Measurement of Subsurface Unsaturated Hydraulic Conductivity |
| |
Authors: | D F Holland M Yitayew A W Warrick |
| |
Affiliation: | 1Member, ASCE 21Res. Assoc., Dept. of Agric. and Biosystems Engrg., Univ. of Arizona, Tucson, AZ 85721. 32Assoc. Prof., Dept. of Agric. and Biosystems Engrg., Univ. of Arizona, Tucson, AZ. E-mail: myitayew@u.arizona.edu 43Prof., Dept. of Soil, Water, and Envir. Sci., Univ. of Arizona, Tucson, AZ. E-mail: awarrick@ag.arizona.edu
|
| |
Abstract: | Measurement of unsaturated hydraulic conductivity is needed for precise control of water and solutes in the vadose zone. Because of the spatial variation of soils, a large number of surface and subsurface measurements are needed to characterize a field. In this work, permeameters were developed and tested for estimating subsurface unsaturated hydraulic conductivity. The permeameters apply water under tension; they are easy to use and have adequate accuracy. Unsaturated hydraulic conductivity was determined by measuring the steady flow rates for various values of negative pressure. Tests using a soil of known hydraulic conductivity showed that the permeameters provided valid measurements. Two types were used, a porous cloth model that was inflated against the soil and a porous ceramic cup that was rigid. The field testing determined that a rigid design using a ceramic cup coupled to the soil by a layer of fine sand was easier to use, was reliable, and provided good results. |
| |
Keywords: | |
|
|