A. Rastegarnia; mehdi karami; M. Ghafoori
Abstract
Introduction: Water resources quality assessment of the dam sites is one of the primary studies in the designing of these structures. The main challenges in Iran are the reduction of water resources and the limitation of groundwater exploitation. Much of these resources are formed in karst water resources ...
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Introduction: Water resources quality assessment of the dam sites is one of the primary studies in the designing of these structures. The main challenges in Iran are the reduction of water resources and the limitation of groundwater exploitation. Much of these resources are formed in karst water resources in the karstic susceptible formations such as the Asmari carbonate formation in Zagros Mountain, Iran. In this study using laboratory and field studies, various parameters and indices were assessed to investigate the water resources quality of Bazoft dam site for different purposes. Bazoft dam is a double-curvature arch dam with a height of 211 meters which is located in Chaharmahal and Bakhtiari Province of Iran. The bedrock of the dam site consists of limestone and dolomite rocks of the Asmari and the Jahrom formations. The Jahrum formation formed the right abutment, the riverbed and the lower parts of the left abutment. The Asmari formation formed the rocks in the middle and upper part of the left abutment.
Materials and Methods: After field studies, chemical analyses have been performed on the collected water samples from the water resources such as springs, river and the exploratory boreholes in the dam site. PH and electrical conductivity (EC) were measured by pH meter and electrical conductivity apparatus was measured at 25 ° C. Concentration of ions such as calcium, magnesium, bicarbonate was measured by titration method. The concentration of ions such as sodium and potassium, sulfate and nitrate were measured using the Flame-Photometry, and Spectrophotometry methods, respectively.. The test error in all cases was low and the results were confirmed. The indices such as Langelier saturation index and Ryznar stability index, sodium adsorption ratio (SAR), soluble sodium percentage, residual sodium carbonate, permeability index, Kelly ratio, were calculated based on related equations. Principal factor analysis (PCA) is used to determine the most influential variables when the number of variables is investigated and the relationship between them is unknown. In this method the variables are set on the elements so that the first factor is reduced to the next factor of the variance, hence the variables that are based on the first factors are the most influential. PCA reduces the dimensions of the initial data by turning the main components around the vertical and horizontal axes of coordinates. This rotation actually increases the variance between the main components and therefore it is called Variance Maximize Varimax or orthogonal rotation. The Varimax command is one of the most common methods of orthogonal rotation that preserves the independence between the extracted agents. This method reduces the number of the larger factor loadings to the lowest number. In this method, the scree plot chart determined the number of factors extracted. Parameters of R2 and RMSE in order to investigate the performance of relations have been used. As R2 is closer to the one and the RMSE is closer to the zero, the proposed relationship will yield better performance.
Results and Discussion: Anions such as HCO3, Cl, SO4, CO3 and NO3 and cations such as Ca, Na, Mg, and K are the most, respectively. From the viewpoint of hardness, all waters are placed in the hard category. According to the percentage of Na, the spring’s water is excellent, the water of the borehole is good and the river is acceptable. The results of factor analysis showed that 87.13 percent of the water quality variations are controlled by four factors. The most important factors affecting the water quality of the dam site include EC, TDS, Na %, SAR, Cl, SO4, alkalinity, Na, and CO3 with 50.91 %. The second factor include calcium, magnesium, potassium ions with 15.82 %, the third factor include nitrate, bicarbonate, and hardness with 11.61 % and pH and carbonate with 7.17 % are fall into the fourth factor. The correlation matrix of the parameters was investigated and the accuracy of some relationships was examined on the basis of different statistical criteria. The relationships of LSI with RSI and EC with TDS in the dam site and their comparison with previously suggested equations indicated that there is a high correlation and each relationship is applicable for a particular area. Also, the trend of points obtained from each equation has the appropriate consistency but the RMSE of the assessed equations is high. EC plot against TDS to determine the relationship between the two parameters in the Bazoft dam site is TDS=0.70Ec-31.24.
Conclusion: The concentration of all assessed cations and anions is lower than the WHO permissible limit. The water resources are corrosive and all indices indicated the appropriate quality of water resources for farming and drinking.
Hanye Jafari Vafa; Fayez Raiesi
Abstract
Introduction: Land application of organic wastes and biosolids such as municipal sewage sludge has been an important and attractive practice for improving different properties of agricultural soils with low organic matter content in semi-arid regions, due to an increase of soil organic matter level and ...
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Introduction: Land application of organic wastes and biosolids such as municipal sewage sludge has been an important and attractive practice for improving different properties of agricultural soils with low organic matter content in semi-arid regions, due to an increase of soil organic matter level and fertility. However, application of this organic waste may directly or indirectly affect soil bio-indicators such as microbial and enzymatic activities through a change in the activity of other soil organisms such as earthworms. Earthworms are the most important soil saprophagous fauna and much of the faunal biomass is attributed to the presence of these organisms in the soil. Therefore, it is crucial to evaluate the effect of earthworm activity on soil microbial and biochemical attributes, in particularly when soils are amended with urban sewage sludge. The purpose of this study was to evaluate the earthworm effects on biochemical and microbiological properties of a calcareous soil amended with municipal sewage sludge using Factor Analysis (FA).
Materials and Methods: In the present study, the experimental treatments were sewage sludge (without and with 1.5% sewage sludge) as the first factor and earthworm (no earthworm, Eiseniafoetida from epigeic group, Allolobophracaliginosa from endogeic group and a mixture of the two species) as the second factor. The study was setup as 2×4 full factorial experiment arranged in a completely randomized design with three replications for each treatment under greenhouse conditions over 90 days. A calcareous soil from the 0-30 cm layer with clay loam texture was obtained from a farmland field under fallow without cultivation history for ten years. The soil was air-dried and passed through a 2-mm sieve for the experiment. Sewage sludge as the soil organic amendment was collected from Wastewater Treatment Plant in Shahrekord. Sewage sludge was air-dried and grounded to pass through a 1-mm sieve for a uniform mixture with soil matrix.Heavy metals concentrations were found to be below the maximum permissible limits for municipal sewage sludge. After applying sewage sludge treatments, the pots were irrigated (70% soil field capacity) for three months to achieve a relative equilibrium condition in the soil. Eight adult earthworms with fully-developed clitellum were added to each pot. In the pots with both earthworm species, 4 specimen of each earthworm species was added. At the end of the experiment (90 days), soil samples were collected from treatments and were separately air-dried for chemical analysis or kept fresh and stored (4oC) for microbial analysis. Finally, data obtained from the study were analyzed using multivariate analysis.
Results and Discussion: Factor analysis led to the selection of three factors with eigen value greater than 1. The first, second and third factors were accounted for 62, 17.7 and 9.2% of the variability in soil data, respectively. The three factors together explained 89% of the original variability (i.e., variance) in the soil dataset. Consequently, three factors were retained to represent the original variability of the dataset. The first factor had 16 highly weighted variables with a negative loading for soil pH and positive loadings for other variables. The first factor, which included most soil indicators as input variables, clearly separated sewage sludge treatments. Most of the soil microbial characteristics were increased by sewage sludge application due to the high contents of organic matter and nutrients in sewage sludge, as well as low concentrations of heavy metals. Fungal respiration, bacterial respiration and microbial biomass carbon loaded heavily on the second factor with a negative loading for fungal respiration and positive loadings for bacterial respiration and microbial biomass carbon. The second factor, which included microbial biomass and community composition, noticeably discriminated earthworm treatments. In sewage sludge treatments, the dependence of E. foetidaspecies on soil microorganisms as a food source declined, because of the consumption of organic waste by this epigeic species. However, the activity and impact of A. caliginosa species from endogeic group was only related to soil microbial biomass probably due to selective feeding of soil microorganisms.
Conclusion: Factor analysis was used successfully in discriminating the effects of sewage sludge and earthworm either alone or in combination on soil microbial and biochemical parameters. A. caliginosa species in soils amended with sewage sludge had a positive effect on microbial community and biomass, while E. foetidaspecies had no such effect. A. caliginosa species indirectly benefited from sewage sludge application following the increase of soil microbial biomass. In summary, A. caliginosa species positively affected microbiological and biochemical properties in soils amended with sewage sludge due to its less dependence on this organic resource.
Hossain Shohab Arkhazloo; H. Emami; Gholam Hosain Haghnian; Abazar Esmali
Abstract
Introduction: Gully erosion is an important type of soil erosion in Iran and Ardebil province (Moghimi and Salami, 2011; Khatibi, 2006). Increasing the cross section of gullies is an indicator for gully developing (Deng et al, 2015). Topography and soil properties are two important factors in gully developing ...
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Introduction: Gully erosion is an important type of soil erosion in Iran and Ardebil province (Moghimi and Salami, 2011; Khatibi, 2006). Increasing the cross section of gullies is an indicator for gully developing (Deng et al, 2015). Topography and soil properties are two important factors in gully developing in various regions of worldwide (Poesena et al, 2003). Despite the importance of soil properties in gully erosion, the direct effect of these agents was less investigated and few researches have been carried out to the effect of physical and mechanical soil properties on gully erosion. Therefore, the objectives of this research were to determine 1) the effect of topography on gully erosion, 2) effect of surface and subsurface soil physical and mechanical properties on increasing the cross section of gullies and 3) to select the most important soil properties affect developing the cross section of gullies in three regions of Ardebil province (Ortadagh, Molla Ahmad, and Sarcham). In addition, the relationship between the most soil properties and topographic agents was investigated
Materials and Methods: The effect of topography on gully erosion was investigated by using of two methods i.e. topographic threshold of gully forming (as , where A and S is gully watershed cross section and slop, respectively, a and b is local coefficients) and the relationship between slope classes with gullies density. In regard to catchment characteristics, a set of similar gullies was selected in each region and the changes of cross section area for gullies in four points along its length were measured as indicator of gully development during two years. 17 physical and mechanical of surface and subsurface soil properties in each point were measured and the most important properties that affect on gully development were selected based on principle component analysis (PCA) method. Finally, the stepwise regression model was fitted to the soil properties selecting from PCA for gully's development in each region.
Results: The relationship between Slope classes and gully density showed that in MollaAhmad region gully density was increased with increasing the slope. In OrtaDaghregion, similar trend was observed up to 20-30% slope, while in Sarcham region these was no relationship between slope classes and gully density. According to the topographic threshold it seems that runoff is the main agent for gully forming in MollaAhmad,but in Sarchamthe piping and tunnel erosion might have caused gully formation and in Ortadagh both surface and subsurface flows were recognized as effective agents for gully formation. Increasing values of the cross section for the selected gullies during 2 years was 0.9, 0.6, and 0.8 m2 for Ortadagh, MollaAhmad, and Sarcham regions respectively, which were 41, 44 and 61 percent more than their initial cross sections. Among mechanical soil properties, liquid limit (LL), plastic limit (PL) and shear strength (SS) had the negative and significant correlations with increasing the cross sections of gullies in 3 regions. Among the particle size fractions, Water dispersible clay had the most effect on increasing the gully’s cross sections and except for surface depth of Molla Ahmad, its correlation with gully’s cross section was significant. Principle component analysis (PCA) demonstarated that in MollaAhmad and Ortadagh mainly mechanical properties of soil and aggregate stability had the more effect on increasing the gully cross section, but in Sarcham soil particle size classes and aggregate stability indices had more effect on gully’s cross section.
Conclusion: According to topography threshold, it can be concluded that surface runoff is the main agent for gully forming in MollaAhmad and gully density increases by increasing the slope classes. In this region the effect of surface runoff on surface soil erosion was sever. In Sarcham there was no relationship between slope and gully density and it was found that the subsurface flow is predominant factor for gully forming. In OrtaDagh both surface and subsurface flows were the main factors for gully forming, so due to increasing the surface flow up to slope 20-30% class, maximum gully density was noted in this slope class and the effect of subsurface soil properties in developing gully cross section was higher than surface soil properties. In general, the relationship between gully density with slope classes, topographic threshold and soil physical and mechanical properties which were effective on gully development indicated the close consistency between the type of hydrologic flow in gully forming and the most important soil properties on increasing the gully’s cross section.
nona sheikholeslami
Abstract
Evapotranspiration is one of the most important parameters that its understanding is necessary for estimating crop water requirement and design of irrigation systems. This phenomenon is greatly influenced by climatic parameters. In this study, the relative importance of variables affecting this phenomenon ...
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Evapotranspiration is one of the most important parameters that its understanding is necessary for estimating crop water requirement and design of irrigation systems. This phenomenon is greatly influenced by climatic parameters. In this study, the relative importance of variables affecting this phenomenon was evaluated and the reference evapotranspiration was estimated using principal component analysis and factor analysis. Daily scaled measurements for the period of 1991-2005 were obtained from synoptic stations located in Mashhad Khorasan Razavi provience, Iran. Mashhad has a semi-arid climate area. The measurements included the relative influence of temperature (T) (maximum, average and minimum), relative humidity (RH), sunshine hours (Rs), and the wind speed at a height of two meters above the ground (U2). The multiple linear regressions were used to estimate evapotranspiration. T-statistic with a significant level of 5% was used for the main components. The evapotranspiration was correlated more with T (minimum. maximum, and average), and relative humidity as than wind speed or sunshine. PC1 had more effect than PC2 (with coefficients of 0.694 and 0.556, respectively). MLR-PCA and MLR with coefficients of 0.903 and 0.897 (respectively) indicated higher ability for PCA method.
J. Dowlati; Gh. Lashkaripour; N. Hafezi Moghadas
Abstract
Zahedan aquifer is located in the northernof Zahedanwatedshed. It is essential to evaluate the quality of groundwater resources due to proving some part of drinking water, agricultural and industrial waters of this city. In order to carry out ground water quality monitoring, and assess the controlling ...
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Zahedan aquifer is located in the northernof Zahedanwatedshed. It is essential to evaluate the quality of groundwater resources due to proving some part of drinking water, agricultural and industrial waters of this city. In order to carry out ground water quality monitoring, and assess the controlling possesses and determine cations and anions sources of the groundwater, 26 wells were sampled and water quality parameters were measured.The results of the analysis showed that almost all of the samples proved very saline and electrical conductivity varied from 1,359 to 12,620μS cm−1. In the Zahedan aquifer, sodium, chloride and sulfate were predominant Cation and Anions respectively, and sodium-chloride Na-Cl( and sodium - sulfate)Na-So4) were dominant types of the groundwater. The factor analysis of samples results indicates that the two natural and human factors controlled about the 83/30% and 74/37% of the quality variations of the groundwater respectively in October and February. The first and major factor related to the natural processes of ion exchange and dissolution had a correlation with positive loadings of EC, Ca2+, Mg2+, Na+, Cl-, K+ and So42- and controls the 65.25% of the quality variations of the ground water in October and the 58.82% in February. The second factor related toCa2+, No3- constituted the18.05% of the quality variations in October and 15.56% in February, and given the urban development and less agricultural development in the aquifer, is dependent on human activities. For the samples collected in October, the saturation indices of calcite, gypsum and dolomite minerals showed saturated condition and calcite and dolomite in February showed saturated condition for more than 60% and 90% of samples and gypsum index revealed under-saturated condition for almost all samples.The unsaturated condition of Zahedan groundwater aquifer is resulted from the insufficient time for retaining water in the aquifer to dissolve the minerals. So42- and No3- Ions in more than 70 percent samples showed unnatural sources (the sewer infiltration).
M. Ghorbani Aghdam; yaghoub dinpazhoh; A. Fakheri Fard; S. Darbandi
Abstract
Having a correct view of the effective factors on climatic changes by explanation of a considerable part of the total variance in data with limited number of principal components the analytical methods of decreasing data dimensions, such as PCA are important tools in water resources planning. In this ...
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Having a correct view of the effective factors on climatic changes by explanation of a considerable part of the total variance in data with limited number of principal components the analytical methods of decreasing data dimensions, such as PCA are important tools in water resources planning. In this study factor analysis method as a tool for projecting the information space on the limited and specific axes, has been applied. The main aim of this study is regionalization of Urmia Lake basin from the view of drought using factor analysis. For this purpose monthly precipitation data of 30 weather stations in the period 1972-2009 were used. For each of the selected stations three and twelve months SPI value were calculated. Factor analysis conducted on SPI values to delineate the study area with respect to drought characteristics. Homogeneity of obtained regions tested using the S-statistics proposed by Wiltshire. Resultes of factor analysis of 3 (12) months SPI values showed that 5 (6) factors having eigen values greater than 1 acounted for 68.08 (78.88) percent of total variance. Urmia Lake basin delineated to 5 (6) distinct regions considering the eigenvectors following rotation using the 3 (12) month time scale. Results of homogeneity test indicated that all of the obtained regions were homogeneous.
