluntary public-private partnership program sponsored by the U.S. Environmental Protection Agency, which seeks to help homeowners and businesses improve water efficiency and reduce their costs by promoting efficient irrigation technologies such as weather-based irrigation controllers and certification programs for irrigation contractors.

There is a convergence of trends occurring in the market place today that is putting additional pressures on the use of water. Those trends include but are not limited to rising costs of water, landscaping demands, radical weather changes, governmental regulation, limited resources and increasing population pressures. As our populations increase there is an increasing demand put on the water delivery infrastructure. Water delivery entities are faced with having to rebuild water treatment and delivery systems to keep pace with population growth or to develop water conservation plans that can extend the life of the current systems. Additionally, the cost in energy dollars to deliver water to the end user is ever

On-Site Water Management

Don Cooper

increasing. By choosing to implement water conservation programs additional savings are realized in energy savings.

Within the world’s water supply 97% lies in oceans and seas and 2% of the supply is locked up in glacial ice. This leaves 1% available for human consumption. Anywhere from 15% to 60% of a property’s water usage goes to maintaining lawns and landscapes. Of that amount approximately 60% of landscape usage is lost due to over-watering and runoff.

Typically irrigation controllers are set to water by “rule of thumb” programs. Typically that watering schedule is for the watering days to be set for three days per week with zone run times of 20 minutes per day for sprays and 40 minutes per day for rotors. Any deviation to this schedule is left to the discretion of the property owner or manager. At best there will be four (4) adjustments per year. If the property is being managed by a professional turf manager the best that can be hoped for is twelve (12) adjustments per year. By using a controller that responds to onsite weather conditions you should expect 365 adjustments.

ET (evapo-transpiration) based watering is not new to the irrigation industry. It has been used for 30 plus years, starting in agriculture and slowly wending its way into the turf and landscape industry. However, until recently, ET based scheduling was only available in very expensive, high-end controllers well beyond the reach of the common user. Recent innovations in irrigation controller design

On-Site Water Management

Don Cooper

have enabled the manufacture of ET based controllers that are affordable for all users.

There are four different methodologies being employed today in the manufacture of ET based controllers.

1) Paging based systems that rely on data gathered from remote weather

stations and then sent via page to the associated controllers.

2) Internet based systems that rely on data gathered from remote

weather stations and then accessed through an Internet connection.

3) Historical based systems that use historical data to derive their

watering schedule.

4) On-Site systems that derive their data from weather conditions that

are occurring on the irrigated site through the use of on-site sensors.

Weathermatic’s SmartLine has it own local SLW Weather Station on-site and is the first irrigation controller to combine each of the fundamental elements of effective and efficient weather based watering – Real Time, On-Site, Input By Zone.

1) Real Time – Weather data is monitored 24 hours per day with instant

On-Site Water Management

Don Cooper

notification of rain or freeze events.

2) On-Site – Reporting of microclimate specific weather information for

the irrigated property. With the weather station being on-site the restrictions of terrain limitations, signal footprint and regional weather variability are no longer a concern.

3) Input By Zone – Parameters set by zone are Sprinkler Type, Plant Type

and Soil Type allowing the controller to address each microclimate within the irrigated property.

With the typical user of irrigation controls not understanding the parameters necessary for the typical ET formula calculations it is imperative that the user interface be simple and usable while at the same time giving the professional user the ability to set the input parameters as precise as the available data. With user understanding being a primary requisite certain defaults were established for each of the inputs.

1) Zip Code – Sets the latitude that the controller is located.

2) Sprinkler Type – sets precipitation rate for each zone. Defaults are

Spray, Rotor, Drip and Bubbler with the ability to enter actual precipitation rates from .2” to 3 inches in .1” increments.

On-Site Water Management

Don Cooper

3) Plant Type – set the crop coefficient for each zone. Defaults are Cool

Turf, Warm Turf, Annuals, Shrubs, Trees and Native with the ability to enter the actual crop coefficient from 10% to 300%.

With the above data and the weather information being returned to SmartLine from the SLW Weather Station, SmartLine will calculate how much water the irrigated property has lost to ET and calculate the zone run time necessary to replenish that amount of water on a daily basis.

By entering the Soil Type and Slope Setting for each zone SmartLine will automatically calculate a Run/Soak setting by zone to eliminate runoff.

Finally, using the More/Less setting to trim in each individual microclimate within the irrigated property. This addresses zone specific requirements such as shade settings, sprinkler efficiencies, or any abnormal features of the zone.

By addressing on-site weather and site conditions and with the Auto Adjust features activated water savings of 20% to 50% of the irrigated water can be achieved.