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Soil Science Society of America Journal Abstract -

Improved Apparatus for Measuring Hydraulic Conductivity at Low Water Content


This article in SSSAJ

  1. Vol. 56 No. 6, p. 1758-1761
    Received: July 8, 1991

    * Corresponding author(s):
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  1. John R. Nimmo ,
  2. Katherine C. Akstin and
  3. Karen A. Mello
  1. Water Resources Division, U.S. Geological Survey, MS-421, 345 Middlefield Road, Menlo Park, CA 94025



A modification of the steady-state centrifuge method (SSCM) for unsaturated hydraulic conductivity (K) measurement improves the range and adjustability of this method. The modified apparatus allows mechanical adjustments to vary the measured K by a factor of 360. In addition, the use of different flow-regulating ceramic materials can give a total K range covering about six orders of magnitude. The increment of K adjustment is a factor of about 1.6. This makes it potentially useful for measuring targeted values of K or, through a trial and error procedure, of water content (θ). The range extension afforded by this modification has led to the lowest steady-state K measurement to date: 1.1 × 10−11 m/s at θ of 0.068 m3 water/m3 for a sandy soil of the Delhi series (mixed, thermic Typic Xeropsamment).

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