US Salinity Laboratory Research Articles

Identification and evaluation of hydrogeochemical processes on river Cooum, South India

The salient features of the river water chemistry and the seasonal variations on the individual chemical parameter were evaluated and characterized. The order of abundance of the ions in the water is determined for both seasons. The contribution of chemical weathering to the water chemistry has been determined using the (Ca(2+) + Mg(2+))/(Na(+) + K(+)) ratio, ternary, and Gibb's diagrams. The results show that the chemical composition of river water during premonsoon is controlled mainly by evaporation-crystallization, while in the postmonsoon, the rock-water interaction dominates. The unique characteristic of the river water is the linear relationship among the principal ions. Hydrochemical characteristics of ions in the water were studied using 1:1 equiline diagrams. The nature of the water samples was determined using the piper diagram. The influence of trace metals on the chemical composition and the quality of the river water in the study area has been assessed using Wilcox and US Salinity Laboratory diagrams.

Groundwater quality in the lower Varuna River basin, Varanasi district, Uttar Pradesh

The lower Varuna River basin in Varanasi district situated in the central Ganga plain is a highly productive agricultural area, and is also one of the fast growing urban areas in India. The agricultural and urbanization activities have a lot of impact on the groundwater quality of the study area. The river basin is underlain by Quaternary alluvial sediments consisting of clay, silt, sand and gravel of various grades. The hydrogeochemical study was undertaken by randomly collecting 75 groundwater samples from dug wells and hand pumps covering the entire basin in order to understand the sources of dissolved ions, and to assess the chemical quality of the groundwater through analysis of major ions. Based on the total dissolved solids, two groundwater samples are considered unsuitable for drinking purpose, but all samples are useful for irrigation. Graphical treatment of major ion chemistry by Piper diagram helps in identifying hydro-geochemical facies of groundwaters and the dominant hydrochemical facies is Ca-Mg-HCO3 with appreciable percentage of the water having mixed facies. As per Wilcox’s diagram and US Salinity laboratory classification, most of the groundwater samples are suitable for irrigation except two samples (No’s 30 and 68) which are unsuitable due to the presence of high salinity and medium sodium hazard. Irrigation waters classified based on residual sodium carbonate, have revealed that all groundwaters are in general safe for irrigation except one sample (No. 27), which needs treatment before use. Permeability index indicates that the groundwater samples are suitable for irrigation purpose.

Environmental impact assessment and seasonal variation study of the groundwater in the vicinity of River Adyar, Chennai, India

Hydrochemical investigations of the groundwater and the seasonal effect on the chemical budget of ions along the course of the polluted river Adyar were carried out. From the geochemical results, it has been found that the seasonal effect does not change the order of abundance of both cations and anions, but it does change the concentration of various ions present in the groundwater. Among the chemical budget of ions, sodium and chloride were found to be the most predominant ions. The nitrate concentration in the groundwater ranges from 4.21 to 45.93 mg/l in pre-monsoon and in post-monsoon it ranges from 1.02 to 75.91 mg/l. The nitrate concentrations in the post-monsoon are high in some places especially in the upper stretch of the river. The intense agricultural activities near the upper stretch of the river may be an important factor for the higher concentration of nitrates in these aquifers. In order to determine the geochemical nature of water, the data was interpreted using the piper diagram wherein the results show the predominance of NaCl and CaMgCl types. Equiline diagrams, 1:1, were applied to evaluate the affinity ion relationship between various ions present in these waters. The quality of the groundwater was assessed with regard to its suitability to drinking and irrigation. A comparison of the groundwater quality in relation to drinking water quality standards shows that most of the water samples are not suitable for drinking, especially in post-monsoon period. US Salinity Laboratory's, Wilcox's diagrams, Kellys ratio and magnesium ratio were used for evaluating the water quality for irrigation which suggest that the majority of the groundwater samples are not good for irrigation in post-monsoon compared to that in pre-monsoon. Moreover the source of the ions in the water was examined and classified accordingly using Gibb's diagram. The analytical results reveals that the TDS values of the pre-monsoon samples were found to be lower than the post-monsoon reflecting that leaching predominates over that of the dilution factor.

Groundwater Quality Evaluation in KalarTown-Sulaimani/NE -Iraq

The Kalar town which is situated at the north east of Iraq was chosen for the investigations of the effect of rapid population increase on the quality of groundwater. The results showed that there are slight changes in ion concentrations due to dilution by rainfall. Pollutions with nitrate, phosphate and fluoride were detected in some water samples. The chemical relationships in expanded Durov, Chadha diagram, and Gibbs diagrams suggested that the groundwaters mainly belong to Ca-HCO3 type, and are controlled by chemical weathering of rock-forming minerals. Areal contour maps for electrical conductivity and ion distributions have shown that water samples from the town center are relatively rich in these values compared with other places in the town. This is attributed to the anthropogenic activity. A comparison of the groundwater quality in relation to drinking water quality standards proves that most of the water samples are suitable for drinking. US Salinity Laboratory’s diagrams, used for evaluating the water quality for irrigation and indicated that the majority of the groundwater samples are good for drinking, irrigation, and suitable for some industries like textile, chemical pulp but not paper industry.

Hydrochemical characteristics of groundwater in the Zhangye Basin, Northwestern China

The Zhangye Basin, located in arid northwest China, is an important agricultural and industrial center. In recent years rapid development has created an increased demand for water, which is increasingly being fulfilled by groundwater abstraction. Detailed knowledge of the geochemical evolution of groundwater and water quality can enhance understanding of the hydrochemical system, promoting sustainable development and effective management of groundwater resources. To this end, a hydrochemical investigation was conducted in the Zhangye Basin. Types of shallow groundwater in the Zhangye Basin were found to be HCO3 −, HCO3 −–SO4 2−, SO4 2−–HCO3 −, SO4 2−–Cl−, Cl−–SO4 2− and Cl− . The deep aquifer groundwater type was found to be HCO 3 − –SO 4 2− throughout the entire area. Ionic ratio and saturation index calculations suggest that silicate rock weathering and evaporation deposition are the main processes that determine the ionic composition in the study area. The suitability of the groundwater for irrigation was assessed based on the US Salinity Laboratory salinity classification and the Wilcox diagram. In the study area, the compositions of the stable isotopes δ18O and δD in groundwater samples were found to range from −4.00 to −9.28‰ and from −34.0 to −65.0‰, respectively. These values indicate that precipitation is the main recharge source for the groundwater system; some local values indicate high levels of evaporation. Tritium analysis was used to estimate the ages of the different groundwaters; the tritium values of the groundwater samples varied from 3.13 to 36.62 TU. The age of the groundwater at depths of less than 30 m is about 5–10 years. The age of the groundwater at depths of 30–50 m is about 10–23 years. The age of the groundwater at depths of 50–100 m is about 12–29 years. For groundwater samples at depths of greater than 100 m, the renewal time is about 40 years.

A hydrochemical profile for assessing the groundwater quality of Jaipur City

A study was conducted to evaluate the water quality of Jaipur City. Groundwater samples from hand pumps and tube wells of eleven sampling stations were analyzed during monsoon session with the help of standard methods of APHA. The analytical results shows higher concentration of total dissolved solids, electrical conductivity, total hardness and nitrate, which indicate signs of deterioration but values of pH, calcium, magnesium, sulphate and fluoride are within permissible limit as per WHO standards. From the Hill-Piper trilinear diagram, it is observed that the majority of ground water from sampling stations are calcium-magnesium-chloride-sulphate type water. The values of sodium absorption ratio and electrical conductivity of the ground water were plotted in the US salinity laboratory diagram for irrigation water. Most of the samples fall in C3S1 quality with high salinity hazard and low sodium hazard. Chemical analysis of groundwater shows that mean concentration of cation (in meq/l) is in order magnesium > sodium > calcium > potassium while for the anion (in meq/l) it is chloride > bicarbonate > sulphate > nitrate > carbonate > fluoride.

Spreadsheet Optimization for Parameter Estimation of Pressure–Saturation Equations Used for Two-Phase Groundwater Flow

Spreadsheet optimization using a range of nonlinear error functions was utilized for parameter estimation of the two-phase pressure–saturation models developed by van Genuchten, Brutsaert, Russo and Kosugi. The data was obtained from the UNSODA database (US Salinity Laboratory, Riverside, California). Results show that spreadsheet optimization is a practical platform for evaluations based on minimizing nonlinear error functions, consequently allowing for a broader mathematical approach to parameter estimation. An error function representing the sum of the squares of errors provided the best fit for a majority of the soils evaluated, although the fractional error function provided the best fit for silts and loams. Outcomes indicated that the van Genuchten parameters m and n may also be estimated individually as opposed to following the published relationship of m=1−1/n.

Mapping of groundwater quality in the Turonian aquifer of Oum Er-Rabia Basin, Morocco: a case study

This study takes the groundwater of the Moroccan limestone aquifer of Oum Er-Rabia as an example of statistical and cartographical approaches in water resources management. Statistical analyses based on frequency distribution and PCA methods revealed the homogeneity of waters with the existence of abnormal points and have helped to assess correlations between the studied variables. The mapping approach illustrated that waters are influenced by the lithology of the surrounding rocks and are of Ca–Mg–HCO3, Ca–Mg–Cl–SO4, and mixed types according to the Piper classification. The quality of water is of high to medium, north of the basin, but it is of medium to bad, NE and south, due to excessive contents of chloride, sulfate and nitrate. According to the US Salinity Laboratory classification, water used for irrigation in the eastern and the southern parts of the basin should take into consideration the drainage conditions, the nature of plants and the addition of gypsum doses.

Seasonal variation of groundwater quality in a part of Guntur District, Andhra Pradesh, India

The area in Guntur district, Andhra Pradesh, India, is selected to discuss the impact of seasonal variation of groundwater quality on irrigation and human health, where the agriculture is the main livelihood of rural people and the groundwater is the main source for irrigation and drinking. Granite gneisses associated with schists and charnockites of the Precambrian Eastern Ghats underlie the area. Groundwater samples collected seasonally, pre- and post-monsoons, during three years from forty wells in the area were analyzed for pH, EC, TDS, TA, TH, Ca2+, Mg2+, Na+, K+, CO 3 2− , HCO 3 − , Cl−, SO 4 2− , NO 3 − and F−. The chemical relationships in Piper’s diagram, Chebotarev’s genetic classification and Gibbs’s diagram suggest that the groundwaters mainly belong to non-carbonate alkali type and Cl− group, and are controlled by evaporation-dominance, respectively, due to the influence of semi-arid climate, gentle slope, sluggish drainage conditions, greater water–rock interaction, and anthropogenic activities. A comparison of the groundwater quality in relation to drinking water quality standards proves that most of the water samples are not suitable for drinking, especially in post-monsoon period. US Salinity Laboratory’s and Wilcox’s diagrams, and %Na+ used for evaluating the water quality for irrigation suggest that the majority of the groundwater samples are not good for irrigation in post-monsoon compared to that in pre-monsoon. These conditions are caused due to leaching of salts from the overlying materials by infiltrating recharge waters. A management plan is suggested for sustainable development of the area.

(227) Does Salinity Reduce Boron's Toxic Effect in Broccoli?

High salinity and boron often occur together in irrigation water in arid climates, but very little research has been done to study the interaction of the two. A greenhouse experiment was conducted at the US Salinity Laboratory in sand tanks to evaluate the interactions between B and saline drainage water on the performance of broccoli. Particular interest in this study was directed towards the composition of the salinizing solution to determine what role various salts have on the salinity-boron interaction. Results from this study indicate that both Cl-based salts and those characteristic of saline drainage water (i.e., a mixture of salts dominated by sodium sulfate) showed a significant salinity–boron interaction. At high salinity, increased B concentration was less detrimental, both visually and quantitatively (i.e., biomass), than it was at low salinity. That is, plants could tolerate a higher solution B-concentration at higher salinity. However, there was no significant difference between salt types. The effects on head weights were more exaggerated than those on shoot biomass. Shoot B concentration was influenced by salinity, but interestingly the direction of influence was dependent upon the B concentration in the solution. Regardless of the composition of the salinizing solution, increased salinity increased shoot B concentration when B concentrations in the solution were relatively low (i.e., 0.5 mg·L-1). At the highest solution B concentration (28 mg·L-1), increased salinity reduced shoot B concentration. Solution B in itself had very little influence on shoot ion accumulation, but both salinity (i.e., EC) and salinity composition had very strong influences on shoot tissue ion composition. Therefore, these data indicate that salinity and B are antagonistic.

Evaluation of salt-tolerant forages for sequential water reuse systems: I. Biomass production

Reuse of saline drainage waters is a management option that has been suggested for the San Joaquin Valley (SJV) of California in order to reduce both the area affected by shallow water tables and the volume of drainage effluent requiring disposal. Salt-tolerant forages may play an important role in this strategy, while at the same time producing a food source for sheep and cattle. Crop selection for reuse systems, however, will depend upon production potential under saline-sodic conditions. To identify potentially suitable crops, a controlled study using an elaborate sand-tank system was conducted at the US Salinity Laboratory to evaluate ten promising forage crops irrigated with synthetic drainage waters dominated by Na 2SO 4 with an EC of either 15 or 25 dS/m each containing 500 μg/L Se and Mo as SeO 4 2− and MoO 4 2−. Forages were cut several times over the year-long duration of the experiment. The forage species tested performed differently in terms of absolute biomass accumulation and biomass production relative to salinity level. Cumulative biomass production of alfalfa ( Medicago sativa L.), a relatively salt sensitive crop, was higher than most other forages at moderate salinity. As salinity increased to 25 dS/m, however, cumulative biomass of the alfalfa cultivars were reduced by nearly half whereas biomass of the most salt tolerant grasses was reduced between 0 and 20%. Although most forage species tested showed promise, those that performed particularly well based on biomass accumulation, overall salt-tolerance, and forage quality were ‘Jose’ tall wheatgrass, bermudagrass and ‘PI 299042’ paspalum.

The use of the language interface of R: two examples for modelling water flux and solute transport

Beyond its statistical usage, R is a noteworthy programming environment for C and Fortran code. We describe features of the programming interface and illustrate it by a simple example and a more complex example that is of interest on its own. The latter makes available SWMS_2D within the R environment, a free software for two-dimensional modelling of water fluxes and solute transport by Simunek, Vogel and van Genuchten (Technical Report 132, US Salinity Laboratory, Riverside, CA, 197pp.).

Irrigation water quality as indicator of sustainable rural development

The sustainable rural development more and more depends on the efficient usage of water resources. Most often, at least in one part of the year, the rain is not sufficient for plant growth and rain plant production significantly depends on the yearly precipitation variation. The increase and stability of the agricultural production is possible in the irrigation conditions. The most part (around 70%) of the global water resources is used for food production. Irrigation water quality indicator is used to show if the available water resources have the required quality for application in agriculture. Irrigation is characterised by the complex water-plant-soil relationship, and in that eco-system the man as the end user of the irrigated fields occupies a very important place. That explains the difficulties in producing one universal classification of irrigation water quality. The paper analyses numerous water quality classifications from the aspect of the applicability on the quantifying of this indicator. The adopted classification should possess understandable, qualified and internationally comparable indicator. Thus, local classifications (Neigebauer, Miljkovic) cannot be used for this indicator. United Nation Food and Agricultural Organization (FAO) and US Salinity Laboratory (USSL) classifications are used for the evaluation of the irrigation water quality throughout the world. FAO classification gives the complex picture of the usability of the irrigation water from the point of its influence on the soil and the plants. However, the scope of the analyses is not often suited to the needs of that classification, which makes it difficult to apply. The conclusion is that the USSL (US Salinity Laboratory) classification is best suited to this range of chemical water analyses. The evaluation of the irrigation water quality indicator in the Juzna Morava river basin, upstream from the Toplica river estuary is given in this paper. Based on the obtained results, it can be concluded that the irrigation isn?t limitation for sustainable rural development.

Rosetta: a computer program for estimating soil hydraulic parameters with hierarchical pedotransfer functions

Soil hydraulic properties are necessary for many studies of water and solute transport but often cannot be measured because of practical and/or financial constraints. We describe a computer program, rosetta, which implements five hierarchical pedotransfer functions (PTFs) for the estimation of water retention, and the saturated and unsaturated hydraulic conductivity. The hierarchy in PTFs allows the estimation of van Genuchten water retention parameters and the saturated hydraulic conductivity using limited (textural classes only) to more extended (texture, bulk density, and one or two water retention points) input data. rosetta is based on neural network analyses combined with the bootstrap method, thus allowing the program to provide uncertainty estimates of the predicted hydraulic parameters. The general performance of rosetta was characterized with coefficients of determination, and root mean square errors (RMSEs). The RMSE values decreased from 0.078 to 0.044cm3cm−3 for water retention when more predictors were used. The RMSE for the saturated conductivity similarly decreased from 0.739 to 0.647 (dimensionless log10 units). The RMSE values for unsaturated conductivity ranged between 0.79 and 1.06, depending on whether measured or estimated retention parameters were used as predictors. Calculated mean errors showed that the PTFs underestimated water retention and the unsaturated hydraulic conductivity at relatively high suctions. rosetta's uncertainty estimates can be used as an indication of model reliability when no hydraulic data are available. The rosetta program comes with a graphical user interface that allows user-friendly access to the PTFs, and can be downloaded from the US Salinity Laboratory website: http://www.ussl.ars.usda.gov/.

RETMCL: Incorporating maximum-likelihood estimation principles in the RETC soil hydraulic parameter estimation code

RETC is a public domain computer code for estimating parameters of the water retention curve and hydraulic conductivity functions of unsaturated soils. RETC was developed at the US Salinity Laboratory and is now used world-wide with thousands of copies distributed. Evaluation of the final estimation results in the code has been improved to yield a new version, RETCML, based on the maximum-likelihood theory for the special case of weighted least-squares estimators. This paper first explains the theory of maximum-likelihood and introduces the principles of model adequacy and parameter uncertainty on a formal basis. Next, this paper presents a user guide for the code. RETCML is also free and has been programmed to be almost fully compatible with the original RETC input files, thus making it easy to re-analyze previous data. The output of RETCML includes a thorough evaluation of estimation results.

Effects of Saline Water on the Chemical Properties of Some Tropical Soils

AbstractSurface and subsurface samples of soils representing the Tropical Red Earths and Tropical Red Deserts were equilibrated with unbuffered salt solutions which had the composition of sea water and ranged in concentration between 0.61N and 0.0061N. The effects of these treatments on soil pH, the concentration of soil solution, and exchangeable sodium percentages were subsequently characterized. The original acidities of these soils were highly resistant to change. Neither soil showed a tendency to accumulate salts by extraction from percolating solutions. Studies of exchangeable sodium percentages at the various concentration levels supported the valance‐dilution principle. At high salt concentrations, however, the observed affinities of these soils for divalent cations were higher than those predicted by the commonly used US Salinity Laboratory regression equation.To eliminate the possible interference by CaCO3 in observed ionic equilibria, Na‐Ca exchange studies were conducted on carbonate‐free soil samples. Isoconcentration isotherms were constructed at electrolyte concentrations of 0.01, 0.1, and 1.0N, compared with isotherms calculated from the US Salinity Laboratory's regression equation. Large discrepancies were observed at 1.0N concentration, particularly for the lowest soil horizons. For that concentration, it was found that predictions of ionic distribution based on the theory of the diffuse double layer can closely describe Na‐Ca equilibrium when large values of surface charge densities are assumed.

Extraction of Cations from Silicate Minerals During the Determination of Exchangeable Cations in Soils

AbstractThe extent to which silicate minerals release Ca, Mg, Na, and K during the determination of exchangeable cations in soils by the ammonium‐acetate‐extraction procedure was evaluated. The method of exchangeable‐sodium evaluation used by the US Salinity Laboratory was employed for this study with the exception that soil samples were replaced with reference mineral samples. Amounts of cations equivalent to 0.3 to 21.8 meq/100 g were extracted from the minerals by ammonium acetate. In general, the proportions of cations extracted decreased in the order Ca + Mg>> Na> K. Because of this phenomenon, complications are expected to occur in the evaluation of exchangeable Ca and Mg in arid‐land soils, but not for exchangeable Na except under unusual circumstances. The latter circumstances are described and the general extent of error that may occur is estimated.

Economics of Water Use on Different Classes of Saline and Alkali Land in the Semi-arid Plains of West Pakistan

Soil salinity and alkali pose a major problem for agriculture in West Pakistan. According to one estimate [5, p. 39], out of the gross area of 46.5 million acres of the Indus Plains, 4.8 million acres were strongly saline and 11.1 million acres were partially affected by salinity. Although soil alkali was also recognized as a problem [1], it was generally considered to be of limited extent. Its full significance was realized only after studies in 1962 and 1963 by the Water and Soil Investigation Division of WAPDA and the US Salinity Laboratory in the Salinity Control and Reclamation Project No. 1 (WAPDA 1966). The soil surveys carried out by the Soil Survey Project of Pakistan have subsequently provided further information on saline and alkali soils.