فهرست مطالب esmaeili varaki

Reducing fresh water resources and the quality of water in the agricultural has led to importance of the finding new sources of water for irrigation. In this regard, the use of non-conventional waters is one of the options. Using of drainage water as a non-conventional water source is one of the solutions to solve the water deficiency problem in agriculture. The present study was carried out to evaluate and simulate the quality of the drainage water of the rice fields in the city of Soumatserra, located in the F4 unit of Sefidrud Irrigation and Drainage Network for reuse in irrigation and evacuated to the environment. In order to investigate the quality of drainage water for discharge to surface water resources and reuse in irrigation, the concentration of the nitrate, orthophosphate, ammonium, biological oxygen demand, dissolved oxygen, total dissolved solids and acidity was measured in nine points in May-July 2017 and was compared with the standards of the Environmental Protection Agency, the Environmental Protection Agency of Iran, Institute of Standards and Industrial Research of Iran. The highest concentration of nitrate, orthophosphate, ammonium, and biological oxygen demand were 1.25, 0.184, 2.91 and 89 mg/ l in May and the lowest concentration of dissolved oxygen and the highest concentration of total dissolved solids were 3.6 and 289 mg/l in July. Also, the highest and lowest value of pH was 8.23 in May and 7.26 in June. Drainage water in terms of nitrate, orthophosphate, total dissolved solids and acidity, according to the mentioned standards was allowed in reuse in irrigation and discharge to surface water resources. But in terms of dissolved oxygen, biological oxygen demand and ammonium was diagnosed over the limit for reuse in irrigation and discharge to surface water resources. According to estimation of the pollution load of the drain to the Anzali wetland, it was found that the highest amount of pollution during the sampling period was occurred in May.

Flow water passing through spillways of dams has a high level of kinetic energy, which can lead to extensive damage to downstream facilities and bring about severe erosion of river beds. Energy dissipation would usually be accomplished by creating structures such as still basins at downstream of weirs, flip buckets, or steps in weirs. Stepped spillways are one of the common structures for energy dissipation, as well as reduction of the dimensions of still basins. The effects of labyrinths on total energy dissipation at downstream of the stepped spillways with slopes of 1:1, 1:2 and 1:3 was investigated; the height of labyrinths was 0.5 and 0.75 of the height of steps (h), working interspaces were equal to two times of the height of steps, and three roughness heights on the step face were 0.002, 0.004 and 0.006 m. The results showed that in first case, 1:1 slope of the stepped spillway, a labyrinth with height of 0.5h, working interspaces of 2h and equal length of the steps caused an increase of 12.7 percent in dissipation of relative energy. The comparison of results showed that for slope of stepped weir of 1:2, installation of a labyrinth with a height of 0.75h, interspaces of 2h and equal length to the height of the steps, the relative energy dissipation increased by 8.4 percent. When stepped weirs with slopes equal to1:3 were used, results indicated that installation sill with a length h, a height of 0.5h instead of labyrinths on steps, caused an increase of 4.7 percent in relative energy dissipation. Result showed that increase surface roughness of studied weirs reduced the relative energy dissipation by 3.6 percent.

Cylindrical weir is one of the hydraulic structures used in open channels and reservoirs to regulate and control the water levels. Compared to the other shapes of structures, cylindrical weir has some advantages such as easy flowing of floating objects over it, simplicity of its design and construction, less loss, and greater discharge coefficient. Much work has been long done on the hydraulic of cylindrical weirs in non-roughness conditions. However, the effect of the roughness of the structure body that can affect discharge coefficient, flow loss, and formation of the critical depth as well as the characteristics of the boundary layer has received little attention and lack of comprehensive research on this is quite evident in previous studies. Therefore, in this study, the effect of roughness on the hydraulic of cylindrical weirs has been analyzed in details with different diameter, discharge and roughness in the laboratory and finally the obtained results was compared to other researchers. Experimental model is composed of full cylinder with three different diameters and four levels of roughness of PVC, 1.5, 3 and 4.5 mm for each diameter. The results show that for the same cylinder and with the equal flow rate, an increase in the roughness of surface of the weir from PVC to 4.5 mm, results in a reduction of discharge coefficient(cd) value around 10.7% and leads to an increase of energy loss about 22.3%. Moreover, it has been concluded that the critical depth formed about 78.8% closer to the crest. While the effect of roughness on the discharge coefficient in smaller diameters is more visible, the effect of roughness on energy loss doesn’t depend on the diameter of cylinder. Furthermore, there is a decreasing in cd and energy loss value with increasing of the cylinder diameter under the same surface roughness. By increasing of the inlet discharge, discharge coefficient increases and energy loss decreases and the distance of critical formation point from crest, increases. The achieved results regarding the dimensionless ratio of crest depth on the critical depth (Hcrest/Hc) is in conformity with the results achieved by Chanson and Montes`s research in the case of non-roughness.

Infiltration is a major soil hydraulic property that has effective role on water and soil resources researches. Field methods of infiltration measuring are time consuming and costly. Therefore an indirect estimation method such as transfer functions is concerned. In this study were derived pedotransfer functions of infiltration of surface irrigation in both GMDH neural network and regression methods by the chemical and physical properties of soil and water. Due to this purpose, 17 soil samples were gathered from Foumanat plain of Guilan province. Physical and chemical properties of soil including soil texture, soil size distribution, particle density, bulk density, soil water retention curve, electrical conductivity, sodium absorption ratio, organic matter content and pH were measured and infiltration experiment were conducted in physical model to evaluate the effects of three treatments of water height on soil surface including 3, 5 and 7 cm and three treatments of sodium adsorption ratio including 1.7, 2.5 and 9. The results showed that GMDH neural network method estimate infiltration more accurate (R2 =0.82) than regression method (R2 =0.75). Regression equations showed that hydraulic parameters of irrigation water including water standing on soil surface and contact surface of water with soil had more effect on infiltration than chemical properties of water and soil. In GMDH method, SAR of water resource, sand percentage and soil moisture in 100 cm matric potential were recognized more effective parameter on infiltration estimation.

Salinity and nitrate of drainage water are the main reasons of agricultural pollutant. Decentralization of agriculture land, variety of contaminants and the high volume of agricultural waste led to reduce the performance of conventional strategies of nitrate and salinity removal. This study aimed to evaluate the phytoremediation strategy to reduce salinity and nitrate in agricultural drainage, and reduced ability to absorb nitrate salt by three Vetiver, Typha and Reed was investigated in the region of Guilan province in a randomized complete block design with three replications. So 9 cylindrical boxes with 50 cm diameter and 80 cm height and Silty loam soil texture were prepared and after planting, two treatments of nitrate concentrations including of 10 and 20 mg/l nitrate were exposed during testing. Ability of nitrate and salinity reduction in two depths 35 and 70 cm was determined by measuring the amount of nitrate and salinity in soil extracts. Results showed that the highest amount of nitrate uptake of Reed in concentration 10 mg/l and in 70 cm depth was 98.59% and the lowest nitrate uptake in concentration 20 mg/l and in 70 cm depth was 34.96% for Vetiver. In addition, three plants were significant differences in reduction of pH but the salinity reduction was not significant in 5% level.

In this research, the effects of pile cap thickness and its top level of installation, arrangement and diameter of piles on variation of local scour around the inclined bridge piers group were investigated experimentally. A Physical model of piers group having two inclined rectangular piers with 28 degrees inclination angle was constructed on a pile cap. Experiments were performed on piles group with relative diameters ( ) of 0.6 and 0.9, piles arrangement of 2×2 and 2×3, relative pile cap thicknesses ( ) of 0.9 and 1.4 and the pile cap relative installation levels ( ) of 1.5, 1, 0.5, 0 and also its buried condition at the level of -0.7 and -1.2. Comparison of the maximum scour depth indicated that the change of pile arrangement from 2×2 to 2×3 caused 50 and 60 percent increases in the scour depth related to the ratio of with the amount of 0.6 ad 0.9, respectively. However, changes of the pile diameter and arrangement did not have any effect on the maximum scour depth as pile cap installed in the same level of bed or lower than it i.e. in buried condition. Comparison of the results showed that changes of the pile cap thickness from 0.9 to 1.4 times the pier width, caused the maximum scour depth for all pile geometry and top level installation of the pile cap to be increased 20 percent approximately. Furthermore, as pile diameter increased from 0.6 to 0.9 bridge pier width, the maximum scour depth for installation of the pile cap above the bed increased 5 and 10 percent approximately for pile arrangement of 2×2 and 2×3, respectively.

Nitrogen fertilizers used in agriculture are a source of environmental and water resources pollution and using simulation model to recognize its cycle could be important role to control and reduce environmental pollution. In paddy fields¡ nitrogen has complex cycle due to irrigation management and submerged condition. In this study¡ HYDRUS model was used to simulate and study nitrogen cycle under different fertilizer management treatments including 24¡ 48 and 72 hours remaining duration of fertilizer and releasing it by runoff. Micro lysimeters were used for simulating the nitrogen cycle in paddy field. The soil texture of this experiment soil was silty clay loam and after applying the urea fertilizer and treatments of the research¡ ammonium¡ nitrate and nitrite concentrations were measured for 4 months (June to September) at depths of 15 and 30 cm. Changes rate of ammonium to nitrite¡ nitrification and denitrification was obtained more at depth of 15 cm than depth of 30. Model could be simulated ammonium and nitrate more accurately than nitrite so that correlation coefficient of simulation were 0.79¡ 0.70 and 0.60¡ respectively. At a depth of 30 cm changes rate of ammonium to nitrite did not affect by fertilizer management treatment.

After construction of bridge pier in a river, eddy flow pattern forms around the piers and erosion of bed material and scouring occur, and if foundation depth or piles depth is insufficient, the bridge will be collapsed. In this research, effects of the installation angles of piers group on scour dimensions under different hydraulic conditions and top levels of foundation installation were investigated experimentally. The model of bridge piers group was placed on a rectangular foundation with 3 angles of installation (vertical, degrees of 28, 38 and 45). Experiments were conducted under two different relative velocities (ratio of flow velocity to corresponding inception of motion velocity, 0.8 and 0.95) and three relative levels of foundation (ratio of top level of foundation to width of it, zero, -0.5 and -1). Comparison of the results showed that at zero relative level of foundation, the top level of foundation played as collar and the minimum scour occurred at the vertical installation angle. At the other relative levels of foundation and among the different installation angles of the piers, the angles of 28 and 38 had the maximum and minimum scour depths respectively. Furthermore, variation of the maximum length of scour had a similar trend to the scour depth.

Advancement of technology in construction of structure caused to design modern type of bridge piers including inclined bridge piers group. Due to importance of identifying effective mechanisms of scour around this type of bridge piers, in this research the effect of flow parameter and level of bridge foundation on the scour depth was investigated. Bridge piers group included two inclined rectangular piers of 2.5cm width and 3.5cm length which installed at the angle of 28 degree on the top of rectangular foundation of 10cm width and 16cm length. Experiments were performed for various relative velocities, depth of flow and relative top level of the foundation from the channel bed (Z/D*) -1 up to 1. The results showed that the velocity of flow has more effect on the local scour depth in comparison of the flow depth. Comparison of results for different levels of the foundation showed that level of the foundation has significant effect on the scour depth. A maximum and a minimum scour occurred for relative foundation level 1 and -0.5. Furthermore, except of relative foundation - 0.5, the scour at the inclined bridge level is more than individual pier.

Determination of the appropriate velocity distribution and accurate estimation of river discharge is important to water resource management, water supply and safe design of hydraulic structure. Common methods in measurement of flow rate are on the basis of direct measurement of flow velocity. These methods are time consuming; costly and impracticable during flood in wide rivers. Therefore, use of methods that, while having sufficient accuracy, and the time required is also cost effective, In this research, using the principle of maximum entropy and Chiu’s velocity distribution, velocity distribution and flow in several cross sections of the Pasikhan river in Guilan province were estimated and the results were compared with measured data collected during 1389-1390. It’s found that there is a good agreement between predicted velocities and discharges based on Chiu’s method and the measured values with R2= 0.996 and RMSE= 3.9. So, it can be used as a quick and easy way to be replaced with conventional methods for estimating flow velocity distribution in rivers, especially in times of floods.

Phosphorus is one of the main pollutants of agricultural surface drainage; that over standard doze of it cause eutrophication in surface water resource. This study investigates evaluation the ability of Semnan''s zeolite، that modified by hexadecyltrimethylammonium، to removal phosphorus under flow conditions in agricultural drainage. In this regard، after modifying natural zeolite، at first was absorption kinetics، adsorption isotherms، affecting of pH and temperature experiments on phosphorus removal conducted by modified zeolite in laboratory scale. The experiments were done in 3-5 mm size of zeolite for investigating effect of zeolite size on phosphorus removal. In order to assess the flow conditions on phosphorus removal physical model of agricultural drainage and the modified zeolite filter ponds were constructed in length of 2، 3 and 5 cm. The both discharge 0. 05 and 0. 1 lit/s were applied in drainage and changes of phosphorus concentrations were measured at various times after passing through the filter ponds. The sorption kinetic experiments showed maximum phosphorus removal by modified zeolite occurred in the first 2 hours. Moreover، percent phosphorus removal with increasing the pH from 3 to 8 decreased and increased from 8 to 12. Also percent removal with increasing temperature in the range of 17 to 30 °C decreased. The results showed Langmuir isotherm had good agreement for explan phosphorus removal by modified zeolite. The results of physical model showed that higher percent phosphorus removal occurred in higher discharge and lower length of filter pond due to more contact drain water with the modified zeolite.

In this research, the adverse hydraulic jump formed in a gradually expanding stilling basin of rectangular cross section is investigated both theoretically and experimentally. The experiments were conducted in a specially designed model for a wide range of bed slopes and diverging angles of the basin walls in addition to classic jump for a wide range of Froude numbers. A momentum-based theory is presented to determine the sequent depth ratio. The results show that there is good agreement between theoretical and experimental data. Comparison of important parameters of a diverging hydraulic jump on the adverse slope, such as length, sequent depth and energy loss, with those in the classic jumps indicated that any increase in the adverse bed slope and the diverging angle of basin wall would cause a reduction of the sequent depth and relative length of jump and increase in the relative energy loss in comparison to the classical hydraulic jump.

Stilling basins are one of the most common structures for energy dissipation of flow with high velocity and among different sections and types of these basins، diverging basins have better performance and lower constructional costs. In this research، the feasibility of 3D numerical simulation of diverging hydraulic jump in rectangular basins was investigated using standard and RNG turbulence models using Fluent software. The free surface was determined using the VOF method. The outputs of numerical model in comparison with the results of physical model of hydraulic jump in diverging rectangular basins with diverging angels of and showed that the standard turbulence model evaluated the free surface of water، jump length and maximum velocity in defined sections better than RNG turbulence model. this model show that the efficiency of diverging basins in decreasing length of jump is more better than the classic basins. So this model is recommended for simulating hydraulic jump in diverging sections. Results showed that the mean relative error of water surface obtained from numerical model and measured values is about 7 percent. Modeled Velocity profiles were in good agreement with measured data. Also the numerical model showed the vortices that were accrued because of diverging walls as well as experiment investigations. These vortices accrued near the right side of diverging wall in high Froude numbers and in lower values of Froude numbers، accrued in both two sides of walls. The intensity of vortices was increased by increasing the angle of diverging walls.

The hydrodynamic behavior of approaching flow and the amount of sediment entry into right-angled lateral intakes in diversion dams were investigated using a laboratory channel by experimental measurement and observation. The velocity field upstream of the intake in the main channel and before it at the sluice gate was measured at different elevations of flow at different discharge rates of the river, intake and sluice gate. Velocity profiles were also measured from upstream to downstream for the intake and the amount of sediment entry into it. Analysis of the velocity data showed that discharge at the sluice gate strongly affected velocity profiles and the mechanism of sediment entry. All velocity profiles where the sluice was closed had an inflection point, where the flow direction changed, leading to a return velocity near the bed. The elevation of this point was a function of the intake discharge and approximately equal to the height of the entrance sill. Observation showed that sediment entered the intake in whirlpool vortices. The strength and frequency of the vortices depended on the intake and sluice gate discharges. Analysis of sedimentary data showed that the amount of sediment entering the intake increases with an increase in intake discharge. In addition, for any given intake discharge rate, an increase in the sluice gate discharge caused an increase in sediment entry into the intake.