SEDL / STP / STP1283-EB / STP16122S

Geostatistical Characterization of Unsaturated Hydraulic Conductivity Using Field Infiltrometer Data

Miller, SM
Univ. of Idaho, Moscow, ID

Kannengieser, AJ
Univ. of Idaho, Moscow, ID

Pages: 18    Published: Jan 1996

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Abstract

Estimation of water infiltration and retention in surficial soils is a critical aspect of many geotechnical and environmental site evaluations. The recent development of field-usable tension infiltrometers now allows insitu measurements of unsaturated hydraulic conductivity (K^u), thus avoiding some uncertainties associated with remolded soil samples tested in the laboratory. Several different geostatistical “mapping” methods can be used to spatially characterize K^u, including ordinary and indicator kriging, as well as spatial simulations that provide realizations (stochastic images) of K^u that exhibit more natural variability than do the smoothed spatial estimations of kriging. Multivariate procedures, such as cokriging and Markov-Bayes simulation, can incorporate information from a secondary attribute (e.g., particle size information) to enhance the spatial characterization of an undersampled K^u field. These geostatistical procedures are demonstrated and compared for a case study at a 700 sq. meter site comprised of coarse soil material. Results indicate that percent-by-weight fractions can be used effectively to enhance insitu spatial characterization of K^u.