Evaluation of time-rated infiltration families for noncracking soils

The time-rated infiltration families proposed by Merriam and Clemmens were further developed and evaluated using infiltration data for noncracking soils. Infiltration experiments were monitored, using a double-ring infiltrometer, at 10 field sites in New South Wales (NSW), Australia. Published infiltration data for soils in Botswana were also included to extend the range of soil types and field conditions in the study. A methodology was developed for identifying the infiltration family of soil at a given field. The time-rated infiltration family concept along with the methodology developed was evaluated under a range of field conditions. For 80% of field situations, the error introduced in infiltration characteristics due to the use of the family concept is <35% with an average value of the error about 20%. The infiltration characteristics of soil at a given site in this study exhibited a high variability although the measurements were made only a few meters apart. This observation reinforces potential benefits of using infiltration family concepts in the design and management of irrigation systems.