A COMPARATIVE STUDY TO CALCULATE HYDRAULIC CONDUCTIVITY IN ULTISOLS ON AN EAST TENNESSEE HILLSLOPE

Hydraulic conductivity (K) is the measurement of how easily groundwater flows through the pores of soil and rock. K values can be measured by both field and lab experiments. The objective of this study is to compare different methods for measuring K values with published values from USDA. Two field tests, Well Bail Test and Auger Hole Test, and two laboratory tests, Constant Head Permeameter Test and Grain Size Distribution Test, (GSD), were chosen on the clay rich Ultisol soils on an East Tennessee Hillslope in the Valley and Ridge Physiographic Province. The Hazen, Alymani & Sen, and the Slichter methods were used to compute the K values from the GSD Test. Two sites were tested with all four methods, one in an upland pasture area close to a monitoring well and the other on the floodplain of an existing stream. The Alyamani & Sen, Slichter, and permeameter method all produced similar K values ranging from 9.521 x 10^-6 to 1.254 x 10^-3 cm/sec. These are similar to the USDA K values ranging from 2.82 x 10^-4 to 8.06 x 10^-4 cm/sec. The Hazen method overestimated the K values and ranged from 8.100 x 10^-3 to 1.089 x 10^-1 cm/sec. The well bail test yielded a lower K values (ranging from 4.577 x 10^-8 to 1.7829 x 10^-8 cm/sec) than the USDA values as expected from deeper soil horizon at a depth of 8.5 meters. Comparing these values will help to better understand differences between K estimation methods.