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Hydraulic conductivity

About: Hydraulic conductivity is a research topic. Over the lifetime, 12066 publications have been published within this topic receiving 339713 citations.


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Book ChapterDOI
01 Jan 2005
TL;DR: In this article, the authors used flow in a vertical soil column to derive and illustrate Darcy's law and Laplace's equation for any direction in the soil and applied it to solve groundwater seepage and drainage problems.
Abstract: Understanding movement of water in saturated soil is important in drainage and groundwater studies. The French hydraulic engineer Henry Darcy (1803–1858) determined experimentally the law that governs the flow of water through saturated soil (1856), which is called Darcy's law. The chapter uses flow in a vertical soil column to derive and illustrate Darcy's law. However, the law and principles developed in the chapter apply for flow of water in any direction in the soil. Hydraulic conductivity in natural field soil is governed by factors such as cracks, root holes, worm holes, and stability of soil crumbs. Texture, that is, the percent of the primary particles of sand, silt, and clay, usually has a minor effect on hydraulic conductivity, except for disturbed soil materials. The hydraulic conductivity of natural soils in place varies from about 30 m/day for a silty clay loam to 0.05 m/day for clay. To solve groundwater seepage and drainage problems, it is desirable to have a general differential equation, and Laplace's equation, which is a familiar equation occurring in nearly all branches of applied mathematics, applies. Laplace's equation is derived from Darcy's law and the equation of continuity. The equation of continuity states mathematically that mass can neither be created nor destroyed.

2 citations

Proceedings ArticleDOI
06 May 2015
TL;DR: In this paper, the authors proposed a double constraint method to calibrate the hydraulic conductivities of groundwater basins using direct and indirect measurements of hydraulic heads and fluxes, which can be made more reliable by repeated calibrations under different hydrological conditions.
Abstract: Modeling of groundwater flow through basins has to be based on regional-scale hydraulic conductivities. We show how regional conductivities can simply be calibrated using direct and indirect measurements of hydraulic heads and fluxes. Groundwater models are conventionally based on recharge flux specified on the model’s top boundary. In the 1960s Toth presented a model of regional groundwater flow based on head specified on the top boundary. This approach resulted in the discovery of local, intermediate and regional flow systems. On the other hand, a top head condition may lead to unrealistic recharge rates. Combining the advantages of both flux and head boundary conditions, we analyze groundwater flow using two models: a flux model and a head model. The difference between the two solutions shows the regions where measured heads and fluxes can calibrate the initial hydraulic conductivity, as well as the regions where measured heads and fluxes cannot. Using Darcy’s law to the differences results in calibration. This so-called Double Constraint Method can be made more reliable by repeated calibrations under different hydrological conditions. A Kalman Filter then determines an uncertainty that is appreciably smaller than the observation error.

2 citations

Journal ArticleDOI
TL;DR: In this paper , a hydraulic conductivity test system with 2-mm-thick specimens was developed, which was evaluated in terms of test accuracy and showed that the results showed less variation particularly for the consolidation test results, indicating that the macroscopic hydraulic behavior was consistent with Darcy's law.

2 citations

Journal ArticleDOI
TL;DR: In this article, the effect of the inclusion of winter cover crops in different cropping sequences on capacity and intensity indicators of soil physical quality was evaluated at two different sites, one with a silty loam Argiudoll and the other with a sandy loam Hapludoll.
Abstract: Soil physical degradation is a current problem in Molisols of the Pampas Region under no-tillage (NT), that has been related to over-simplified agricultural systems with scarce or no rotations and long winter bare fallows. Soil physical quality (SPQ) is a key factor of soil health and productivity, as it controls root development and air and water fluxes and storage in the soil, which in turn affect nutrient uptake and plant growth. Cover crops have been proposed as a companion agricultural practice to improve NT performance and SPQ. The aim of this study was to evaluate the effect of the inclusion of winter cover crops in different cropping sequences on capacity and intensity indicators of SPQ in two soils of different texture under NT and to compare it with different traditional crop sequences, including non-agricultural plots. SPQ was evaluated at two different sites, one with a silty loam Argiudoll and the other with a sandy loam Hapludoll. Treatments included plots with and without cover crops, with different summer crop sequences (continuous soybean and corn – soybean rotations). Also, a corn – wheat/soybean rotation with and without pastures was evaluated. All treatments had more than 15 years under the same management. We measured soil organic carbon (SOC), and capacity SPQ indicators (bulk density, total porosity, pore size distribution, air capacity, plant available water, relative field capacity and S index). We also measured dynamic SPQ indicators derived from field infiltration tests (saturated and near saturation hydraulic conductivity, effective macro and mesoporosity, and porosity connectivity indexes for different pore families). On the silty loam Argiudoll, cover crops increased SOC but failed to improve SPQ. This was related to soil physical degradation and the low ability of these soils for structure regeneration. On the sandy loam Hapludoll, cover crops had mixed effects on SOC and pore size distribution, but increased near saturation hydraulic conductivity, in the case of the corn – soybean rotation with cover crops, reaching values similar to those of a natural grassland.

2 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20241
2023635
20221,052
2021488
2020527
2019502