SportsTurf provides current, practical and technical content on issues relevant to sports turf managers, including facilities managers. Most readers are athletic field managers from the professional level through parks and recreation, universities.
Issue link: https://read.dmtmag.com/i/318924
There are a number of options for drainage on the market. Ultimately, the system chosen will depend on several factors: • the specific use or uses of the field • the local climate • the availability and cost of materials • the quality and characteristics of local stone • the financial resources and commitment of the owner • time constraints for field construction, and • the annual amount and intensity of rainfall, local codes and regulations regarding storm water management. Find a good partner If you find the array of options confusing, arrange for assistance. A design professional who understands field construction and who has worked with drainage for synthetic fields can understand the issues and help devise a plan that works in your situation. The professional will specify pipe diameters or the sizes of flat drains, location and distance of laterals, collection systems and storm sewer tie-ins for the drainage system. To facilitate discussions with your drainage designer, you can estimate the amount of water your field will need to handle with the following formula: Length of the field in feet x width of the field in feet x .623 gal- lons = gallons of water produced by 1" of rainfall Note: Drainage products are rated by gallons of flow per hour. There are various types of subsurface drainage systems used with fields. One type consists of flat drains, 6"-18" wide and 1"-2" thick, with or without a wrapping of filter fabric, placed horizontally on the subgrade in a diagonal, herringbone pattern. Because synthetic turf fields drain quickly and have the potential to capture significant amounts of water, internal drainage lines usu- ally can be placed farther apart (15' to 25') than for natural grass. However, the closer the lines are placed, the more quickly the field will drain. Closer drain line spacing will cost more. The rate of drainage also will depend on the depth of the sub- grade and the slope of the drains, usually .5% - 1%. The deeper the drains are placed, the slower the initial response time. Ideally a sports field, particularly synthetic turf, will be used only for sports; however, if you are aware that other activities will take place, and if these have the possibility of puncturing or damaging the turf, make sure the builder knows that the drainage system must be deep enough to protect it from potential damage. An alternate system uses perforated pipes, 4" - 10" in diameter, laid in a diagonal or herringbone pattern 10' – 30' apart. Pipes must be sized and spaced correctly by the design professional, depending on the amount of water they should be expected to handle. These perforated pipes are laid in trenches, surrounded by filter fabric and clean stone or coarse sand. Whether using flat drains or traditional drainage pipes, water flowing into the drainage system can carry with it silt or clay par- ticles or other contaminants. Therefore, it is important to surround the drainage pipes with clean stone (without silt or clay contami- nation) or coarse sand. Stone and sand can function as a filter to remove those particles and prevent them from entering the drainage system. www.stma.org June 2014 | SportsTurf 37 Stone and sand can function as a filter to remove those particles and prevent them from entering the drainage system. ›› Photo courtesy of Stantec Sport, Boston, MA