نتایج جستجو برای: soil hydraulic parameters

تعداد نتایج: 769656  

Journal: :پژوهش های خاک 0
محمد امیدی فرد دانش آموخته کارشناسی ارشد دانشگاه شیراز سید علی اکبر موسوی استادیار دانشگاه شیراز

hydraulic attributes play important role in hydrological studies, soil conservation, designing irrigation and drainage systems, soil conservation, and controlling soil erosion in watersheds. their measurements are very tedious and time consuming and due to high spatial variability, a large number of measurements are required for obtaining reliable values. nowadays, prediction of these attribute...

2011
J. Šimůnek A. de Vos

An overview is given of the issues of parameter estimation, model verification, and model validation as applied to field-scale subsurface flow and transport problems. We briefly review inverse optimization methods for estimating soil hydraulic parameters from a variety of field experiments, including tension disc infiltrometry, cone penetrometry, and gravity drainage experiments. An example is ...

2011
Thomas Wöhling Jasper A. Vrugt

[1] In the past two decades significant progress has been made toward the application of inverse modeling to estimate the water retention and hydraulic conductivity functions of the vadose zone at different spatial scales. Many of these contributions have focused on estimating only a few soil hydraulic parameters, without recourse to appropriately capturing and addressing spatial variability. T...

2011
Donald M. Reeves Rishi Parashar Greg Pohll

It is common for subsurface flow to transition between porous and fractured media. Two examples include vertical infiltration of precipitation through a permeable soil overlying a fractured bedrock, and horizontal ground water flow through a combination of porous and fractured geologic units. A reduction in flow or flow impedance may occur across these interfaces caused by head losses associate...

2001
Shmuel Assouline Daniel M. Tartakovsky

We present a new two-parameter expression for relative hydraulic conductivity (RHC) of partially saturated soils. It is based on the premise of Assouline et al. [1998] that soil structures evolve from a uniform random fragmentation process. This assumption allows us to derive hydraulic properties of soils (water retention curves and unsaturated hydraulic conductivity) from primary properties, s...

2010
Peng Wang Daniel M. Tartakovsky

Soil heterogeneity and the lack of detailed site characterization are two ubiquitous factors that render predictions of flow and transport in the vadose zone inherently uncertain. We employ the Green–Ampt model of infiltration and the Dagan– Bresler statistical parameterization of soil properties to compute probability density functions (PDFs) of infiltration rate and infiltration depth. By goi...

2005
Marcel G. Schaap

The unsaturated soil hydraulic properties are often described using Mualem–van Genuchten (MVG) type analytical functions. Recent studies suggest several shortcomings of these functions near saturation, notably the lack of second-order continuity of the soil water retention function at saturation and the inability of the hydraulic conductivity function to account for macroporosity. We present a ...

2007
P. L. G. Vlek

cial neural networks have become a common tool for modeling complex “input–output” dependencies. In the past, neural network models have been used as a special class of pedotransfer functions (PTFs) using feed-forward back propagation or radial basis functions to approximate any continuous (nonlinear) function (Hecht-Nielsen, 1990; Pachepsky et al., 1996; Schaap and Bouten, 1996; Minasny and Mc...

Journal: :Water science and technology : a journal of the International Association on Water Pollution Research 2011
Stefan Fach Carolina Engelhard Nina Wittke Wolfgang Rauch

In cold climate regions winter conditions significantly influence the performance of stormwater infiltration devices. Frozen soil and water storage by snow changes their operation. In this paper winter operation of a grassed infiltration swale was investigated using on-site and laboratory measurements. The field investigation of a grassed swale at a parking place in an Alpine region showed that...

2009
J. A. Huisman J. Sorg H. Vereecken

0022-1694/$ see front matter 2009 Elsevier B.V. A doi:10.1016/j.jhydrol.2009.10.023 * Corresponding author. Tel.: +49 (0)2461 618607. E-mail address: [email protected] (J.A. Huis Coupled hydrogeophysical inversion aims to improve the use of geophysical data for hydrological model parameterization. Several numerical studies have illustrated the feasibility and advantages of a coupled appro...

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