فهرست مطالب mohammad sedghi asl

St. John's wort (Hypericum perforatum L.) is a medicinal plant that is more than 2000 years old. Drought stress is one of the most limiting environmental factors in the growth and production of plants. Plant symbiosis with mycorrhiza fungi and foliar spraying of essential elements can be one of the most effective solutions to deal with drought stress. This research also aims to evaluate the effect of mycorrhizal fungus and zinc sulfate foliar spraying on some biochemical traits and economic yield in St. John's wort under different irrigation regimes in a split factorial experiment with a basic randomized complete block design in three repetitions carried out during the three cropping years of 2018, 2019 and 2020. The main factor is irrigation regimes at three levels (100, 75 and 50% of irrigation needs); sub-factors were ZnSO4 foliar spraying at three levels (0, 3 and 6 per thousand) and inoculation with an AMF (Funneliformis mosseae) at two levels (inoculated and uninoculated). The results showed that the triple interaction of irrigation regimes + foliar spraying + mycorrhiza in all three years had a significant effect on chlorophyll content, proline, soluble sugars, malondialdehyde and economic yield. Increasing irrigation stress had a reducing effect on chlorophyll content, economic yield, and the relative water content of leaves, but on proline, soluble sugars and malondialdehyde had an increasing effect. At each stress level, the highest economic yield was obtained in the treatment of 6 per thousand foliar spraying + inoculation with mycorrhizal fungi. Generally, foliar spraying of zinc sulfate + mycorrhiza increased the content of chlorophyll, sugar solvents and the relative water content of the leaf, caused the adjustment of the stress conditions and increased the resistance of the plant against drought, and by improving the quantitative and qualitative biochemical traits, it increased the economic yield of the St. John's wort plant.

Zinc, copper and nickel are classified as micronutrients in plant nutrition and as trace elements in environmental chemistry. These elements are essential for plants and organisms, but they cause toxicity in high concentrations. The main mechanisms of entering these elements into the food chain is the soil-plant pathway. Trace elements are present in soil in different forms with different solubility. Determining the fractions of these elements reveals more precise information about their status, and the probability of their deficiency or toxicity in long period, and in the case of changing environmental conditions. Fractionation sequence is a procedure for determining different forms of elements.

The present study was conducted on 13 calcareous soil samples around Yasuj. The samples were selected from virgin and agricultural fields without pervious application of trace elements fertilizers, and were not contaminated trace elements. Different forms of zinc (Zn), copper (Cu) and nickel (Ni) were successively extracted with F1) distilled water (soluble), F2) neutral one molar ammonium acetate (Exchangeable|), F3) one molar ammonium acetate with pH 5 (Carbonatic); F4) 0.04 molar hydroxylamine hydrochloride (NH2OH.HCl) in 25% v/v of acetic acid with a pH of 3 (FeMn-oxid associated); F5) 30% hydrogen peroxide (pH 2) with 5 ml of 0.3 M NH4OAc ammonium acetate in 20% by volume of nitric acid (OM associated); and F6) 7 M nitric acid (Residual) in duplicate and were measured with atomic absorption spectroscopy.

Water extractable zinc, copper and nickel; and neutral NH4OAc extractable copper and nickel were not detectable in the studied soil samples. Neutral NH4OAc extractable zinc was detected in 5 soil samples. The abundance of zinc, copper and nickel chemical forms were as follows: Zn- NH4OAc pH 7< NH4OAc pH 5 Zn< H2O2 Zn< NH2OH.HCl- Zn< HNO3- Zn; H2O2 Cu

The present study showed that the amount of trace elements is generally less than 100 mg/kg and most of these elements exist in residual or stable form. An increase of calcium carbonate can be associated with a decrease in the total amount of these elements and cause their deficiency.

The Homotopy Analysis Method (HAM) was first proposed by Liao (1992) to solve functional equations. This method is based on homotopy and provides an approximate-analytical solution for functional equations. In recent years, this method and its modifications have been effectively used to solve a wide range of linear and nonlinear problems in applied sciences to find solutions to series of various types of nonlinear equations, including algebraic equations, ordinary differential equations, partial differential equations, and differential-integral equations (Abbasbandy et al. 2006). The purpose of this research is to provide an analytical solution of time delay with acceptable accuracy for the non-linear equation of non-Darcy flow in coarse-grained media using the HAM method, which previous researchers had recommended to conduct further research in this field.

In this research, the governing equation of the non-Darcy flow was solved by the HAM method for the first time, then the water level profiles of the final equation of the HAM method obtained for the 6 inlet flow rates with different boundary conditions and in two coarse-grained porous media including rounded and sharp-edged materials. The results of the water level profile using the HAM method have been compared with the laboratory data of Sedghi Asal (2010) reported at the Stuttgart laboratory in Germany. The normal objective function (NOF) has been used to compare the HAM method results with the experimental data of Sedghi Asal (2010).
 

The comparison of the results of HAM method with the experimental data of Sedghi Asal (2010) has been done under upstream and downstream boundary conditions for different discharges and with a slope close to the horizon S = 0.00001. The results have shown that flow rates of q=30 lit/s, with a NOF error percentage of 0.000099828 in the porous medium of sharp corners and q = 26.25 lit/s, with a NOF error percentage of 0.000102162 in the porous medium of round corners depict better accuracy than the experimental data in higher input flow rates. This method has logical solutions in horizon slopes and the water level profiles in HAM method and experimental data have coincided or are close to each other in most of the points. However, the subject of permanent and uniform flow needs a dependent research.

The results showed that the water level profiles are close to each other in most cases. This illustrates the accuracy of the developed approach based on HAM method. However, when the difference between the upstream and downstream water levels increases, the percentage of error escalates. In other words, with the increase of the hydraulic gradient in the porous medium, the error also grows. Finally, by evaluating the results of the HAM method compared to the laboratory data, it can be concluded that this method shows better accuracy in the porous medium with sharp-cornered materials compared to round-cornered materials due to higher flow rates and higher porosity of this media.

Due to environmental considerations, application of rockfill in designing of hydraulic structures, such as rockfill dams is increased. According to hydraulic principles, by increasing water surface and bed slope as well as significant curvature of streamlines, the vertical pressure distribution is deviated from hydrostatic state. Therefore, because of severe energy loss and big difference between upstream and downstream water surface elevation in rockfill porous media, pressure distribution is expected to be non-hydrostatic. In this study, using the distribution of non-hydrostatic pressure, the energy equation and considering the quadratic form of friction loss for non-Darcy flows, the equation representing the longitudinal profile of the water surface inside the rockfill dam is presented. In order to check the accuracy of this equation, experiments on homogeneous rockfill dams consisting of round river materials with average diameters of 1.68, 2.27, 4.07 and 4.84 cm and in two lengths of dams (50 and 100 cm), were performed in the hydraulic laboratory of the department of Irrigation and Reclamation Engineering, University of Tehran. Numerical solution of the equation representing the free surface flow inside the rockfill dam in comparison with the laboratory observations show that the equation is well able to calculate the longitudinal profile of the water surface in rockfill dams at low and high discharges. Statistical analysis of the results shows that the average relative error of estimates is 3.96%.

The issue of water seepage from foundations and abutments is one of the main challenges related to the design and construction of dams. One of the most important parameters in dam design in the study of seepage is to determine the permeability of the dam site, especially in rock formations. In this study, first, the permeability of Haigher roller compacted concrete dam site, located in Fars province, was determined through extensive Lugeon tests before and after the grout curtain. Then, using PLAXIS 3D FEM software, the site topography was modeled in three dimensions and three-dimensional dam seepage analysis was performed. The efficiency of the grout curtain was evaluated using numerical analysis. The results show that the total seepage discharge in the Haigher dam construction site without grout curtain is 1.075 * 10-2 and after the construction of the grout curtain is reduced to 2.305 * 10-3 m3/s, which indicates a reduction of about 80% seepage discharge due to construction of grout curtain. The results of the parametric study showed that with increasing the depth of the grout curtain, the seepage flow decreases and with increasing the upstream water level, the seepage flow rate from the dam increases linearly.

The sheet piles are used below hydraulic structures to reduce seepage flow rate and hydraulic gradient at the outlet of such structures rested on permeable foundations. Up to now, for analysis of seepage under hydraulic structures much research work has been carried out in the form of numerical models. However, less field and laboratory works have been performed to study and compare boiling phenomena for evaluating of the numerical models. By simulating an experimental model of a sheet pile inserted in a sand foundation by computer code FLAC based on the finite difference method, the soil behavior mechanism flow has been investigated under seepage effect. The results indicate that computer code FLAC underestimated uplift pressures compared to the experimental data. In order to study the boiling, the soil treatment analyzed at the most critical condition as well. The numerical model presented in computer code FLAC, is properly able to simulate the soil and foundation behavior. Comparing the results obtained from numerical model with experimental data also confirms well, because this model predicts the boiling observations with reasonable accuracy and it was possible to predict heaving mechanism based on the stress analysis before performing the plan.

In the present study, laboratory methods were used to investigate the drainage conditions of the steady-state with the surface recharging. In the study, fine and coarse sandy soil samples were used to study changes in groundwater level. The test specimen was poured into a large-scale flume, with 5.4 m long, which led to uniform vertical precipitation and vertical drainage on both sides. The parameters of precipitation rate, soil gradation and water level within the drains were investigated as variables in this study. The results showed that the maximum change in water height in coarse sand due to increasing water height in drains from 0 to 40 cm is equal to 56.9 cm and 72.5 cm, respectively, which caused an increase of 15.6 cm. However, in fine sand these changes are very small (2 cm) and equal to 87.2 cm in free drainage conditions and equal to 89.2 in water conditions of 40 cm inside the drains. The obtained laboratory results were compared with the Dupuit-Forchheimer analytical relationship, according to which this relationship is able to accurately predict the level of water in the fine sand, but in coarse sand, the relationship underestimates the water table height in the soil.

The increase of flow velocity and Reynolds number in coarse porous media and the subsequent violation of Darcy's law, force to analyze the flow based on nonlinear relations of hydraulic slope and flow velocity. So, it is necessary to study nonlinear relationships more accurately. The purpose of this study was to investigate the performance of fractional-order model and the effect of conformable derivatives on improving the relationship between flow velocity and hydraulic gradient. Therefore, by determining the acceptable range for the fractional-order model, a nonlinear model based on conformable derivatives of the Izbash equation for the fully developed turbulent flow was presented and solved analytically and the parameters of the proposed model were determined using laboratory data analysis. The optimal values of the model parameters including coefficient a and the order of fractional derivative α, which can be varied in the range of (0-2), were calculated for each laboratory data set. The results were compared with the experimental data and the analytical solution of Izbash equation and a good agreement was found to the non-Darcian flow laboratory data. Moreover, using dimensional analysis method, Reynolds number was introduced as an effective factor on α coefficient and a suitable relationship was observed between the order of fractional derivative α and Reynolds number indicating the hydraulic concept of fractional-order model. According to the present study, the fractional order α is not only a fitting coefficient, but it represents a physical concept.

Labyrinth weirs are some cost-effective structures, having trapezoidal, triangular and other formats, utilized for increasing the output efficiency in a limited width. Raising the capacity of labyrinth weirs via increasing their width is not always possible. The labyrinth weirs are used due to the increase in their efficient length on a given hydraulic height and width. The present study investigates the weirs having trapezoidal polyhedron format, on the wings of which some new labyrinth have been added so that their spillover discharge rate will be reinforced. The experiments in this study were conducted on 27 laboratory models having 9 different discharge rates, on whose wings double labyrinth have been added, totally through 243 experiment. Besides the spillover simulations were performed using the Flow-3D software. The results obtained from the numerical analysis for the determining the spillovers discharge rate coefficient were validated using laboratory data and it demonstrated a good correspondence between the numerical solutions and laboratory findings. It is also suggested that the Flow-3D software has a high potential in simulating the flow on labyrinth weirs. Laboratory results also indicated that, regarding all the compound polyhedron trapezoidal weirs, the parameter ratio, flow rate coefficient to ratio (Ht: total hydraulic load and P: spillways height) firstly raise and then start to reduce once they reach the maximum level. The spillover discharge rate increases for a given when the effective length of the weirs’ wing is raised. The discharge rate on the weirs having semi-circular compound format is better than this rate of ones having the square format and the ones having compound square format have spillover discharge rates better than the ones having simple trapezoidal format, in a manner that the discharge rate of the current flow is increased 15 percent more than the trapezoidal dam labyrinth spillways and flow rate coefficient interval increases from 0.4 percent of dam labyrinth spillways to 0.65 on the compound spillways.

In this study, the fractional-order differential equations in range of (0,1) were used to model the water surface profile under Darcy's law condition in porous medium for a fully developed turbulent flow. The developed equation is solved analytically. The laboratory model used in this study consists of a coarse-grained porous medium with 6.4 m length, 0.8 m width and 1 m height, including rounded corner materials, which are tested for different flow rates and three longitudinal slopes of 0, 4, 20.3%. Then, parameters of model and porous media were calibrated based on laboratory data. In order to evaluate the proposed analytical solution, the obtained results from fractional-order differential model were compared with the laboratory data. The results showed a satisfactory agreement with experimental data of water surface profile (seepage line) in all three slopes. The maximum error of the proposed model is 3.5% compared to the experimental data. It can be concluded that the proposed method can provide better description of water surface profile analysis under non-Darcy flow conditions as compared to Darcy model in porous media.

Assessing the variation of different soil properties through the land use changes may provide useful information for land managers. The present study aimed to assess the soil quality variation due to the land use changes from dense (non-degraded) to semi-dense (degraded) oak forest and then to dry-farming in Mokhtar plain located in Yasouj region. A total number of 100 surface soil samples were collected in order to analyses of the selected physicochemical soil properties. After statistical analyses, the continuous distribution maps were prepared for all soil variables using ordinary kriging and inverse distance weighting methods in ArcGIS software (ver. 10.2; ESRI). Analyses of the average values of selected soil properties showed that after changing the land use from dense to the degraded oak forest and then to dry-farming, organic matter and CEC changed in a decreasing trend and bulk density changed in an increasing trend. Moreover, electrical conductivity, carbonate calcium equivalent and clay percentage decreased in lower contents; whereas soil pH and sand percentage inconsiderably increased. Among the soil properties, organic matter content as one of the most important soil quality indices showed a significant change with an average of 6.74%, 3.42% and 1.58% in dense forest, degraded forest, and dry-farming lands, respectively. Supporting these findings, spatial distribution maps of the selected properties revealed that the most optimum soil properties were found in the southwest of the studied area, i.e. in the soils covered with dense oak forest; whereas increasing distance to the dry-farming lands in the northeast of the area, the selected soil properties were adversely changed. According to these findings, it can be stated that wide deforesting and land use change have been led to the considerable soil quality decline and therefore if deforesting will not be stopped a huge portion of the studied soils may lose their vital capabilities.

In this paper, subsurface flow profiles through coarse porous media have been simulated using a 3-D numerical model with and without surface discharge and their results have been compared with experimental data as well as with analytical solutions. SEEP/3D model, which is based on the finite element method, was used to simulate subsurface flow. The experimental model was consisted of coarse porous media with 6.4 m in length, 0.8 m in width and 1 m in height. The experiments were performed for different boundary conditions with two bed slopes of 4 and 20.3 %. The simulated data of watertableprofiles and seepage discharges were compared with those corresponding experimental data. In no recharge conditions with 4% slope, the numerical data were compared with both experimental and analytical dataindicating that the numerical results underestimated the watertable profilesas compared to the experimental ones. The results was better for the 20.3%-slope. In surface recharge condition, the numerical results only compared with analytical solution of Bear (1972), and the results indicated underestimation as compared to the experimental data.

In recent decades, site-specific management (SSM) has been specifically considered to achieve to increased input efficiency, improved economic margins of crop production and reduced environmental risks. Short-scale spatial variability of soil properties caused more necessity of SSM techniques. Natural variability of soil results from complex interactions between geology, topography and climatic factors, as well as land use change and land management strategies. Deforesting and vast land use changes are considered as the important land management strategies that have been extensively used in recent decades. Therefore, determining the effects of land use change on soil properties in conjunction with local environmental conditions and on the spatial variability of soil properties may drastically help the land use planners. Therefore, the present study was done aimed to explore the effects of oak trees deforesting in Shah-Mokhtar region in Yasouj and land use changes to dry farming on the spatial variability of nutritional elements using geostatistical techniques. The present study was conducted in a Shah-Mokhtar, north, and northwest of Yasouj, in Kohgiluyeh Province, southern Iran. Spatial variability of seven soil fertility properties, including N, P, K, Fe, Cu, Zn, and Mn concentration in soil, were examined in three land uses, including dense forest, degraded (semi-dense) forest and rain-fed lands. A total of 100 surface (0-30 cm) soil samples were collected and analyzed for the nutritional elements after preparing in the laboratory. Data were analyzed statistically and their normal distribution pattern was examined using the Kolmogrov-Smirnov test. In the geostatistical analyses step, the spatial structure of studied variables was analyzed by fitting the suitable authorized models on calculated experimental semi-variograms. The concentration of studied elements was interpolated using ordinary kriging (OK) and inverse distance weighting (IDW) estimators and finally, the spatial distribution map of each soil nutrient was prepared using ArcGIS 10.3. The results showed that the highest mean soil concentration of almost all of selected nutrients belonged to the dense forest lands and due to the land use changes to the degraded forest and then dry farming, average values of selected elements significantly decreased. Among the studied properties, soil N concentration with an average of 0.34%, 0.17% and 0.08% in dense forest, degraded forest, and rain-fed soil samples, had the most decrease caused by deforesting. Semi-variogram analyses showed that spherical model had the best performance. For interpolating the soil K and Mn concentration, IDW method and for other studied elements, OK method was efficiently used. The spatial correlation class was strong for N, Cu, and Fe; whereas a moderate class was calculated for soil P and Zn concentration. The spatial distribution maps of selected nutrients revealed that the dense forest and dry farming soils had the highest and lowest contents of soil nutritional elements. According to the findings of the present study, it can be stated that degradation of oak forest may lead to the significant decrease of soil nutritional elements, specifically soil N concentration as one of the main soil fertility quality. Therefore, it seems that not only the significant soil quality decline but also the extensive degradation of whole ecosystem and unfavorable climatic consequences will be the unavoidable results of deforesting in Shah-Mokhtar region.

This research was aimed to evaluate the available equations provided for non-Darcy flow in rockfill porous media, when there is a free surface flow, and when vertical pressure distribution is non-hydrostatic. Most of previous investigation about non-Darcy flow performed in permeameter that simulate one dimensional flow in porous media. Because of severe energy loss and considerable difference between upstream and downstream water surface elevations in rockfill porous media, a non-hydrostatic pressure distribution was expected. To carry out the research, a series of laboratory experiments have been conducted on rockfill materials with three differet diameters (1.68, 2.27 and 4.84 cm) and in a medium of 100cm in length, where water temperature varied between 10 and 29 °C. Results indicated that difference between water depth and piezometric pressure increased as water surface and water discharge increased.  Based on statistical analysis of existing experimental data, the most suitable model for energy loss in free surface flow in rockfill materials was introduced. Moreover, it was found that the introduced model had the lowest sensitivity to the variation of the input parameters, and the porosity, apparent velocity, median rockfill diameter and kinematic viscosity, respectively, had highest influence on head-loss results.

Increasing the slopes of water surface and bed or making a considerable curvature of streamlines, resulted in the vertical pressure distribution deviate from hydrostatic distribution. Because of severe energy loss and big difference between upstream and downstream water surface elevations in rockfill porous media, it is expected that pressure distribution be non-hydrostatic. In this paper, with the aid of Buckingham π theorem and regression analysis, a relationship is proposed for water surface profile in rockfill porous media. Moreover, a non-hydrostatic pressure distribution for rockfill porous media is derived by applying Euler equation including the effects of streamlines curvature and large slopes. A series of laboratory experiments have been conducted on rockfill materials with diameter of 1.68 cm and two media length of 0.5 and 1.0 m. It is found that the introduced model gives satisfactory results compare to the experimental results so that mean absolute relative error of water surface and longitudinal pressure profile between two series of the data are 1.31 and 1.71 percent, respectively.

Applicability of rockfill dams which has been made from large rock materials for purpose of flood detention reduces over the time because of siltation of pore system with sediment contained basin outflow. Since some of structures which were built with large rock materials should convey suspended sediment contained flows therefore routing process of these type flows have been investigated. The investigation around advection and dispersion of sediments particles through the large porous media usually is being done with breakthrough curve. This investigation is usually common for pollutants in rivers, sewer system and fine porous media. Previous researchers used from various techniques like numerical solving, parameter estimation and exact solution for solving of above mentioned problems. But unfortunately any general inquiry about suspended sediments was not accomplished yet. The exit breakthrough curves in many cases are asymmetrical and have Skewness in their falling limbs. Therefore some researchers after collecting the series of field data have discovered it and have presented a new model named transient storage model. Some investigators by considering Asymmetry in exit breakthrough curve have joined first order mass transfer equation with ADE equations and have extracted exact solutions with various primary and boundary conditions. The important criterion in this regard is to use them in similar primary and boundary conditions. Therefore in many cases the investigators are using from temporal and spatial moment technique according to experimental data series. By emphasis to above mentioned criteria and as regards to this fact that any coherent research in the investigation of behavior of suspended sediments through the large porous media were not accomplished yet therefore in this research tried to focus on it.
In this research by creating a laboratory model of large porous media and employing suspended sediment particles, tried to acquire an experimental data series in order to investigate longitudinal convection and dispersion phenomenon of suspended sediments through the large porous media. In this investigation by application of 2 media diameters, 4 inflow discharges and different hydraulic gradients over the media, the breakthrough curves of suspended sediments were extracted. The BC curves were extracted with water sampling from media end and then the samples have been passed from filter paper and dried. The concentration-time graphs were extracted after weighting of dried sediment particles. Also by using of parameter estimation technique for classical advection dispersion equation and temporal moments method, the longitudinal dispersion coefficients were extracted.
The results showed that due to the inherent properties of exit breakthrough curve, the temporal moments method has a better estimation accuracy rather than classical advection dispersion equation. Additionally by dimensional analysis method a relationship has been acquired for estimation of longitudinal dispersion coefficient with average relative error of 30% which is reliable in sediment transport studies. Furthermore, the results of analysis of BC curves exhibited that the curve has an Asymmetric limbs in rising and falling stages which this observation is because of temporary storage of sediments and gradual release of them through the downstream flow.

Many analytical methods proposed for solving two-dimensional problems of groundwater are concerned with functions which transform the problem from a geometric status where solution must be found, to another status in which the solutions are known. Conformal mapping and its appropriate techniques allows us to change complex flow problems into regular geometric shapes. In this paper, an analytical solution is provided for calculating uplift pressure in alluvial foundations below dams. In the present study, velocity Hodograph and Schwartz-Christoffel integrals are used to determine the uplift pressure in alluvial foundations in different depths and sizes of sheet pile and upstream blanket. An important point in this study is the asymmetric insertion of blanket relative to sheet pile along the longitudinal path. Finally, the results obtained from this method and the results of laboratory methods were compared to evaluate the accuracy of analytical results and to critically discuss the strengths and weaknesses. The results indicate that in some cases new analytical method underestimates uplift pressure while in some circumstances there is a good agreement between them.

Stability and safety of the dam is one of the most important challenges during construction and performances. The aim of this study is to make accurate water table and piezometric heads through embankment and its foundation of the shahghasem dam which is located near Yasouj city. Applying geostatistical, Simple Kriging, Ordinary Kriging and Weighted Moving Average, interpolation was done using Gaussian, exponential and spherical models. For comprising the results, we use the statistical index including MAE, MBE, RMSE and GSD. Results indicated that Simple Kriging with Gaussian model is the best one, while Ordinary Kriging with Gaussian model and Ordinary Kriging with spherical model are in the next order. The Weighted Moving Average method with different exponents indicated a significant error comparing to other methods. As a result, the depicted maps show a hole through foundation near right abutment of the dam. Finally, being a hole in foundation could strength piping and internal erosion.

So far، for the analysis of seepage under hydraulic structures much research has been conducted in the form of numerical models. However، few field and laboratory works have been done to study boiling phenomena for evaluating numerical models. In the present work، a laboratory model was built to simulate seepage and its controlling measures under sheet piles. The model consists of a 2. 2 m long، 0. 8 m deep and 0. 4 m wide flume، in which vertical sheet piles were provided by Perspex sheets. The flume was made of a steel frame and Perspex as well as thick glass sheets. The effect of position and depth of the sheet pile on the seepage flow، exit gradient and uplift pressure have been demonstrated in the form of dimensionless curves. The results indicate that the ratios and with the maximum upstream water level are best possible depths، for both vertical and inclined sheet piles in the depth of the foundation sheet pile. In other words، inclined sheet piles are much more effective in reducing and controlling seepage، uplift pressure and hydraulic gradient than vertical ones.

Use of large grained gravel is increasing in hydraulic structures due to their specific features as regards filtration، canal covers، stilling basins، rockfill dams، etc. Flow behavior in high porosity media and as well in rockfill dams is very complex due to the existence of large pore size and consequently turbulence in the flow. Given the importance of flow within the rockfill materials، an investigation of the characteristics of this type of flow is indispensable. Considering the widespread use of large grained materials in civil projects، scrutinizing the flow properties in these materials and obtaining their hydraulic parameters is important as for non-Darcy flow studies. In order to study the flow behavior in grained materials، a constant-head permeameter was designed built. Experiments were carried out on three types of gravel grains with average diameters of 8. 69، 13. 08، and 16. 62 mm. During the course of experiments، the outlet discharge، upstream and downstream heads as well as a measurement of the pressure drop (difference between water levels in upstream and downstream tanks)، were recorded and their characteristics studied. The laboratory results indicate that the relationship between flow velocity and gradient is non-linear، following non-Darcy’s law. The evaluation of results using goodness of fit criteria and their comparison with Kadlec and Knight (1996) and as well Ergun (1952) relations show that the Kadlec and Knight (1996) relation is of a higher reliability than latter. Variation of Reynolds number versus friction factor shows that the more the diameter of materials، the lower the abrasion factor and the higher the Reynolds number. The friction factor in higher Reynolds numbers decreases so that it is independent of the grain diameter and of Reynolds'' number. The low pressure equations and relations obtained in this study can be used for calculation of water surface profile through dams and rock drains.

Minimum environmental flow in rivers provides a certain level of protection for the aquatic environment. In Iran using hydraulic method of wetted perimeter could be a step forward in this field. How to identify the critical point in P-Q curve is still faced with uncertainty in this method. Slope, Curvature and Ideal Point Methods presented by different researchers in this filed. In this article beside description of wetted perimeter method, the environmental flow of Beshar River calculated by using hydraulic parameters. The average of results of Slope, Curvature and Ideal Point Methods is 23%, 8.4% and 20.6% of average annual flow of river, respectively. The results of Slope and Ideal Point Methods are in the acceptable rang of the Tennant method. But the Ideal Point method is superior choice due to the direct use of the chart and more rapidly in calculation.