Public school system makes the change

PHOTOS COURTESY OF PAUL GREENWELL.
The irrigation system is running on the newly sprigged practice field at Archer High School.

The ever-increasing population of Gwinnett County, Ga., was putting a strain on the water supply. For the past 20 years, it has been one of the fastest-growing counties in the U.S. The Gwinnett County Public Schools have been expanding to keep pace with the rapid population growth; two new high schools were added just this summer, bringing the count to 18. As grounds maintenance coordinator, I oversee the school properties, including over 80 athletic fields.

Our irrigation water was supplied by the local water department with use governed by state, county and local restrictions. As with all school systems, time and budget are constant considerations, and our turf management program reflects that. We’re in the warm-season turf zone and use hybrid bermudas, primarily Tifway 419 and T-10, because of their aggressiveness and wear-resistance.

Evaluating the options

Some of the local golf courses were using reclaimed water, also referred to as gray water, supplied by the county. The major plus was having access to water during drought-related restrictions, but there were numerous negatives. First, we would have had to overcome the logistics in running pipelines from the water treatment plant to the various school sites. Stipulations within the agreements required taking a minimum amount of gray water a month and paying the fees for that water, therefore there would be months we would have to pay for the water and pump it somewhere other than the fields. Our high school sites have little unused space where this water could be directed.

When we considered the amount of roof square footage, parking lot space, sidewalks, running tracks and other impervious areas, we saw that a tremendous amount of water that used to soak into the soil was now running off on our developed properties. We had already created retention ponds to capture rain runoff at each site, and we planned to back up that source with the small lakes and creeks on some of our sites and establish wells where possible when the rain didn’t provide an adequate supply of water.

We consulted with Dr. Randy Kath, geologist at the University of West Georgia, about water availability for wells on our properties. Kath tried to identify three locations per site, ranking them based on how confident he was that a well drilled there would produce. On some sites, there was no use drilling.

Next, we interviewed people in the well drilling industry. We wanted a company that would be capable of handling multiple wells on multiple sites and had a proven record of dependability. We found that fit with Mark Hubner of Middle Georgia Water Systems.

The reservoir used to store the water being pumped to the athletic fields.

Making the change

Ideally, the well is close to the pond and the pond is close to the fields, but we couldn’t count on that, especially with the older school sites.

We didn’t require any site changes to divert water to our existing retention ponds. They’d been designed to capture runoff water and slowly release it. We relied on engineers to inspect these existing ponds and determine their water-holding capacity. In many instances, we needed to widen or deepen the ponds. Architects designed ponds on the new sites to hold the needed water for irrigation and detention.

The detention ponds are equipped with water level rods that tell the pumps to turn on or off as the level of the water is lowered from usage. When a pond gets low, the rods tell the well’s pump, or the creek or lake’s pump, to turn on and maintain a certain level.

Generally, the basic change required in the irrigation systems to make those sources workable was the installation of the proper sized pumps. Pump size was based on the number of fields, the distance and elevation change from the ponds to our fields, and the size of the existing irrigation systems on-site.

The pump representative came out for a site visit, and we supplied him the elevation numbers based on architectural drawings. The needs in gallons per minute were determined based on our farthest valve and our two biggest irrigation systems at each site. I wanted to be able to irrigate two fields at a time to reduce the time needed to irrigate the fields at night.

We set our detention pond pumps right at the pond’s edge, so the only new piping required was to connect the pump’s output to the existing system’s main line. We simply tied into the closest main line to the pump. Our existing irrigation piping, valves and heads needed no replacements or adjustments to work with the new system. We already had a backflow preventer at all of the meters. We’ve cut and capped the line between the backflow and meter for additional peace of mind.

Our older school sites have a control clock at every field. We designed the irrigation system at our newer sites based on the location of the fields and the square footage of each field and have been able to equip them with a central controller for all the fields at that site. No changes were required in the existing controllers to handle the converted systems. We went with a pressure-controlled system. If you turn the clock on, the valve opens and the pressure drops, turning the pump on.

We have not attempted to incorporate any new technology, like soil moisture monitoring devices, into our irrigation systems, but we would like to do so in the future.

These controls activate the well pump if the pond gets low. The rods indicate the water level, telling the system the pond is low so start the transfer or the pond is full and stop. These controls monitor the rods in the water
 
The interior of the submersible pump components. The pump is below this box submerged in the water.

Changing mindsets

Our coaches and school personnel have as much input on irrigation programming as they want to have. We do work with them to increase irrigation efficiency and reduce water use. At times that’s tough, especially when some people think more water is better. I like to show them our schools where the coaches schedule the fields’ irrigation for only Friday through Sunday. They do a deep watering on the weekends and no water during the weekdays when the fields are in use. This way, the roots dive deep looking for water and the turf is tough and drought-tolerant. The people who keep their fields too wet usually learn the hard way. The root system is too shallow, and after the first game or practice they see huge divots and learn that more water isn’t better.

The conversion has helped make people aware that there is limited water in storage, which has made them more conscientious of water conservation. It’s no longer an unlimited supply. If our back-up sources can’t provide enough water to refill the pond and it goes dry, there’s no irrigation. So, they are more apt to conserve.

Benefits

We’ve been monitoring the fields closely since making the conversion to determine if any changes in the turf management program would be needed. It appears the turf is actually doing better since we have eliminated the use of the chlorinated water.

Since our athletic facilities are not dependant on potable water, we’re not constrained by the water restrictions in place in the metro Atlanta area. We were able to maintain green grass on our fields through the end of the spring season while facilities using the potable water supply were not. And, because we have access to irrigation water, we were able to undertake the new field construction and existing field renovation projects that were scheduled for the summer.

Paul Greenwell is grounds maintenance coordinator for Gwinnett County Public Schools in Lawrenceville, Ga.