IRWD Research Studies

IRWD Research Studies

 Landscape Irrigation Studies

For more than a decade, IRWD's water conservation department has partnered with local, regional and state agencies to conduct research studies in landscape irrigation, irrigation controllers, and runoff reduction.

Commercial ET-Based Irrigation Controller Water Savings Study

This September 2006 report estimates that commercial customers who installed ET controllers saved 601 gallons per day on average over a five-year post-installation period. Moreover, water savings observed in the first year tended to persist with no observable decrease in water savings over the five-year post-installation period.
Executive Summary of the Residential Runoff Reduction (R3) Study

Begun in Fall 2001 and concluded in 2003, this research project resulted in an average annual water savings of 10% for those study participants using "smart" weather-based controllers to schedule and regulate their landscape irrigation systems.

View or print the complete R3 Study report. 

Water Dex Remote Effectiveness Study

In 2012 IRWD completed a pilot study of the WaterDex, a remote irrigation controller schedule adjustment device.  The WaterDex is a wireless add-on device that allows users to easily adjust the irrigation schedules on their irrigation controllers on a regular basis.  The study found that overall, there was a high level of customer satisfaction with the WaterDex, and the average water savings associated with the device is 3.7% or 13 gallons per day per household.
Reducing Potable Water Demand on Agricultural Crops: Recycled Water for Strawberry Production

IRWD studied how recycled water affects the growth, flowering and fruit quality of strawberries, a crop considered to be salt-sensitive. If the strawberry production is acceptable to the farmers, using recycled water on strawberries could save approximately three acre-feet of potable water per acre of strawberries in production. To date, the strawberries receiving recycled water have shown no reduction in size or quality. 835 acres of strawberries, including some avocado groves, have been irrigated with recycled water within IRWD's service area.

 Water Use Efficiency in Technology

IRWD water conservation study in system pressure reduction:

Is System Pressure Reduction a Valuable Water Conservation Tool?

According to the results of this 2003 study of IRWD residential customers, reducing system pressure can measurably reduce the amount of water used for residential landscape irrigation, without increasing customer complaints.

IRWD commercial and industrial water conservation studies in supermarket cooling and water re-circulation:

Calfed Supermarket Cooling Study, Executive Summary

This study, published September 2003, investigated the potential water savings of advanced water treatment on typical urban supermarket cooling systems. The goal of the study was to quantify the water savings potential and the economic feasability of advanced water treatment in cooling systems, and to look for water saving opportunities in other water uses found in supermarkets.

Converting X-Ray Machines from Water Pass-Through to Re-Circulating

IRWD study finds water re-circulation technology improves x-ray film processor water-use efficiency by 98 percent.


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