The feasibility of recharge rate determinations using the steady-state centrifuge method
The establishment of steady unsaturated flow in a centrifuge permits accurate measurement of small values of hydraulic conductivity (K). 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 K 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 K 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 K values led to preliminary recharge rate determinations that are reasonable considering the known hydrology and topography of the site.
Citation Information
Publication Year | 1994 |
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Title | The feasibility of recharge rate determinations using the steady-state centrifuge method |
DOI | 10.2136/sssaj1994.03615995005800010007x |
Authors | J. R. Nimmo, David A. Stonestrom, K.C. Akstin |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Soil Science Society of America Journal |
Index ID | 70017578 |
Record Source | USGS Publications Warehouse |
USGS Organization | Toxic Substances Hydrology Program |