Journal of Water and Soil Conservation
Year:2016 | Volume:23 | Issue:1|Papers Count:27

Background and Objectives: Soil pollution by heavy metals is a major environmental problem which has negative effects on human, animal, ecosystem and agricultural productions health. Phytoremediation, a technology that involves plants, is an effective, cheap and environmental friendly method for cleaning polluted soils. Chemical phytoextraction is a method that makes use of chelating agents and mineral acids to enhance uptake of heavy metals by plants. The aims of this study were: (a) determining the potential of the radish plant for Zn extraction from polluted soils, (b) assessing the effects of different additives (EDTA and H2SO4) on enhancing Zn uptake by radish plant and (c) assessing the effects of different levels of soil Zn on radish growth and Zn concentrations in above and below ground parts of this plant.Materials and Methods: A Factorial experiment was conducted in soil science lab, using a completely randomized design and three replications. The experimental factors were types and rates of additives (10 and 20 mg EDTA /kg and 0, 750 and 1500 mg H2SO4/kg) and levels of soil Zn (0, 200, 400, 600, 800, 1000 and 1200 mg/kg).Results: The results showed that the application of additives increased the concentrations and uptake of Zn in above and below ground parts of radish and decreased their dry weights. Application of 20 mg EDTA/kg soil caused the highest concentrations of Zn in the above and below ground parts of radish and increased 304 and 182 mg/kg respectively compared to the control. Application of 20 mg EDTA/kg soil increased Zn uptake by plant by 28.7 percent.20 mg EDTA /kg soil, 10 mg EDTA /kg soil, 1500 mg H2SO4 /kg soil and 750 mg H2SO4 /kg soil were better treatments respectively. Zinc concentrations in aerial parts were higher than those of below ground parts and the highest concentration of Zn in these parts were 810 and 425 mg/kg respectively. The dry weights of above and below ground parts of radish decreased but Zn concentration of these parts increased as the Zn levels of soils increased. An antagonistic effect between p, K, Fe and Zn uptake was also observed.Conclusion: In general the results showed that the radish was a Zn hyper accumulator plant having translocation factor of greater than 1 and can be used for phytoremediation of Zn polluted soils. The application rate of amendments had significant effects on their performance and inappropriate application rate, had negative effects on phytoremediation. Based on the results obtained in this experiment, the application of 20 mg EDTA/kg soil is recommend for Zn phytoremediation.

Background and Objectives: Digital soil maps with fine resolution are one of the basic needs of users and decision-makers in agriculture, natural resource and environment. However, in our country, there is scarcity of this kind of data and producing fine resolution soil data is very costly. Therefore, downscaling digital soil maps arises as a suitable option in order to produce fine resolution soil data. Objectives of this study were to examine and evaluate downscaling digital maps of some soil surface properties from block supports 50, 100 and 250 m to block support 10 m using direct approach across Merek sub catchment in Kermanshah province with an area of 24000 ha.Materials and Methods: Firstly, spatial structure information of soil surface properties including %sand, %silt, %clay, %organic carbon, %equivalent calcium carbonate and %gravel were determined using legacy data (320 randomized point samples) and variography. Then, block kriging maps were produced with block support 50, 100 and 250 m. Terrain attributes, Landsat images, geology map, geomorphology and land use maps were used in this study as auxiliary variables. Correlation coefficient between auxiliary variables and target variables was calculated and auxiliary variables were significant at the 0.01 level selected as model inputs. Afterwards, downscaling direct approach was used. In this approach, relationship between the soil properties and auxiliary variables with coarse resolution were identified using generalized linear models (GLMs) and regression tree. Next, calibrated parameters and fine resolution covariates were applied to prediction soil properties in fine resolution. Models were trained on 75% of the block support data in accordance with original data and evaluated on the remaining 25%, using k-fold validation (k=4) procedure.Results: The results showed that amount of sand and gravel had minimum and maximum correlations with covariates, respectively. Considering all the pixel sizes, the highest correlation were obtained among soil properties and elevation, direct duration, convexity, slope, topographic wetness index and mrvbf. Downscaling gravel map from block support 50 m to 10 m by GLMs showed best performance (RMSE=5.57%). Downscaling sand, clay, equivalent calcium carbonate and organic carbon from 250 m block support and silt from of 50 m to 10 m block support using regression tree led to estimate the lowest root mean square error (3.9%, 3%, 4.39%, 0.21% and 2.31% respectively). Besides, regression trees showed the best performance in downscaling of soil properties with different pixel size.Conclusion: It seems that direct approach would be able to downscale digital maps of soil variables (such as silt, calcium carbonate equivalent, organic carbon content and gravel) with acceptable accuracy and efficiency. Obviously, GLMs and regression tree can lead to strong results if the correlation between soil properties and auxiliary variables is high. It can be concluded that various auxiliary variables at diverse pixel sizes have different relationships with the target variable which affect the performance of the downscaling.

Background and Objectives: Natural rivers are one of the main sources of water and energy. Design and management of natural rivers need a complete understanding of mechanics of flow pattern and sediment transport. The complex three-dimensional flow characteristics in river bends necessitates the use of a three-dimensional numerical model. The purpose of this study is to predict the flow pattern and location of erosion and deposition in Sine-Generated channels, Also, the effect of Froude number and the ratio of width to depth on flow and bed shear stress was considered.Materials and Methods: The numerical model used in the present study is called SSIIM, an acronym for sediment simulation in intakes with multi block option. In this study the flow pattern and location of erosion and depositional in Sine-Generated channel having0  50 with rigid bed was predicted. The k-e and SST k-e models were used to predict the turbulence in this simulation. For verification of the results of the numerical model the experimental data (da Silva and Tape) was used.Results: By changing the Froude number from 0.15 to 0.41, flow pattern and velocity distribution did not change but increased erosion. Also by decreasing width to depth ratio from 12.5 to 4, the number of rotary cells in section increased from 2 to 3 and it was found in wider rivers, power of secondary flow decrease but the downward upward trend was the same as deep rivers.Conclusion: The result of simulation shows that SST k-w model has better accordance with experimental data than k-e model. Distribution of bed shear stress depends on Froude number although secondary flow is independent. Furthermore, distribution of bed shear stress and secondary flow is dependent on the width to depth ratio, so that for b/h<8, another rotary cell occurs near the outer bank.

Background and Objectives: In the soils of areas close to saline lakes, due to the transport of salts from saline water of lake, salinization of soils occurs and depending on cationic composition of these lakes, different types of soils such as saline, sodic and saline- sodic soils develop around saline lakes. Recognition of morphological, physico-chemical and mineralogical properties of these soils has a great of importance for their sustainable management.Materials and Methods: In order to study the effects of Urmia Lake on physicochemical and mineralogical properties of soils in Dizadj Dol region, 24 soil profiles in two soil sequences with the similar parent material, topography and climate were investigated. One of these sequences is affected by Urmia Lake and the other one is not affected.Results: According to the results, all of the profiles which have been affected by the Lake have natric horizons. Natric horizons in these soils have been formed due to high amounts of sodium ions resulted from Urmia Lake. Varivace analysis of physico-chemical properties of these soils showed that the values of soil organic carbon, CEC, EC, exchangeable Na, ESP and pH of the two sequences were significantly different (P£0.01), but soil depth, clay content and calcium carbonate equivalent were not significantly different. Analysis of clay mineralogy showed that the clay mineral composition in these sequences were mostly smectite, illite, kaolinite, chlorite and vermiculite. Smectites and vermiculites in these soils are mainly of pedogenic origin and have been formed via transformation of illite. In the soils which have been affected by Urmia Lake, the main origin of smectites was neoformation process from soil solution. Illites, chlorites and kaolinite are inherited from parent material.Conclusion: Comparison of results in these two sequences showed that the uprise of Urmia Lake has led to low amount of organic carbon and to high amounts of EC, exchangable sodium, ESP, CEC, pH and higher amounts of smectite in the soils affected by Urmia Lake.

Background and Objectives: The calibration of hydrologic models is a worldwide challenge due to the uncertainty involved in the large number of parameters and the inability to reliably measure the distributed physical characteristics of a catchment results in significant uncertainty in the parameterization of physically based, semi-distributed models. Therefore, a successful application of a hydrologic model in applied water research strongly depends on calibration and uncertainty analysis of model output. Different studies indicated that in parameter uncertainty of the stream flow and sediment modeling only a few parameters affected the final simulation output significantly. In this paper, the Generalized Likelihood Uncertainty Estimation (GLUE) method was combined with the Soil and Water Assessment Tool (SWAT) to quantify the monthly stream flow in the eastern Gorganrood river basin.Materials and Methods: The Golestan Regional Water Company (GRWC) monitoring site at Gazaghly was chosen as the outlet for the entire watershed since it is the lowest monitoring station on the river not subject to dam influence. Annual precipitation decreases in the west to east direction, low (200 mm) to high (880 mm) and from south to north direction. Model has been calibrated and validated using monthly runoff flow data of ten years 1984 and 1993. Data pertaining to year 1984-1990 has been used for calibration and 1991-1993 for validation.Results: In semi-distributed models such as SWAT, it is necessary to identify the most sensitive parameters to obtain a better understanding of the overall hydrologic processes before calibration. Based on this study, only a few parameters affected the final simulation output significantly. The parameters such as CN2 (curve number), GWQMN (threshold in the shallow aquifer), RCHRG_DP (deep aquifer percolation fraction), ALPHA_BNK (base flow alpha factor for bank storage), ESCO (soil evaporation compensation factor) and SOL_K were found to be the most sensitive parameters. According to results, the parameter CN2, was the most effective parameter on the output discharge of the studied area and CN2, was identified as a main source of uncertainty in results. Statistical model performance measures, coefficient of determination (R2) of 0.80, the Nash-Sutcliffe simulation efficiency (ENS) of 0.72, for calibration and 0.83 and 0.80, respectively for validation, indicated good performance for runoff estimating on monthly time step in the outlets of the Gazaghly gauging station.69-74% of the observed runoff data fall inside the 95% simulation confidence intervals in the calibration and validation periods. The evaluation statistics for the daily runoff simulation showed that the model results were acceptable, but the model underestimated the runoff for high-flow events.Conclusion: SWAT was applied to simulate monthly runoff in part of the Gorganrood river basin. Results of uncertainty analysis indicated that SWAT model had large uncertainties for calibration period, although the simulation of monthly runoff for the Gazaghly station was satisfactory during the calibration period and in the model calibration stage 69 of runoff observations were within the corresponding 95% confidence interval. This study would provide useful information for hydrology modeling related to policy development in the Gorganrood river basin and other similar areas.

Background and Objectives: Snow water equivalent (SWE) is a key parameter in hydrological cycle. In Iran, measurement of snow depth and its water equivalent is usually is limited due to lack of automated snow measuring instruments. According to research conducted in the field of snow water equivalent, wind speed, temperature, precipitation and elevation are the factors affecting the amount of snow water equivalent. Because values for wind speed, temperature and precipitation can affect the long-term snow water equivalent, therefore the aim of this study was using meteorological and geographical parameters to estimate snow water equivalent of snow stations in the study area.Materials and Methods: In the current study, based on meteorological data and interpolation method snow water equivalent was estimated. In this regard, first, average amounts of precipitation, air temperature and wind speed were computed during periods of 10, 20, 30, 40 and 50 days. Then, binary correlations between snow water equivalent and the parameters were estimated. Parameters that had the highest correlation were selected. Then in SPSS software between these parameters and the elevation of the stations, the snow water equivalent to a multiple regression was obtained. The regression equation were validated with snow water equivalent data measurement in snow stations Results: Based on these results, the average precipitation, 40-days temperature and wind speed of 30-days, showed the highest correlation with snow water equivalent, respectively. The best snow water equivalent equation was obtained using the relevant parameters. Estimated data was also compared with the observed data, based on the Nash- Sutcliffe criteria (NS=0.83) and regression coefficient (r=0.91). The results showed an acceptable accuracy of the equation on snow water equivalent estimation.Conclusion: In this study, due to the lack of meteorological measuring in snow stations, the interpolation methods for estimating the amount of precipitation, wind speed and temperature parameters the location station was used. The results indicated that among the interpolation methods, radial basis functions with model of Inverse Multiquadric for average wind speed of 10 to 50 days, Completely Regularized Spline model to estimate the average temperature of 10 to 50 days and kriging method with Gaussian model for estimating the average precipitation 10 to 50 days, had the high accuracy in the snow stations. Using the parameters that were most correlated with snow water equivalent, a regression equation to estimate snow water equivalent was obtained. Evaluation showed regression equation can be used to estimate snow water equivalent in the respective stations.

Background and Objectives: Using computer models as a cheap, fast and at the same time accurate method in studying and simulating the flow in a porous media has attracted the attention of many researchers and experts. The aim of this research is to investigate the effects of constructing Roudab dam on Sabzevar Roudab aquifer, which is located dam downstream.Materials and Methods: Sabzevar Roudab catchment basin, with an area about 1828 km2, is located in northeast of Iran in west of Khorasan Razavi province. To manage the surface waters and to supply part of water demand in Roudab plain area, a dam is under construction on Roudab's river. In order to study the water flow system of Roudab plain aquifer groundwater in Sabzevar and the effect of constructing Roudab dam on it, groundwater model of Sabzevar Roudab aquifer has been simulated using MODFLOW code in GMS software with conditions of existing and not existing of Roudab dam. The aquifer model in steady state condition has been calibrated for the year of 2010 and in unsteady state condition has been verified for 12 month period in year 2011.Results: The hydraulic conductivity from the calibration of aquifer model in steady state condition is between 4 to 14.7 meter per day and specific yield changes in unsteady state condition calibration is optimal and has been estimated to be between 0.06 to 0.22. The aquifer model studied here has the highest sensitivity to the hydraulic conductivity and to the discharge of the extraction wells. The reason is that the major portion of the aquifer depletion is done by the extraction wells and natural discharge has a smaller share in the aquifer depletion. Due to the excessive exploitation of Sabzevar Rudab aquifer, water table has dropped in this plain. The severity of the decline in several areas depends on the amount of recharge and discharge of an aquifer. In other words, the general trend of the plain hydrograph is descending and its water balance is negative.Conclusion: The model results show that the water table curves presented by the aquifer model, before and after constructing the Roudab dam do not show any significant changes, because the groundwater water balance before and after constructing the dam is not significantly different and also because it is almost unaffected by the surface recharge. It is worth mentioning that constructing Sabzevar Rudab dam would lead to further decline of the water table elevation of the aquifer. It has been predicted that average decline of the water table in Roudab aquifer in years of 2014, 2015 and 2016 will increase about 0.17, 0.2 and 0.23 meters, respectively.

Background and Objectives: Accuracy of spatial estimation of soil properties such as clay, organic matter and calcium carbonate equivalent is very important in plant nutrition and environmental planning. The most important step before statistical analysis and using geostatistical estimators is data check. In addition to investigation of outlier data and data distribution, another important action in geostatistical studies is trend surface analysis. Analyzing trend surface can evaluate the role of factors such as stone kin, climate, topography and generally regional anomalies. The objective of this study was trend-surface analysis and its effects on variogram modeling and mapping of clay, organic matter and calcium carbonate equivalent.Materials and Methods: For this purpose, 100 surface soil samples in 0-15 cm depth were selected randomly based on different classes area slope from 41353 ha area in Selin plain farmland located in Kaleibar region, East-Azerbaijan. Soil properties such as clay, calcium carbonate equivalent and organic matter were measured by hydrometer, return titration and wet oxidation method, respectively. For analyzing trend surface used multiple regression models which its independent variables was geographical coordinate and dependent variable was soil properties. For zoning clay, organic matter and calcium carbonate equivalent and residuals of removing trend ordinary kriging was used. The effect of removing trend surface in variogram modeling and kriging estimating were evaluated by cross-validation method with indexes mean error (ME), root mean square error (RMSE) and determination coefficient (R2).Results: Trend surface analysis showed that the best regression models for trend determination of clay, calcium carbonate equivalent and organic matter were first order, first order and quadratic, respectively. Removing the detected trend led to decrease in sill but the nugget effect did not change. However, no significant difference was observed between accuracy of kriging estimator in presence and removal of trend. This can be attributed to both abnormal manner of environment and activations of human. So that, the regression models of the trends were 35, 18 and 21% of clay, organic matter and calcium carbonate equivalent variations, respectively. However, removing the detected trend led to increase 9.1, 2.7 and 6.6% of R2 for clay, organic matter and calcium carbonate equivalent, respectively.Conclusion: Generally, investigation of trend surface is recommended in soil studies dealing with spatial data, because the trend depends on the location and conditions of the study area as well as the source of the creating trend.

Background and Objectives: Iran as an arid and semiarid country has been faced with low precipitation and water shortage. In this regard, the application of suitable management practices using plant residues is one of the most important strategies resulting in the improvement of organic matter content as well as water retention of soils. Therefore, in many soils of arid and semiarid regions, organic matter is as the best amendment to increase water content and improve physical properties of the soil. Plant residue can increase soil moisture content through the improvement of soil organic carbon content and the reduction of runoff and evaporation. Application of plant residue is one of the common methods for improving soil properties. However, in some areas, plant residues are removed from the field or burnt by the farmers. This study was performed to investigate the effect of different types of plant residues and their management on soil moisture content as well as aeration properties under field conditions.Materials and Methods: The experiment was conducted under field conditions as factorial statistical design based on RCBD consisting three replicates. The first factor was residue type including barely straw and alfalfa residue and the second factor was different managements of the residues including 1) incorporating one percent of the plant residues with the soil, 2) incorporating 0.5 percent of the plant residues with the soil, 3) surface retention of plant residues, 4) burning plant residues and 5) control. After nine months, the final soil moisture content at seven suctions including 0, 30, 50, 100, 500, 1000 and 1500 kPa was measured. In addition, the available water content and aeration porosity were calculated.Results: The results showed that among the experimental treatments, the incorporation and also surface retention of plant residues increased soil moisture compared to control, whereas, burning the plant residues reduced the moisture content. In comparison to the control, the incorporation of one percent barley straw to the soil led to the highest increases in the moisture content at PWP (70%) and the available water (12.5%). Reversely, burning of barley straw showed the highest reduction in the moisture content at PWP (34.5%) compared to control. In addition, the surface retention of plant residues resulted in the highest increase (48%) in aeration porosity compared to control.Conclusion: The findings of this study showed the favorite efficiency of incorporating and surface application of organic sources in improving soil moisture and aeration porosity.

Background and Objectives: Dust deposition widely occurs in arid to semiarid areas of the world. Since dust particles are fine-sized, they have a high adsorption potential and; therefore, can easily carry the contaminants. Therefore, heavy metals could be distributed in large scales by adsorbing into airborne dust particles. Dust causes great damages to humans in urban regions. The objective of this research was to assess the temporal and spatial distribution of magnetic susceptibility (MS) and its correlation with selected heavy metals in atmospheric dust of Kerman.Materials and Methods: Dust samples were taken monthly for a period of 7 months from 35 locations distributed over the city of Kerman from April 20 to November 20, 2012 (a total of 245 samples) using glass traps installed on the roof of one-story buildings. The magnetic susceptibility of dust samples was determined using a MS2B sensor. Also, the total concentration of Mn, Pb, Ni, Cu and Zn was determined using an atomic absorption spectrometer following the sample extraction with 6N HNO3.Results: Temporal distribution of magnetic susceptibility showed that the highest MS values belonged to October (389×10-8 m3.kg-1) and the least values to July (269×10-8 m3.kg-1) and August (261×10-8 m3.kg-1) and these values followed the same trend as the temporal variability of Cu, Pb and Zn concentrations. Also, the spatial patterns of variables indicated that the highest MS was found in dust samples collected from the western sites of Kerman city where the concentration of Cu, Pb and Zn in dust was also high.Conclusion: Topography appears to play a significant role on the distribution of heavy metals and MS values in dust, particularly in the western areas of Kerman city. Considering the role of human activities in increasing pollutants concentration in Kerman, proper management practices should be exercised to reduce air pollution resulting from various industries.

Background and Objectives: In recent years, several researches have been done for remote sensing of soil texture using radar data. While there is no report on application of passive and free satellites data including ETM+ and MODIS. The remote sensing of soil texture also is limited by the presence of vegetation on soil surface. So the current research was aimed to evaluate applicability of ETM+ data for remote sensing of the soil texture as well as assessment of the vegetation effects on precision of the predictions.Materials and Methods: To achieve the goal of the project, the soil separates were measured in 225 different points within the study area on the northern slopes of Mount Sahand which is located between longitudes of 46 degrees 22 minutes and 23 seconds to 46 degrees 28 minutes and 5 seconds and latitudes of 37 degrees and 43 minutes and 7 seconds to 37 degrees 50 minutes and 8 seconds. Also, the available ETM+ data over the study area were downloaded. Several methods including empirical, statistical and black box (artificial neuron network, ANN) models using Excel, SPSS and Matlab software’s were applied to create different functions for remote sensing of soil separates. Applied models were evaluated using the statistical criteria including Root Mean Squared Error (RMSE), assessment error (E) and coefficient of determination (R2).Results: The results showed that in the presence of vegetation on the soil surface, prediction accuracy dropped to zero. However, in the bare soils and soils without vegetation, predictions were sufficiently accurate. Although empirical and statistical approaches showed low accuracy (with R2 lower than 0.3) for remote sensing of the soil separates, black box model using ANN algorithm was accurate enough (with R2 higher than 0.5).Conclusion: The results showed that the use of statistical methods and regressions to remote sense soil separates using ETM+ data had very poor accuracy in whole study area with four different land-uses (poor pastures, drylands, irrigated areas and bare soil) and even in bare soils. However, the results of using artificial neural network algorithm for remote sensing soil separates in bare soils significantly increased the accuracy of the predictions.

Background and Objectives: Quantitative prediction of river discharge is one of the most important elements in the management of surface water resources, especially to take suitable decisions in occurrence of floods and drought events. Various approaches introduced in hydrology to predict river discharge among them conceptual models as well as data-driven models are the most important ones. In this study, long term recorded data sets in Araz-Kouseh watershed with 1678 km2 area located in northern Iran (Golestan province) were used to investigate the precision of different river discharge prediction models. The IHACRES model as a conceptual hydrological model and KNN and M5 as data mining models were selected for modeling of monthly river discharge and the results were compared to examine the accuracy of studied models. In some studies, the expressed models were used for daily river discharge prediction but the main objectives of this study are application of these models to predict monthly discharge for a watershed.Materials and Methods: The 29 years (1985-2013) daily rainfall and discharge data belonging to Araz-Kouseh hydrometry and meteorological stations were used to extract monthly time series for modeling. The required quantity and quality conditions of datasets for modeling were confirmed using different statistical tests. Recorded datasets were divided in two subseries, first one was used for calibration period and second one used for validation of investigated models. The results of models in calibration and validation period were analyzed considering model efficiency goodness of fit criteria.Results: The results of IHACRES conceptual hydrological model for both calibration and validation periods (correlation coefficients equal to 0.81 and 0.79 for calibration and validation periods respectively) showed suitable ability of this model to predict monthly river discharge. Moreover investigation of results of both M5 and KNN data mining models (correlation coefficient equal to 0.94 and 0.89 for calibration and validation periods respectively for KNN model and equal to 0.92 and 0.88 for calibration and validation periods respectively for M5 model) reveals that application of these models led to significant increase in prediction precision in comparison with IHACRES model.Conclusions: The results of this study indicate the data mining models, i.e. M5 and KNN, outperform conceptual hydrological model, i.e. IHACRES, for prediction of monthly river discharge considering different goodness of fit criteria. It is clear that the accuracy of the prediction of data mining models are very close to each other but the M5 model is selected as best model in this study because of its explicit equations for prediction. Furthermore, investigation of time series of predicted river discharge show data mining models had better prediction for low discharges in comparison with high discharges.

Background and Objectives: Mulching is one of the most common ways to soil stabilization, prevent wind erosion and control dusts. Some types of mulches is not economically practical choices, thus use of inexpensive and safe industrial wastes in the mulch compositions have both economically and environmentally important (waste recycling). Therefore, a key objective of this research is to use two types of industrial waste for preparation of mulch. Since Proctor method has been considered to test and compare the strength of mulches, so another purpose of this research is simplification of Proctor method to estimate the strength of soil stabilizer mulches under the influence of wind erosion.Materials and Methods: Based on the results of previous studies and pre-treatments, some mulches were tested. These mulches were non-living composed of different percentages of stone powder, converter sludge, clay soil and sandy soil. Instron device was used to measure the compressive strength of the mulch. Considering applying of the Proctor method for working with Instron device, simplification of the procedure was also performed. These two methods were called as “Proctor” and “simplified Proctor” methods, whose results were compared as the criterion for utilizing the simplified method. The treatments included five types of mulch in three replications, where their compressive strength was measured by the two methods of “Proctor” and “simplified Proctor” and were compared by the random factorial designs.Results: Reducing the clay percentage from 80 to 50 and increasing the percentage of sand from 20 to 50 in the treatments containing clay and sand in both methods resulted in compressive strength reduction of mulches. Increasing the percentage of the stone powder from 5 to 25 and simultaneous reduction of clay percentage from 85 to 65 together with constant percentage of converter sludge led to decreased compressive strength through the simplified Proctor method. The differences between the results of the two Proctor and simplified Proctor methods were not significant, but the simplified Proctor method had specific order in the results.Conclusion: Compressive strength reduction with reduced clay percentage and increased stone powder percentage was shown in the comparison of the treatments containing clay and stone powder through the simplified Proctor method. However, the results of the Proctor method lacked a logical order. The comparison of the treatments containing clay and sand indicated that in both methods, as the clay decreases and the sand increases, compressive strength reduced. Compressive strength test results using Instron device was compared in both simplified Proctor and Proctor methods, therefore it was shown that these two methods did not have a significant statistic difference, although orderly changes of the simplified Proctor method results was found. Considering the simplicity and time reduction in the simplified Proctor method, this method is recommended for mulch comparisons in wind erosion.

Background and Objectives: Emitters discharge is influenced by various factors such as pressure, manufacturing coefficient of variation, clogging or irrigation water temperature changes. Emitting pipes according to the hydraulic and technical specifications, the use of them in the trickle irrigation systems are increasing. Therefore investigation of the relationship between discharge – pressure and discharge – temperature is required in these pipes in order to improve the efficiency of trickle irrigation systems. Maroufpoor and Parvini found with investigation of the relationship between discharge – pressure and discharge- temperature, that in all emitter and tested temperatures power of the discharge – pressure equation was less than 0.2 and all emitters were pressure compensating. The effect of temperature on the discharge of 3 emitters at 95 percent was significant and was non-significant for other emitters.Materials and Methods: In order to evaluate the effect of temperature and pressure on emitters discharge, 8 emitting pipes, 6 types of non-compensating and 2 compensating ones were tested on the constructed physical model of drip irrigation in the water laboratory of University of Kurdistan. In each experiment, according to the standard on every model from the emitting pipes slices, 25 slices were selected randomly. Each slices was consisted of 5 unit emitters. Slices length varied proportional to the distance of unit’s emitters in the range of 2 to 5 m. The effects of four different water temperatures (13, 23, 33 and 43°C) with different pressure ranges (between zero and 1.2 times more than the maximum pressure) on the emitters were evaluated. The thermostat and element were used to supply water temperatures of 23, 33 and 43°C. To supply water temperatures 13°C was used for the ice pieces. Generally in every temperature, discharge of compensating emitting pipes was measured at 10 pressures and in the non-compensating emitting pipes was measured at 7 pressures. Data analysis was performed in a randomized complete block design using SAS software.Results: According to the results obtained from the experiments of discharge- pressure at all temperatures, in the both C1 and C4 emitting pipes, power of the discharge – pressure equation was less than 0.2, therefore, as compensating were acceptable and of good flexibility. As well as in the rest of the emitting pipes power of equation was variable between 0.2 and 1 and as non-compensating and of the high degree of flexibility. According to the results obtained from the experiments discharge – temperature, in the all emitting pipes of non-compensating, the effect of temperature on discharge at 95 percent was significant, that generally discharge had increased with increasing temperature. In the compensating emitting pipes with increasing temperature from 13°C to 23°C, flow rate has increased at 95 percent significantly, but from temperature of 23°C to temperature 43°C there was no significant difference between emitters discharge.Conclusion: In general it can be concluded that the relationship of discharge – pressure in the external and internal emitting pipes of common market is acceptable and desirable. Also it is suggested that, in the design of trickle irrigation systems that uses emitting pipes, the effect of temperature on the discharge of emitting pipes units must be ensured and the necessary correction coefficients be applied for emitter nominal flow rate.

Background and Objectives: The effect of mineral clogging by soil particles is one of the main factors affecting the performance of drainage systems. Many drainage systems designs do not pay attention to laboratory and local studies on certain important parameters and some of them use to be specific for a given conditions. Several studies carried out in The Netherlands have shown that nearly 80% of drainage projects’ failure happens as a result of inappropriate performance of drain filters. Since field studies in order to evaluate drain envelopes is not economical from viewpoint of time and cost. Therefore laboratory evaluation is proper for envelopes. The main goal of this study was obtaining a set of empirical equations in order to estimate hydraulic and clogging parameters using hydraulic head and discharge through drains which are easy to measure. Removing the effect of piezometers installed the Permeameter was another goal.Materials and Methods: To conduct this research, The Permeameter which designed and was made according to ASTM-5101 standard, was used PP-450 and gravel envelope were evaluated according to USBR standard. Required soil for this experiment was collected from a drainage project in the north of Khorramshahr at 1.65 m depth. The test was conducted in laboratory using Permeameter by producing 4 different hydraulic pressure head (25, 50, 75, 100 cm). In this study, special parameters (envelope hydraulic conductivity, soil hydraulic conductivity, soil-envelope hydraulic conductivity, gradient ratio) were calculated by measurement of outflow changes in soil envelope system and hydraulic pressure head of manometer.Results: After the tests were completed, the values of hydraulic conductivity for soil-envelope system, soil and geotextile envelope were estimated as functions of hydraulic head and outflow values. Furthermore, other relations were proposed for gradient ratio. The relations between different parameters were analyzed by Sigma Plot software and proper relations were proposed. The errors of the fitting equations and the difference between measured and estimated values were analyzed using the statistic indices. Results showed that these models are accuracy estimation of assessed parameters.Conclusion: Correlation coefficient of these equations for pp450 envelope for soil-envelope hydraulic conductivity, soil hydraulic conductivity, envelope hydraulic conductivity and gradient ratio are 0.96, 0.96, 0.62 and 0.96 respectively and for gravel envelope for soil-envelope hydraulic conductivity, soil hydraulic conductivity and envelope hydraulic conductivity are 0.98, 0.98 and 0.63 respectively. Low correlation coefficient for estimation of envelope hydraulic conductivity is related to envelope clogging during experiment time. Using of proposed equations can be estimate clogging and hydraulic performance of drainage envelopes in different conditions.

Background and Objectives: Some of heavy metals such as copper (Cu) and manganese (Mn) are toxic and represent as hazardous pollutants due to their persistence in the environment. Heavy metals can be introduced into soils and aqueous environments by natural processes or anthropogenic activities. They are non-degradable in nature and highly toxic to plants, animals and human beings. Various methods exist for the removal of heavy metal ions from solution, such as filtration, chemical precipitation, ion exchange and sorption by activated carbon and others. Discarded tires are an interesting and inexpensive medium for the sorption of heavy metals. There has been little research on heavy metal sorption into tire rubber in competitive systems. Therefore the present study was conducted to assess the sorption behavior of Cu and Mn on different sizes of tire rubber in a competitive system.Materials and Methods: The finely ground discarded tire rubber with three sizes including 0.088-0.125, 0.177-0.250 and 0.353-0.500 mm were prepared from Yazd Tire Company in Iran. A batch experiment was conducted by adding of 200 mg of ground tire to 10 ml of Cu+Mn aqueous solution of the desired concentration (10 to 50 mg L-1). After 24h, supernatant was separated by filtration and analyzed for remaining Cu and Mn by atomic absorption spectroscopy technique.Results: Sorption of Cu and Mn on tire rubber increased with increasing metal concentration from 0 to 50 mg L-1. The greatest sorption of Cu (1088.9 mg Kg-1) was found at the smallest tire rubber size (0.088-0.125 mm) and decreased by 35% when the largest size (0.353-0.500 mm) was used. At the highest concentration, sorption of Cu was restricted by Mn competition. In the whole range of studied metal concentrations, Mn occupied the least sorption sites of tire rubber. The sorption of Mn was not affected by tire rubber size and was restricted by Cu competition. Based on average, the experimental data were fitted in Langmuire (R2=0.94) better than Freundlich one (R2=0.87), showing monolayer sorption of Cu and Mn on discarded tire rubber. The values of maximum sorption capacities calculated from the fitted Langmuir equation showed that Cu sorption was higher than Mn. There was an increase in the qm values of Mn when the tire rubber diameter decreased. In this study, separation factor (RL) was used to predict if an adsorption system is favorable or unfavorable. In all cases, the values of RL were between 0 and 1, pointing to the favorable sorption of Cu and Mn on three size of rubber.Conclusion: Results clearly showed that ground discarded tire rubber (especially, the smallest size) are an effective adsorbent for the removal of Cu and Mn in competitive system. The equilibrium sorption isotherm of Cu and Mn onto discarded tire rubber is well described by the Langmuir and Freundlich models, but the Langmuir model fits the experimental data better than the Freundlich model.

Background and Objectives: Changes in the pattern of land use through the process of industrialization, infrastructure development and agricultural development is causing environmental issues such as soil pollution. The soil contamination with heavy metals is a serious and expanding problem. Heavy metals entering the food chain, threaten ecosystem and human health. This study aimed to assess and monitor soil contaminants including heavy metals and total petroleum hydrocarbons (TPHs) in soils of five oil refineries.Materials and Methods: In the current study oil-contaminated soils from five refineries including Abadan, Isfahan, Tabriz, Tehran and Shiraz were collected and physical, chemical and biological characteristics of soils examined. Total petroleum hydrocarbons (TPHs) and heavy metals (cadmium, chromium, lead and nickel) in soil samples were measured and the data was ststistically analysed.Results: TPH levels in contaminated soils of Abadan, Isfahan, Tabriz, Tehran and Shiraz were 6.4, 13.8, 11.5, 2.1 and 15.4 percent respectively and positively correlated with organic carbon of soil samples. The values obtained here were higher than the national and international standards. The highest concentration of chromium (mg/kg) was recorded in Abadan (83.3), Tehran (212) and Shiraz (61.1) refineries. The highest concentrations of nickel (mg/kg) were obtained from Tabriz (76.3) and Isfahan (122.1) respectively. The amount of cadmium and nickel in soil was higher than the standards of Europe and the world. A significant negative correlation was observed between heavy metal and hydrocarbon concentrations and microbial respiration, suggesting negative effects of pollutants on soil microorganisms which may also affect plants and other organisms.Conclusion: In terms of heavy metals and petroleum hydrocarbon contamination, Tehran Refinery is in a better situation compared to other refineries and this might be due to an environmental action plan running in this refinery. Given the contamination of refineries soil, it is recommended that environmental monitoring and industrial cleaning is taken into consideration. It is also recommended to use filtering programs, including bioremediation of soil in these areas.

Background and Objectives: The flood is second destructive incident in Iran. Greater understanding of different points of view Hydro meteology and watershed systems and analysis modeling of rainfall, runoff, determination of flood zone reference the hydrological and hydraulic conditions in the watershed, not only in terms of financial and legal, but also to predict and help flood warning systems are helpful ways. The purpose of this research is to provide the perfect solution to establish flood warning system using hydrological models and hydraulic models in the basin upstream of the Germichay dam.Materials and Methods: In hydrological studies after restructuring the data, flood frequency analysis has been done daily at the station. To choose distribution for all stations using the Bestfit test based on L-moments of stations, three parameters were normally distributed.Results: Applying the ratio of the maximum one-day flood into flood peak moment values for different return period, flood peak moment of the river at the dam site Germichay was calculated. River flooding, especially in the current conditions of relatively high recurrence caused flooding along the river due to the low slope terrain of the river.Conclusion: By examining the persistence of storms and their levels, early warning alarms were calculated for each of the stations. After determining the set time alarm events based on the frequency of Mianeh station, flood warning system for flood areas within the flood level was designed to suit the threshold.

Background and Objectives: Nowadays the importance of reservoirs management makes the use of gates on the spillways crucial. This causes the change in hydraulic flow over the spillway and the aim of this study is to explore some of these hydraulic changes.Materials and Methods: In this research by using Flow-3D and volume of fluid (VOF method) and k-ε (RNG) turbulence model, chute spillway with ogee crest and flip bucket has been simulated.Results: Additionally investigation on the effects of 4 openings 15%, 30%, 45% and 100% which is done by radial gates, has shown that the increscent of openings causes increscent velocity, depth and cavitation potential on spillways. Also in some openings with low discharge, due to the formation of low discharge which is lower than sweep discharge, formation of flow aggregated on the spillway is possible and the hydraulic effects of this phenomena should be taken into consideration. Also by simulation of jet trajectory from the flip bucket, results showed low error in length and maximum height of the trajectory.Conclusion: In conclusion, using Flow-3D for prediction of tail water preservation is highly recommended. Eventually, two correlation for the dependency of length of the trajectory, maximum height, flow discharge and opening gate ratio were presented.

Background and Objectives: Climate as one of the affecting factor on soil erosion has special importance in the assessment and management of soil erosion. Among climatic factors, role of the rain as water erosion beginner is undeniable. On the other hand, evaluation of frequency distributions for rainfall erosivity factor analysis has been less considered. Thus, the present study aimed to identify and evaluate different frequency distributions fitted to the amount of rainfall erosivity factor in monthly, seasonal and annual scales in Iran.Materials and Methods: The entire available rainfall events reported for 20 years in 70 stations were analyzed based on the Wischmeier and Smith erosivity index. The different frequency distributions were then fitted to data in each time scale and station using the EasyFit software with the help of chi-square test.Results: According to the results, the maximum Gumble distribution was selected as the best fitted distribution in most of months and seasons and 3-parameter lognormal, gamma and 2-parameter lognormal frequency distributions stood in the first rank group among the fitted frequency distributions for annual scale. In addition, stations with more stable rainfall regime and influenced by similar rainfall regimes had less variability in the type of fitted distributions in different time scales.Conclusion: According to the findings of the present study, the selection of frequency distributions was influenced by the spatial variations and temporal scales of the rainfall erosivity factor. The selected frequency distributions were therefore dissimilar in different scales and stations. The findings of the present study can effectively facilitate drawing appropriate strategies for soil and water resources management in Iran.

Background and Objectives: Erosion rate in Golestan province has a high rate due to geographical location, climatic and resource degradation. Determining a suitable method for measuring soil erodibility is one of the priorities in the prevention of destructive erosion. Wishmeyer and Smith equation (1978) is one of the important methods for calculating soil erosion, that is known as the Universal Soil Loss Equation. In this equation, cover management (C) is one of the six factors affecting soil water-erosion that its measuring is not simply possible. One of the widely used methods for estimating this factor is using satellite imagery. So, in this research, relevant indicators derived from satellite images of different agronomic main crop growth in Golestan province and their relation with real erosion in the farm was obtained.Materials and Methods: C factor was measured by using simulated rainfall with 2 intensity of 32 and 105 mm/h in duration of 20 minute in 6 consecutive times. Cover management factor also was measured using CERL method, and vegetation indices (SAVI & NDVI) were computed from of Landsat 8 images in 6 consecutive times using ERDAS IMAGIN 2011. Then, the relation between CSERL factor and vegetation indices (SAVI & NDVI) were obtained using Excel software and adjusted coefficient of determination, regression coefficient and correlation were used as evaluation indices.Results: According to the results, NDVI index (R2=0.76) in order to predict CSERL factor using satellite images is more suitable comparing SAVI index (R2=0.54). The vegetation indices derived from satellite images have higher relationship with C factor derived from higher rain intensity.Conclusion: According to the results, NDVI index had a best estimation with CSERL in higher intensity (R2=0.76) and so this index is offered as a method with proper accuracy.