Water and Soil

Abstract Introduction: Rice is a staple food source and the most important grain in developing countries, which is most commonly consumed by more than 90 percent of the world populations. Moreover, this plant is produced and consumed in Asia. However this major crop faces severe limitations such as water scarcity and other environmental stresses. Limited water resources along with climate change effects, have increased attention to methods which improve water use efficiency in crops such as rice cultivation. On the other hand, traditional irrigation methods for rice production often waste considerable fraction of irrigation water. Therefore, it is necessary to modify irrigation and other farming methods. Furthermore, using biochar and nitrogen fixing bacteria as organic biofertilizers can be effective methods to improve water use efficiency and yield attributes of rice plant. Therefore, the present research was conducted to investigate the effect of biochar and Azosprillum lipoferum rhizobacteria on yield and water use efficiency on Tarom Hashemi rice cultivar of under flooded and alternating irrigation regimes. 
Materials and Methods: This study was conducted at the research fields of the Sari Agricultural Sciences and Natural Resources University in 2017 and 2018. The experimental site is located at 36º 39ʹ42ʺ N latitude and 53º03´54ʺ E longitude with -11 m above sea level. Soil samples were taken from depths of 0-30 cm before land preparation. The experiment was done in factorial split-split plot arrangement with complete randomized blocks based design with three replications. Treatments included two irrigation management methods (flooding and irrigation regimes) in combination with nine fertilizers levels (100% of recommended nitrogen or N100, N100+ 10 ton biochar or biochar 10, N100+ biochar 20, N75, N75+ biochar 10, N100+ biochar 20, N50, n50+ biochar 10 and N100+ biochar 20) as main plots and seedling inoculation with Azospirillum lipoferum bacteria (without inoculation was also included as control) as sub plots.Plot ridges were covered by plastic sheets and inserted into the soil at 50 cm to prevent water flowing from one plot to the others. The plots were then leveled and 3-4 leaf seedlings stage. A specific number of seedlings were gently washed and placed for 30 minutes in a pan containing 10 L of water mixed with 1 L of bacterial inoculum. Carboxymethyl cellulose, 15 g, was added to increase adhesion of bacteria into the plant roots. Nitrogen, phosphorus and potassium fertilizers were applied according to the results of soil analysis. Weeds and pests were controlled mechanically or by hand and no herbicides or pesticides were used.
Results and Discussion: Results showed that biochar and nitrogen fertilizers, irrigation methods, and seedling inoculation with bacteria had significant effects on water use efficiency indices. Comparison of means of interaction effects showed that the highest paddy yield (5950.43 and 5330.78 kg/ha, respectively) were observed by flooding irrigation method in combination with N50 + biochar 20 treatment and inoculated by Azospirillum lipoferum bacteria and alternating irrigation management method which was along with N50 + biochar 20 without inoculation. Alternating irrigation plots experienced water shortage in some growth stages and therefore slightly lower paddy yield is acceptable. Application of biochar 20 and flooding or alternating methods which treated by N75 and N50, respectively showed 49.1% increase in economic efficiency index.
Conclusion: In general, application of 20 ton biachar along with 75% nitrogen fertilizers led to 42.8% increase in economic advantages in alternating irrigation method as compared to the flooding systems. These observation indicates beneficial effect of fertilizer in economic advantage enhancement in rice cultivation.

Abstract Introduction: Horizontal subsurface flow constructed wetlands have long been applied to improve water or wastewater quality. Previous studies on wetland systems have focused on trying to comprehend the processes leading to the removal of pollutants. Comparatively, there have been fewer studies dedicated to the assessment of flow distribution on hydraulic behavior through the wetland. Researchers declared the aspect ratio (length to width ratio), inlet-outlet configuration, the size of the porous media and the loading rate of constructed wetland could influence hydraulic retention time (HRT). Su et al. (2009) have stated that in free water surface constructed wetlands, when the aspect ratio is greater than 5, the hydraulic efficiency will reach 0.9, or even higher. If the project site or field area cannot meet the theoretical standard, the recommended aspect ratio is higher than 1.88 to ensure some hydraulic efficiency greater than 0.7. The present study was an attempt to analyse, with the aid of 3D numerical simulation and tracer study, how flow distribution affected hydraulic behavior by using 3 different input flow layouts. Materials and Methods: The treatment system consisted of a horizontal subsurface flow in a constructed wetland having an aspect ratio of 6.5 and the bed slope of one percent. The geometry of this system, which was 4 m wide × 26 m long × 1 m deep, was planted with Phragmites australis. Inlet configurations were selected as a variable parameter. Three different inlet flow configurations including midpoint-midpoint (A), corner- midpoint (B) and uniform-midpoint (C), with the same fixed outlet configurations, were studied. The average flow discharge in each configuration was 6.58, 6.52 and 6.4 m3/day, respectively. Dye tracer was used to draw retention time distribution curves in each configuration for assessing the internal dispersion, short-circuiting and hydraulic parameters such as effective volume rate which is derived by division of mean retention time per nominal retention time. The 3D model presented, which was built on the Comsol Multiphysics platform, was implemented for fluid flow to show internal hydraulic patterns in the system. Hence, the hydraulic model used the Darcy equation to simulate a stationary water flow through the bed. The simulations were verified by using real data obtained from the existing constructed wetland. It was mostly used to show pressure throughout the system for each configuration of the inlet and the outlet. Results and Discussion: The mean retention time for each configuration was found to be 4.53, 3.24 and 4.65 days, respectively. A marked reduction of the mean hydraulic retention time signified leaving tracer concentration from the outlet rapidly, high short-circuiting and dead volume and finally defective treatment process influenced by changing the inlet to the corner. According to tracer breakthrough curve, the effective volumes for configurations A and C were 87.5%, as compared to 62.1% for the configuration B. The two-day difference of tpeak between configurations 2 and 1, and 3 was probably due to the establishment of preferential streamlines resulting in short-circuiting and areas of dead volume in the system. The value of tpeakis related to dispersion, in the sense that a retention time distribution curve with a small peak time generally contains low dispersion. Simulation results showed the pressure difference from the inlet to the outlet ranged from 12-14, 14-15 and 10-13 cm H2O for A, B and C layouts, respectively. It was shown that the maximum pressure gradient occurred at the outset of the influent wastewater at the inlet, and it was gradually reduced to the lowest values at the outlet ports. Consequence of surface pressure demonstrated uniform pressure from inlet toward outlet at configuration C. Simulated streamlines approved this result, while range of high and low pressure area at configuration B was the most. There was a strong association between tracer experiments and simulation works. One of the major findings of this study was the significant shorter hydraulic mean retention time of the corner inlet setup. There are many that may cause these effects, although short-circuiting may be the primary one. A large low-pressure zone appeared at the opposite corner that was neither inlet nor outlet in this configuration. Conclusions: This paper investigated the hydraulic performance and short-circuiting effects on water flow due to three different inlet patterns (i.e. midpoint, corner, and uniform) in horizontal subsurface flow wetlands based on dye tracer measurements and numerical modeling. The results showed that the uniform inlet could provide the highest hydraulic efficiency (i.e. longest hydraulic retention time, HRT), in comparison to other two setups. The performance of the three different layouts was also investigated in terms of hydraulic parameters. Short-circuiting was influenced by lower hydraulic retention time, leading to inadequate treatment. Uniform-midpoint and midpoint-midpoint yielded the best effective volume as compared to the corner-midpoint. It was demonstrated that these two cases increased dispersion and used the whole capacity of the constructed wetland for the treatment process. The most important result of this paper was the evaluation of internal hydraulic pattern thorough the wetland, something not investigated in previous research works. Based on the simulation results, the spatial pressure distribution in wetland cells was depicted. Finally, it can be concluded that the best configuration of inlet-outlet layout based on both numerical simulations and physical experiments is uniform-midpoint. Meanwhile, midpoint-midpoint is preferable to corner-corner by all performance criteria.

Abstract Introduction: Water is one of the most important factors limiting agricultural developments in arid and semiarid regions in the world. To avoid and exit from water crisis, a proper agricultural and water resource management is required. One of the important parameters in this regard, is determination of crops’ evapotranspiration. Evapotranspiration, water evaporation from the soil surface and transpiration of vegetation cover have a major trend and a key element in hydrological cycle for management of water resources, particularly in arid and semi-arid. Evapotranspiration is function of the soil, climate, land use, aerodynamic resistance levels and topography of the area. To provide a suitable irrigation schedule and apply an optimal water use management, determination of water requirement and crop coefficients in various growth stages seems necessary. Crop coefficient can be found through dividing the actual evapotranspiration by the potential evapotranspiration. Since the cuminum is commonly used in Birjand and has cultivated in farm and crop coefficients has not been determined , this study aimed to determine the crop coefficients of cuminum using lysimeter water balance in arid and semi-arid climatic conditions. Materials and Methods: In this research, in order to determine cuminum crop coefficients, that is one of the important herbs, a lysimetric experiment was conducted during growth season in faculty of agriculture, Birjand university. This project, was done in lysimeter. For this purpose and due to the size and plant height in three lysimeter (as replications) with a diameter of 20 and a height of 16 cm was used order to the cultivation of Cuminum. In order to drainage at the bottom of each lysimeter was built orifice. For easily of lysimeters drainage, lysimeter floor was poured by small and large sand and lysimeter was filled by soil and animal Fertilizers for better plant growth. Three lysimeters were used; and water requirement of cuminum was calculated using water balance method. To calculate potential evapotranspiration, grass with 12 centimeters height was used as the reference plant. Crop coefficient can be achieved by dividing the actual evapotranspiration to reference evapotranspiration and is not fixed growth period. The cumin plant growth period was divided four stages (initial, development, middle and end). The initial phase of up to 10% on seed germination and plant growth, from 10 percent to flowering development stage, middle stage and final stage of the start of flowering to product reaches to harvest is the end of the middle stage. In each lysimeter average number of 20-15 of seed to increasing germination, were planted on the February 9, 2012. To control weeds, weed was done handing during the growing season. Drainage water is controlled over a period of time measured with weighting method and deep and volume of water was measured. Soil moisture at field capacity using pressure plates was measured. Measuring soil water content and determine irrigation time. Results and Discussion According to the results obtained for the crop coefficient can be concluded that in the initial stages of plant growth that plant size is small, transpiration is low and therefore Kc have low value. In the middle and development stage increases canopy and increased transpiration rate and increases Kc. At the end stage to reducing activity of the leaves (old leaves) reduced transpiration. The average crop coefficient of cumin in the initial phase of growth during the study to 0.65, then with increasing plant growth, leaf area index were increased and crop coefficient increased to 0.92 in development stage. In the middle of this amount is 1.21 and in the end the 0.85 reached. Average crop coefficients for a four-stage is 0.9. Duration of growth stages for cuminum crops in Birjand region is 24 days for initial stage, 40 days for middle stage and 31 days for development and 19 days for end stage of growth stages. Conclusions In this study according to important of drug and economic for cuminum plant and that there isn’t report for crop coefficient cuminum and Birjand region, we cultivate cuminum in arid area of Birjand in 2011 year. The results of lysimeters showed that Duration of plant growth stages and value of crop coefficients in the initial , development, middle and end stages, respectively (24, 40, 31 and 19 days) and (0.65, 0.921.21 and 0.85) respectiely.

Abstract The present study was aimed to determine the effect of drip irrigation methods and nitrogen levels and their interaction on corn root development and study of the root movement model. For this purpose, a split plot field experiment based on randomized complete block with irrigation method in two levels (surface and subsurface drip) as main treatment and Nitrogen fertilization in two levels (50 and 100% of fertilizer requirement) as sub main treatment at 3 replications was conducted at Agricultural Engineering Research Institute, Karaj, Iran using corn variety 370 double-cross. Monitoring of root depth was performed by digging trenches and observation of soil profile. The samples were collected during the growing season with 10 day intervals (8 times totally) and root weight in different soil layers was measured by harvesting of soil monoliths and washing in plastic filters under water pressure. Results showed that the depth of root development up to 20 days after planting was significantly more in surface irrigation method compare to subsurface drip irrigation method; but it was not significant in 30 to 80 days after planting at 5% level. The depth of root development was not significantly different in different nitrogen levels in fertigation method at 5% level. Interaction of irrigation methods and nitrogen levels also didn’t show significant effect on depth of root development at different corn stages growth at 5% level. Root width development was not significantly different in all treatments. The most root distribution observed at 20 to 40 cm and 0 to 20 cm of soil layer in subsurface drip irrigation and subsurface drip irrigation methods, respectively. The lowest root density was observed at 40 to 60 cm soil layer in both studied irrigation methods. Also the roots were more uniformly distributed in soil in subsurface drip irrigation method compare to surface drip irrigation method. The most accurate root depth estimation was achieved by the linear, Borg & Grims and Cropwat models, respectively.

Abstract In arid and semiarid regions, controlled drainage is the next logical step towards improving water management in irrigated agriculture and reducing the environmental impacts of subsurface drainage flow. Controlled drainage has been practiced in humid areas for a long time. In this research a controlled drainage system in Khuzestan Province, Southwest Iran was tested as a strategy for continuous water table management with the benefits of optimizing water use and reducing unnecessary drainage and nitrogen losses from agricultural fields. To study the feasibility and performance of water table management, Field experiments were carried out on a 63.41 ha with 3 treatments on the farms under subsurface drainage of Imam Khomeini's sugarcane agro-industry. 3 treatments compared consisted of a free drainage treatment (FD) and tow controlled drainage treatment with water table controls set at 90 centimeter (CD90) and 70 centimeter (CD70) below the soil surface. Collected data during a sugarcane growing season included water table depth, drained volume, nitrate-nitrogen and ammonium-nitrogen concentration in the drainage water and groundwater. Controlled drainage had a significant hydrological and environmental effect during studding period. Compared with CD, the total drain outflow from CD70 and CD90 area were 62.48 and 48.98% less, respectively. Compared with CD, the total amounts of nitrate-nitrogen and ammonium-nitrogen in drain outflow were about 45 to 60 % and 50 to 65 % less, respectively. Nitrate-nitrogen and ammonium-nitrogen concentration in the both of drainage water and groundwater did not differ significantly in all of the treatment. These data suggest that controlled drainage can be applied at big scale in the Khuzestan Province with the most installed subsurface drainage in Iran, with advantages for water conservation and environment.

Abstract Introduction: The water is the major key in sustainable development, so it is necessary to be managed and conserved. The quality of surface water resources is mainly controlled by natural or geogenic factors including chemistry of recharge water, soil and geology processes, as well as the man-made contaminant. Qualitative indicators are used as effective managing tools in decision making programs. Water quality indices (WQI) are the simple and suitable tools to determine the quality statue of the water. In order to calculate the water quality index, many parameters are integrated in mathematical formula to represent the quality condition of the water with a number which classifies the quality in the scales of the weak to excellent. Many water quality indices were introduced by researchers and organizations around the world. Aji-Chay, one of the most important flowing rivers in East-Azerbaijan province, northwest of Iran, is passing through Tabriz plain in its way and finally ends to the Uremia lake. Regarding the focused industrial zones, agricultural field and urban areas in this plain, the river is highly vulnerable to pollution and quality degradation. So, this study was aimed to assess the Aji-chay River based on quality indicators, in order to helps its better management.
Materials and Methods: In this research for assessing pollution of the Aji-Chay river using water quality indices, 16 sampling stations were located along the river and water samples were collected during wet (May 2016) and dry (September 2016) seasons. Electrical conductivity (EC), temperature, dissolved oxygen (DO) and pH were measured in the field and total dissolved solids (TDS), turbidity, major ions (Ca, Mg, Na, K, HCO₃, Cl, SO₄), nitrate (NO₃), phosphate (PO₄), biological oxygen demand (BOD), chemical oxygen demand (COD) and biological contaminants (fecal coliform) were determined in the laboratory. Quality indicators including the US national sanitary foundation water quality indices in the two forms of multiplicative (NSFWQI_m) and additive (NSFWQI_a) and Iranian surface water quality index (IRWQI_sc) were used to assess the quality of the Aji-Chay river.
Results and Discussion: Turbidity and Electrical conductivity (EC) is high at the upstream which is related to movement of the River in upper red formation (Miocene series) which enhances the chloride, sodium, calcium and sulfate. Arsenic concentrations are exceeding the drinking standards (0.01 ppm) across all samples mainly from a geogenic sources as well as discharge of wastewater in some areas. The elements Cd, Mn, Ni, Pb, Mo, Co, Zn, Fe and Al are mainly geogenic, whereas Cu, Ba and Cr are mostly originated from anthropogenic activities. Based on the results, river quality at the wet season is highly controlled by the main branch and Gomnab-Chay, but Mehran-rood plays the major role in downstream water quality at the dry season due to its higher discharge rate. The process was confirmed by Piper and Schoeller diagrams. Most of the parameters are increased in middle parts at the river where the concentrated sources of contaminates and discharge of wastewater increased the organic and biological constituents and nutrients especially in dry season. Assessing the river quality for agricultural uses based on modified Wilcox diagram shows except for Mehran-rood, the other samples are unsuitable for agriculture and the dry season quality is better than the wet season. Based on the results, increase in most parameters and so, pollution and quality degradation of the river are observed to the downstream. Assessing quality of the Aji-Chay river using US national sanitary foundation water quality indices in the two forms of multiplicative (NSFWQI_m) and additive (NSFWQI_a) and Iranian surface water quality index (IRWQI_sc) confirmed the bad to very bad qualitative statue of the river in most stations especially in the middle parts of the Tabriz plain. The results revealed that quality degradation of Aji-Chay river is probably due to discharge of contaminants from municipal and industrial wastewaters (effluents), highlighting the need for managing actions to improve quality of this important river. Comparing the quality indices showed the priority of NSFWQI_m (multiplicative form of US national sanitary foundation water quality indices) in quality classification and pollution assessment of the Aji-Chay river.
Conclusion: Quality degradation of Aji-Chay river is probably due to discharge of contaminants from municipal and industrial wastewater effluents, indicating the need for managing actions to improve quality of this river. In this study priority of NSFWQI_m (multiplicative form of US national sanitary foundation water quality indices) in quality classification and pollution assessment of the Aji-Chay river was confirmed.

Abstract Introduction: Biochar is a material produced from organic matters under high temperature and low oxygen conditions. In recent years, scientific attention has been focused on its effects on soil amendment and ecological restoration.Due to its properties related to surface area and porosity, bulk density, nutrient content, stability, cation exchange capacity (CEC), pH value, and carbon content, biochar has the potential to improve physical and chemical soil properties and thus improve crop productivity and contribute to carbon sequestration. Biochars can have very different properties depending on the feedstock they are produced from and the pyrolysis conditions used to generate them.Biochar retains nutrients for plant uptake and soil fertility. The infiltration of harmful quantities of nutrients and pesticides into ground water and the runoff that erodes the soil and enters into the surface waters can be limited with the use ofbiochar. The actual effects of biochar on soil properties depend on the soil type and the plant species grown on the area of application, as well as biochar type and application rate.The aim of this study was to evaluate the effect of the biochar types and rates on some soil properties and nutrient availability in a calcareous soil. Materials and Methods: An incubation experiment was conducted in a completely randomized design with three replications. The treatments were three type of biochar (apple pruning wastes, grape pruning wastes and wheat straw), and five biochar rates (0, 1, 2, 4 and 8% w/w). Biochars used in the experiment wereproduced at the final temperature of approximately 350°C for almost 3 hours. The biochars were ground and sieved over 1 mm sieve for the incubation experiment.100 g of soil sample was weighed into polyethylene pots and then thoroughly mixed with 1, 2, 4 and 8 g of the biochar samples. Soil controls were run without any amendment. Distilled water was added to the soil–biochar mixtures (soil samples) in order to keeptheir moisture content to 60% of their water-holding capacity. The incubation was carried out in a controlled incubation chamber at 25oC for incubation in aerobically controlled non-leached conditions during 8 weeks.After 60 days, the samples were dried andsoil pH and electrical conductivity (EC) were determined in 1:5 soil to water extracts. Also, to determine mineral N, the soil samples with biochar were extracted with 2 M KCl. Organic matter was determined by dichromate oxidation. Soil extractable P and K were extracted with 0.5 M NaHCO3 (ratio 1:10) (Olsen-P) and 1 N NH4Ac (1:20) (NH4Ac-EK), respectively. DTPA-extractable Fe, Mn, Cu, and Zn were analyzed by atomic absorption spectrometry method (Shimadzu AA-6300). Results and Discussion: The results indicated that adding biochar changed some soil properties such as soil organic carbon, pH, electrical conductivity and the availability of some macro and micro nutrients. These changes were also more evident with increasingin the rate of biochar. Soil organic carbon (SOC) contentsin the amount of 8% apple pruning wastes, grape pruning wastes and wheat straw biochar were 3.78, 3.80 and 5.24 times more than control, respectively. Available potassium and phosphorus increased further in derived biochar from wheat straw in the amount of 8% compared with apple pruning and grape pruning wastes. Soil available potassium in wheat straw biochar was 2.19 and 1.88 times higher than apple pruning and grape pruning wastesbiochars, respectively. Wheat straw biochar greatly increased soil EC compared to control, and a higher biochar addition finally resulted in a higher value of soil EC. Also, the mineral – N, comprising of ammonium nitrogen (NH4-N) and nitrate nitrogen (NO3-N), concentrationshowed significant reduction when different rates of biochar were added to the soil. Increase in the rate of applicationmarkedly reduced the concentration of both NH4-N and NO3-N. Wheat straw biochar significantly reduced available iron. Also, soil available copper significantly decreased by increasing the rate of biochar. But, soil available manganesesignificantly increased by increasing the rate of biochar. The type and rate of studied biochars had no significant effect on available Zn. Conclusions: Generally, the soil organic carbon (SOC) markedly increased with an increase in rate of application ofbiochar during the 60 days of incubation. This suggests that the biochar has great potential for carbon sequestration in soil.In conclusion, it became clear that in order to allow for accurate prediction of the effects ofbiochar on soil characteristics and nutrient availability, a deeper understanding of interactions between soil type, biochar production method, biochar feedstock, application rate and field crops is essential. Further research is needed to determine long term impacts of biochar on these soils.

Abstract Introduction: Investigation of water passing through soil is one of the most important problems in soil mechanics and environmental engineering. It is an important parameter for predicting the movement of water and contaminants dissolved in the water through the soil and measured on soil samples in the lab and sometimes tests carried out in the field. Soil permeability generally depends on two factors, the first one is soil Specifications contains an empty space of soil, surface roughness of solid particles, saturation, and another one is characteristics of the fluid (water) that passes through soil. Already few efforts have been made to recognize the characteristics of anisotropy in the geotechnical designs therefore this study has been done. Physical and mechanical properties of soils and sedimentary rocks are generally heterogeneous and hydraulic conductivity (k) is not an exception. The anisotropy of hydraulic conductivity of soils has a great influence on the fluid flow and the transmission of contamination. Knowing the hydraulic conductivity in cases such as flow through dams and dikes, internal erosion in soil masses, settling of consolidated clay levels, optimal design of water and oil wells, and the design of drainage systems for roads, airports and agricultural land. Generally, the hydraulic conductivity is more in the horizontal direction than the hydraulic conductivity in the vertical direction, and the hydraulic conductivity anisotropy is shown with a non-dimensional parameter rk which is equal to the ratio of the horizontal hydraulic conductivity to the vertical hydraulic conductivity. According to Chapuis et al. (1989), on more than 100 measurements of hydraulic conductivity along with the results of the experiments of Chapuis et al. (1990), Rice et al. (1970) and Leroueil et al. (1990), the anisotropy of the hydraulic conductivity of clays, sands and sedimentary rocks are almost like each other. The degree of anisotropy may depend on the shape of the particles, their arrangement, or the orientation of the free space among the particles of the soil, which appears to be less than 4. Due to the impossibility of preparing intact samples from grain materials, as well as the lack of suitable measuring instruments for grain samples, there are few valid results for non-sticky materials. As Chapuis et al. (1989) and Sferlazza et al. (2009) in accordance with most of the experimental results, the anisotropy of hydraulic conductivity increases with density, and also the degree of anisotropy decreases with increasing porosity ratio. Materials and Methods: In order to conduct the present research, measurement device was designed and built. This device is a cube with 150 mm ×150 mm × 173 mm dimensions. The components of the device are: bleeding valves, inlet and outlet valves, porous plates and the size of the sample respectively. In this study, four uniform soil samples were selected for test. Samples are prepared in falling manner, with three porosity and under three different hydraulic gradient were tested. In Table 1 The general pattern of research experiments is presented. In this study, 36 tests were performed. Table 1-Pattern of research experiments Parameter Diameter particle Void ratio Water head The number of test cases 4 3 3 To measure vertical permeability, due to large grains samples, according to ASTM D-2434 standard fixed-load test method has been used. First, the porous plate is placed on the bottom of the measuring device to prevent the soil from entering and exiting the water penetration then The soil is inserted from the fixed height into the device and the porous plate is placed on the sample. Then place should be located at the top of the device and close the screws so there should be no water leak. Then the weight of the soil should be measured and connect the system to the water. Then the outlet tap should be opened and water should be passed through the soil sample until the sample would be completely saturated and no air bubbles come out of the outlet pipe and fix water level. Then the water head and weigh the empty container and the duration of the outflow of water for a given water volume should be measured. After performing the test at a specified head, the elevation of water should be changed by reservoir adjustment and the permeability coefficient would be measured in other loads. Results and Discussion: The effect of hydraulic loads on horizontal and vertical hydraulic conductivity coefficients for uniform samples Horizontal and vertical hydraulic conductivity tests were performed on uniform samples including coarse aggregate materials with a diameter of 0.85, 2, 6.35, and 5.9 mm. In Figures (1) to (3), the effect of hydraulic load on horizontal and vertical hydraulic conductivity for uniform samples in minimum and maximum conditions is shown. (B( (A( (D( (C( Figuer1- According hydraulic conductivity to hydraulic gradient for uniform samples with A) vertical hydraulic conductivity, minimal porosity B) Horizontal hydraulic conductivity, minimal porosity C) vertical hydraulic conductivity, maximum porosity D) horizontal hydraulic, maximum porosity Investigations showed that in all cases, with increasing hydraulic load, the horizontal and vertical hydraulic conductivity decreased and then the process of change was almost constant. Investigation of the effect of porosity on horizontal and vertical hydraulic conductivity of uniform samples The results showed that the horizontal hydraulic conductivity coefficient for all samples was higher than the vertical hydraulic conductivity coefficient. Also, the results showed that the minimum hydraulic conductivity (e = 0.46) and maximum porosity (e = 0.97) were about 34.33 and 0.35 percent higher than the hydraulic hydraulic conductivity, respectively. Investigation of the effect of porosity on the anisotropy coefficient of hydraulic conductivity of uniform samples: The results showed that with increasing porosity, the coefficient of heterogeneity of hydraulic conductivity for uniform samples was reduced and this coefficient was for uniform samples in the range of 0.89 to 1.35. Conclusions: The final results can be summarized as follow: 1. The permeability in the horizontal direction is often greater than the permeability in the vertical direction. 2. The anisotropy permeability for uniform sample is between 0.85-1.35. 3. The anisotropy permeability decreases with increasing porosity. 4. In the uniform samples, maximum permeability occurs at higher hydraulic conductivity. 5. With increasing the uniformity coefficient, the amount of hydraulic conductivity decreases.

Abstract Introduction: Drought is a natural phenomenon and was described when precipitation is less than expected. Since the precipitation amounts in terms of spatial and temporal characteristics are different from one region to another, so this phenomenon is known as a multivariate phenomenon. This phenomenon often characterized by different variables such as drought duration, severity, intensity and spatial extent. Although site specific analysis can provide useful information on drought occurrences in a limited area, but these results have a fundamental uncertainty to drought risk assessment in a large region. Therefore regional drought analysis, provides a more comprehensive assessment in each region, and is essential for short and long term management of water resources. Meanwhile, the copula functions has been developed as a new advanced technique for modeling the two or multivariate joint probability distribution in different fields such as financial, hydrology, water resources and risk management. So, in this research, regional analysis of drought severity and percent of drought area were performed using the copula functions in Lake Urmia basin, as one of the Iran's drought-prone basin. Such study with emphasis on bivariate analysis of drought severity and drought areal extend were conducted for the first time in the study area. The main objectives of this study are: 1) Modeling drought characteristics in Lake Urmia basin, 2) Evaluation of copula functions in modeling the structure of the region's drought characteristics, and 3) Develop the Severity-Area-Frequency curve using the appropriate copula. Materials and Methods: Copula is the stochastic model and based on probability. In other words, copulas are function for modeling the two or multivariate random variables. Copulas can be easily coupled the marginal distributions to multiple distributions. There are many parametric copula families available, that seven copula functions such as archimedean (Clayton, Frank, Gumbel and Joe), extreme value (Galambos), elliptical (Normal) and others (Plackett) were used. The SPI-1 was determined at each station and then, the whole area was divided into small grids with cell size of 2000×2000. Distances between the grid centers with all the selected stations were calculated with a programming code. Finally, the SPI values in each grid were calculated using IDW method. The severity and percentage of drought area variables were determined and used for regional drought modeling in the study area based on drought threshold equal to zero. After determining the best statistical distribution of two variables, the appropriate copula function was conducted based on different goodness of fit tests. Finally, the Severity-Area-Frequency curve for the study area was developed based on the appropriate copula function and conditional return periods. Results and Discussion: The correlation between the two variables of percentage of drought area and severity was assessed using different graphical (Kendall plot and Chi plot) and statistical tests (Spearman rand order correlation and Kendal tau). The results showed a positive correlation between the drought severity and percentage of drought area variables. Based on Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC) and graphical test, the Lognormal and Beta probability distributions were select as a best fit distribution of severity and percentage of area under drought, respectively. Finally, the Frank copula among other type of copulas was selected as an appropriate copula for modeling joint drought severity and percentage of area under drought for the study area based on Maximum log likelihood, AIC, BIC and RMSE criteria. The S-A-F curve was developed using conditional return periods based on Frank copula. According to S-A-F curve, it can be seen that increase in the percentage of area under drought in the study area led to increase in drought severity and vice versa. For example, drought severity with return period of 20 years and drought with 20 percent areal extend is obtained equal to 0.37. Conclusions: Copula functions are of great importance in the analysis of drought, due to preserve correlation between variables and not have any limitation to have a same marginal distribution in long-term prediction of drought events. In this study, using best fit copula (Frank copula) and conditional return periods, the relationships between drought severity and percent of area under drought for the study area named S-A-F curve were developed. These curves can be useful for planning and management of drought in the region. Drought risk assessment based on the results of this study can be high priorities for drought monitoring in large areas.

Abstract Introduction: The study of flow diversion in open channels which has been, since long, under consideration by hydraulic engineers, is much used to divert flow from a main channel or from a river into an irrigation or hydropower channel. When a water intake with an angle is installed at one side of the channel, the streamlines of the flow deflect towards the intake. As a result, a separation zone is produced in the lateral channel. The separation zone develops in the lateral channel and reduces the discharge capacity and efficiency of water intake by delimiting the channel width available for the flow. Therefore, determination of water intake geometry and flow conditions to produce minimum separation zone is very important and they are the focus of this study. The majority of previous studies was conducted on sharp edged water intake entrances. Therefore, in this study, to find the optimum radius for a round edged entrance water intake, a comprehensive experimental program was carried out in a laboratory flume and the separation zone dimensions and Alpha and Beta coefficients were measured. Materials and Methods: The experimental model was built in hydraulics laboratory. The water intake was installed at 55 degrees to the main channel. The main channel consisted of a rectangular cross-section with a base width of 0.5 m, height of 0.4 m and a length of 15.80 m. The lateral diversion channel was 0.25 m wide, 0.40 m high. According to previous experiments that performed by Keshavarzi and Habibi (2005), radii of 10, 15 and 20 cm were selected for the edges of the intakes, upstream of the 55 degree water intake. The velocities of the flow in transverse and flow directions were measured using an electromagnetic velocity meter at three distances Z= 3 cm, 6 cm and 12 cm, in which Z is the distance from the bed. Then the size of the separation zone, Alpha and Beta coefficients were determined. Results and Discussion: To find a relationship between the radius of the round edge entrance in the 55 degree water intake and the size of separation, the geometry of the separation zone must be determined. To find the geometry and pattern of separation zone for different flow conditions, the particle traces technique was employed using Tec plot Software version 8.0. In open end flow condition, for discharge ratios of 0.2, 0.4, 0.6 and 0.8, and for the radii of 10, 15 and 20 cm, flow separation occurs at 3 cm and 12 cm distance and only upstream of the intake inlet. The separation size in r=20 cm is less than for other radii. Also, the separation size for Qr = 0.8 is minimized and for Qr =0.2 is the maximum and for r/Wb=0.8, the length and width of separation are minimum. In close end flow condition and for radii of 10, 15 and 20 cm, the size of separation zone at upstream of water intake is much larger than that in downstream. Comparing with the separation length downstream of the intake it can be concluded that with increasing the inlet radius, the separation length upstream of the intake inlet decreases. Therefore, in close end conditions, rounding of the intake inlet is effective to decrease separation length at upstream side of water intake. Also, in close end conditions, flow separation occurs at downstream side of water intake. Furthermore, the separation size for r=20 cm is less than for other radii, therefore, r/Wb=0.8 is the optimum radius ratio with a minimum separation size at the 55 degree water intake. Conclusions: When a water intake with an angle is installed at one side of the channel, the streamlines of the flow deflect towards the intake. As a result, a separation zone is produced in the lateral channel. The separation zone development in the lateral channel and reduces the discharge capacity and efficiency of water intake by delimiting the channel width available for the flow. In this study, to find the optimum round inlet radius, the experimental tests were carried out at a water intake installed in a rectangular channel with rounded edge with 10, 15 and 20 cm inlet radius. Then separation zone dimensions and alpha and beta coefficients determined. These experiments were carried out in close end and open end flow conditions for diversion flow ratio 0.2, 0.4, 0.6 and 0.8. Using particle trace plot for different flow pattern, the values of length and width of flow separation upstream and downstream of the intake were determined. The result showed that the separation size for Qr = 0.8 is minimized, whereas it is maximum for Qr =0.2. Furthermore, the separation size for r=20 cm is less than for other radius, therefore, r/Wb=0.8 with a minimum separation size was selected as the optimum radius ratio.

Abstract Particle size distribution (PSD) is one of the most important soil physical properties. The Grey Model GM(1,1) is a new method and different from empirical and parametrical models for description and estimation of soil particle size distribution. In this study, the models of Grey GM(1,1) and Skaggs have been used to estimate PSD in five soil textural classes including 138 soil samples taken from Shahrekord Plain. For evaluating and comparison of two models, four statistical indices (MSE, MAPE, AAE, R2) and 1:1 lines were used. The results showed that the performance of both models was relatively good in all five textures. However, Skaggs and Grey GM(1,1) had the best performance in loam and clay textures, respectively. It seems that the performance of Skaggs and Grey GM(1,1) models improved when soil textures changed to coarser and finer textures, respectively. Absolute cumulative error (AAE) of the Skaggs model in some textures tended to decrease while that of the Grey GM(1,1) tended to slightly increase with increasing uniformity and curvature indices of soil.

Abstract Introduction: Cracking of earth dams is a one of the main threat causes of stability of embankment dams. In this research by modeling of the behavior of an embankment dam and employing conditions of the earthquake, the reasons of cracking were inspected using by modeling of earth dam behavior. Based on the literature, one of the main causes of dam failures is sliding and cracking of the dam structure during earthquake. Localized liquefaction of foundation soils was one of the causes of the observed post-earthquake distress within these dams. Material and Methods: In order to study the causes and the results of crack on earth dams, Mahmoodabad earthen dam with a height of 19 m, is located in Zanjan province, northwest of Iran, which suffered a longitudinal crack on the crest and slight sliding of the upstream slope due to 2001 Avaj earthquake was studied. This dam has faced earthquake two times with an interval of two years. During the first earthquake with the magnitude about 6.6 in Richter scale small longitudinal cracks had created on the crest. The developed cracks had been repaired by injecting the cement and then has been hidden by passing the time. After the second earthquake with the magnitude about 6.5 in Richter scale the hidden cracks had been appeared again and the slight movement of the upper slopes of dam reported. Based on the site investigation and documented information about dam, including maps and parameter data, the behavior of the dam has modeled by using Plaxis as a finite element model. In order to check the accuracy of the design of dam, the stability analysis has been conducted using by Xslope as a limit equilibrium model. The foundation conditions and the Geotechnical properties of the layer beneath the dam has been inspected by open excavation. Results and Discussion: Underground investigation about Geotechnical properties of dam foundation has showed that there is a thin sandy layer confined in alluvium material of the river base beneath the dam structure. In fact , this layer has not been considered in the analysis as well in design. Because of fully saturated condition of this layer in an operation period of dam it might subjected to liquefaction during the happening of the earthquake. Evaluation of liquefaction potential of this layer based on Seed and Idriss (1971) diagram showed probability of this phenomenon. To prove this hypothesis, the stability analysis had been conducted in two different conditions by including the thin sandy layer and without considering the mentioned layer. The analysis showed in the case of absence of sandy layer the required safety factor was satisfied, but including the sandy layer leads cause the safety factor dropped to 0.84 that means accruing of liquefaction in the thin layer would lead to structural instability of the studied dam. The simulation of the behavior of dam by employing the accrued earthquake acceleration confirmed the liquefaction has been accrued in the thin sandy layer. The results of finite element simulation showed the depth of the cracks on the crest is about 2 meters and also the upstream slope has slipped about 81 mm to the reservoir of the dam. These results was consistent with the observed values. To overcome the next risks, also to repair the damaged parts of the dam, 3 different methods had been proposed. The curing technics was deploying of the reservoir and removing of the damage part of the dam and as well the thin sandy layer and reconstructed that part of dam, Deploying of reservoir of the dam and adjusting the slope of the upper shoulder to stable condition and at least repairing the developed cracks by injecting cement slurry and tolerate the current condition without imposition any additional costs to the project. The third method has been selected, but for any probable risky condition monitoring of the dam has been advised. Conclusion: Based on the overall results of the investigations, it was concluded that cracking and sliding of upstream shell is mainly due to the presence of a loose, fine sandy layer under the base of the dam which was liquefied during the earthquakes. In order to overcome the problem, one of the three offered solutions, including modification of cracks by injecting cement slurry, was applied and after roughly 9 years, the provided reports confirmed the adequacy of the applied solution.

Abstract Introduction: Exact prediction of transported sediment rate by rivers in water resources projects is of utmost importance. Basically erosion and sediment transport process is one of the most complexes hydrodynamic. Although different studies have been developed on the application of intelligent models based on neural, they are not widely used because of lacking explicitness and complexity governing on choosing and architecting of proper network. In this study, a Genetic expression programming model (as an important branches of evolutionary algorithems) for predicting of sediment load is selected and investigated as an intelligent approach along with other known classical and imperical methods such as Larsen´s equation, Engelund-Hansen´s equation and Bagnold´s equation. Materials and Methods: In this study, in order to improve explicit prediction of sediment load of Gotoorchay, located in Aras catchment, Northwestern Iran latitude: 38°24´33.3˝ and longitude: 44°46´13.2˝), genetic programming (GP) and Genetic Algorithm (GA) were applied. Moreover, the semi-empirical models for predicting of total sediment load and rating curve have been used. Finally all the methods were compared and the best ones were introduced. Two statistical measures were used to compare the performance of the different models, namely root mean square error (RMSE) and determination coefficient (DC). RMSE and DC indicate the discrepancy between the observed and computed values. Results and Discussions: The statistical characteristics results obtained from the analysis of genetic programming method for both selected model groups indicated that the model 4 including the only discharge of the river, relative to other studied models had the highest DC and the least RMSE in the testing stage (DC= 0.907, RMSE= 0.067). Although there were several parameters applied in other models, these models were complicated and had weak results of prediction. Our results showed that the model 9, with the most DC and the least RMSE (DC=0.694, RMSE= 0.081), had the relative advantage to the other none dimensional models. Finally it is clear that the model 6 had more predicting capability rather than the model 9, so among all the models, model 6 was the best referring model for estimation of sediment load of the Ghotoorchay river. Conclusion: It was observed that the model including only the discharge of the Ghotoorchay river the best model for estimation of sediment load and it was applied for comparing all the other sediment predicting models such as some classic methods that includes Larsen´s equation, Engelund-Hansen´s equation and Bagnold´s equation and optimized rating curve. Among all methods, it was concluded that the genetic programming was superior to other methods in predicting sediment load of the mentioned river. Therefore, genetic programming that is a branch of evolutionary algorithms, with high prediction capability was offered as a powerful tool for optimizing and explicit predicting of total sediment load of the Ghotoorchay River.

Abstract Introduction: Iron cycle is one of the most important biogeochemical processes which affect the availability of iron in soils. Ferric iron oxides are the most abundant forms of iron in soils and sediments. Ferric iron is highly insoluble at circumneutral pH. Present investigations have shown that the structural ferric iron bound in clay minerals is reduced by some microorganisms. Anaerobic bacteria reduce ferric iron which bound to soil clay minerals under anaerobic conditions. They have the ability to use ferric iron as a terminal electron acceptor. Many studies presented that dissimilatory iron reducing bacteria (DIRB) mediate the transfer of electrons from small organic molecules like acetate and glucose to various humic materials (electron shuttles) which then pass electrons abiotically to ferric iron oxyhydroxide and phyllosilicate minerals. Electron shuttles like AQDS, a tricyclic quinone, increase the rate of iron reduction by iron reducing bacteria on sites of iron oxides and oxyhydroxides. By increasing the rate of bioreduction of ferric iron, the solubility and availability of iron enhanced meaningfully. Royer et al. (2002) showed that bioreduction of hematite (common iron mineral in soils) increased more than three times in the presence of AQDS and Shewanella putrefaciens comparedto control treatments. Previous works have mostly used synthetic minerals as electron acceptor in bioreduction process. Furthermore, the effect of quinones as electron acceptor for microorganisms were studied with poorly crystalline ferric iron oxides . The main objective of this study was to study the effect of AQS, humic acid and fulvic acid (as electron shuttle) and Shewanella sp. and Pseudomonas aeruginosa, on bioreduction of native ferric iron in two acidic and calcareous soils. Materials and Methods: An experiment was conducted in a completely randomized design with factorial arrangement and three replications in vitro condition. The soil samples collected from locations in Mashhad and Guilan cities, Iran, in 2015. The soil samples were air dried in a glasshouse and later subjected to general analysis. Some part of the soil samples were kept at 4 oC as fresh soil samples for bioreduction assay. In that part of experiment, all soil samples were treated with glucose (10 mM) as electron donor. Native ferric iron considered as electron acceptor. Then soil samples were treated with AQS, humic acid and fulvic acid (as electron shuttles) and inoculated with bacterial cells (Shewanella sp. and P. aeruginosa) and they were incubated for 30 days in an incubator at 30 and 37 oC according to the optimum temperature for bacteria in an anaerobic condition. At the end of incubation time, ferrous and acid extractable iron were determined with Ferrozine assay by spectrophotometer in 562 nm (8, 25). Results and Discussion: Results showed that the AQS had a noticeable effect on ferrous iron concentrations in both acidic and calcareous soils. In these cases ferrous iron concentrations were 8 and 15.7 times higher compared to initial concentration in acidic and calcareous soils, respectively. The Shewanella sp. intensified ferrous iron concentration 7.2 and 16.3 fold in acidic and calcareous soils, respectively but P. aeruginosa increased it 5.6 and 12.1 fold compared to initial concentration of ferrous iron. In acidic soil, in the presence of Shewanella sp. and AQS, ferrous and acid extractable iron concentrations were 1.45 and 4.50 mg g-1, respectively. Results showed that 11.7 fold enhancements occur in the presence of Shewanella sp. and AQS compared to initial (0.385 mg g-1) concentration of iron in acidic soil. When P. aeruginosa was inoculated in acidic soil in the presence of AQS, soluble ferrous iron concentration was 1.27 mg g-1. The acid extractable iron in this treatment was 2.85 mg g-1. The concentration of soluble ferrous iron in calcareous soil was 0.81 mg g-1, when AQS was added to Shewanella sp. treatments. That value was 0.54 when P. aeruginosa was added. The acid extractable iron was 3.90 mg g-1 in the presence of AQS and Shewanella sp. By adding P. aeruginosa, acid extractable iron was 2.84 mg g-1 compared to control treatments. Conclusions: Dissimilatory ferric iron reduction is a potentially important process in controlling contaminant fate. It has the potential for being particularly useful in the remediation of metals and radionuclides. Means for stimulating ferric iron reduction will be useful in enhancing bioremediation process. Results illustrated that the Shewanella sp. and P. aeruginosa were enhanced the bioreduction of ferric iron in the presence of AQS, humic acid and fulvic acid in soils. When soil samples were inoculated with Shewanella sp., and AQS was added to the soil samples (in acidic and calcareous soil samples) the concentration of ferrous iron increased intensively.

Abstract Introduction: There have been several indices for agricultural drought monitoring such as Palmer Drought Severity Index (PDSI), Crop Moisture Index (CMI) and Reconnaissance Drought Index (RDI). These indices model the general conditions of soil moisture as a function of climatic parameters such as temperature and rainfall and they are not appropriate to any specific crop. Crop- Specific Drought Index (CSDI) is among few indices which directly take into account evapotranspiration for drought monitoring. This index is defined based on the ratio of actual evapotranspiration (ETa) to potential evapotranspiration (ETp). Literature review of agricultural drought monitoring in Iran reveals that was mainly used Reconnaissance Drought Index (RDI) and in some cases Drought Severity Index Palmer (PDSI) which have less associated with the growth or performance of the specific crop or not. In this paper, a Crop Specific Drought Index (CSDI) model was evaluated for rain-fed wheat in a cold-temperate climate. Then, it’s correlation with RDI was assessed. Materials and Methods: In this study, using 9 years of data of meteorology, soil, and crop yield and phenology, a CSDI model has been calibrated and validated for rain-fed wheat. A two-layer model of daily soil water balance was used to CSDI calculation. The first layer is the current root growth zone which its depth increases with time. The second layer is between the first layer and maximum depth of root growth which its depth decreases by root growth and the thickness of this layer becomes zero when the root growth is Maximum. Actual daily Evapotranspiration (ETa) was calculated based on two-layer model of daily soil water balance. For this, we used the moisture content of the first layer (active), potential evapotranspiration and daily rainfall values. The statistical indices of error analysis like RMSE, MAE and Index of Agreement was used for assessment of CSDI model. Then, to investigate the correlation possibility of crop specific drought severity, Reconnaissance Drought Index (RDI) was used which is based on two variables of potential evapotranspiration and precipitation. In fact, RDI considers the precipitation as a factor of moisture input and the potential evapotranspiration as a factor of moisture exhaust. Results Discussion: At Kermanshah station high coefficient of determination (0.95), relatively high index of agreement (0.747), and low error values (RMSE =0. 098 and MAE =0. 068) was obtained. Sensitivity coefficients during vegetative and productivity stages were obtained 1.31 and -0.0542, respectively. As a result, crop yield at vegetative stage severely affected by aridity stress while at productivity stage there was no sensitivity. In fact, water demand supply is vital at vegetative stage .Range of RDI at Kermanshah station was between 1.13 to -2.59. This threshold is the condition between "moderately wet" and "extreme drought". Correlation between the two index was started from March (R2 =0. 467) and persisted to September (R2 =0. 717). But the highest coefficients of determination were related to July to august (0. 738). Although CSDI didn’t affect by drought stress during October to February, it affected by moisture of March onward. RDI incorporating precipitation and potential evapotranspiration is one of the most recent developments for the assessment of drought severity through drought indices. That is why this index is chosen to investigate the relationship with CSDI. Actually, both indices get evapotranspiration factor in the agricultural drought monitoring. Based on the results, there is a good correlation between two indices. Since the CSDI is relay on ETa to ETp ratio and RDI is based on the P/ ETp ratio, it can be concluded that there is a possible to replacement of ETa with rainfall (R) in the CSDI equation. Conclusion: Many indices and indicators are available to assist in the quantitative assessment of drought severity, and these should be evaluated carefully for their application to each region or location and sector. This paper presents a CSDI model which compared with RDI. Based on the results of this analysis, CSDI model was performed well in high values of coefficients of determination and Index of Agreement, and low values of errors. Therefore, the CSDI seems to be a reliable index to assess agricultural drought. Furthermore, it is observed a reliable relation between CSDI and RDI during crop growth period. Due to good correlation of CSDI and RDI, it can be proposed to replacement of rainfall (R) instead of ETp in the CSDI equation.

Abstract Introduction: Air temperature as an important climatic factor can influence variability and distribution of other climatic parameters. Therefore, tracking the changes in air temperature is a popular procedure in climate change studies.. According to the national academy in the last decade, global temperature has raised 0.4 to 0.8⁰C. Instrumental records show that, with the exception of 1998, the 10 warmest year (during the last 150 years), occurred since 2000, and 2014 was the warmest year. Investigation of maximum and minimum air temperature temporal trend indicates that these two parameters behave differently over time. It has been shown that the minimum air temperature raises noticeably more than the maximum air temperature, which causes a reduction in the difference of maximum and minimum daily air temperature (daily temperature range, DTR). There are several factors that have an influence on reducing DTR such as: Urban development, farms’ irrigation and desertification. It has been shown that DTR reduction occurs mostly during winter and is less frequent during summer, which shows the season’s effect on the temperature trend. Considering the significant effects of the climatological factors on economic and agricultural management issues, the aim of this study is to investigate daily air temperature range for yearly, seasonal and monthly time scales, using available statistical methods. Materials and Methods: Daily maximum and minimum air temperature records (from 1950 to 2010) were obtained from Mashhad Meteorological Organization. In order to control the quality of daily Tmax and Tmin data, four different types of quality controls were applied. First of all, gross errors were checked. In this step maximum and minimum air temperature data exceeding unlikely air temperature values, were eliminated from data series. Second, data tolerance was checked by searching for periods longer than a certain number of consecutive days with exactly the same temperatures. Third, a revision of internal consistence was done, verifying that daily Tmax always exceeds daily Tmin. Fourth, the temporal coherency was tested by checking if consecutive temperature records differ by more than 8 degrees. The homogeneity of the series was tested by means of the Standard Normal Homogeneity test, the Buishand range and the Pettitt tests, on yearly, seasonal and monthly time scales. Breakpoint can be detected by means of these methods. In addition, Von Neumann ratio test was used to explore the series’ randomness. Having investigated data’s randomness in this study, series’ trend was determined by the Kendal-Tau test. Furthermore, the slope of the series’ trend was calculated using the Sen’s slope method. Results Discussion: Results indicated a decreasing trend in DTR during last 60 years (1951-2010) in Mashhad climatological station. Moreover, the results revealed that the slope of yearly DTR was decreasing (-0.029 ⁰C per year), which indicates that minimum air temperature values raise more maximum air temperature values. A breakpoint was detected during 1985. During 1951-1985, the average amount of DTR was 14.6⁰C, while this parameter reduced to 12.9⁰C for the period 1985-2010. The Kendall-Tau test was used to obtain the significance of trend during 1951-2010, 1951-1985 and 1985-2010. The results showed that during 1951-2010, DTR significantly reduced at a rate of 0.29oC per decade. However, between 1951 and 1985, DTR trend increased at a rate of 0.61oC per decade, while DTR trend between 1985 and 2010 reduced at a rate of 0.19 ⁰C per decade, which was not significant (P-value=5%). In the seasonal DTR series, the highest trend’s slope was calculated for the summer data (-0.43 ⁰C in a decade), while the lowest one accrued in spring (-0.15⁰C in a decade). From 1951 to 1985, DTR had an increasing trend, due to minimum air temperature’s downward trend. But from the late 1980 to 2010, as it was expected, downward DTR trend was observed, because during this period minimum air temperature increases more than the maximum air temperature, thus the difference between Tmax and Tmin was reduced. Monthly DTR analysis also revealed a decreasing trend from 1951 to 2010, except for March and April, which had a non-significant increasing trend. In monthly DTR series, as it was expected, similar to the yearly and seasonal time series, the breakpoints accrued around 1985 in 8 out of 12 months. During February, March, April and November no significant breakpoint was detected. Conclusion: DTR decreasing trend indicated that minimum air temperature increase was greater than maximum. This can cause a significant effect on the agricultural sector, hence in an appropriate agricultural management, these points should be considered. For example, changing the sowing time is one of the decisions which a manager can make.

Abstract Introduction: The phenomenon of climate change and its consequences is a familiar topic which is associated with natural disasters such as, flooding, hurricane, drought that cause water crisis and irreparable damages. Studying this phenomenon is a serious warning regarding the earth’s weather change for a long period of time. Materials and Methods: In order to understand and survey the impacts of climate change on water resources, Global Circulation Models, GCMs, are used; their main role is analyzing the current climate and projecting the future climate. Climate change scenarios developing from GCMs are the initial source of information to estimate plausible future climate. For transforming coarse resolution outputs of the GCMs into finer resolutions influenced by local variables, there is a need for reliable downscaling techniques in order to analyze climate changes in a region. The classical statistical methods run the model and generate the future climate just with considering the time variable. Multi-site daily rainfall and temperature time series are the primary inputs in most hydrological analyses such as rainfall-runoff modeling. Water resource management is directly influenced by the spatial and temporal variation of rainfall and temperature. Therefore, spatial-temporal modeling of daily rainfall or temperature including climate change effects is required for sustainable planning of water resources. Results and Discussion: For the first time, in this study by ASD model (Automated regression-based Statistical Downscaling tool) developed by M. Hessami et al., multi-site downscaling of temperature and precipitation was done with CGCM3.1A2 outputs and two synoptic stations (Rasht and Bandar Anzali) simultaneously by considering the correlations of multiple sites. The model can process conditionally on the occurrence of precipitation or unconditionally for temperature. Hence, the modeling of daily precipitation involves two steps: one step, precipitation occurrence and the other step precipitation amounts and the modeling of daily temperature is performed in one step. The choice of predictor variables is one of the most influential steps in the development of statistical downscaling scheme because the decision largely determines the character of the downscaling results. It is essential to remember that predictors relevant to the local predict and should be adequately reproduced by the host climate model at the spatial scales used to condition the downscaled response. To test this approach over the current period and to compare the results with observed data, temperature and precipitation, from 2 stations, model is evaluated and calibrated by using NCEP (National Center for Environmental Prediction) reanalysis data before the use of GCMs as input variables. Then climate was predicted for three periods which each period consist of thirty years in the future, 2011-2040, 2041-2070 and 2071-2100. ASD reduces the problem of predictor selection and it is capable of performing all steps of statistical downscaling automatically. In order to select dominant predictors in multi-site modeling backward stepwise regression method was used; so that some predictors like 850 hPa geopotential, 850 hPa specific humidity, 1000 hPa specific humidity, screen air temperature (2m) were the most important variables for temperature models, and 850 hPa geopotential, 1000 hPa zonal velocity, 1000 hpa specific humidity, and screen air temperature (2m) played a main role in temperature modeling. For downscaling of precipitation, the amount of explained variance (R2) is 0.336 for NCEP data and it is 0.89, 0.922 and 0.855for maximum, mean and minimum temperature, respectively. The results underlined certain limitations to downscale the precipitation regime and its strength compared to downscale the temperature regime. To evaluate the performance of the multi-site statistical downscaling approach, several climatic and statistical indices were developed. For instance, based on daily total precipitation, two precipitation indices was used including percentage of wet days, maximum number of consecutive dry days. The results showed the increase of the average temperature and precipitation decreases for future mainly. In this case study, the decrease of 0.30 mm day-1 in the average rainfall on the second period of future, 2041-2070, and the reduction of 7.25% on the 3rd period, 2071-2100, in climate index of the percentage of wet days was predicted, compared to the based period. However, the results illustrated an increase in the mean of maximum, mean, and minimum temperature, 3.17, 2.5 and 2.8 °C, for the 3rd period of future from 2071 to 2100, respectively. Conclusions: The aim of applying this new method is to demonstrate the importance of multi-site models and developing a suitable context to calculate the uncertainty of climate predictions. Further works are needed to evaluate in depth the fundamental assumption of multi- site statistical downscaling, i.e. the stability of the relationships between predictors and predict and in altered climate and test their plausibility and consistency.

Abstract Introduction: Drought is a recurrent feature of climate that caused by deficiency of precipitation over time. Due to the rise in water demand and alarming climate change, recent year’s observer much focus on drought and drought conditions. A multiple types of deficits and relevant temporal scales can be achieved through the construction of a joint indicator that draws on information from multiple sources and will therefore enable better assessment of drought characteristics including return period, persistent and severity. The Standardized Precipitation Evapotranspiration Index (SPEI) combines information from precipitation and temperature in the form of water surplus or deficit according to Standardized Precipitation Index (SPI). Rainfall over some regions of Iran during some resent year was below average while mean and maximum temperatures were very high during this period, as was evaporation. This would suggest that drought conditions were worse than in previous recent periods with similarly low rainfall. The main objective of this study is to assess the influences of humidity on the SPEI index and investigate its relation with SPI and Reconnaissance Drought Index (RDI) over six different climatic regions in Iran. Materials and Methods: Iran has different climatic conditions which vary from desert in central part to costal wet near the Caspian Sea. In this study the selection of stations was done based on Alijani et al (2008) climatic classification. We chose 11 synoptic stations from six different climatic classes including costal wet (Rasht and Babolsar), semi mountains (Mashhad and Tabriz), mountains (Shiraz and Khoram Abad), semi-arid (Tehran and Semnan), arid (Kerman and Yazd) and costal desert (Bandar Abas). The Meteorological datasets for the aforementioned stations were obtained from the Iran Meteorological Organization (IRIMO) for the period 1960-2010. The compiled data included average monthly values of precipitation, minimum and maximum air temperature, mean relative humidity, sunshine hours) and wind speed at 2 m height. A probability-based overall water deficit assessment was achieved from multiple drought-related indices (i.e. SPEI, SPI and RDI). The humidity conditions were monitored for given stations based on each index during annual, short term (1, 3 and 6 months) and long term (9 , 12, 18 and 24 months) periods. This research further examine the Locally Weighted Scatter plot Smoothing (LOWESS) graphical method and nonparametric Man- Kendal test to evaluate the trends associated with humidity deficiency in annual and monthly time scales during 51 years period (i.e. 1960-2010). Results and Discussion: Our results revealed that the maximum correlation between SPEI index with indices of SPI and RDI was achieved in the coastal wet region and with a declining trend in relative humidity condition in the rest of the regions, this correlation is down over both short- and long-term periods. A comparison between SPI and SPEI also performed that the SPI index was able to reflect prolonged drought over the costal wet region where it showed significant inconstancy in desert and semi desert regions. SPEI result suggested substantial deficiencies in relative humidity at the beginning of 1997 during long term period which indicated an increasing trend of drought statues during last decades. Overall, according to the results of SPEI index in 1month periods monthly drought assessment showed a declining trend in drought magnitude during autumn, winter and spring season months (October to June) at investigated stations excepts Tehran and Shiraz stations and with a potential deficiency in relative humidity conditions. Unlikely, annual trend showed increasing trends in drought frequency and persistent over last decade. Conclusion: Our results can be summarized as below: Focusing on various types of deficits, the result of humidity based deficiencies indicated that for semi-mountains, mountains, semi-arid, arid and costal desert regions the period of 1997 to 2010 has a large total moisture shortage over all climatic regions. Most of the climate stations showed moisture deficits (decline trends) during October to June (9-month) at many stations expect Tehran and Shiraz stations which revealed a significant increasing over 51 years. We recommend using SPEI index for arid and semi-arid regions because it includes temperature variability in drought model so it reflects drought conditions better than other indices. Furthermore, three drought indices (i.e. SPEI, SPI and RDI) have similar sensitivity to water deficits over wet climatic regions; therefore, each of those indices can be used.

Abstract Introduction: Better use of water and soil resources in paddy fields, increase in rice production and farmer's income, installation of subsurface drainage system is necessary. The main goalof these systems, are aeration conditions improvement prevention of water logging, yield increase, land use increase and multiuse of the land. In different countries, installation of subsurface drainage cause yield increase and working condition on the land, but no research has been conducted in different depths and spacing. On the other hand, spacing and depth are the most important parameters in the installation of drainage systems, have a direct effect on incoming water into the drains. The aim of this research, is an investigation of the effect of subsurface drainage with different depths and spacing on discharge rate variation and water table fall, in order to analyze the improvement of water flow movement in the soil. Also, study the effect of different drainage systems on the increase of the canola yield as the second cultivation in these treatments have been compared. Materials and Methods: To measure hydraulic conductivity in different depths, the auger holes have been dug (excavated). The saturated hydraulic conductivity in these holes wasdetermined using Ernst method (1950) before installation of drainage systems. In the drainage pilot plot of Sari Agricultural Sciences and Natural Resources University three subsurface drainage systems with mineral envelope have been installed. 1- The first one with the 0.9 m depth and 30 m spacing (D90 L30), 2- The second one with 0.65 m depth and 15 m spacing (D0.65 L15) and 3- The third one with 0.65 m depth and spacing (D0.65 L30) and one bi-level system with mineral envelope including four drains of 15 m spacing with 0.9 m and 0.65 m depths were installed alternatively. After auger hole equipment installations, in the middle spacing of two subsurface and water table reading possible, the water table fluctuation and drain outlet discharge rate from farm drains during canola growing season were measured on a daily basis. Also, canola yield during 4 years after drainage systems were monitored. Results and Discution: The results showed that mean discharge rates of drainage systems have increased with time and in the fourth year it was better than first and second years. Duringthe second year, the highest discharge rate onthe first day was in the low depth treatment and after 3 days the discharge rates become the difference among less. In the third year, the discharge rates of high spacing drains (D0.65 L30) have become higher than of spacing drains (D0.65 L15) discharge rates. But, in the first day its discharge rate was less and one can conclude that it is due to horizontal flow. With passing time and soil structure improvement, one can observe better yield from drains with higher spacing (30 m) also. By performance of drainage and soil conditions improvement in the third and fourth year, the deeper drainage systems have becomes better and water table fall of deep drain discharge rate and soil condition improvement in these systems become higher. In bi-level drainage, by increasing deep percolation, the water table fall in this treatment increased with time. Also, based on monitoring water table, in the first and second years after 5th day and in the third and fourth years after 4th day the water tables of deep drains decreased to lower depth drains. Due to heavy soil in paddy fields and existence of hardpan, the performance of low depth drains in falling water table was better in the first years. With passing time and performance of drainage the conditions for water movement in the soil become better and performance of deep drainage systems improved and at the fourth year, deep drainage systems had better performance in draining water with respect to low depth drainage systems. Also, canola yield as second cultivation, has increased from first to fourth year and along with important of soil aeration conditions and performance of drainage systems, the grain yield hasincreased in different drainage treatments. The results showed a direct relationship between improvement of system performance and increase in grain yield. In the second year, grain yield increased in all treatments. On the other hand, the yield under drainage systems with deeper depth (D0.9 L30) even higher in the 2nd and 4th years than with low depth drain (D0.65 L30). This was because of more fall in water table levels during days after rainfall and also with next rainfall, saturation of soil up to surface layer in the plots with deeper drains were performed later and it may not reach up to thesoil surface. Conclusion: Due to betterconditions of deep drains and with higher spacing in the improvement of paddy field use and also less environmental harm use of drains with higher spacing are recommended for these lands. On the other hand,a low increase in drain depth from 0.65 m to 0.9 m along with increase in spacing of30 m with respect to 15 m and even with 0.65 m depth, will have less cost. Due to decrease in the costs of drain installation with higher spacing, due to improvement of conditions, the performance of these systems in 2 to 3 years one can have cheaper drainage systems in the longest time and will improve the economic situation of farmers due to higher yield.

Abstract Introduction: Bridges are certainly one of the most important structures but costly service elements in a transport system. The bridges are very required to access the damaged areas in emergency situations such as floods and earthquakes. Scour around the foundations of bridge piers exposed to the flowing water than can destroy the bridge itself is a subject of major concern. Flow pattern is known as responsible for all changes in stream bed. Any obstacle in the channel can form new flow patterns causing additional shear stress exerted on the bed than the equilibrium condition of the absence of the obstacle. Appropriate shaping of flow pattern and proper selecting of pier geometry and the location of bridge piers can be one of the proper methods in reduction of scour amount which is the main subject of the present study. Materials and Methods: Inclined bridge group pier is a type of bridges with modern geometry based on development in building technology of structures. Many of these bridges have been built all around the world and the 8th bridge built crossing the Karun River in Ahvaz is a sample of the Iranian ones considered in this research. Hydrodynamic behavior of flow is investigated around the inclined bridge group pier settled on foundation using the FLOW-3D numerical model. Inclined bridge group pier investigated in this study, includes two rectangular piers which are 2.5 cm long and 3.5 cm wide and set in an angle of 28 degree on rectangular foundation which is 16 cm long and 10 cm wide and installed in three different foundation levels namely at, above and below the bed levels. The physical model of prototype pier considered in this study was constructed to the scale of 1:190 of the Ahvaz 8th bridge. In order to verify the accuracy of the numerical model, velocity data obtained from image processing technique were used. Results and Discussion: Due to non- linearity and interactions between various phenomena involved, flow pattern around the piers group is entirely different than that for a single pier and consequently the outcomes of the flow pattern around single pier cannot be generalized to the pier group. At all levels of foundation setting, longitudinal component of flow velocity increases surrounding the first pier. The increase in the area and its extension towards downstream is caused by the constriction the flow due to the pier and area rotating of the wake vortex in downstream. When the pier foundation is set at the stream bed, the bed rotating flows extend to a distance between the two piers from near the bed up to the middle of flow depth while in upstream of the second pier and near water surface, the stream lines become parallel to the bed. The comparison of the results of the changes in bed shear stress in the situations of foundation setting in different levels showed that the maximum shear stress occurred when the foundation level is at the bed level and the maximum shear stress exerted on the bed decreases by factors of 17% and 53% in the cases of foundation level to be below and above bed levels, respectively. In addition, the results showed that, the amount of vortex flows increased in upstream piers group and near bed in the case of setting the foundation above the bed. This is because of the fact that the volume of piers group acted as obstacle against flow was more than other level settings. Furthermore, based on the obtained results, in the case of foundation level is set at the bed, the quantity and development zone of vortex flow are much higher than those observed when the setting foundation is below the bed level. This can be attributed to the higher effect of the second pier on the flow pattern being between the first and the second piers. Stream lines turn downward in the range between piers group, and after the collision to bed turn upward to water surface and cause to form rotating flow and hence high turbulence intensity in the area. In the near water surface and the center of group piers, stream lines were observed to be parallel to the bed and caused low turbulence intensity in this area. Conclusions: The results showed that the levels of setting foundation have a significant effect on hydrodynamic characteristics and flow pattern around the piers. By increasing the dimensionless height of the setting foundation from -1 to 0.5 vortices formed in the downstream piers group is strengthen more and the results from the numerical model are consistent with the results of experimental scour around piers group in all three levels of setting foundations. When the foundation setting is at the bed level, the maximum bed shear stress is observed. The maximum bed shear stress is decreased by factors of 17 and 53 percent when the foundation to be set below and above bed levels, respectively.

Abstract Introduction: River discharge as one of the most important hydrology factors has a vital role in physical, ecological, social and economic processes. So, accurate and reliable prediction and estimation of river discharge have been widely considered by many researchers in different fields such as surface water management, design of hydraulic structures, flood control and ecological studies in spetialand temporal scale. Therefore, in last decades different techniques for short-term and long-term estimation of hourly, daily, monthly and annual discharge have been developed for many years. However, short-term estimation models are less sophisticated and more accurate.Various global and local algorithms have been widely used to estimate hydrologic variables. The current study effort to use Lazy Learning approach to evaluate the adequacy of input data in order to follow the variation of discharge and also simulate next-day discharge in Talar River in KasilianBasinwhere is located in north of Iran with an area of 66.75 km2. Lazy learning is a local linear modelling approach in which generalization beyond the training data is delayed until a query is made to the system, as opposed to in eager learning, where the system tries to generalize the training data before receiving queries Materials and Methods: The current study was conducted in Kasilian Basin, where is located in north of Iran with an area of 66.75 km2. The main river of this basin joins to Talar River near Valicbon village and then exit from the watershed. Hydrometric station located near Valicbon village is equipped with Parshall flume and Limnogragh which can record river discharge of about 20 cubic meters per second.In this study, daily data of discharge recorded in Valicbon station related to 2002 to 2012 was used to estimate the discharge of 19 September 2012. The mean annual discharge of considered river was also calculated by using available data about 0.441 cubic meters per second. To estimate the discharge of considered day, three methods of constant, linear and quadratic functionscontrollers based on the local linearization provided by the lazy learning algorithm were considered. Lazy learning is a memory-based linear technique for local modeling approach which is reported as a high-efficient algorithm for simulating variables with low input data.The series of input data was categorized into previous 6, 8, 10, 15 and 20 days, 1 and 2 months, 1, 2 and 3 seasons and also 1 and 2 years to evaluate which series is appropriately enough to predict next-day discharge inthe river. Then, mean absolute error and root-mean square error were calculated for all series and modelsin order to find the best estimator model and the most appropriate series of input data. Results: Results showed that constant and linear model had the minimum root-mean square error of 0.001 and 0.057 respectivelywith previous 60 days’ data series. Whilethe quadratic model had its best estimation with previous 2 season data series with the minimum root-mean square error of 0.059. The result indicated that the more input data increase, the best quadratic model estimate until 60 days. But after 60 days, estimation error gradually increased. Consequently, not more data but adequate areneeded for accurate estimation. Also, RMSE in linear model had less fluctuation and therefore less sensitivity compared with other models. And quadratic model had less fluctuation and sensitivity to neighborhoods. Also, according to results, the more variation in each period increase, the better estimation is accrued by lazy learning algorithm. Hence, it was expected that next-day discharge prediction in low-water period needs longer data series than high-water period. Conclusion: Regarding to thousands of prepared training models, constant model with previous 60 days’ data and minimum error of 0.0001 was selected as the most accurate estimatefor next-day river discharge in Talar River. Results showed that despite of some limitation and demerits, the local Lazy Learning algorithm has significant efficiency in time series simulating. Although the accuracy of simulation increase with more input data, but this algorithm can runby at least 5 training data. However we find lazy learning to be the best performing approach on average goodness indicators (such as mean absolute error and Root-mean square error). On the other hand, the lazy learning predictor can be quickly developed and easily kept up-to-date by adding new data to its database. Also, it does not face with overfitting problems which are common in global modeling approaches.According to some noteworthy features of lazy learning noticed in this regards, this approach will have good performance for time-series studies.

Abstract Limitation of water resources in Iran motivates sustaining and preserving of the resources in order to supply future water needs. Fulfilling these objectives will not be possible unless having accurate water balance of watersheds. The purpose of this study is to estimate the water balance parameters using a distributed method. The large number of distributed models and methods was studied and “Quasi Distributed Water Balance model” (QDWB) was written in the MATLAB programming environment. To conduct this model, it is needed that each data layer (precipitation, potential evapotranspiration, land use, soil data,..) to be converted into grid format. In this research the 500m * 500m cell size was used and water balance parameters for each cell was estimated. Runoff and deep percolation obtained from surface balance equation and irrigation needs were estimated based on soil moisture deficit. The study area of 9157 square kilometers is Neyshabour- Rokh watershed. The results showed there is a good correlation between water balance parameters such as precipitation-runoff, precipitation-evapotranspiration, and precipitation- deep percoulation and demonstrate that QDWB model is consistent with the basin hydrological process.Change in soil moisture at basin wide is 1 MCM in 1388-89 and 40 MCM in 1380-81. The evapotranspiration results from a distributed model” SWAT” and QDWB model were in good agreement.

Abstract Introduction: Soil Hydraulic conductivity is considered as one of the most important hydraulic properties in water and solutionmovement in porous media. In recent years, variousmodels as pedo-transfer functions, fractal models and scaling technique are used to estimate the soil saturated hydraulic conductivity (Ks). Fractal models with two subset of two (solid and pore) and three phases (solid, pore and soil fractal) (PSF) are used to estimate the fractal dimension of soil particles. The PSF represents a generalization of the solid and pore mass fractal models. The PSF characterizes both the solid and pore phases of the porous material. It also exhibits self-similarity to some degree, in the sense that where local structure seems to be similar to the whole structure.PSF models can estimate interface fractal dimension using soil pore size distribution data (PSD) and soil moisture retention curve (SWRC). The main objective of this study was to evaluate different fractal models to estimate the Ksparameter. Materials and Methods: The Schaapetal data was used in this study. The complex consists of sixty soil samples. Soil texture, soil bulk density, soil saturated hydraulic conductivity and soil particle size distribution curve were measured by hydrometer method, undistributed soil sample, constant head method and wet sieve method, respectively for all soil samples.Soil water retention curve were determined by using pressure plates apparatus.The Ks parameter could be estimated by Ralws model as a function of fractal dimension by seven fractal models. Fractal models included Fuentes at al. (1996), Hunt and Gee (2002), Bird et al. (2000), Huang and Zhang (2005), Tyler and Wheatcraft (1990), Kutlu et al. (2008), Sepaskhah and Tafteh (2013).Therefore The Ks parameter can be estimated as a function of the DS (fractal dimension) by seven fractal models (Table 2).Sensitivity analysis of Rawls model was assessed by making changes)±10%, ±20% and±30%(in input parameters (porosity, fractal dimension and the intake air suction head).Some indices like RMSE, AIC and R2 were used to evaluate different fractal models. Results and Discussion: The results of the sensitivity analysis of Rawls - Huang model, showed the least sensitivity to changes in porosity and suction entry air and the most sensitivity to changes in fractal dimension. The saturated hydraulic conductivity is underestimated by increasing the fractal dimension in Rawls - Huang model. The high sensitivity of the combined model to changes in fractal dimension, is considered as one of the model limitations.In other words, fractal dimension underestimation increased the error related to the hydraulic conductivity estimation. Sensitivity analysis of Ks regression model was done among parameters like bulk density, dry density, silt, sand, fractal dimension of particle size and porosity. Results showed less sensitivity to fractal dimension and porosity. The highest RMSE was 0.018 for fractal dimension and porosity (in the range of ±30% changes). The results showed that the amount of clay in the estimation of fractal dimension is of crucial importance. Statistical analyzes indicated the high accuracy of the PSF models based on soil texture data.Error indices showed the high accuracy of Rawls and three-phase fractal (pore- solid- fractal) models combination in estimating the Ks value. The results suggest that Huang and Zhang model, with the highest correlation, the least Root Mean Square Error and the least Akaike criteria among the studied fractal models for estimation of the Ks values. Fuentesand Hunt models, overestimated soil saturated hydraulic conductivity. Fuentes et al. (1996) as an experimental fractal model to estimate the saturated hydraulic conductivity indicatedvery poor results. Bird model had higher error values compared with the best model, (RMSE =0.73). This model fit well with the measured values compared to Sepaskhah and Taylor models particularly at low Ksvalues. Taylor's two-parameter model, which is similar to the Brooks - Corey and the Campbell model, was inserted in the fourth priority. The RMSE values of Sepaskhah and Taylor models were 0.62 (cm/h) and 0.55(cm/h) respectively. The fractal dimension is a function of soil texture. Heavy soils resulted in a larger fractal dimension and less hydraulic conductivity. Therefore, the Huang-Zhang model as a result of clay value using model (lower values for Ks), had a close fit with the measured data in probability distribution. Conclusions: The results showed that the soil clay percent had a significant role in fractal dimension calculation.

Abstract Abstract Soil contamination with heavy metals is a serious problem in all over the world. Soils are contaminated by many different sources of heavy metals. Currently different methods are used by researchers for identifying heavy metal contamination. Assessing soil metal toxicity with bacterial bioluminescence is one of the new techniques. In this study, different concentrations of zinc and copper (0, 5, 20, 120 300,755, 2000 mg/kg for Cu, 0, 10, 30, 70, 160 400, 1000, 3000 mg/kg for Zn in sulphate form) were applied to Lincoln soils, New Zealand, in two different sites. After one year, the total concentrations of copper and zinc were measured in soil samples. Bacterial bioluminescence technique (Bioluminator) was used for determination of toxicity threshold of Cu and Zn for E.coli.. The results showed that the bacterial bioluminescence decreased by increasing copper and zinc concentrations. We also found that the bacterial bioluminescence decreased, 50% compared to control plot at 450 and 65 mg/kg Cu and Zn concentrations respectively. The correlation between bioluminescence and total metal concentration showed that zinc was more toxic to E. coli than copper. Keywords: Bioluminescence, Heavy metals, Zinc, Copper. E. coli

Abstract Evaluation of Rainfall Effect on Programing of Agricultural Management (Case Study: Golestan region) Abstract Securing of water need in agricultural is important. Precipitation are one of the most important of water resources in agricultural, in Golestan province, especially , because Alborze mountains are in Golestan south. In research has investigated effects of rainfall to cropping pattern and intensification in Golestan farms. Rainfall used: a) have forecasted rainfalls by Minitab-13 program, b) Different probabilities of rainfalls by LST Program. Then estimated effective rainfall (by USDA method). For optimization used Lingo-8 program. Evaluations shown that in southern region (climate is: smi wet), if rainfall decreased, area of tomato and potato decreased , but canola area increased. In central and north regions (climates are: semi dried to dried), if rainfall decreased, watermelon area decreased, but canola area increased. Also if drought conditions, planting of canola, watermelon and cotton crops are important. Key words: Cropping pattern, Intensification, Precipitation, Golestan