Some of the most interesting projects seem to fall in your lap almost by coincidence. That’s how Sinc Constructors Co., Centerville, Utah, picked up the installation that won them the Changing the Landscape Awards 2021 Irrigation category sponsored by Dawn Industries.
“We kind of stumbled onto it. I must’ve been curious that day,” says General Manager Mike Sowby. While the company usually doesn’t pursue municipal work, a friend had suggested that he come along to check out the West Valley City pre-bid meeting.
When they heard the criteria for an irrigation system installation for a local park, Sowby says he thought the team had a chance of landing the job. “We decided to put a bid in on it. That’s how we got involved.” Sinc, which is celebrating its 10th anniversary this year, does almost all commercial work with the occasional residential customer, focusing on industrial and multifamily properties. During peak season, the company keeps about 50 employees, though the year-round average is about 35.
“After looking at the overall design, the plans and everything, we were excited about the openness of the park,” says Blake Tingey, vice president of business development. Normally when Sinc works with general contractors on multifamily properties, they juggle multiple subcontractors in a tighter area. “But with the park, it was a big, open space, and we felt that it’d be an opportunity to be able to get a lot of work done fast and efficiently.”
The park project lended itself to Sinc’s specialties, requiring technical work with larger pipe sizes. “Not a lot of other contractors out here can do work like that, so we felt we had a niche here,” he says. It also called for work with screening and amending the topsoil, which was a project the team felt they could do well. The work being done at the 104,500-squarefoot area helped bring it from an open lot to a well-kept local park.
From the source
The overall intent of the park’s irrigation system was to utilize a secondary water source available in the subdivision, says Tingey.
Uphill from the park, a construction development had uncovered a steady source of fairly clean groundwater, says Blake Wilson, vice president of operations.While the city had diverted the water to the storm drains initially, “they had this source that someday they could tap into to use that as a secondary source. That was the purpose, they wanted it in the city park to save massive quantities of culinary water.”
As an open lot in the middle of the city, the site wasn’t drastically different from others they’d worked on, says Wilson. Before they did anything with the secondary water source, they had to contend with bringing in the culinary water source from one corner of the property and incorporating it with the rest of the system.
“We had to bring it from their point of connection to a central point where the pump was,” Wilson says. “The idea being, we wanted to pump the secondary water source as much as possible, then when we needed to supplement with the culinary water, the flow switch kicks on and it adds to it so there’s sufficient water to run.”
“There’s two water sources that are feeding the cistern,” says Sowby. “There’s the secondary that comes in from the groundwater that was provided. And then we brought the culinary system over to that system as well to supplement when the groundwater source wasn’t keeping up. Both of those sources came to the central point and then were pumped out into the irrigation mainline as needed.”
The initial design for the irrigation plan came from ArcSitio Design, Salt Lake City, says Tingey.
“We’ve got to give a shout-out to the architect,” he says. “They’re one of the better landscape architects and irrigation designers in this market.”
It incorporated about 30 zones with multiple types of irrigation equipment, including drip line and bubblers along with water-efficient rotary nozzles on spray heads dependent on the size of the area to be covered. The larger strip areas used 40- to 50-foot spray rotors, with the medium areas taking 20- to 30-foot rotors. Park strips used even smaller nozzles to make the best use of the space without wasting water, and the drip line and bubblers were used with planter beds and trees.
Sinc would put the plan into action, but any irrigation professional knows there are differences between what the plan calls for and the reality of what’s necessary in the field.
“We had that initial design to go off of, but we have to make field adjustments and make recommendations based on field conditions,” says Tingey.
Adjusting the design
There was some trial and error in bringing the plan together. During installation, Sinc tested the flow pressure from the secondary source and realized that they had a few obstacles that needed addressing. “It was all great on paper, but there were a couple things that were brought to our attention that didn’t quite match up with the design,” says Wilson. First, there wasn’t a provision for a bypass on the pump in case of maintenance or a shutdown.
“If you have trouble, then you can use the culinary source as a reliable source of water, so we helped with that,” Wilson says.The pump system only worked within a certain range of gallons per minute, between 20 and 70. Several of the irrigation zones in the field fell beneath the 20 gpm range, which would cause the areas to be underwatered, he says. The controller used a timer to water multiple zones at once, and part of the installation process was a complicated math solution to determine how to keep the pressure up for correct irrigation throughout.
“It was like the world’s biggest story problem to figure out what grounds we could run together and always keep the pump in the safe range,” says Wilson. “That was a big challenge that we solved for them.”
One of the nice things about the pump system is that it tracks all the flows individually for each of the zones. “Those were the low-flow areas that the pumps were struggling with,” says Tingey. “We were able to stack or combine multiple drip zones to get us into that safe flow region. We tried to keep it to where everything was still watering efficiently like it should be but also keeping that flow.”
That was a matter of going zone by zone and calculating the flow to figure out which could be watered at the same time to reach the correct gallons per minute, Tingey says.
While it would’ve been helpful if adjustments such as the pump bypass and gallons per minute range had been set in the design from the start, it’s the responsibility of the irrigation installation team to make those minor changes as a part of the team, says Sowby.
“It would’ve been nice if those things were considered in the design so we wouldn’t have to field-test and adjust,” he says. “But that’s our job. We’re there to be partners in this project and help the city end up with a good product.”
Solving the cistern
Wilson says the city had a valve that could be opened to bring the water to a cistern with a fill line and drain line, allowing it to calculate how much water could be held in the tank.
One of the major struggles with the holding tank was getting two float sensors installed to make efficient use of both the culinary and secondary water sources, says Tingey.“We needed to get these float sensors on this tank precisely installed at the correct height so that if there was enough water, the pump would turn on and suck the water out and use it,” he says. “But then there was also a secondary supplemental fill so that when the water got too low, the supplemental fill would turn on and increase the volume of water. It was intricate, trying to get these floats at the right height to make sure there was enough water for the pump to use and not burn up if there wasn’t enough.”
The system was initially set up for one flow, says Tingey, but they had to incorporate both the ground-water source and the culinary water source in the cistern. As the pump kicked on, if the system was drawing more water than the groundwater source could supply, one of the float sensors would drop and the culinary water source would supplement it. As the tank filled again, it would trigger the sensors to stop the culinary water source flow and rely on the groundwater source until it was full again. Getting that setup to work correctly took a lot of calculation and trial.
“There was brain damage,” Tingey jokes. “There were quite a few phone calls and testing different heights and calculating volumes to maximize the water usage.”
The team turned on the larger rotor zones that would draw the most water overall to get a sense for the water level for what the pump would drain to those areas, says Tingey.
“After we ran those zones, we were kind of able to make an estimate on the water level, because everything else would pull at a lower rate,” he says. “We based it off of a worst-case scenario, as far as water usage as those big zones ran.”
Even after crunching the numbers, getting the sensors in the appropriate high and low points meant climbing down into the cistern and drilling into the side of the concrete system to maximize the water volume, says Tingey.
Even with those obstacles, Sowby says the stars aligned for this project, with a good client, manufacturer, architect and contractor.
“We’re able to do our best work when we have a good design and are able to work with an owner and architect who understand things, because we all know that design is a starting point,” Sowby says. “One of our strong suits is being able to make educated and informed recommendations to the owner, architect or manufacturer based on what we find in the field. We can do the math and everything can look good on paper. But at go time, if there’s not enough water in the system, it doesn’t matter how much math we do.”
Sinc kept regular communication with the various groups throughout the process, so the crew had buy-in on their recommended plans as they dealt with issues, Sowby says.
As the installation job wrapped up last May, the city has seen use of some of Sinc’s work in saving water, and the bypass has gotten use for maintenance, says Sowby. Because of the unique filtration needed for the groundwater source and the possibility of algae, the system has needed repeated cleaning.
“The fact that we put in that bypass system is now really praised. Because if we hadn’t, the system would have to be shut off and not running during the cleaning process to be able to water a lot of landscaping,” he says. “With that in place, we’re able to actually continue to keep running while they’re able to do the maintenance on it.”
This project has paved the way for new work developed around the team’s now-growing expertise.
Sinc finished one similar project and is currently working on another with multiple water sources and two cisterns and another large pump system. “This will be the third one we’ve done, coming up, that’s the same concept of splitting water sources. We’re getting good at it,” Tingey says.
“What we learned from the last one is that we’re asking all the questions up front,” he says. “We’re able to steer it a little easier now with the bypass and with everything. We can have these conversations with the ownership group so that we don’t have to do that kind of trial and error.”
The author is editor-in-chief of Irrigation & Green Industry magazine and can be reached at firstname.lastname@example.org.