نتایج جستجو برای: unsaturated soil

تعداد نتایج: 195589  

2009
T. Blume

Spatial patterns as well as temporal dynamics of soil moisture have a major influence on runoff generation. The investigation of these dynamics and patterns can thus yield valuable information on hydrological processes, especially in data scarce or previously ungauged catchments. The combination of spatially scarce but temporally high resolution soil moisture profiles with episodic and thus tem...

2002

Effects of soil heterogeneity have been the focus of both field and theoretical research for the past decade (e.g., Hills et al., 1991; Hopmans et al., 1988; Mantoglou and Gelhar, 1987; McCord et al., 1991, Russo, 1991; Ünlü et al., 1990; Wierenga et al., 1991; Yeh et al., 1985a,b; Yeh et al., 1986). Analytical models are essential tools for investigating the effect of heterogeneity on flow and...

2002
F. N. DALTON

Dalton, F.N. and van Genuchten, M.Th., 1986. The time-domain reflectometry method for measuring soil water content and salinity. Geoderma, 38: 237--250. This paper discusses the physical principles and use of time-domain reflectometry as a new tool for studying water and solute transport in unsaturated soils. In-situ measurements of water content and bulk soil electrical conductivity are shown ...

2015
F. Ries J. Lange S. Schmidt H. Puhlmann M. Sauter

Knowledge of soil moisture dynamics in the unsaturated soil zone provides valuable information on the temporal and spatial variability of groundwater recharge. This is especially true for the Mediterranean region, where a substantial fraction of long-term groundwater recharge is expected to occur during high magnitude precipitation events of aboveaverage wet winters. To elucidate process unders...

2002
Jinzhong Yang Renduo Zhang Jinquan Wu

An analytical solution of macrodispersivity was derived for the adsorbing solute transport in physically and chemically heterogeneous unsaturated soils under the condition of gravity-dominated flow. The unsaturated hydraulic conductivity and water content were treated as spatial random functions. The chemical adsorption was described by a linear equilibrium isotherm, and the adsorption coeffici...

2013
Albane Saintenoy Jan W. Hopmans

We are interested in Ground Penetrating Radar (GPR) as a geophysical tool useful for determining the depth of the ground water table (GWT) and for monitoring shallow water infiltration in sandy soils. At hydrostatic equilibrium, the water content distribution in a homogeneous unsaturated soil down to the water saturated zone depends on the soil water retention function. A classical way to fit r...

Journal: :international journal of civil engineering 0
m. mojezi no. 21, arghavan, north dibaji, dr. lavasani st., tehran, iran m.k. jafari no. 21, arghavan, north dibaji, dr. lavasani st., tehran, iran m. biglari razi university, kermanshah, iran

experimental study of the cyclic behavior of unsaturated materials is more complex than that of the saturated materials due to the required equipment, experience and time. furthering investigations in the field of unsaturated materials is necessary to better understand its complexity and sensitivity of unsaturated cyclic parameters to different determinants such as suction path, stress path, lo...

2011
John B. Gates Bridget R. Scanlon Xingmin Mu Lu Zhang

Soil conservation measures undertaken to address land degradation can alter the hydrologic cycle by changing partitioning of water fluxes at the land surface. While effects on runoff are well documented, impacts of soil conservation activities on fluxes to groundwater are poorly understood. The goal of this study was to examine fluxes to groundwater in a semi-arid area of China’s Loess Plateau ...

2015
Grigorios G. Anagnostopoulos Simone Fatichi Paolo Burlando

Extreme rainfall events are the major driver of shallow landslide occurrences in mountainous and steep terrain regions around the world. Subsurface hydrology has a dominant role on the initiation of rainfall-induced shallow landslides, since changes in the soil water content affect significantly the soil shear strength. Rainfall infiltration produces an increase of soil water potential, which i...

2017
Jorge A Leiva Peter Nkedi-Kizza Kelly T Morgan Davie M Kadyampakeni

Imidacloprid (IMD) is a neonicotinoid pesticide soil-drenched to many crops to control piercing-sucking insects such as the Asian citrus psyllid (ACP). Neonicotinoids are persistent in the environment and transport analyses are helpful estimate leaching potential from soils that could result in groundwater pollution. The objective of this study was to analyze IMD breakthrough under saturated wa...

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