Since nearly all sprinklers are sprinkling over circular areas, a certain amount of overlap is always necessary for uniform water distribution.
The degree of the uniformity of water distribution in the field can be expressed numerically by the index-Uniformity Coefficient (C_u) which is defined by the equation C_u=100 (1.0-ΣX/m·n).
This index is an important factor for planning and controlling the sprinkler irrigation system and has been evaluated from such experiments as the Pan tests and the Can test.
In this report, the authors propose a method of calculation to evaluate the Uniformity Coefficient from the distribution pattern formed by a single sprinkler and to use an electronic computer in order to process this calculation.
Then, an optimum spacing for a certain sprinkler discharge profile and an optimum sprinkler discharge profile for a certain spacing are studied by using this calculation technique.
These data and the proposed calculation technique may be very useful for the planning and control of a sprinkler irrigation system.