The NRCS Intake Families for Furrow Irrigation — Old and New

In the 1950's various personnel of the Soil Conservation Service (SCS) of the USDA began a concerted effort to develop general intake relationships to support surface irrigation assessments when field measurements were not available. More than 1600 Ring infiltrometer tests were made primarily in alfalfa fields of Colorado, Wyoming, North Dakota, South Dakota, and Nebraska. In 1959, J. T. Phelan proposed the intake families now found in the USDA-SCS National Engineering Handbook, Section 15, Chapters 4 — Border Irrigation and 5—Furrow Irrigation. These intake families were revised in 2004 to make them more compatible with field data that have evolved since the original publication. This paper summarizes the history of the original development and the rationale for the later revisions. A comparison between original and revised intake families for furrow irrigation is presented along with detailed correspondence tables. English units are used herein to coincide with the original work.