In the present work, we construct several artificial neural networks (varying input data) to calculate saturated hydraulic conductivity (KS) using a database with 900 measured samples obtained from Irrigation District 023, in San Juan del Rio, Queretaro, Mexico. All of them were constructed two hidden layers, back-propagation algorithm for learning process, and logistic function as nonlinear tr...

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 ...

0309-1708/$ see front matter 2008 Elsevier Ltd. A doi:10.1016/j.advwatres.2008.11.009 * Corresponding author. E-mail address: [email protected] (P. Dost This paper concerns efficient uncertainty quantification techniques in inverse problems for Richards’ equation which use coarse-scale simulation models. We consider the problem of determining saturated hydraulic conductivity fields condi...

abstract information on spatial and temporal variations of soil hydraulic conductivity (k) is essential to improve soil and water management. however several techniques have been proposed for measuring of soil hydraulic conductivity above water surface table, but reliability and easy use of these methods in various conditions were always concern for engineers. the purposes of this study are mea...

Soil absorption systems (SAS) are used commonly to treat and disperse septic tank effluent (STE). SAS can hydraulically fail as a result of the low permeable biomat zone that develops on the infiltrative surface. The objectives of this experiment were to compare the hydraulic properties of biomats grown in soils of different textures, to investigate the long-term acceptance rates (LTAR) from pr...

We studied relationships among branch hydraulic conductivity, xylem embolism, stomatal conductance (gs), foliar nitrogen (N) concentration and specific leaf area (SLA) of seven tree species growing at four temperate woodland sites spanning a 464-1350 mm rainfall gradient. Specifically, we examined the question: are gs and foliar N concentration coordinated with branch hydraulic conductivity and...

A new type of in-situ hydraulic permeameter was developed to determine vertical hydraulic conductivity (VHC) of saturated sediments from hydraulic experiments using Darcy's law. The system allows water to move upward through the porous media filled in the permeameter chamber driven into sediments at water-sediment interface. Darcy flux and hydraulic gradient can be measured using the system, an...

The determination of the fate of aircraft de-icing fluids in near runway soils is important in evaluating environmental impacts and in the design of treatment system. The effect of biodegradation of the primary component of de-icing fluids, propylene glycol (PG), was tested in waters-saturated sand columns. Biogrowth significantly reduced the hydraulic conductivity of the sand. This change in h...