Relationships between common irrigation application uniformity indicators

The coefficient of uniformity, CU, and the distribution uniformity, DU, are perhaps the two most common indicators of irrigation application uniformity, especially for pressurized irrigation methods. The magnitude of CU is usually greater than that of DU, but this is not the case for all data sets, as has been observed in practice by irrigation engineers and researchers. This paper describes the conditions under which CU > DU, and vice versa, proving that either situation can occur in practice. A comparison of some alternative measures of irrigation application uniformity is also compared using two data sets from agricultural sprinklers operating at different pressures.