This article was published on: 05/4/15 12:00 AM
By Scott Hammers / The Bulletin
On a Thursday morning at Drake Park, Bend Park & Recreation District landscape manager Mike Duarte fished his phone from his pocket and pulled up a screen full of tiny green icons — the irrigation system at Big Sky Park, 4 miles across town.
Provided he’s connected to the Internet, with a touch Duarte can turn the sprinklers on or off at Big Sky Park, or at any of 42 of the district’s 53 irrigated park properties.
The new control system was installed at Drake Park within the last month, Duarte said, and as it’s been expanded to more and more parks in recent years, the district has been able to cut back the amount of water it uses to keep its turf green and its plants healthy.
With help from the new system, a warm but not hot fall, and skipping watering days to accommodate an abundance of park events, the district trimmed its water use by nearly 20 percent last year.
Duarte said there’s no guarantee the district will see similar reductions into the future, particularly as new parks are added to the district’s inventory. But over time, he said the new upgrades should help reduce human errors and ensure parks are getting only as much water as they need.
Overwatering, particularly watering just after a rainstorm, is a particular concern for the district. Not only is it wasteful and sometimes damaging to the grass, Duarte said it’s a public-relations headache for the park district. Local residents are all too happy to call the district offices and let them know the sprinklers are on at an already sodden park.
Duarte said in the past, he and others with the park district’s maintenance department would try to get ahead of such calls on rainy nights, driving around town to disable the timers that controlled the irrigation systems in person.
“Irrigation is probably the hardest thing we do, it really is, because you can’t predict everything that’s going to happen,” Duarte said.
Along with allowing Duarte and others in the department to control the irrigation system from anywhere, the new system can, at least in some cases, make some of those predictions for them.
The system can monitor weather forecasts and adjust how much water should be applied on any given night. At some parks, including Drake Park, sensors have been installed a few inches below the soil to monitor moisture levels, allowing the system to make similar adjustments without human input. If the soil is sufficiently moist, the system will dial back how long the sprinklers should run.
“It’s the same as any homeowner. If your sprinkler comes on while it’s raining, can you break away from work and go turn that off?” Duarte said. “You’d like to, but at the same time, you can’t be everywhere at once.”
Even with last year’s reduction, the district’s water use is still substantial.
The district drew nearly 95 million gallons from the city of Bend and Avion Water systems, which represents about 75 to 80 percent of its total water use. River water is used to irrigate parks along the banks of the Deschutes, Pine Nursery Park takes its water from the nearby North Unit Canal and a handful of parks, such as the Skyliners Sports Complex, are supplied by on-site wells.
Assuming a loose estimate of last year’s water use at 125 million gallons, how much water is that? It’s roughly 2 hours and 40 minutes of all the water flowing over Benham Falls at current flow rates, 188 Olympic-sized swimming pools, or enough to cover Drake Park nearly 30 feet deep.
Jim Figurski, a landscape architect with the park district, said the district is working to design its new parks to use less water than older ones. Plant choices play a role, he said, but so can the layout.
Because grass is the thirstiest plant used in most parks, the district looks to limit its use when developing new parks, Figurski said, identifying play areas that can be planted with grass and ringed with other plants, rather than planting grass right to the edge of the park. Edges where grass meets other plants or impervious surfaces often invite overspray and overwatering, he said, so the district tries to design an irrigation system and a layout that work together.
“Most of the designers you’ll see involved in park work are very concerned about the sustainability of the park environment,” Figurski said. “Not just the resources it uses, but the resources needed to maintain it.”
Within the last year, city of Bend Water Conservation Manager Michael Buettner has been conducting irrigation audits for the park district and Bend La-Pine Schools, looking to assess how efficiently they’re using water in irrigated areas.
Buettner said the process involves using aerial images to calculate how a space is divided between impenetrable surfaces such as pavers or parking lots, grass and other plantings. This information allows him to estimate how much water is needed — grass requires about 30 inches of water a season, other common landscaping plants around 20 — which, combined with usage information taken from the city’s water meter, is used to determine the efficiency of the irrigation system and watering schedule.
Audits of Compass Park and Columbia Park have been completed, Buettner said, and both were found to be roughly 80 percent efficient — meaning they’re using about 20 percent more water than needed. Such a figure is a “very respectable number,” he said, given the layout of both parks.
Buettner said he sympathizes with how Duarte and others at the park district are torn between competing interests of keeping parks attractive while minimizing water use. With city water available for $1.68 per 100 cubic feet, some desirable irrigation system upgrades can’t pay for themselves, he said, and with landscape crews constantly busy, some embarrassing episodes of overwatering are inevitable.
“It’s unfortunate. It’s definitely a public perception problem that all irrigators and landscape managers deal with,” Buettner said. “You can innovate until the cows come home. If you’re watering the sidewalk or the street, it’s there for everybody to see.”