Download or read book Comparison of Laboratory and Field Methods for Determining the Quasi Saturated Hydraulic Conductivity of Soils written by and published by . This book was released on 1997 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laboratory and field ponded infiltration tests in quasi-saturated soils (containing entrapped air) exhibit the same three-stage temporal variability for the flow rate and hydraulic conductivity. However, the values for the hydraulic conductivity may differ by as much as two orders of magnitude due to differences in the geometry and physics of flow when different laboratory and field methods are applied. The purpose of this paper is to investigate this variability using a comparison of results of ponded infiltration tests conducted under laboratory conditions using confined cores, with results of field tests conducted using partially isolated cores and double-ring infiltrometers. Under laboratory conditions in confined cores, during the firs stage, the water flux decreases over time because entrapped air plugs the largest pores in the soils; during the second stage, the quasi-saturated hydraulic conductivity increases by one to two orders of magnitude, essentially reaching the saturated hydraulic conductivity, when entrapped air is discharged from the soils; during the third stage, the hydraulic conductivity decreases to minimum values due to sealing of the soil surface and the effect of biofilms sealing the pores within the wetted zone. Under field conditions, the second stage is only partially developed, and when the surface sealing process begins, the hydraulic pressure drops below the air entry value, thereby causing atmospheric air to enter the soils. As a result, the soils become unsaturated with a low hydraulic conductivity, and the infiltration rate consequently decreases. Contrary to the laboratory experiments in confined cores, the saturated hydraulic conductivity cannot be reached under field conditions. In computations of infiltration one has to take into account the variations in the quasi-saturated and unsaturated hydraulic conductivities, moisture and entrapped air content, and the hydraulic gradient in the quasi-saturated or unsaturated soils.

Download or read book Comparison of Four Laboratory and Field Methods for Determining Saturated Hydraulic Conductivity in the Unsaturated Zone written by Dana Candice Rogerson and published by . This book was released on 1995 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Comparison of Laboratory and Field Methods for the Estimation of Hydraulic Conductivity in a Sand and Gravel Aquifer written by Linda Peiperl Warren and published by . This book was released on 1992 with total page 494 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Evaluation of Methods for Determining Soil water Retentivity and Unsaturated Hydraulic Conductivity written by John M. Marion and published by . This book was released on 1993 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Comparison of Three Field Methods for Measuring Saturated Hydraulic Conductivity written by Jay Dunton Dorsey and published by . This book was released on 1989 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Variability and Estimation of Hydraulic Conductivity in C Horizons of Sandy Loam Glacial Till Soils Comparison of One step Outflow Laboratory Method to an I n S i t u Method for Measuring Hydraulic Conductivity written by Dan B. Jaynes and published by . This book was released on 1978 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Comparison of Methods for Measuring the Saturated Hydraulic Conductivity of Four Field Soils Having a Range of Textures microform written by Lee, Doreen M. (Doreen Mary) and published by National Library of Canada. This book was released on 1984 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Comparison of Field Methods for Measuring Hydraulic Conductivity of Soil written by L. S. Ying and published by . This book was released on 1977 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Comparison of Field and Laboratory Methods for the Determination of Hydraulic Conductivity of the Cohansey Sand Formation in Gloucester County New Jersey written by Martin Patrick Derby and published by . This book was released on 1992 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Comparison of Field and Laboratory Measurements of Hydraulic Conductivity written by A. Guerra and published by . This book was released on 1992 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: The hydraulic conductivity of a soil was measured in the laboratory and in the field. Although each technique used yielded consistent results, the hydraulic conductivity obtained differed over several orders of magnitude. These differences in hydraulic conductivity can only be attributed to macroscopic features that weigh differently depending on the mass of soil affected by the different tests.

Download or read book Comparison of Different Methods of Measuring Soil Hydraulic Conductivity written by Luciano Behnke Duhart and published by . This book was released on 1958 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Comparison of Laboratory Measured and Calculated Hydraulic Conductivity Values of Unsaturated Soils written by Mitiku Mamo and published by . This book was released on 1988 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scaling Methods in Soil Physics written by Yakov Pachepsky and published by CRC Press. This book was released on 2003-03-26 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt: The scaling issue remains one of the largest problems in soil science and hydrology. This book is a unique compendium of ideas, conceptual approaches, techniques, and methodologies for scaling soil physical properties. Scaling Methods in Soil Physics covers many methods of scaling that will be useful in helping scientists across a range of soil-rel

Download or read book Characterization and Measurement of the Hydraulic Properties of Unsaturated Porous Media written by M. Th Van Genuchten and published by . This book was released on 1999 with total page 844 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Laboratory and Field Testing of Unsaturated Soils written by Alessandro Tarantino and published by Springer Science & Business Media. This book was released on 2008-12-28 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume details recent global advances in laboratory and field testing of unsaturated soils. Coverage includes mechanical, hydraulic, and geo-environmental testing and applications of unsaturated soil monitoring to engineering behavior of geo-structures.

Download or read book Soil Physics written by William A. Jury and published by John Wiley & Sons. This book was released on 2004-03-25 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt: The completely revised and updated edition of the classic guide to soil physics The revised edition of an environmental soil science classic, Soil Physics, Sixth Edition presents updated and expanded material on the latest developments in the industry, providing the best preparation for students and a state-of-the-art reference for professionals. Through a systemic use of physical principles, Soil Physics, Sixth Edition demonstrates how to simplify the general theory used in transport processes for specific applications. With broad coverage of the role soil plays in the environment, this Sixth Edition offers more than seventy worked problems illustrating specific lessons in the book, and features: * New material on soil's influence on the health of an ecosystem * Expanded coverage of modern in-site and noninvasive field-scale subsurface measurement techniques * Discussions on the latest advances in regional and watershed hydrology * Up-to-date information on the use of algorithms and computers in the study and modeling of soil processes * New coverage of preferential flow Soil Physics, Sixth Edition is an essential volume for students and professionals in soil science, natural resource management, forestry, agriculture, hydrology, and civil and environmental engineering.

Download or read book Procedures for Field Sampling and Laboratory Measurement of Saturated and Unsaturated Hydraulic Conductivity on Large Soil Cores written by Neil James McKenzie and published by . This book was released on 1993 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Methods for measuring saturated and unsaturated hydraulic conductivity on large intact soil cores are presented. Soil horizons are wet in the field using a trickle irrigation system before excavation and sampling of the large soil cores. A convenient and accurate method for measuring saturated hydraulic conductivity suited to the large cores is then described. The same cores are used for the measurement of usaturated hydraulic conductivity at potentials close to zero. The system uses a drip infiltrometer to supply water at a constant flux. Unit gradient is achieved by adjusting the potential th the lower boundary with an adjustable outflow tube. Matric potential in the core is monitored using tensiometers and water content is measured gravimetrically. Detailed descriptions of the apparatus and calculations are presented. Alternative methods for supplying water using a constant potential device are also considered.