I recently obtained a digital copy of Hewlett’s 1961 description of the variable source area concept. This document, which is part of an annual report of the US Forest Service Southeastern Forest Experiment Station and at the time was based out of Asheville, NC, is regarded as the first publication of the concept in English. There were simultaneous works published in France (Cappus 1960) and Japan (Tsukamoto 1961), but Hewlett’s version is often credited as the first. While this 1961 report is not my favorite description of the variable source area concept, it is probably the most difficult to find and that is why I am posting it here (I think copyright is not an issue since it is a federal report). I prefer the description by Tom Dunne from Kirkby’s Hillslope Hydrology book, but apparently Hewlett did not agree that version. Anyway, it’s a shame that Hewlett (or Cappus or Tsukamoto) did not explicitly publish his ideas in a peer-review journal in the early 1960s.