David A. Stonestrom
K.C. Akstin
J. R. Nimmo
1994
<p>The establishment of steady unsaturated flow in a centrifuge permits accurate measurement of small values of hydraulic conductivity (<i>K</i>). This method can provide a recharge determination if it is applied to an unsaturated core sample from a depth at which gravity alone drives the flow. A<span> </span><i>K</i><span> </span>value determined at the in situ water content indicates the long-term average recharge rate at a point. Tests of this approach have been made at two sites. Unsaturated<span> </span><i>K</i><span> </span>values were measured easily for sandy core samples from a site in the San Joaquin Valley of California. The results indicate that a better knowledge of the matric pressure profiles is required before a recharge rate can be determined. Fine-textured cores from a site in southeastern Washington required new developments of apparatus and procedures, especially for making centrifuge measurements with minimal compaction of the samples. Measured<span> </span><i>K</i><span> </span>values led to preliminary recharge rate determinations that are reasonable considering the known hydrology and topography of the site.</p>
application/pdf
10.2136/sssaj1994.03615995005800010007x
en
ACSESS
The feasibility of recharge rate determinations using the steady-state centrifuge method
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