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Smart Irrigation Controller Technology - Pt. 2

How Utilities Can Benefit from Implementing Pilot Projects [Part 2]

The water savings achieved by smart irrigation controllers can vary depending on a number of factors. For example, a 2009 study of smart controller programs implemented statewide by California water agencies identified pre-existing irrigation application rates (i.e., the amount of excess irrigation) and the method of installation (i.e., professionally installed or self-installed) as key factors affecting overall program success. The programs surveyed in this study utilized various strategies to promote smart controller installation: rebates, direct install, and exchange/distribution. What sets pilot-based projects apart from these other approaches, however, is a utility’s ability to strategically tailor the scope of their pilot program to their conservation objectives. By targeting specific customers and teaming with a manufacturer or contractor to properly install the controller, a utility can yield greater program success through enhanced involvement and oversight.

This past summer, AIQUEOUS teamed up with a private utility and an ET-based smart controller manufacturer to design and implement a smart irrigation controller pilot program. The initial results from this pilot program reflect the advantages of targeting a specific group of customers, as noted above. To help measure the effectiveness of smart irrigation controller technology, the project team selected a pilot and control group from a neighborhood where a high penetration of in-ground systems had been observed. As the figure below shows, average water usage for the control group was higher than the pilot group. Due to these differing water use behaviors, the control group was used as a proxy to measure the accuracy of predicted usage for the pilot group during the months of July, August, and September 2016. The project team used these predictions, which were based on usage, precipitation, and temperature trends from 2010 to 2015, to determine the overall water savings associated with the smart irrigation controllers.

Based on these predictions, the following table describes the range of potentials savings estimated for the pilot group according to three likelihood scenarios. The percent savings are broken out by water user type: low users (700 gallons per day or less); medium users (between 700 and 900 gallons per day); and high users (900 gallons per day or above).

As these results demonstrate, greatest potentials savings are attached to high water users, whose estimated total gallons saved represent 9 to 23% of their total water consumption over the three-month period. The reason for this, of course, is because high water users typically over-water their landscape, but the smart irrigation controllers adjusted their watering schedules to apply a more appropriate amount of water to their landscaping. Overall, the thirty pilot group participants saw as much as 267,700 in total gallons saved over the pilot program period, which translates to 16% total water savings for the entire group.

Beyond achieving water savings, smart irrigation controllers can also be employed as a strategy for reducing peak water demand. In the figure below, daily coincidence peak for the pilot group is shown. According to this figure, daily peak demand fluctuated quite significantly. For instance, water consumption on August 17th was nearly 28 times the amount on August 10th.

For the pilot program , peak watering times were observed during the hours of 5:00 a.m. to 7:00 a.m. During this two-hour period, 45% of the total water consumption was occurring. The figure below illustrates this lack of well-distributed watering schedules.

A closer look at the distribution of hourly coincidence for different irrigation intensity days also highlights interesting trends. For instance, on a normal watering day (in terms of total water consumption), the distribution of watering schedules spreads more evenly across the day compared to an intense water day, which peaks during the hours of 5:00 a.m. and 7:00 a.m. Alternatively, on a low watering day, hourly coincidence peak spreads across a five-hour time period and is very minimal in comparison to the normal and intense watering days.

Although not utilized in this pilot program, smart irrigation controller technology offers control settings that allow daily watering times to be spread out across the day. If you would like to gear your program towards reducing peak water demand, using the smart controller technology to track peak watering times can be extremely helpful. This information can, in turn, be used to encourage alternative watering times in order to adjust outdoor water demands to other times ideal for outdoor watering.

As you begin scoping and planning your pilot program, deciding what conservation objectives that you would like your pilot program to serve and which the customer type your program will target will be critical questions to address early on in the development process.

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