A drainage system is installed at the Lodi Grape Bowl in California.
Photo Courtesy of Beals Alliance.
Drainage is not the world's most compelling subject - until it's not working. Then it will suddenly become all a field manager can think about. In fact, a soupy ball field, a sports field that can't seem to shed water (or even a tennis court with enormous puddles, should that happen to be on the sports complex grounds), will create a sudden education in just how important an efficient water removal system is.
Unfortunately, there are many reasons why drainage systems fail. Some are easily fixed, while others require professional intervention or, at the least, knowledgeable guidance. So, how do you separate the do-it-yourself projects from the ones that require specialized equipment? Start by doing your best to keep them from happening. Many drainage problems are simply the result of maintenance errors or facility upkeep practices. Here is a quick primer designed to help avoid some of those problems.
Two kinds of fields come into play here: natural grass and artificial turf. Artificial turf fields generally have their own underground mechanical drainage systems that move water off the field. If trouble is suspected with an artificial turf field's drainage system, you may wish to consult the contractor who installed the field. If the system is still under warranty, the contractor should deal with the problem. It may be something that you can fix yourself, but a call to the contractor can help determine that.
Baseball and softball infield present their unique drainage challenges.
Photo courtesy of Stantec.
Some things you should be doing regularly to help maintain good drainage include checking the drains around the perimeter of the field and making sure none are clogged with grass, sticks, mud, sand or other debris. Also, clean all drains and ensure that water can enter and exit them freely.
If the field continues to be wet, take note of whether the dampness is in one spot or evenly dispersed over the field. These are all issues a contractor will need to know.
Drainage of natural grass fields is a science unto itself. The way a field sheds water depends on several factors, including soil composition, field slope and the amount of water the field receives either through rain or irrigation.
Natural grass fields generally fall into several categories: A native soil field, which uses only the soil found at the site; a modified native soil field, which includes the introduction of amendments such as sand, peat, compost or porous ceramics to provide a better growing medium and/or a more stable base; or a sand cap field, in which the top 2 to 8 inches of soil is replaced with sand, either during construction or over time. Another type of field is the sand-based system, in which the native soil is completely removed and replaced with an under-drain system; a drainage media layer, principally stone; and rootzone material, principally sand, to improve drainage.
The main problem with native soil fields is drainage. Most native soils absorb water quite slowly and cannot handle large amounts; therefore, without additional provisions for drainage, these fields easily become muddy, worn and unplayable. As a side note, many fields, particularly those built on a budget, are native soil fields, since these represent the smallest investment from a construction standpoint.
Since a limited amount of water can be handled effectively by the soil, the field must be designed to shed water. Typically, athletic fields are sloped (tilted in a single plane) or crowned (sloped in more than one direction from a single point or line, generally midfield) in order to move water off the surface.
It is recommended that a perimeter collection drain be included to move water away from the field, otherwise those areas where the slope terminates - often the bench area or the area beyond the goals - are likely to become muddy, worn and/or unusable. In addition, eliminating any barriers to water runoff is essential. Check to make sure there is no buildup of dead grass or other debris around fences or other areas that can create a dam and hold water on the field.
This seems self-evident, but few natural fields can handle an overabundance of water, especially in sustained amounts. Unusually heavy rains or overwatering can overwhelm the field and render it unplayable, necessitating its closure.
Again, something that might seem unnecessary to point out, but is often overlooked: the only water falling on the field should be rain or planned direct irrigation. Rain should not be dripping onto the field from any other source, including running down nearby hills or slopes, dripping off the bleachers or dugouts, or receiving overspray from other areas that are being irrigated. This point applies to both artificial turf and natural grass fields, and will be one of the first things any consultant will want to know.
Assuming the field manager is taking care of all aspects within his control, and there has not been an overabundance of rain or irrigation, a field designer or contractor can be consulted to provide additional input, such as determining whether or not additional drainage needs to be installed; if unforeseen weather conditions are to blame (and may not occur again); or whether the soil is insufficient for use in an athletic field.
Baseball and softball fields are unique in that they have a combination of skinned and grassy areas, both requiring special care. Ball fields require mowing of grassy areas and dragging of the skinned areas in order to maintain an even playing surface.
For sports complexes with additional facilities such as tennis or basketball courts, preventive maintenance can help with drainage.
Photo courtesy of Foresite Design, Inc.
Unfortunately, one of the downsides of dragging is that it often creates a buildup of material where the grass begins. This means that when the grass is watered or when rain falls, the lip of the built-up surface material creates an impaction that does not allow water to move off the grass or may hold it on the skinned area, making it overly muddy. The result: An incredibly soupy field that sustains damage from players, particularly those wearing cleats.
Field managers should note that after the skinned area of the ball field is dragged, someone needs to follow behind with a small rake or broom to remove any built up material and eliminate the lip so water is able to move off the field. The same care should be given to the area near the warning track if it is also dragged.
As with sports fields, make sure the area near the bottom of the fence is kept free of grass clippings, leaves and other debris so the field is able to shed water.
Other sports facilities
If a sports complex additionally has facilities such as tennis or basketball courts, preventive maintenance can help with drainage. Keeping mulch, grass clippings and other materials away from the edges of the courts can help water move off from these areas. Additionally, a paved sports surface, such as a tennis court, is subject to exacting tolerances. After a rain, any puddles that linger on the surface should be dry within an hour. In addition, none of these should be deep enough to cover a nickel. Anything that remains wet or covers a nickel is considered to be out of tolerance and needs to be repaired.
Drainage isn't a sexy topic. It's not glamorous, and generally it isn't exciting. Good maintenance practices and keeping an eye out for problems can help you ensure that the excitement remains on the field during games and not in your office in the form of complaints.
Mary Helen Sprecher is the technical writer for the American Sports Builders Association (http://www.sportsbuilders.org).