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Metro Parks employs latest technology to conserve irrigation water

January 10, 2018


Weather-based system ensures sustainability, saves money, time

Water. Virtually no resource on earth is as precious. Without it, humanity could not survive and the world as we know it would cease to exist.

Because public water is available in cities with a twist of the tap, it’s easy for many of us to take the supply for granted.

Not so at Metro Parks Tacoma, where water is a valued commodity: not only critically important but expensive.

During dry months, typically between May or June and mid-October, Metro Parks waters dozens of public areas, landscaped parks and athletic complexes to keep turf healthy and green. The price tag: an average of $1.7 million annually.

While cost is a major concern, it’s not the only one. Future drought could force Metro Parks to severely restrict its use of water.

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Awareness of the need to conserve prompted Metro Parks managers more than a dozen years ago to invest in a weather-based irrigation control system. With money from the district’s 2005 capital bond issue, the first installations took place in 2009.

Now Metro Parks irrigates nearly all of the sites that use the most water with an automated system called Calsense, and manage most via computer and smart phone or tablet. System upgrades and additions are continuing, using $170,000 from the bond issue approved by voters in 2014.

Metro Parks underscored its commitment to water conservation in 2015 when it completed its Sustainability Plan. The three-year plan set a water-use reduction goal of 9 percent by the end of 2018. As it turned out, Metro Parks was able to cut water consumption by 9.5 percent in just the first year. Some of the improved efficiency can be attributed to irrigation controls.

“Mother Nature plays a large role” in park maintenance, said Joey Furuto, Metro Parks community and neighborhood parks manager. “Everyone’s aware of water conservation now. Whether it rains or not, we still have to conserve our natural resources.”

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Weather conditions vary not only seasonally and daily, but between neighborhoods. That’s why Metro Parks years ago set up mini weather stations at multiple locations which represent the diversity of micro-climates throughout the Metropolitan Park District.  Now, all of that rainfall and evaporation data is automatically collected daily and analyzed by Calsense.

To reduce the amount of moisture that would be lost to evaporation in the daytime, Metro Parks irrigates at night. To keep lawns green, most grasses require between an inch and 1 ½ inches of water weekly. That’s a big deal, especially for sites with lots of open areas, such as Vassault Park. In summer, it’s not uncommon for Vassault to soak up between 60,000 and 70,000 gallons of water nightly: almost half the volume needed to fill Kandle Pool.

Using Calsense, Metro Parks controls not only how much water is applied, but also where and when. For example, the baseball field at Heidelberg/Davis Park typically gets priority over the grassy areas outside the chain-link fences, where grass is sometimes allowed to temporarily go brown.

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Every evening, Calsense factors in weather data. In the days after rainfall, the program automatically stops watering, and may gradually resume if the weather dries and temperatures rise.

The fact that the system is controlled remotely, via the Internet, immensely improves efficiency because there’s no need to physically adjust thousands of water valves. The system also identifies potential problems with red alerts, which Metro Parks maintenance leaders check daily. That includes electrical shorts, breaks in irrigation lines, and excessive or inadequate water flow, among other things.

The reports make it easy to quickly identify and repair broken valves or lines. Before Metro Parks adopted Calsense, it sometimes took weeks to discover lost sprinkler heads, said Mike Yaden, who leads a crew of maintenance workers who care for parks on Tacoma’s west side.

Calsense also keeps detailed records, on both weather and water consumption. So Metro Parks managers can adjust usage if it exceeds budgeted amounts long before Tacoma Public Utilities sends the bill.

The latest versions of the Calsense system, in place at Franklin and Kandle parks, permit remote control of other electronic systems such as restroom door locks, fans, and interior and exterior lights.

“In the past, a whole lot of labor went into conserving water,” Furuto said. “Now we no longer have to send somebody out to each location to make adjustments.”