Most golf courses today employ state-of-the-art irrigation systems that deliver water very accurately to wherever it is needed. An 18-hole irrigation system can cost millions of dollars and, if properly maintained, deliver water very exactly.
A golf course superintendent relies on the system’s ability while using the least amount of water required for healthy turfgrass growth. Sadly, no matter how sophisticated or extensive an irrigation system may be, water deficiencies remain on any golf course.
Grass species, soil type, soil layering, irrigation system performance and hydrophobic soil conditions can cause water deficiency symptoms (dry spots) in turf. Historically, superintendents dealt with one or more dry spots by increasing irrigation run times in those zones. The problem with this approach was that, in some cases, an individual irrigation zone could include three or more large, 50-gallons per minute irrigation heads and cover thousands of square feet – even though the need for localized irrigation was very small.
Only the upper-end golf courses have single-head control. Most courses, depending upon their capital construction budget, are designed with paired fairway heads and individual head control around greens, just to keep initial costs of the system down. Systems designed with a lower budget sometimes have three or more fairway heads per zone, with paired heads on the greens and surrounds. The fewer heads in an irrigation zone, the greater the capital costs of the system.
Irrigation design tends to have costs tied to controlled water application; the greater the control over where and how water is applied, the higher the system’s cost. Lower-cost irrigation systems aren’t well-suited to applying minute quantities of water to very small areas, so it becomes kind of like using a sledge hammer to kill a mosquito.
If you only had two or three small, 120-square-foot areas that were showing drought stress, but that irrigation zone encompassed 2,000 or 3,000 square feet, then large areas would be overwatered. Using an irrigation system to address a few small water-deficiency problems can lead to water wastage and possibly the creation of wet areas. In light of water conservation goals, this approach is unacceptable in some situations, and is where hand watering has become the preferred method of dealing with smaller dry areas that show drought stress.
Hand watering is popular because you only apply water to the areas specifically showing drought stress symptoms, i.e., a darkening in coloration of the turf. This allows a superintendent to add the least amount of water necessary to make the drought symptoms disappear – aiding in water conservation efforts.
There is an economic consequence of hand watering – it requires one person on the end of every hose. Some people do nothing but hand water from two to eight hours a day, and this impacts the labor budget. Not all golf courses can afford to have a team of hand waterers heading out every morning to solve localized dry spots on the golf course. But sometimes the political consequences of not doing this are just as negative, especially when numerous board members and guests are on the course. And, if one is to use the larger irrigation system to apply the extra water, there are negative consequences (wet spots being created, large volumes of water being wasted, reduced efficacy of fertilizers and pesticides applied, etc.).
Hand watering can pose physical problems as well. Too much pressure and a focused stream of water can disrupt the fine sand particles at the greens’ surface, causing problems with wind exposure (reducing wear tolerance), physical damage to plant tissue and disruption to the uniformity of the playing surface. It’s always best when hand-watering to simulate natural rainfall or normal irrigation water application rates. Most hand watering is done with water breakers on the end of the hose that disrupt the flow of water into smaller, less forceful streams. Water is also sprayed in a sweeping fashion from side to side to reduce water concentrations when it hits the turf surface.
The most efficient form of hand watering is to locate and identify problem dry areas. Once they are identified and known, volumetric moisture readings are routinely taken in these areas that record soil moisture levels, which allows you to predict when the dry spots will start to show up.
Not every golf course can afford to deal with small areas of drought-stressed turf. But for those that can, hand watering allows them to use the least amount of water to create the best playing surface for golf.