نتایج جستجو برای: hydraulic conductivity

تعداد نتایج: 75578  

Journal: :Tree physiology 1996
J A Panek

Stomatal conductance in trees is related to both foliar carbon-isotope abundance and stem hydraulic properties. By combining these relationships, I hypothesized that carbon-isotope abundance in foliage should vary with limitations to water movement through supporting branches. I sampled Douglas-fir branches (Pseudotsuga menziesii (Mirb.) Franco) from six sites across a climate gradient in Orego...

2008
DIRK SCHULZE-MAKUCH DOUGLAS S. CHERKAUER Dirk Schulze-Makuch Douglas S. Cherkauer

Tests on several scales were analyzed and conducted in a dolomite aquifer of southeastern Wisconsin to examine the variation of hydraulic conductivity and longitudinal dispersivity with scale of measurement. Scale behavior of hydraulic conductivity was shown to be dependent on the hydrofacies. In vuggy fades dominated by porous flow hydraulic conductivity increased relative to scale linearly wi...

ژورنال: علوم آب و خاک 2014

In order to assess hydraulics of LNAPLs in soil, the soil retention curves of petroleum and water were both determined through hanging column method. And, the hydraulic conductivity of petroleum and water were determined by steady head method. The water and petroleum hydraulic conductivities were 7.27 and 57.84 cm.day-1, respectively. The soil retention parameters were obtained based on van Gen...

Journal: :Journal of experimental botany 2003
Stefan Mayr Barbara Rothart Birgit Dämon

Xylem within trees varies in its hydraulic efficiency and safety. Trees at the alpine timberline were expected to exhibit a hydraulic architecture protecting the leader shoot from winter embolism. Hydraulic and related anatomical parameters were compared as well as seasonal courses of winter embolism in leader shoots and twigs of Norway spruce trees growing at 2000 m. Leader shoots had a 1.4-fo...

2010
Valentijn R. N. Pauwels Peter A. Troch

[1] The estimation of catchment-averaged aquifer hydraulic conductivity values is usually performed through a base flow recession analysis. Relationships between the first time derivatives of the base flow and the base flow values themselves, derived for small and large values of time, are used for this purpose. However, in the derivation of the short-time equations, an initially fully saturate...

ژورنال: علوم آب و خاک 2013
بیژن نظری, , حامد ابراهیمیان, , محمود اکبری, , مسعود پارسی نژاد , ,

This study was conducted on subsurface drainage network under operation in Behshahr. DRAINMOD model was used to simulate drainage system using measured data in 2006. The model was evaluated to estimate soil hydraulic conductivity by comparing the measured and predicted values of water table depth and drain discharge for different values of hydraulic conductivity. The results of this method were...

2017
Yu-Pin Lin Yu-Wen Chen Liang-Cheng Chang Ming-Sheng Yeh Guo-Hao Huang Joy R. Petway

This study presents an approach for obtaining limited sets of realizations of hydraulic conductivity (K) of multiple aquifers using simulated annealing (SA) simulation and spatial correlations among aquifers to simulate realizations of hydraulic heads and quantify their uncertainty in the Pingtung Plain, Taiwan. The proposed approach used the SA algorithm to generate large sets of natural logar...

2011
S. Straface E. Rizzo F. Chidichimo

The characterization of a heterogeneous aquifer involves a wide spectrum of high resolution direct measurements of the characteristic parameters, defined in itinere according to the various approaches used. This information is usually obtained from the pumping tests and the relative measurements of the drawdown induced. Unfortunately, these methods are intrusive and the hydrological system is p...

Journal: :Tree physiology 1992
M T Tyree J Alexander J L Machado

Despite many studies of the percent loss of hydraulic conductivity in excised branches, there is doubt as to whether cutting stems in air introduces unnatural embolism into the xylem at the cut surface. To address this question, hydraulic conductivity was measured in seedlings of northern red oak (Quercus rubra L.) and rooted scions of eastern cottonwood (Populus deltoides Bartr. ex Marsh.) tha...

2005
C. Fallico

Papers published in Hydrology and Earth System Sciences Discussions are under open-access review for the journal Hydrology and Earth System Sciences Abstract In the context of studies aiming at the estimation of effective parameters for unsaturated zone modelling, this work tackles the problem of experimental data quality, considering the large collection of data gathered at an experimental sit...

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