New Irrigation System Is Sustainable Coup For Scorching Summer

October 16, 2010

It's been a challenging summer to be sure for Richard Bussert, among whose responsibilities is keeping the Morningside grass green, the shrubs leafy and the flowers blooming - despite what's headed for the record books as New York City's hottest summer ever.

Bussert, who's Director of Landscape and Grounds for the Morningside campus and Baker Field, is quick to recall July 4, 5 and 6, with their temperatures of 96, 99 and 103, respectively. But he's equally quick to talk about the "coincidence" of a new, upgraded irrigation system that's keeping the grounds lush in this torrid summer. And just as important, even with greater water use because of the heat, the system is contributing from yet another operational area to Columbia's sustainability efforts.
The Rain Bird irrigation system was installed about a year ago on Lower Campus, College Walk and Low Plaza green spaces totaling about four acres. In many respects, the rotating sprinkler and mist heads look like most other domestic and commercial watering applications. The primary difference with Columbia's system, however, is that the irrigation grid with its 5,004 rotor heads is controlled and monitored by what's known as a cluster control computer in the Grounds Operations office on the lower floor of Uris Hall.
The customized system is now enhancing campus environmental efforts by conserving water and power. An added economic advantage is a reduction in labor previously required for lawn maintenance. Bussert says that the system's inaugural summer is helping him create a statistical baseline, and that electric and water savings are projected at about 20 percent. "We'll have better information a year from now," he says.
Each morning Frank Molina, Campus Operations supervisor, checks the computer log for data gathered through Rain Bird's Maxicom software, reviewing what's happened with the irrigation system in the previous 24 hours. "I'm looking for reports of excessive flow, zones where water isn't running, projected water run times versus actual run times, and rain amounts," Molina says.
In this setting, "the computer is interfacing with our environment," says Scott King, field services engineer for Rain Bird.
Grasses include perennial ryegrasses, creeping bentgrass, annual bluegrass and creeping red fescue - mostly cool season turf. They're watered by rotating spray or mist heads whose spray distance reaches just to the edge of the various turf areas - however irregular their shapes, thus preventing water from being wasted on concrete.
Precision programming for the timing and amount of irrigation is key. "We're trying to replace just the water used yesterday - the evapotranspiration, or the water used by a plant for its botanical activity and what evaporates from its soil surface," King says.
"So we want to replace only what the plant uses. Overwatering leaches nutrients, while underwatering stresses the plant, which then becomes drought intolerant," he says.
Four variables contribute to the amount of water and length of irrigation time controlled by the computer: solar radiation, humidity, temperature and rainfall. What's described by Bussert as looking like "a coffee can with a grate on top" outside Carman Hall measures rainfall in 1/100-inch increments and pulses the information back to the cluster control computer. Other information comes from assorted sources, including local weather services. When the remaining three Morningside acres and other sites owned by the University are added in the near future, Bussert says the project's completion will also include Columbia's own weather station.
Bussert says "we're monitoring more than we ever have, especially using flow meters. Excessive flow is one piece of information Molina looks for each morning in the hour-by-hour readout of how much water is being used. If water flow exceeds programmed amounts in a given area, the computer shuts off the water there and redirects it. "So we're not losing any water," Molina says. "In the past, the water could run for two to three days without our catching the break. Now we're never running water foolishly."
The current system relies upon information to and from satellite areas in the field that exchange radio-transmitted data with the cluster control unit. "We used to have to send a person to make changes manually," King says. "Now one guy at the computer for one and a half minutes and a touch of the mouse makes all the adjustments."
Besides the lawn irrigation control, the fountains in front of Low Plaza have also been added to the cluster control. Their electronic mechanisms are in pits below the Plaza, and required crawling into the pit to turn off and on. Over the years, this resulted in 24/7 operation and excessive use and power consumption during temperate months. Since the fountains have become part of the computer operation, they run from 10 a.m. until 6 p.m. each day.
"If you can think of something you want to do, we can figure out a way to do it," says King.

--courtesy of Columbia University Environmental Stewardship