نتایج جستجو برای: soil unsaturated hydraulic conductivity
تعداد نتایج: 265684 فیلتر نتایج به سال:
Unsaturated hydraulic conductivity (K) is a measurement of soil water-retaining ability in unsaturated soil. The properties are necessary to predict the movement water current study aims create an alternative experimental device estimate theKusing moisturesensors. set up was designed and fabricated order measure volumetric content using GS3 (Campbell) sensors at different heights. data obtained...
abstract disc infiltrometer is one of those devices that used in recent years in measurement of hydraulic conductivity of entire soil. in order to analyze the data taken by disc infiltrometer a variety of methods based on wooding’s base analyze have been introduced. the objective of this study was to compare the performances of ankeny and weir methods for predicting soil hydraulic properties us...
to examine hydraulics of lnapls in soil, the retention curves of diesel fuel and water were both determined by hanging column method. the soil retention parameters were obtained based on van genuchten, brooks-corey and campbell’s models. in addition, the soil hydraulic conductivity for both fluids were predicted based on mualem- brooks-corey, burdine- brooks-corey, mualem-van genuchten and camp...
In this study, we derive analytical solutions of the first two moments (mean and variance) of pressure head for one-dimensional steady state unsaturated flow in a randomly heterogeneous layered soil column under random boundary conditions. We first linearize the steady state unsaturated flow equations by Kirchhoff transformation and solve the moments of the transformed variable up to second ord...
A semianalytical solution is presented for transient streaming potentials associated with flow to a pumping well in an unconfined aquifer, taking into account the effect of flow in the unsaturated zone above the water table. Flow in the unsaturated zone is modeled with a linearized form of Richards’ equation using an exponential model for soil moisture retention and unsaturated hydraulic conduc...
Direct measurement of soil unsaturated hydraulic conductivity (K(h) or K(θ)) is difficult and time-consuming, and often in many applied models, predicting hydraulic conductivity is carried out according to measurements of soil retention curve and saturated hydraulic conductivity (Ks). However, using KS as a matching point in many procedures may result in over-estimation of unsaturated hydraulic...
Leakage rates are evaluated for a landfill barrier system having a compacted clay liner (CCL) underlain by a vadose zone of variable thickness. A numerical unsaturated flow model SEEP/W is used to simulate the moisture flow regime and steady-state leakage rates for the cases of unsaturated zones with different soil types and thicknesses. The results of the simulations demonstrate that harmonic ...
As compared with mineral soils, there are few in situ measurements of the unsaturated hydraulic properties of peat soils available. We used parameter estimation (inverse) methods to estimate the water retention and hydraulic conductivity functions of drained peat soils from both laboratory and field data. The laboratory data were obtained on small cores using the traditional evaporation method,...
Measurement uncertainty is a key hindrance to the quanti_cation of water ~uxes at all scales of investigation[ Predictions of soil!water ~ux rely on accurate or representative measurements of hydraulic gradients and _eld! state hydraulic conductivity[ We quanti_ed the potential magnitude of errors associated with the parameters and variables used directly and indirectly within the DarcyÐBucking...
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