|Mohanty, B. - U.C. RIVERSIDE|
|Kanwar, R. - IOWA STATE UNIV.|
|Everts, C. - ES&E INC.|
Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 18, 1993
Publication Date: N/A
Interpretive Summary: Different measuring methods may produce different saturated hydraulic conductivity values which may in turn lead to discrepancy in the prediction of water flow and chemical transport in subsurface environment. We evaluated and compared the performance of such different method (i.e., the Guelph permeameter, velocity permeameter, disk infiltrometer, double tube method, and constant head laboratory method) at different depths in a glacial till soil. In general, the Guelph permeameter gave the lowest saturated hydraulic conductivity, whereas the disk permeameter and the double tube methods gave the highest saturated hydraulic conductivity with minimum variability, possibly because of the large sample size. The constant head laboratory method using small undisturbed soil cores produced large macropores. Other qualitative advantages and limitations of each of these methods are discussed. Findings sof this study can give an important initial guideline for application of these methods to different soil types, depths, and topographic setup.
Technical Abstract: Hydraulic conductivity is the single most important hydraulic parameter for flow and transport-related phenomena in soil, but the results from different measuring methods vary under different field conditions. To evaluate the performance of four in situ saturated hydraulic conductivity (Ks) measuring methods, Ks measurements were made at four depths (15, 30, 60, and 90 cm) and five locations on a glacial-till soil of Nicollet (fine-loamy, mixed, mesic Aquic Hapludoll)-Clarion (fine-loamy, mi mesic Typic Hapludoll) association. The four in situ methods were : (I) Guelph permeameter, (ii) velocity permeameter, (iii) disk permeameter, and (iv) double-tube method. The Ks was also determined in the laboratory on undisturbed soil cores collected from all the five sites and four depths. The Guelph permeameter method gave the lowest Ks values, possibly because of small sample size, whereas the disk permeameter and double-tube methods gave maximum values for Ks with minimum variability, possibly because of large sample size. Maximum variability in Ks values for soil cores at shallow depths may have occurred because of the presence or absence of open-ended macropores. Estimates of Ks, however, are most comparable for the velocity permeameter and the laboratory method using a constant-head permeameter.