A simple irrigation system providing sufficient watering needed to make a plant grow is not very difficult. However, to set up a system which provides uniform distribution of water is more difficult. Uniformity coefficients such as Distribution Uniformity and Christiansen coefficient of Uniformity can be used to compare systems and layouts. After measuring the distribution of water from a single sprinkler, a densogram is created with software. The densogram is a numerical and graphical representation of the overlap pattern that the sprinklers create on a given area of surface that is being irrigated. By varying the distance between the sprinklers and also changing the pattern in which they are laid out, the program is able to show which layout is the most efficient. Optimum sprinkler spacings (resulting in the greatest uniformity) for a commonly-used rotary sprinkler were 38 feet for a triangular layout and 31 feet for a square layout. For the square layout, there was little loss of uniformity for spacings up to about 48 feet. For a commonly-used spray sprinkler, optimum spacings were 12 feet for a triangular layout and 15 feet for a square layout.
Karschnik, Kody L.
"Optimal Spacings for Two Common Landscape Irrigation Sprinklers,"
The Journal of Undergraduate Research: Vol. 3
, Article 5.
Available at: http://openprairie.sdstate.edu/jur/vol3/iss1/5