A safe, pristine sports field can only be developed by implementing an irrigation system that consists of high quality components that are designed with sports fields in mind. In order to determine the right irrigation products for a particular field, the turf manager has to focus on a few key points including player safety, aesthetics, and cost. Finding the right combination of components can only be accomplished by thoroughly understanding efficient irrigation practices. One of the most important factors the manager must consider is how the field is used and how often. The manager must also need to have a firm grasp on basic irrigation hydraulics, plant/soil/water relationships, and irrigation terminology. Not only does the manager need to be personally educated, they need to keep their entire staff educated as well. The basic steps that need to be considered for either a new or renovated field are the same for any field across the country, and are imperative to field success.
The design of an irrigation system is the “roadmap” for the contractor who is installing the system. There are professional irrigation designers who specialize in this process and understand the hydraulics required for an efficient system. It is generally best to contract one of these seasoned professionals, especially for a new build. They can identify many of the technical specifics involved with planning such as the point of connection, water supply, elevation changes, available water pressure, and so on. These items must be reviewed before a design can take place. The project also needs to meet local codes for backflow devices, meters, and electrical configurations. Most importantly, a professional designer can match the right irrigation and maintenance equipment needed for a specific site.
The “heart” of an irrigation system consists of the electric or battery operated valves, which can be arranged into various configurations depending on water pressure and zone sizes. Valve size is important, especially for larger zones of sprinklers. Generally 1.5 or 2-inch valves are used. The valve needs to have slow closure to ensure no “water hammering” takes place. Pressure regulation devices are often installed on the valve to optimize the sprinkler’s dynamic, working pressure. Captive parts are imperative when someone might need to work on the valve after installation. Quick coupler valves offer easy access to pressurized water in isolated areas. The more quick couplers that are included in the design, the better. They are usually installed on the mainline, which makes it easy to hit hot spots quickly and effectively.
The irrigation controller is the “brain” of the system, as its scheduled run times are what activate and deactivate field watering. Versatile scheduling capabilities within the controller allow the manager to implement a customized set of run-times that provide the ideal amount of water to each zone of the system. To ensure irrigation doesn’t occur in conjunction with natural precipitation, most professional-grade controllers are equipped with rain sensors that temporarily cancel irrigation. There are also “solar sensors” that track daily weather patterns and automatically adjust runtimes to the optimal irrigation level. These sensors not only save the health of the field, they save water and money as well. Flow sensors are another add-on device designed to save water and protect landscape health. In the event of a pipe or component breakage, a flow sensor will not allow the zone to receive irrigation. With many system designs, more than one zone will often need to operate at the same time, so it is important to select a controller that features multiple programs and runtimes.
There are a few key features that should be considered when selecting the rotors that will be irrigating the field. The rotors must have a small exposed diameter on top and an attached rubber cover to ensure player safety. A strong spring within the sprinkler will provide positive retraction and ensure that sprinkler caps do not stick up above the grade level of the field. Manufacturers spend a tremendous amount of time creating nozzles that provide an even distribution of water over the turf area. Without these features and specialized nozzles in the rotors, brown “doughnuts” can occur, which looks bad and can become a player safety issue. An increasingly large number of managers are also responsible for synthetic turf surfaces these days, which need irrigation for cleaning and cooling. There are new rotors on the market that can provide the radius and flow required to do these jobs. Care needs to be taken in the initial design to ensure there is enough water and pressure available.
After the design has been created and the products have been selected, the field manager needs to do his or her homework to find a professional contractor. When searching for a contractor, be sure to ask for references, referrals, and their certifications. When it comes to installation, it is of the utmost importance to ensure that the installers closely follow the installation specifications provided by the manufacturers. Additionally, sprinklers should not be buried too low, operating pressure should not be too high, and the valve box should be filled with gravel and wired with the correct waterproof wire connectors. Make sure to have the contractor provide an “as built” design (how it was actually installed/ built), and put a copy of this in the controller cabinet for maintenance of the system. This can come in tremendously handy, as site observations are cheap insurance policies during the installation process.
After the design and installation has taken place, the final step to an efficient, safe playing field is in the hands of the manager. This person needs to understand what the products do and how to troubleshoot all of them, if required. Also, understanding the specific site is very valuable when it comes to the water supply, quality and available pressure. Many turf managers have taken classes on plant/soil/water relationships, and this knowledge is imperative when it comes to scheduling the amount of water the turfgrass needs and how quickly it might infiltrate through the different soil types. Education is probably the most important issue when it comes to maintenance and management. Basic irrigation classes on hydraulics, precipitation rates, distribution uniformity, and electricity are just a few topics that are offered by various associations both nationally and locally. It’s imperative that all sports field managers become members of STMA, Sports Turf Managers Association and then complete their certification. By becoming a CSFM (Certified Sports Field Manager), they add a professional endorsement to their resume and location of employment.
Lynda Wightman is Industry Relations Manager for Hunter Industries and the 2004 recipient of STMA’s prestigious Harry C. Gill Memorial Founders Award.
There are many knowledgeable people in the irrigation industry that can assist with the education and consulting of an irrigation system. The following links offer different educational opportunities and networking for someone who might not be aware of basic irrigation needs:
www.irrigation.org (Irrigation Association)
http://www.atinet.org/cati/cit/ (Center for Irrigation Technology, Fresno)
http://www.asic.org (American Society of Irrigation Consultants)
http://www.landcarenetwork.org/ (PLANET – Professional Landcare Network)