مجله تحقیقات آب و خاک ایران
سال چهل و هشتم شماره 5 (پیاپی 32، بهمن و اسفند 1396)

Water of Baladeh's qanats travels around 15 Kilometers to arrive the lands in Ferdows by a channel. Farmers in order to reduce seepage in transition channels try to make the water muddy. In this research, with measuring seepage in both muddy water and pure water channels, the effects of making muddy water in seepage are investigated. The Seepage in channel 1 and 2 is measured by inflow-outflow test. Noticed that pondage test is employed for channel 3. The results show that making muddy water in a 16 hours period can reduce seepage around 60-67 percent. Also with continuing in making muddy water and controlling the erosion, seepage can be decreased approximately 95 percent. Loss of water in entrance of the channels is twice of the value in channels bed. Also muddy water can decrease seepage around 95 percent in sealing of pores in intake valves. Nowadays the most significant effect of turbid water in Baladeh qanats is closing the output pores of valves.

Assessment of soil quality is one of the most useful tools for evaluating soil management conditions and different land uses. Determination and comparison of quantity indices is one of the best ways to compare the quality of different soil.In this study soil quality indices and selection methods were compared for the effective evaluation of soil quality in different land uses.Seventeen soil physical, chemical and biological properties were selected as total data set (TDS) at five different land uses including orchard, rangeland, irrigated farming, dry land farming and unutilized lands, in slope classes of 0-2, 5-7, and 9-11 %, at some parts of south eastern of Qazvin (Iran). Then, 7 properties selected as minimum data set (MDS) using Principle Component Analysis (PCA). Soil quality was evaluated by integrated quality index (IQI) and Nemero quality index (NQI) in two set of soil properties including MDS and TDS. The results showed that orchard and rangeland had the highest IQI and NQI in both data sets, respectively, however irrigated farming, dry land farming and unutilized lands have the least IQI and NQI in both data sets, respectively and have significant different compared to orchard and rangeland. Correlation coefficient between TDS and MDS was 0.95 and 0.88 for IQI and NQI, respectively, indicating the reliability of the MDS instead of TDS, and indicated that the IQI offers better results for evaluating the soil quality in this case study.

Although the spur dikes have appropriate performance to protect rivers bank, these structures are not immune from the local scour around their tips. Recent researches have shown that the bank attached triangular vanes has less scour depth at their tips toward the spur dikes because of their geometrical shape. One of the methods of flow pattern improvement around the structures is creating slot in structure to reduce maximum scour depth around the structures tips. In order to achieve the purposes of present study a rectangular slot (with opening percent equal to 10 percent of the effective surface vane and the location of the slot is parallel to the chord) has been created in the bank attached triangular vane. Then the effect of slot on bed topography was analyzed at different angles and hydraulic conditions (0.287, 0.304 and 0.322). Results showed that the average reduction of maximum scour depth by means of slot at the angles of 23, 30, 40 and 60 degrees have been 70, 20, 17 and 54 percent, respectively. Also the created slot in the vane caused the maximum scour depth to form away from the outer bank. By increasing the Froude number, the maximum scour depth has increased at sample-slotted vanes.

The increase in water demand, in different aspects of water usages, has highlighted the importance of treated wastewater as new water resources. The main aim of the current paper is to present a new method to specify the best effluents applications, involving fuzzy and entropy approaches, based on the effluents’ characteristics. To achieve this goal, the effluents characteristics of Arak city wastewater plant, from 2013 to 2017, were used. Also six possible consumption options were determined and considered. Following by that the appropriate parameters were selected and the best options were chosen, involving the new derived indices. The mentioned indices are named the Fuzzy Effluents Quality Index (FEQI) and the Entropy Effluents Quality Index (EEQI). The results indicate that not only the proposed indices are sensitive to the input parameters but they also classify the effluents correctly. Moreover, results illustrated that the quality of Arak effluents, in last 5 years, have been improved. As in the last year, according to the new indices the effluents can be used in industrial, environmental, fodder production, cooked vegetables, oil seed production, and artificial groundwater recharge systems.

Dissolved oxygen is a key parameter to study the water quality. In this investigation the classical hydraulic jump as an aeration device was used to increase the dissolved oxygen. Experiments were performed for the Froude numbers in the range of 2 to 4.5 to study the phenomenon. A total of 240 data points were collected for different hydraulic conditions. Although the previous studies indicated that the aeration efficiency of the hydraulic jump should be considered as a function of the jump head loss, the experimental results of this study revealed that it depends also on other hydraulic and qualitative parameters. In this regard Buckingham analysis was used to find the effective parameters in the phenomenon of dissolved oxygen increase using classical hydraulic jump. The mathematical shape of the functional relationship was obtained using the incomplete self-similarity theory. In order to find the dissolved oxygen just after the hydraulic jump, the results of this study indicated that the mean absolute relative errors associated with the relationships proposed in this study and the one available in the literature were 9.09% and 24% respectively. Also the Root Mean Square Error values, RMSE, calculated for the method proposed in this study and that of available in the literature were 0.42 and 1 ppm respectively.

Erosion has been known as an important factor in soil resources degradation and non-point pollutions. A wide range of damaging effects involve social, economic and environmental problems occur when soil erosion rate go beyond the allowable value. There are several method to determine soil loss tolerance that each has specific advantage and limitations. In this paper, two widely used methods have been compared in determining tolerable erosion on a watershed scale. The first approach is based on assessment of the productivity index (PI) and the second approach is based on soil depth and soil quality index. A particular minimum data set of soil properties include infiltration, water holding capacity, organic carbon, aggregate stability, bulk density, and fertility status (nitrogen, phosphorus, potassium) was used to calculate criteria. The results showed the calculated tolerable erosion by two methods are closely related. The average tolerable soil loss for the study area was determined 9.2 and 10.2 ton/ha/year based on soil productivity method and soil depth-quality approach, respectively. The PI-based approach is preferred over the soil depth-quality approach for two reasons: First, the PI-based approach is a depth-wise and chemo-physical properties of topsoil are compared with subsoil layers. Second, the soil depth-quality based approach is a general guide that cannot take the differences between soils into account in details. As both model take into account just onsite effects of erosion, these values can be used for managers and decision-makers to soil conservation regardless off offsite impacts.

Surface water quality have a far-reaching impact on the human health and aquatic ecosystems. The sources of surface water pollutions are including point source (PSP) and non-point source pollution (NPSP). Identify of point source and non-point source pollutions have been critical to evaluated surface water quality and major pollutant sources in a watershed. In this study, Soil and Water Assessment Tool (SWAT 2009) was used to investigate the influence of PS and NPS Pollution on the water quality. The model was calibrated for the period 2000-2009 and then validated for 2010-2011. The values of Nash-Sutcliffe efficiency (ENS) and R2 for simulations of flow and nutrient loads range from 0.84 to 0.96 for calibration period while varies from 0.69 to 0.85 for validation period used for flow simulation. The statistical results revealed that the SWAT model performed satisfactorily in simulating monthly flow and nutrient loads in Seimareh watershed. Also, SWAT was used to identify the critical source areas (CSAs) of sediment, TN and TP at the watershed level. SWAT identified 9 sub-watershed (33% of total watershed area) as CSAs for TN and TP. The sub-watersheds 1, 6, 10, 17, 21,22, 25, 26 and 29 were identified as CSAs of TN and TP while most of these sub-watershed were also identified as sediment CSAs. Then model was also used to simulate the impact of best management practices (BMPs) at controlling nutrient losses. Major BMPs implemented were reducing chemical fertilizer application, and building a filter strip along the river bank. The result of WQI demonstrates that water quality at upstream is generally better than downstream with higher level of nutrient loads. Also, the seasonal variations of the WQI clearly indicate the summer and autumn season as critical time period for nutrient loads within the watershed.

Compositional nutrient diagnosis (CND) are important methods for interpretation of the results of chemical analysis and diagnosis of nutritional status of plants. In order to evaluate the nutritional status of squash (Lagenaria Vulgaris) through CND and to determine nutrient norms for this crop, 122 leaf samples were collected from squash fields of Khoy region and N, P, K, Ca, Mg, Fe, Mn, Zn, Cu and B were analyzed. The squash fields were divided into two high and low yielding groups, based on mathematical and statistical methods and by additive function of variance ratio, then CND indices and norms were calculated. Results showed that there were significantly differences between high and low yielding fields in terms of nutrients concentration. Based on CND indices, potassium and zinc nutrients had the most negative indices. CND nutritional balance index of low yielding fields were greater than zero indicating nutritional imbalances in these fields.

Soil management practices have different impacts on the values of soil resistance at different suctions, which rarely have been evaluated. In this study the combined effects of tillage and cover crop factors on the aggregate stability, aggregates tensile strength and soil penetration resistance at different suctions were evaluated. The tillage factor in three methods, including moldboard plow, chisel plow and no-tillage, and cover crop factor in three types including Vetch, Lathyrus and no cover crop at the factorial design with three replications was applied. Aggregate stability was measured using wet-sieving method. Tensile strength of aggregates and penetration resistance of the undisturbed samples were determined by Dexter and Kroesbergen indirect method and a micro penetrometer, respectively. Soil management practices had the highest effect on the resistance characteristics at 30 kPa matric suction. No tillage treatment reduced tensile strength due to reduced tillage intensity and undisturbing soil. Conservation tillage with Lathyrus cover crop, increased stability of aggregates by 155 percent comparing to no tillage-no cover crop in the spring season. Also conservation tillage with Lathyrus treatment, increased tensile strength of aggregates by 7-45 percent comparing to other treatments in the autumn season. The conservation tillage without cover crop reduced penetration resistance compared to most treatments by 4.5-99 percent at most matric suctions due to reduced plowing and decreasing agricultural machinery traffic. Therefore, we recommend using Lathyrus cover crop with conservation tillage in agricultural fields. The results of studying aggregates strength, with further research, could be used to determine the optimum time of agricultural operations.

The aim of this study was to evaluate the efficiency of WEPP model in estimation of runoff and soil loss under natural events at plot scale in rangelands of Khamesan watershed, Kurdistan. Runoff and sediment induced by events leading to runoff were measured over three years (2011 to 2013) at eighteen plots of 24 m long by 1.8 m wide (6 Hillslopes-three plots in each hillslope). At the same time, the input data including soil characteristics, vegetation and ground cover were evaluated and recorded during this period. In overall, 24 events were investigated. Model validation was performed with 16 remaining events, after calibration the model with eight events data based on the single event section of the model. The model estimated runoff and soil loss with acceptable accuracy under natural events in rangeland hillslopes containing significant amounts of rock fragment. The soil loss estimations were somewhat better than total runoff. In general, the model efficiency was lower in the hillslopes with higher rock fragment (especially rock cover) and higher percentage of lime, than the other hillslopes. It seems that rainfall intensity pattern during each event also had a significant effect on the model estimations. In WEPP model for single event estimations, just some of storm characteristics are used as input, and intra-storm variations are not considered which may have a significant impact on the amounts of runoff and sediment.

In this research, pressurized irrigation systems including 7 center pivot, 3 linear, and 8 solid-set with portable sprinklers systems in the provinces of Tehran, Qazvin, Alborz, and Qom were assessed using by uniformity coefficient, distribution uniformity, Potential Application Efficiency of Low Quarter, Application Efficiency of Low Quarter, and of Irrigation Adequacy indices. In order to compare the assessed systems, weighted averages of all used indexes were calculated. The results showed that the weighted average of mentioned indices are 78, 63, 69, 69 and 49 for center pivot, 75, 68, 64, 55 and 62 for Linear, and 77, 66, 60, 60 and 61% for solid-set with portable sprinkler respectively. By analyzing indices and comparison with field and pumping stations observations, it was found that the incorrect design, mismatch between design, performance and management, and incorrect operation are the main causes of low performance.

With respect to sparseness of solarimeteric stations and the importance of awareness of solar radiation values, development of solar radiation models that’s based on other meteorological variables is necessary. Empirical Angstrom-Prescott equation that is based on sunshine hours has been widely used for the estimation of solar radiation. Hitherward, many studies were conducted to validation of its coefficients for each region based on site specific meteorological conditions but what has not been addressed yet in Iran is the role of air pollution as a reducing agent of receiving radiation. In this article validation of A-P equation was done based on the 3-year data of Karaj station in daily time scale with consideration of air pollution index and in form of logarithmic, linear and exponential equations. Results showed that corrected models with logarithmic structure with Coefficient of determination (0.5911) were partially performed better than the original Angstrom-Prescott models.

The normalized water productivity (WP*) parameter was calibrated for Corn Single Crosses 704 in this study. This parameter is one of the inputs AquaCrop model upon which the daily biomass production simulated. The default value of WP* is 33.7 grams per square meter in the model. This study was conducted for two years (2015-2016) at an experimental farm of Abouraihan collage belonging to the University of Tehran in Pakdasht Region. The total numbers of plots were tree. Each plot size was 25 m2. Biomass yield of corn was measured six and seven times during the growing season in 2015 and 2016, respectively. The data measured in the first year (2015) and second year (2016) were used for calibration and verification, respectively. Calibration was done using two methods of trial and error and Steduto et al. (2009). The WP* was calibrated with a little more accuracy by Steduto et al. (2009) method and its value was estimated equal 32.3 grams per square meter. Root mean square error and mean bias error for the comparison between measured and estimated biomass production are 0.73 and 0.25 ton ha-1 for the tested data set.

The assessment of hydrologic wet and dry periods is the primary and necessary basis of water resource management and planning which need to study and understand of drought occurrence. The aim of this study is the use of Power Law Analysis and analyzing wet and dry period’s patterns of river flow in some gauge stations of Mazandaran Province. Toward this attempt, wet and dry periods of monthly discharge time series in 26 hydrometric stations have been analyzed through a 36-years study period. Therefore, average monthly discharge, threshold limit and start and end of wet and dry spells were calculated and then the number of wet and dry spells occurrence sequences from 1 to 41 months were determined. Results showed that there is an straight relationship between the severity and duration of dry and wet spells. The minimum severity of dry and wet spells were observed in Polur and Hanisk stations with the line slope of -0.87 and -1.29 in southwest and western parts of the Mazandaran Province. The maximum flow duration for dry and wet periods (122.09 and 145.89) were identified in Qoran Talar station at the center of study area. In other words, stations in the main branches of southeast and center of Mazandaran province have dry and wet flow durations more than other studied stations. The proximity of scatter plots to the straight line or parallel lines without intersection in the study area represented a homogeneous regime of dry and wet periods and significant changes with the time hadn’t observed. In this regard, it can be noted that the periodic pattern of monthly discharge and its duration can be determined using Power Law Analysis method.

Soil hydraulic conductivity is an important physical characteristic which used in modeling of water, solutes and pollutants transport. Direct measurement of soil hydraulic conductivity is time-consuming and costly, and due to experimental error and soil heterogeneity, results sometimes are unrealistic. On other hand, it could be estimated by easily measurable soil properties. The purpose of this study is development of genetic programming and linear regression models to estimate the saturated hydraulic conductivity of soil using readily available soil properties. For this reason, 160 soil samples with different properties were taken from different area of East Azerbaijan province of Iran. Then some physical and chemical characteristics of soil such as sand, silt, clay and organic matter, bulk density, pH and EC were measured. Then the data was divided into the two different data sets, namely training (75% of data) and testing datasets (25% of data). GeneXproTools 4.0 and Statistica software’s was used to calibration of Genetic programming and regression models, respectively. Six pedotranfer functions (PTFs) with a combination of different mathematical operators was designed by genetic programming. Finally, one of the PTFs which was more accurate than the others was selected. As well as ridge regression was used to development of regression PTFs. The accuracy and reliability of PTFs were determined by R2, RMSE, and MAE criteria. Results showed that the genetic programming PTF (GP-PTF) is more accurate and reliable than the regression-PTF. So that R2, RMSE (Cm h-1) and MAE (Cm h-1) of GP-PTF for training dataset were 0.91, 1.82 and 1.23 respectively, and for test dataset were 0.92, 2.27 and 1.59, respectively. While values of the above mentioned criteria of regression-PTF for training dataset were 0.70, 3.48 and 2.07, respectively, and for test dataset were 0.76, 3.11 and 1.88, respectively.

Irrigation water salinity is one of important factors in soil salinization, decreasing of the soil permeability and yields. Hence, finding new low cost method in reducing of irrigation water salinity is inevitable. The aim of this study was producing activated carbon from pine cones and evaluation of its application in adsorption irrigation water salinity ions. Adsorption experiments were conducted in batch system and the effect of parameters affecting the adsorption including contact time, initial concentration of salinity ions, adsorption isotherm and kinetics, and the effect of adsorption on irrigation water quality parameters including EC, TDS, TH and SAR, were studied. The results showed that the maximum reduction of salinity in the electrical conductivity of 5.48, 10.41 and 20.4 (dS/m) were 7, 14.3 and 21.5 %, respectively. Adsorption Kinetic and isotherm of salinity ions followed the pseudo-second order reaction and Freundlich isotherm respectively. The maximum reduction in TH and SAR of irrigation water was observed in salimity of 20.4 dS/m that were decreased 14.4 and 14.8 percent, respectively.

Soil moisture is an important factor in hydrological processes. So in this study, uncertainty AOGCM models were investigated in estimation of soil moisture by SWAP model for future period as 2099-2080. The climatology data were produced by ten of AOGCM models and two of emissions scenarios (A2 and B1) and had been downscaled by LARS_WG model and was used in SWAP model. The results showed that INMCM3 and NCARPCM models had the most and lowest amount of soil moisture during weeks of post-growth. The uncertainty of yearly soil moisture showed that INMCM3 model had the most of uncertainty band for A2 and B1 scenarios and GISS-ER model and CGCM3T47 model had the lowest uncertainty band for A2 and B1 scenario, respectively. Also, it was determined by comparison of soil depth's moisture that depth of 60 cm would have more soil moisture than depth of 30 cm.

Cylindrical weirs are one of the most common structures for measuring flow discharge and controlling water level in canals and rivers. Numerous geometric and hydraulic parameters can affect characteristics of the flow passing over these weirs. In the present study, the effect of surface roughness and upstream sedimentation on discharge coefficient, pressure distribution and energy loss was investigated experimentally. The tests were carried out for non-sedimentation channel bed, and sedimentation levels of 1/3 and 2/3 of the weir height. Three different weir diameters and four different surface roughness of the weirs was considered for large range of flow discharge. Comparison of results of discharge coefficient of weirs for different upstream channel bed level and the weirs diameters indicated that by increasing surface roughness from PVC to 4.5 mm, the discharge coefficient of the weir reduces of up to 8%. Also, by increasing sedimentation level from zero to 2/3 of the weir height, the weir discharge coefficient increases up to 3%. In addition, increasing of roughness to 4.5 mm for sedimentation level of 2/3 weir height, leads to decrease the discharge coefficient between 3 to 7 percent. By increasing weir diameter from 150 to 250 mm, the discharge coefficient increases up to 5% and the energy loss decrease up to 15%.. it was found that, in all the tested weirs, by increasing surface roughness, energy loss increases up to 14% and by increasing the sedimentation level to 2/3 the weir height, it reduces about 22%. comparison of the results showed that pressure variation along the weir at a sedimentation level of 2/3 the weir height followed a similar trend to that obtained under non-sedimentation level. However, the magnitude of pressure decreased with increasing sedimentation level.

One of the challenges to progress in hydrology and soil science researches is that the theories applied just to certain time-space scales. This study was carried out to examine the effect of plot size on runoff generation and quantify scale effects. For this purpose, 6 experimental plots with the length of 3 to 60 m and the width of 1 to 6 m were established on a hillside in Saravan region of Rasht, located in Guilan province. Outflow runoff was collected from October 2015 to May 2015 and then the data were analyzed. Also, rain height was measured for each plot by installing rain gauges. Results showed that the amount of runoff per unit area decreases with plots length in non-linear form. Compare the mean values between the plots confirmed that there are no significant differences among plots with length longer than 10 m in terms of runoff yield. However, there were significant differences among plots shorter than 10 m and longer plots (P >0/05). The results verified the optimal length of 10 m for scaling proposes. A two-parameter model was used for scaling hillslope runoff ratio. Model parameters were determined using model calibration. The evaluation of the model showed its appropriate efficiency for plots shorter than 30 m long.

Due to substantial impact of humic substances on a variety of environmental processes, knowledge of the chemical, spectroscopic and structural properties of these substances, are aspects that should always be considered in studies related to the management and remediation of impacted ecosystems. In this study, after from extraction and purification of humic acid (HA) from low grade coals of IRAN, was used from gravimetric technic in order to determination of degree of purity of HA, from non-destructive spectroscopies such as ICP-OES, UV-VIS, FT-IR and CHNOS for measuring of quality and quantity of HA as well as from microstructures of SEM in order to structural study of HA and obtained results were compared with standard Aldrich HA. Results of gravimetric analysis showed that degree of purification of produced HA is 98%. Also, In point of quantity, results of elemental analysis of ICP-OES showed that after from purification of HA, the concentration of various heavy metals in HA are lower from recommended safe limit and there have macro and micronutrients at ranges in HA structure. Also, quality results of FT-IR, UV-VIS and SEM analysis, shown well presence of an aromatic predominant structure and rich from carboxylic and phenolic functional groups with high humification and condensation degree and A type with a loose spongy and heterogeneous porous surfaces for HA. CHNOS analysis also confirmed the suitability of the coal used to extract HA, and showed that the final product is in accordance with the standard HA results.