Further examination of the use of the equivalent salt solutions method for predicting hydraulic conductivity of soils for different salt solutions

Hydraulic conductivities of Pachappa and Waukena soils for different salt solutions, predicted by the equivalent salt solution methods, showed satisfactory agreement with measured values. The values of equivalent salt solutions for these soils were calculated from macroscopic swelling values of extracted clays. The equivalent salt solution method and the simplified domain model method of McNeal predicted equally accurately, the changes in hydraulic conductivities of Pachappa soil in salt solutions with sodium absorption ratio values from 15 to 100.

Download Full-text

Effect of salt solution composition on moisture release curves of soil

Soil Research ◽

10.1071/sr9790089 ◽

1979 ◽

Vol 17 (1) ◽

pp. 89 ◽

Cited By ~ 9

Author(s):

NS Jayawardane ◽

JA Beattie

Keyword(s):

Pore Size ◽

Salt Solution ◽

Electrolyte Concentration ◽

Sodium Absorption ◽

Alluvial Soils ◽

Salt Solutions ◽

Solution Composition ◽

Sodium Absorption Ratio ◽

Wide Range ◽

Size Index

A pore size index was used to express quantitatively the relative decrease in size of common pore of confined columns of krasnozem, red-brown and alluvial soils, with reduction in electrolyte concentration of percolating solutions of a given sodium absorption ratio (SAR). The pore size index of red-brown and alluvial soils decreased markedly with reduction in electrolyte concentration, especially in solutions of high SAR. In the krasnozem soil the pore size index remained fairly constant for a wide range of salt solutions. Moisture release curves of red-brown soil for solutions of decreasing electrolyte concentration and constant SAR and for solutions of increasing SAR and constant electrolyte concentration can be used in combination to obtain moisture release curves of this soil for solutions at any intermediate values of SAR and electrolyte concentration. They also reveal the pattern of volume change of different sized pores.

Download Full-text

Prediction of unsaturated hydraulic conductivity changes of a loamy soil in different salt solutions by using the equivalent salt solutions concept

Soil Research ◽

10.1071/sr9920565 ◽

1992 ◽

Vol 30 (5) ◽

pp. 565 ◽

Cited By ~ 5

Author(s):

NS Jayawardane

Keyword(s):

Hydraulic Conductivity ◽

Salt Solution ◽

Electrolyte Concentration ◽

Saline Water ◽

Saturated Hydraulic Conductivity ◽

Sodium Absorption ◽

Published Data ◽

Salt Solutions ◽

Solution Series ◽

Water Contents

Equivalent salt solutions series have been previously defined as solutions with combinations of sodium absorption ratio (SAR) and electrolyte concentration (E,) producing the same extent of clay swelling in a given soil. These equivalent salt solutions series values have yielded satisfactory predictions of changes in saturated hydraulic conductivity, with changes in salt solution composition and concentrations. In the present study, previously published data on changes in saturated and unsaturated hydraulic conductivities of Gilat soil in salt solutions of cationic ratio 0-50 (mmol dm-3)1/2 and electrolyte concentration 2-50 (m.e. dm-3) were used to compare the equivalent salt solution series values for hydraulic conductivities at different water contents. The equivalent salt solution series causing a given change in saturated hydraulic conductivity of a loamy Gilat soil were derived. These equivalent salt solution values were used to predict the unsaturated hydraulic conductivities of this soil at low water contents. Predictions of unsaturated conductivity at relative water contents (�) ranging from 0.80 to 0.20 agreed closely with the measured values. Coefficients log a1 and b1 for Gilat soil, in the equation log Ec = log a1+b1 log SAR, relating the Ec and SAR values of each equivalent salt solutions series were determined at � values between 1.00 and 0.20. The relationship between log a1 and bl was similar at all water contents, in agreement with the equivalent salt solutions concept. Therefore, equivalent salt solution parameters derived from saturated hydraulic conductivity measurements could be used to predict changes in unsaturated conductivities and hence flow rates of saline water under specified boundary conditions.

Download Full-text

An equivalent salt solutions method for predicting hydraulic conductivities of soils for different salt solutions

Soil Research ◽

10.1071/sr9790423 ◽

1979 ◽

Vol 17 (3) ◽

pp. 423 ◽

Cited By ~ 10

Author(s):

NS Jayawardane

Keyword(s):

Boundary Conditions ◽

Salt Solution ◽

Electrolyte Concentration ◽

Alluvial Soil ◽

Sodium Absorption ◽

Pore Geometry ◽

Specific Pressure ◽

Salt Solutions ◽

Sodium Absorption Ratio ◽

The Relationship

Equivalent salt solutions are defined as solutions with combinations of sodium absorption ratio (SAR) and electrolyte concentration producing the same extent of clay swelling in a given soil. It is suggested that in the presence of different equivalent salt solutions a given soil will have the same pore geometry, the same saturated and unsaturated conductivities at specific pressure heads, and hence the same capacity to transmit such solutions under specific boundary conditions. This concept of equivalent salt solutions was used to develop a method for predicting the saturated hydraulic conductivities of soils for different salt solutions. The basic data required for such predictions in a given soil are the equivalent salt solution values and the relationship between saturated conductivity and electrolyte concentration at a given SAR. Saturated conductivities of a red-brown soil and an alluvial soil for salt solutions of SAR 20 and 10 and different electrolyte concentrations predicted by this method were fairly close to measured values. The significance of this concept to field problems involving flow of the salt solutions through soils is briefly discussed.

Download Full-text

Classification of groundwater suitability for irrigation purposes using a comprehensive approach based on the AHP and GIS techniques in North Kurdufan Province, Sudan

Applied Water Science ◽

10.1007/s13201-021-01443-z ◽

2021 ◽

Vol 11 (7) ◽

Author(s):

Elsiddig Eldaw ◽

Tao Huang ◽

Adam Khalifa Mohamed ◽

Yahaya Mahama

Keyword(s):

Water Quality ◽

Spatial Distribution ◽

Groundwater Quality ◽

Irrigation Water ◽

Research Effort ◽

Sodium Absorption ◽

Irrigation Water Quality ◽

Middle Income ◽

Sodium Absorption Ratio ◽

Deep Aquifers

AbstractDeterioration of groundwater quality due to drastic human interventions is rising at an alarming rate particularly in lower- and middle-income countries. Yet, limited research effort has been devoted to monitoring and ascertaining groundwater quality. The present study develops a comprehensive irrigation water quality index (IWQI) for rating water quality of shallow and deep aquifers in North Kurdufan province, Sudan. The new approach is developed to overcome the deficiencies of the existing irrigation indices and coming up with a unified decision for classifying water quality for irrigation purposes. Because of these indices like permeability index (PI), sodium absorption ratio (SAR), etc., depending on specific elements, entirely subjective, as well as the great variations in their results, particularly when classifying water quality. Thus, IWQI is created based on eight indices that are generally used to evaluate irrigation water quality, plus three physicochemical parameters have been proven an impact on water quality. The analytic hierarchy process (AHP) is applied to minimize the subjectivity at assign parameter weights under multiple criteria decision analysis tools (MCDA). The spatial distribution of IWQI agrees with the spatial distribution of the most parameters. The results of our approach reveal that the majority of samples are suitable for irrigation uses for both aquifers except few wells in the confined aquifer. Also, noted that there are very variations in the irrigation indices results for classifying water quality. The comparison result showed that the new index robust, fair calculations and has best classifying of water quality.

Download Full-text

Hydrochemical assessment of water quality for irrigation: A case study of the wetland complex of Guerbes-Sanhadja, North-East of Algeria

Journal of Water and Land Development ◽

10.2478/jwld-2018-0041 ◽

2018 ◽

Vol 38 (1) ◽

pp. 43-52 ◽

Cited By ~ 1

Author(s):

Sihem Hedjal ◽

Derradji Zouini ◽

Abdelwaheb Benamara

Keyword(s):

Water Quality ◽

Quality Parameters ◽

Irrigated Agriculture ◽

Sodium Absorption ◽

Sodium Absorption Ratio ◽

North East ◽

The Status ◽

Wetland Complex ◽

Eastern Algeria ◽

Irrigation Quality

AbstractThe wetland complex of Guerbes-Sanhadja (north-eastern Algeria), has experienced in recent years a certain economic expansion, particularly agricultural, about 47% of the useful agricultural area marked by several varieties of crops ranging from market gardening to speculative crops, requiring large quantities of water for irrigation purposes, however the swampy areas are the main sources used for irrigation purposes in this practice. It is therefore necessary for this water to have physicochemical properties adapted to plants, in particular the absence of salinity. This study was done to evaluate the status of the swamps areas quality and its suitability for irrigated agriculture. To achieve this objective, water samples from ten swamps areas water were collected from Guerbes-Sanhadja in February and June of 2016. The water quality of these swamps was estimated from different water quality parameters such as pH and electrical conductivity (EC), the chemical parameters like Na+, K+, Ca2+, HCO3−, SO42−, Cl−, BOD5, NO3−, NO2−, NH4+ and PO43−. Based on the physico-chemical analyses, irrigation quality parameters like sodium absorption ratio (SAR), percent sodium (% Na), residual sodium carbonate (RSC), permeability index (PI), magnesium hazard (MH) were calculated. The results showed that the overall concentration of nitrate was very high. About 60 percent of the swampy areas had suitable water quality for chloride, and they had a concentration below the permissible limit for crop irrigation. From the Richards diagram, it is observed that most of the samples from the study area fall in the good to permissible classes for irrigation purpose.

Download Full-text

Solution of Contact Problems for Nonlinear Gao Beam and Obstacle

Journal of Applied Mathematics ◽

10.1155/2015/420649 ◽

2015 ◽

Vol 2015 ◽

pp. 1-12 ◽

Cited By ~ 4

Author(s):

J. Machalová ◽

H. Netuka

Keyword(s):

Solution Method ◽

Mixed Finite Element ◽

Mixed Finite Element Method ◽

Contact Problems ◽

Beam Model ◽

Contact Conditions ◽

Beam Elements ◽

Solution Methods ◽

Euler Bernoulli Beam ◽

Bernoulli Beam Model

Contact problem for a large deformed beam with an elastic obstacle is formulated, analyzed, and numerically solved. The beam model is governed by a nonlinear fourth-order differential equation developed by Gao, while the obstacle is considered as the elastic foundation of Winkler’s type in some distance under the beam. The problem is static without a friction and modeled either using Signorini conditions or by means of normal compliance contact conditions. The problems are then reformulated as optimal control problems which is useful both for theoretical aspects and for solution methods. Discretization is based on using the mixed finite element method with independent discretization and interpolations for foundation and beam elements. Numerical examples demonstrate usefulness of the presented solution method. Results for the nonlinear Gao beam are compared with results for the classical Euler-Bernoulli beam model.

Download Full-text

Computational Methods for Production-Based Asset Pricing Models with Recursive Utility

Studies in Nonlinear Dynamics & Econometrics ◽

10.1515/snde-2017-0003 ◽

2019 ◽

Vol 0 (0) ◽

Author(s):

Eric Mark Aldrich ◽

Howard Kung

Keyword(s):

Asset Pricing ◽

Solution Method ◽

Value Function ◽

Polynomial Solution ◽

Dsge Models ◽

Recursive Utility ◽

Solution Quality ◽

Global Method ◽

Asset Pricing Models ◽

Solution Methods

Abstract We compare local and global polynomial solution methods for DSGE models with Epstein- Zin-Weil utility. We show that model implications for macroeconomic quantities are relatively invariant to choice of solution method but that a global method can yield substantial improvements for asset prices and welfare costs. The divergence in solution quality is highly dependent on parameters which affect value function sensitivity to TFP volatility, as well as the magnitude of TFP volatility itself. This problem is pronounced for calibrations at the extreme of those accepted in the asset pricing literature and disappears for more traditional macroeconomic parameterizations.

Download Full-text