Iranian Water Research Journal

Abstract Sand and gravel mining from the riverbed causes many environmental and social problems in the rivers because of disturbing the natural conditions of the bed and also, its changes. Some of these problems are subsidence of riverbeds and erosion of hydraulic structures its path, bank erosion and damage to land placed in riverbank, the destruction of dewatering openings, drainage of agricultural land placed in riverbank and also, the change of plant and animal environment. In studying the morphological changes of the rivers’ cross-sections, it is often assumed that the riverbanks are non-erodible or the erosion of river banks is less than the erosion of bed, so, river width is considered constant. A closer study of the changes in river alluvial, particularly, with the erodible banks shows that the river width will be faced with significant changes because of material mining.In this study, it has been tried to study the changes in the bed, bank erosion of the river and its causes and also to identify the vulnerable intervals by simulating hydraulic conditions of sediment flow in Khorramabad River with the use of model Fluvial-۱۲. Khorramabad River is located in ۳۶.۴۸-۴۵.۴۷ east latitude and ۱۰.۳۳ to ۵۰.۳۳ North longitude and of the important branches of Kashkan River. The case study includes an interval of Khorramabad River with the length of about ۷ kilometers before the inset of Kakasharaf River. IN this interval, Khorramabad River is a mature river in the plains with the average slope about ۱.۶%, and a flow with u-shaped cross-section. In mentioned interval, there a map with the scale of ۱:۱۰۰۰ that includes about ۹ kilometers of the river and the hydraulic studies were performed on this interval. In this study, ۱۳۷۲ cross-sections surveyed in ۲۰۰۳ were used. According to the changes in the sections along the way due to the construction of the bridge, the protection wall of the bank, river materials mining and encroaching the bed of Moradabad River, firstly the required sections were extracted from the topographic map in the GIS environment using HECGeo-RAS interface and then, these sections were modified in model HEC-RAS and inappropriate sections were removed. With this approach, totally, ۵۱ cross-sections were entered in model HEC-RAS to introduce a geometry of the river in the studied interval. For hydraulic modelling of the sediments of Khorramabad River in the studied interval, the model FLUVIAL-۱۲ was used. The model FLUVIAL-۱۲ was provided in ۱۹۷۲ by Cheng.it a mathematical one-dimension model is used to rout the flow and sediment in the natural and built waterways (Journal of ۳۸۳, Ian Management and Planning Organization, ۲۰۰۷). This model cannot model the unsteady flow. In model FLUVIAL-۱۲, digital techniques and physical relations are used to analyze the momentum, flow resistance and sediment transport. The main parameters required for calibration of the model, are roughness coefficient, Sediment transport equation, coastal erosion factor, bed erosion factor and the factors such as these. Model FLUVIAL-۱۲ has been tested with data from many different rivers in the world that most of the data was used to test and calibrate other models. Roughness coefficient of Khorramabad River in the suited area was estimated by field survey and engineering judgment and completing the checklist of SCS method. To calculate the Manning roughness coefficient which is used in hydraulic model HEC-RAS, the values of vegetation, artificial irregularity and additional roughness of barriers created in the river by the people were considered in the calculation of river roughness coefficient. To calculate and estimate the Manning roughness coefficient in floodplains and main section, US Soil Conservation Service (SCS) and also, field survey were used. The sediment transport was simulated by using the functions of the model, the Graph’s (۱۹۷۰) sediment transport equation, Yang’s (۱۹۷۲-۱۹۸۶) flow power unit, the equation of Engelund & Hansen (۱۹۷۶), the equation of Parker et al.(۱۹۸۲) for sand, the sediment equation of Akers and White, the equation of Meyer-peter & Muller for bed load (Shafaei Bejestan, ۲۰۰۵). Result revealed in the v-shaped sections and the channels with small sections, the bank erosion is developed after armoring the bed materials. Also, In the U-shaped sections and the channels with larger sections, the bed erosion is reduced and the development of bank erosion is inconsiderable after armoring the bed materials. Furthermore, In the sections that the section shape and slope make the stable section, no significant difference will be observed in terms of erosion and sedimentation after armoring the bed materials. As it is mentioned before, importance of studying and discussing the river mining becomes clear. Each river has the sediment transport capacity depending on its discharge. There is a reverse relationship between the transport capacity and the size of the constituent grains, so that the coarse grains have the less transport capacity than the smaller grains. So, determining the river transport capacity, the proper points to mine the materials according to the deposition intervals and the appropriate volumes of material mining according to the bed load requires the comprehensive studies on the potential of material mining in different parts of the country. Also due to illegal river mining activities in recent years, the need for the studies on improving the rivers based on the modelling the current situation and providing the protection plans are essential.

Abstract Increasing global warming and decreasing rainfall is one of the serious concern in world. Population growth and increasing demand of water for irrigation, household and industrial purposes are annually faced with water shortages during the summer months. Lakes and reservoirs are the greatest resource of fresh water. One of the more serious problems faced by industry is the evaporation of water from this type of open storages that allows for the greatest loss of water by evaporation particulary during the harm months. In Sarcheshmeh tailing dam, for example, evaporation rate averages is about. ۲۲۵۰ mm per year while this dam is filled with water to a depth of ۵۰۰۰ mm. In this condition, approximately ۴۵% water might be lost due to evaporation. Thus, employ techniques for reducing evaporation is necessary to aiming at the conservation of water through control of evaporation from open storages supplies. In order to increase water supplies by reducing losses through evaporation have been investigated in both the theoretical aspects and practical applications in a number of countries. The most important is the application of the chemical evaporation reducing layers to surfaces of large bodies of open water such as reservoirs, lake and the like. Such application is especially important in arid and semiarid areas for the purpose of reducing evaporation rates from water surfaces. Among the surfactants tested, biodegradable fatty alcohols of low toxicity presented the highest resistance to water evaporation. In the present investigation, have verified the influence of monomolecular films of fatty alcohols including Hexadecanol and Octadecanol in reducing the evaporation of two water samples collected from tap water and the reservoir of sarcheshme tailing dam during two months. For two sample water were provided, twenty steel rectangular container with dimensions ۱۵*۳۰*۵. Six of containers were filled with ۵۰۰mli tap water and six other containers were filled with water collected from reservoirs Sarcheshme dam. For each water samples, five containers were considered with monolayers film and a container of water with no monolayer was used as the control used monomolecular films in ten containers filled with two samples water, were including pure hexadecanol (C۱۶), pure octadecanol (C۱۸) and mixtures of ۱:۹ , ۳:۷ and ۵:۵ (m:m) of C۱۶ and C۱۸ (C۱۶:C۱۸) on the surface of the samples by adding small volumes of ethanol solution (۴۰gr/L) using a sprayer. Values of cumulative evaporation were collected during a ۲۹-Day Period from ۱۷/۰۷/۲۰۱۶ to ۱۴/۰۸/۲۰۱۶. In all samples tested, at the same condition, performance of fatty alcohol on drinking water and wastewater is different. it was observed that, in samples ۱ that were been covered with a pure hexadecanol film, for container of drinking water, evaporation reduction of ۳۲.۲% was obtained, whereas for container of wastewater the same value of ۱۸.۲% was obtained. The results obtained with the C۱۶:C۱۸(۱:۹) mixture (samples ۲) showed ۳۹% saving water for drinking water and ۳۲.۲% saving water for wastewater. Mixtures of hexadecanol and octadecanol with weight ratios of ۳:۷ (samples ۳) showed the highest performance in reducing evaporation (۵۸.۴۷%, ۵۱.۷۵%) of drinking water and waste water, respectively. For the C۱۶ and C۱۸ mixtures (samples ۴), the best results obtained from drinking water and wastewater (۴۷.۵% and ۴۵.۵%) were at ۱ to ۱ proportions (C۱۶:C۱۸ (۵:۵)). The results obtained from pure octadecanol (samples ۵) were poor. This monomolecular film showed ۲۷.۱% and ۲۱% saving water in drinking water and wastewater respectively. According to the results obtained in the above, the minimum of difference between evaporation rate of drinking water and wastewater is related the mixture of C۱۶:C۱۸ (۱:۹). In presented experiments results, it was found that the water evaporation rate, for all of the tests were performed on wastewater using fatty alcohol, is higher than tests were performed on drinking water. It may be concluded that acidic condition and the organic and inorganic compounds in wastewater of sarcheshmeh tailing dam, with the effectiveness of the monomolecular film led to increase the evaporation rate. It is noticed that in mixed films, the differences in rate of evaporation losses of both drinking water and the wastewater was reduced when the proportion of octadecanol to hexadecanol was increased. It is well known that octadecanol films can reduce water evaporation better than hexadecanol films, but C۱۶:C۱۸ mixed films was reduced evaporation rate higher than pure films.

Abstract Introduction: Multi-criteria decision making (MCDM) and Geographic Information System (GIS) for accurate decision making about the evaluation parameters used in natural sciences. This selection is influenced by different factors such as production and irrigation system expenses, water availability and quality, soil characteristics, climate conditions, labor skills, and cultural acceptability. The present study was conducted over an area of approximately ۱۱۰۸۱ ha in the Izeh plain Khuzestan province, south west Iran during ۲۰۱۵-۲۰۱۶. Results of the comparison (for each factors pair) were described in term of integer values from ۱ (equal value) to ۹ (extreme different) where higher number means the chosen factor is considered more important in greater degree than other factor being compared with. Analytic Hierarchy Process (AHP) is one of Multi Criteria decision making method that was originally developed by Prof. Thomas L. Saaty. In short, it is a method to derive ratio scales from paired comparisons.. The AHP was used for optimization.Spatial analysis to identify susceptible regions for pressurized irrigation systems starts with representing each selected physical sub-criterion by a thematic layer in which each point takes a value (۱ to ۹) which the samples have been gathered in a laboratory or a qualification according to that criterion. In order to layer all the criteria, data are gathered from satellite images and official sources at different available forms (digital and hard copy maps, tables and charts). Then, they are analyzed and treated using GIS and geostatistical tools. Each layer is obtained in raster data model. Spatial data on water characteristics, topography and climate (temperature map) are obtained from “water and power authority’’ of Khuzestan district, which is the Iranian official source of agricultural spatial database. Data are already available in digital format with ۱/۱۵۰,۰۰۰ scale. Methods: Major advantage of AHP is to formalize and renders systematic what is largely a subjective decision process and as a result facilitates ‘accurate’ judgments, that weights of criteria are also provided to decision maker, and that sensitivity analysis is easy to conduct by using computer. The weights of each criterion were computed by using the geometric mean to obtain the weight values. After that the weights should be aggregated and each weight divides on aggregated weights in order to normalize the weights. The normalized weights determine the priority of criteria. The sum of all normalized weights in each Table is equal to unity. The AHP methodology says that prioritizing and weighting the criterions should be done firstly. According to fundamental Saaty 's scale for the comparative judgments and by performing pair - wise comparisons of criteria with respect to the object, here the comparison and calculation of criteria in ۱st , ۲nd and ۳rd levels in general for Localize irrigation system as an example. Most large drip irrigation systems employ some type of filter to prevent clogging of the small emitter flow path by small waterborne particles. New technologies are now being offered that minimize clogging. Considering conditions of water used for irrigation in the study region, suspended materials (W sm) and biological materials (W bm) were seen in the water according to laboratory experiments. Filters were employed in the farm and the water is available in the farm by pumping it from wells, but filters need to be changed after a while so possibility of clogging in the drippers still exists, therefore, these two alternatives have higher weight than available water. The amount of Sodium concentration (W na) was low and has less importance than other criteria except available water. Localized irrigation systems designed for no leaching fraction. High electrical conductivity (EC) and salts applied with the irrigation water may build up in the root zone but EC of the study region is almost low. Alkaline water (refers to pH) could make sediments in the drippers Results: In this study surface irrigation system found to be the best systems for this region. The comparisons expose that the results from the proposed model are in good agreements with results from the field investigations. An additional benefit of the model is that the decision-maker can perform a more exhaustive conceptual comparison of the different decision components. Causing that an extensive set of factors involved in selecting an irrigation system has been included in the proposed model, it can be claimed to be a comprehensive and practical model that can be used in selecting the irrigation methods for various agricultural sites, thereby improving soil and water resources exploitation and productivity.

Abstract Existence periods of drought in the past decade, increasing growth of population, limitation surface water resources, cause the proper management of the reservoirs of dams. Operation of reservoirs is influenced by a lot of goals and generally many of these goals are incompatible with each other. The inflows to the reservoir and the storage volumes are uncertain which increases the operation of the complexity of the reservoir. The main challenge is to find the best release of the reservoir and hydrosystems optimization. Various optimization methods have been introduced for the operation of the reservoir. But some of these methods have disadvantages that use of them are not possible for all issues. Bozorg Haddad (۲۰۰۵) used Honey Bees Mating optimization for solving design problems and o The ant colony algorithm was also used to exploit a four-reservoir system in a discrete space that was able to optimize the problem with greater accuracy and less computing time than the genetic algorithm (Jalali et al ۲۰۰۷). Mousavi et al (۲۰۱۷) used the Harmony Search Algorithm to the optimization of water powerhouse storage projects and reported satisfactory results. Harmony search algorithm was presented by Geem et al for the first time in ۲۰۰۰. In this research Harmony Search Algorithm (HSA) is evaluated to determine the optimal operation of multi-reservoir systems. Then in order to evaluate the ability of the algorithm to solve real problems, the optimal operation of Dez Dam reservoir in Khuzestan province has been considered for a period of ۱۰ years (۱۹۹۰-۱۹۹۲) with ۱۲۰ months. In the single- reservoir issue of Dez Dam, the goal is to provide of agricultural demand of downstream or to determine the optimal monthly release for ۱۰ years operation. The optimum value was obtained by using a linear programming model (Lingo). Lingo model has the ability to solve nonlinear models and provides the global optimum in some cases such as the intended problem where the objective function is convex. Therefore, the solutions obtained from the HSA model were compared with the solutions obtained from Lingo software program. A new heuristic algorithm derived from an artificial phenomenon found in musical performance namely the process of searching for better harmony can be introduced. Music harmony is a combination of sounds considered pleasing from an aesthetic point of view. Harmony in nature is a special relationship between several sound waves that have different frequencies. Musical performances seek the best state (fantastic harmony) determined by aesthetic estimation, as the optimization algorithms seek the best state (global optimum-minimum cost or maximum benefit or efficiency) determined by objective function evaluation. Aesthetic estimation find by the set of the sounds played by joined instruments, just as objective function evaluation find by the set of the values produced by component variables; the sounds for better aesthetic estimation can be improved through practice after practice, just as the values for better objective function evaluation can be improved iteration by iteration. The new algorithm is named Harmony Search (HS) and the steps in the procedure of HS are as follows: Step ۱) Initialize a Harmony Memory (HM). Step ۲) Improvise a new harmony from HM. Step ۳) If the new harmony is better than least harmony in HM, include the new harmony in HM, and exclude the minimum harmony from HM. Step ۴) If stopping criteria are not satisfied, go to Step ۲. Harmony Memory Considering Rate (HMCR), which ranges from ۰ to ۱. If a uniformly generated value between ۰ -۱ occurs above the current value of the HMCR, then HS finds notes randomly within the possible playable range without considering HM. An HMCR of ۰.۸۵ means that at the next step, the algorithm chooses a variable value from HM with an ۸۵% probability. For improving solutions and escaping local optima, yet another option may be introduced. This option mimics the pitch adjustment of each instrument for tuning the ensemble. For computation, the pitch adjustment mechanism is devised as shifting to neighboring values within a range of possible values. A Pitch Adjusting Rate (PAR) of ۰.۱۰ means that the algorithm chooses a neighboring value with ۱۰% probability (an upper value with ۵% or lower value with ۵%. In the present study, first HSA was used to the optimization of a four-reservoir system. The objective function was calculated to equal to ۳۰۸.۲۹۱۵ by using Lingo software, and this amount was calculated to equal to ۳۰۸.۲۹۰۰ by using HSA that had a different of ۰.۰۰۰۵ percent with the global optimum. After the success of HSA in solving the four-reservoir system, a ten-reservoir system was considered. The Objective function was calculated to equal to ۱۱۹۴.۴ by using Lingo software, and this value was calculated to equal to ۱۱۹۳.۱ by using HSA that had a different of ۰.۱ percent with the global optimum. In the single- reservoir issue of Dez Dam, the value of global optimum of the objective function was calculated by using software Lingo ۱.۹۱۸۸ and by using HSA ۱.۹۴۴ that had a different of ۱.۳۱% with the global optimum. So it can be concluded that this algorithm has the ability to solve optimization problems of the real system

Abstract The hydraulic jump is one of the important phenomenon of water flow in channels that in proportion to the intensity of jump, will face a significant energy dissipation. True hydraulic jump form for Froude numbers greater than ۴.۵. Position of steady jump is the least sensitive type to fluctuations in the tail water elevation and forms steadily at the same location. The change of flow state from supercritical to a subcritical state is accompanied by discontinuity in depth of flow, formation of a surface roller, visible air entrainment and two phase flow, significant turbulence, kinetic energy dissipation, generation of spray and sound. The basic characteristics of a hydraulic jump, such as conjugate depth, location of jump, the energy loss in the jump, efficiency of jump, the length of the jump. From the designer's standpoint, hydraulic jump is a powerful energy dissipation mechanism and due to its erosive potential, is the centroid of scour. In order to take full advantage of the hydraulic jump in apron design, the erosive effect of jump should be confined to the limits of the heavily protected bed surface, hence intensive scour energy would not cause any harm to apron. This is why; hydraulic jump should be in a stilling basin with a fixed location. Turbulent flow over a rough surface is an important problem and it has been subject of diverse fields. Using roughness elements at the bottom of the flow causes increase in resistance to the flow hence accelerate the upstream flow development and increase in amount of kinetic energy, converted into the turbulent energy. Using of rough beds are effective factor in reducing costs on energy dissipation basins. So researchers’ next purpose have been the use of roughness beds in the stilling basins bed and investigation the effect it on hydraulic jump characteristics. In this research, experimental investigation effect of bed roughness on hydraulic jump characteristics in a flume with length of ۱۲ meters, width of ۰.۵ meters and height of ۰.۷ meters was done in range of Froude numbers ۵.۵ to ۹ and used ۲۴ cubic rough beds with staggered and strip arrangement, different rows and angles. Discharge was measured by a triangular weir with a ۹۰° angle, placed at the end of channel and size of cubic blocks was ۰.۰۵ meters. Point gauges with a sensitivity of ±۰.۱ mm used to measure the depths of flow. To evaluate the effect of roughness, both staggered and strip arrangement were used in the experiments. For creating a hydraulic jump, sharp sluice gate has been used in a condition which places the rough beds in downstream. Relative depth and relative length was obtained as a function of Froude number. The relative depth values on smooth beds obtained in the present study are in good agreement with the data of Belanger classic jump. Relative depth, relative length and shear force coefficient increase for staggered arrangement, strip arrangement and smooth bed with increasing Froude number. The value of relative depth, relative length in compare to smooth bed in the same Froude number on rough beds is less and shear force coefficient is greater than smooth bed. Equations obtained with SPSS software for jump relative depth. Result shows that relative depth and length for staggered arrangement in compare strip have more reducing ratio smooth bed. Also showed staggered arrangement produced better performance compare to strip arrangement in ratio secondary to primary depth and ratio length to jump primary depth. Both types arrangement a better performance compared to jumps formed on smooth beds. For staggered and strip arrangement the average of length ratio to jump primary depth was obtained ۱.۹ and ۱.۶ times less than smooth bed respectively. In the experiments the ranges of relative for the staggered and strip arrangement were ۲۰.۴۷ to ۳۹.۰۴ and ۴۶.۶۶ to ۲۴.۲۸, respectively. Shear force coefficient that main factor is in reducing of depth and jump length calculated ۶ percent more of smooth bed in both arrangement. On the other hand, comparing of this experimental results with the other similar researches on different types of rough beds expresses match results. Finally, equation for estimate of relative depth and relative length for Froude numbers extracted. Also the effect of arrangements in the level of ۵ percent were proofed for all beds on relative depth and relative length.

Abstract Increasing attention to environmental issues in the management of rivers, causese the development of research in the field of hydraulic parameters and sediment transport in the rivers. Vegetation in many rivers, has a significant impact on the flow hydraulic, morphology and sediment transport processes. Understanding the hydraulics of flow in a compound channel with vegetated floodplains is very important for determining the stage-discharge curve and for supporting the management of fluvial processes. There are few models within CFD codes that conceptually or physically represent the hydrodynamic impact of a vegetation canopy on the velocity field and conveyance characteristics within an estuarine or riverine system. The present research investigates the numerical and experimental modelling aspects of flow in compound channels with vegetated floodplain, emphasis to the suspended sediment transport. This study, has proposed a method for predicting the depth-averaged velocity in compound channels with vegetated floodplains, based on an analytical solution to the depth-integrated Reynolds-Averaged Navier-Stokes equation (RANS) with a term included to account the effects of vegetation. Two dimensional advection-diffusion equation were used to calculate the dispersion coefficients and sedimentation rate, this equation were solved by using a finite volume method. The vegetation is modeled via an additional term in the momentum equation to account for the additional drag force. The method includes the effects of bed friction, drag force, lateral turbulence and secondary flows, via four coefficients f, CD, λ & Γ respectively. This model is able to estimate the velocity distribution in channels with different dimensions, different vegetation densities. This model is able to estimate the velocity distribution in channels with different dimensions, different vegetation densities. The wake interference model given by Nepf (۱۹۹۹) is used to estimate the bulk drag coefficient. Modified forms of the Colebrook–White equation can be used to calculate a local friction factor in compound channels with vegetated floodplains. Several eddy viscosity models have been used in the literature to predict transverse momentum exchange in the mixing layer. Once velocity profile is obtained, the dispersion coefficient is evaluated and the remarkable role of vegetation is shown. Both the velocity profile and the dispersion coefficient have been validated using our new experimental results. The model was applied in inverse mode to estimate the model parameters that quantified eddy viscosity coefficient, secondary flow, longitudinal dispersion, transverse dispersion and filtration in the experiments. In addition, the Elder’s and Neph’s relationships also calibrated to calculate the Longitudinal and transverse dispersion coefficients. A Levenberg-Marquardt algorithm was used to find the values of the model parameters that minimized the sum-of-squared differences between measured and modeled velocities and particle concentrations. Experiments performed in a flume of the Hydraulic laboratory. The experimental channel is employed in this investigation was ۱۰ m long × ۰.۳ m wide and ۰.۶ m deep. The channel has a simple rectangular cross section; however, this was modified by using Plexiglas sheeting to produce an asymmetrical compound shape. The artificial stems were PVC rods of ۵ mm outside diameter, arranged in staggered grid. The model substance used as suspended load was silica of mean particle diameter around ۷µm and density ۲۱۴۳ kg/m۳. Silica suspensions were injected to produce fully mixed inflow concentrations of about ۶ g/l. In general, two series of experiments have been done in this study. In The first series of experiments the depth averaged velocity were measured, the second series have been conducted to estimate the rate of sedimentation. Depth averaged velocity measured by using micro-propeller and pitot tubes. Results showed that the use of constant coefficient of ۰.۰۶۸۳ for eddy viscosity coefficient have not a significant impact on depth averaged velocity. The error about ۱% have been observed between results of numerical modeling and experimental data, when the relationships ۰.۴۱۷δρgS۰ HDr and ۰.۶۲δρgS۰HDr have been used for secondary flow coefficients, to the main channel and floodplain, respectively. Results showed that dispersion coefficient in vegetated channels increased cross the main channel compared to no vegetated case, due to the gradient of velocity. Sedimentation rate coefficients calibrated by comparing the experimental and numerical sedimentation rate. The numerical model underestimates the experimental data about ۸%. Experimental data of Zong(۲۰۱۱) were used to verification of numerical model, the results showed that the modified model overestimates the data with ۲۲% difference. The results show that the quasi ۲D model reproduces a reasonable simulation of the flow field and sediment transport in compound channels with vegetated floodplains.

Abstract Urmia Lake is one of the largest hypersaline Lake in Iran which its capacity is about ۳۲ MCM in its normal condition. In recent years, climate change and decreasing rainfall led to falling water level in the Lake. Although, due to its high salt concentration this fall in water level led to extending areas of saline lands around the Lake. Furthermore, drought occurrence and rainfall decreasing trend cause solute concentration to be increase in the Urmia Lake water. For logical and scientific management of fresh water in Urmia Lake Basin it is necessary to investigate the trends of different characteristics of daily rainfall. The aim of this study is to detect trends in the number of days with different rain depths in five distinct classes in Urmia Lake basin. In order to detect trends the information of the twenty five stations having at least ۱۰ years consecutive daily rainfall data were used. Trends of time series detected using the non-parametric Mann-Kendall method. Moreover, slope of trend lines estimated by using the Sen's estimator approach. In order to analyze the spatial trends for each of the time series some relevant maps prepared in which, the stations having significant trends were shown by markers. This facilitate the interpretation of trends in the area under study. The results showed that the slope of trend lines for days having rainfall less than ۱ mm is often positive. About ۸۴% of the stations had upward trend line. The five stations located in the southern part of the basin experienced (in level of ۱۰% or less) significant upward trend in the number of days with precipitation less than ۱ mm. The slope of trend lines in the case of the days having rainfall depth between ۱ and ۵ mm were almost negative. In the case of days with rain between ۱ and ۵ mm, the ۱۵ stations had downward trend lines, which five of them showed significant trend, whereas the remaining stations had upward trend line slops (insignificant at ۱۰% level). On the other hand, the slope of trend lines for the number of days with rainfall between ۵ to ۱۰ (mm) in ۴۴% of the stations were negative in which, only four of them were significant (in ۱۰% level). Trend line slopes in ۴۰% of the station were positive, in which only one station experienced significant trend at ten percent level. The steepest positive trend magnitude belonged to the station namely Herris with β = ۱. ۶۳۳ (day/year). For the number of days with precipitation between ۱۰ and ۱۵ mm about ۳۲% of the stations had negative trend line slopes, in which only three stations experienced negative significant trend. About ۲۶% of stations had positive trend line, in which only one section (namely Maraghe) exhibited significant trend in ۱% level. The steepest slope of the trend lines was related to station Shahindezh with β = ۰.۵۸۵ (days/year). The slope of trend lines for the number of days with rainfall more than ۱۵ mm were positive for ۵۲% of the stations, in which only one of them experienced significant trend (in ۱۰% level). Moreover, ۲۴% of the stations had negative trend in the mentioned class. Out of the total ۲۵ selected stations only one section (namely Maraghe) had significant negative trend. The steepest slope of the trend lines belonged to the station Herris with β = ۰.۴۶۴ (days/year). In general trends of the number of days having rain depth less equal one mm in Urmia Lake basin was upward. But trends for the time series of the number of days having rainfall in the classes of ۱-۵, ۵-۱۰ and ۱۰ -۱۵ mm were downward. This means that light (shower) storms events in the study area is going to be occur frequently but heavy rains is going to be rare. It can be concluded that the number of light raining days had increasing trend. This implies that such light rains can not to be used for crops and trees. Because such rains immediately lost by evaporation proses after ceasing the rain. On the other hand, heavy rains which showed increasing trends for most of the selected station might be crate huge floods in the rivers flowing into the Urmia Lake Basin.

Abstract Sewage and wastewater are extensive sources of water in the suburbs of many cities of the country. In many parts of the world, treated sewage and wastewater have been successfully used for the irrigation, and many researchers have recognized its benefits. In arid and semi-arid regions have provided good conditions for planting of susceptible species by irrigation with sewage or wastewater for development of green cover and economic exploitation such as wood production. Different eucalyptus species are prepared for planting by irrigation with industrial and household sewage and wastewater, because they have high growth rate and high resistance to biotic and non-biotic stresses and they have high product of wood too. In this regard, a study was conducted by measurements of yield, water use efficiency and some performance indicators in three eucalyptus species that they were planted in drainage lysimeters and they were irrigated with wastewater. This experimental was carried out in Yazd city and greenhouse condition. The research was conducted by factorial experiment in completely randomized design and three replications. Two main treatments were applied: Irrigation with wastewater in three levels (control or without wastewater, ۵۰% water and ۵۰% wastewater, ۱۰۰% wastewater) and eucalyptus species in three levels (Eucalyptus microtheca, Eucalyptus camaldulensis and Eucalyptus rubida). Each treatment was applied to tow eucalyptus trees or two pot. Annual seedlings planted in drainage lysimeters or pot with ۷ liters capacity and they were kept for four months. The soil of the experimental pot was a soil field, with loamy sand texture (۷۶% sand, ۲۰% silt and ۴% clay). Wastewater that was used from the wastewater treatment plant of Yazd city was prepared. Wastewater samples were taken during the irrigation period and examined for mineral, bio materials and biological. The chemical and biological analyses of the wastewater were according to standard methods. We studied the influence of irrigation with wastewater on high and diameter of trees, length and wide of leaves, leaf surface, dry mass of leaves, stem and root, specific leaf area, shoot and root dry mass, chlorophyll content and water use efficiency (WUE). The significance of differences between mean values was determined by one-way analysis of variance. Duncan’s multiple range test was used to compare the means. The use of tree plantations for the renovation of wastewater and the simultaneous production of forest produce is now being widely studied. In the condition of wastewater use, the presence of nutrients and organic matter in the wastewater will help to growth and water use efficiency in some plant species. However, reclaimed sewage or wastewater application may create undesirable effects in soils and plants with direct effects on soil suitability for cultivation and water resources availability. The use of wastewater for irrigation of fast growing trees it can be useful. They can use to excessive fertility elements in the wastewater. Irrigation with wastewater can cause increase of number of leaves, length and width of leaves in plants. Increase of leaves number and leaves area will make the absorption of solar energy better and enhance the efficiency of photosynthesis. Irrigation with wastewater can accelerate the flowering of plants and the seeds produced are also healthier. All of this factors can improve water use efficiency in plant. The results show that the potential for utilizing tree plantations in wastewater management. The results showed that there was a significant difference between irrigation treatments at ۱% level (p <۰.۰۰۱) on morphological characters such as height and diameter of trees, length, width and leaf area. Specific leaf area, leaf water content, chlorophyll content also increased with increasing of wastewater concentration and we absorbed significant different at ۱% level (p <۰.۰۰۱) between of different irrigation treatments. In ۱۰۰% treatment wastewater, chlorophyll content increased up to three times than control treatment. Shoot dry weight and water use efficiency were increased with increasing of wastewater concentration that in subject can be due to the high levels of fertilizer elements in the wastewater. The results showed that there was significant difference between trees species in a number of morphological and physiological characteristics. By increasing the amount of wastewater concentration, these characteristics improved in three species experimented. The E. camaldulensis had higher growth and water use efficiency than other species. This species has a high growth rate and therefore its can use good wastewater conditions. We suggested that for economic use of wastewater for wood producing, E. camaldulensis than other species in this experiment is suitable and its can be used.

Abstract Most part of Iran including Chaharmahal and Bakhtiari province is arid and semi-arid; thus in most parts of the region, groundwater is the only source of water. Thus, in the most parts of the region, groundwater is the only water resource, and is a major constraint on economic and social development. In arid regions, the underground dam is a new industrial site for supplying water for farming, especially in summer. An underground dam is a sub-surface barrier across the stream which retards the natural ground water flow of the system and stores water below ground surface to meet the demands during the period of need. The aim of this study was to prioritize the effective factors in the construction of underground dams and to develop and evaluate a multi-criteria decision making system based on GIS techniques in order to identify and prioritize potential areas for building underground dams in the watershed of Shahrekord. Marghmalek-Shahrekord watershed is located in north east of Chaharmahal and Bakhtiari province. This watershed is located in Sanandaj-Sirjan zone based on structural divisions and the atmospheric rainfall in the basin is mainly influenced by low-pressure Mediterranean systems. In order to accelerate the decision-making process, as well as avoiding the accumulation of excessive information for a surveyed problem, it is first necessary to eliminate inappropriate points by considering a number of key criteria and factors. At the first, suitable areas for establishing underground dams were determined with ommisive criteria and using Boolean logic and suitable areas for establishing underground dams were determined. The axes that do not cut the Qanat's gallery and are suitable from the aspect of length and area of the reservoir were identified. In the next stage, the proposed locations were prioritized using the analytic hierarchy process. Therefore, the indices that are more fit, matches the more suitable axes for the construction of underground dams in the study area. Five scenarios were considered for the prioritization. Quaternary formations are suitable for the construction of underground dam. Poor, medium and good rangelands and garden lands are suitable for underground dam. According to the first, second, third and fourth scenarios, axis number ۴۶ and according to the five scenarios, axis number ۴۱ have the first priority for groundwater dam construction. The results showed that the hydrologic factors and the socioeconomic factors were chosen as the most important factors with weights of ۰.۵۱ and ۰.۳۰, respectively. In determining the value of the indicators, the water quantity (runoff height) with a weight of ۰.۸۳۳ and also the depth of alluvium with a weight of ۰.۷۴۳ are more important than other indicators that this indicates the importance of the hydrologic criterion for experts. The best axes for the construction of an underground dam are in the alluvial river bed with high subsurface flow, the large reservoir capacity, high runoff volume and areas with high permeability and low slope. By integrating the maps of the Qanats axis of the study area and the map of possible gaps of underground dam construction, ۱۵ axes were identified for the construction of underground dam in Marghmalek-Shahrekord watershed. The results of the reservoir analysis indicated that suitable subsurface reservoirs in these areas are matched with this fact that with decreasing slope, the length of the reservoir increase, that ultimately causes increases the volume of the reservoir. The large area of the watershed upstream of the dam has a higher priority and value because the high amount of runoff passes through the construction site. The depth of the alluvium has the most relative importance among the axis indices, because in the economy of an underground dam, length and depth of axis are most important. By investigating the results of the reservoir depth, it was found that the best region are alluvial bed with a depth of less than ۱۰ meters, that is consistent with the results of Chezgi (۲۰۱۵). The water of these tables is very good in terms of quality because they are naturally refined by constituent lands. Also, they have a high subsurface discharge. These valleys are the best and most suitable place for underground water extraction. According to the obtained results about the slope, the relative importance of the slope increases with its lowering. The results of this study showed that most of waterways ۳ and ۴ were located at slopes less than ۵ percent, which are suitable areas for building underground dam because the gradient factor has inverse relationship with reservoir volume and permeability and is consistent with results of Nilsson (۱۹۸۸); Rezaei et al. (۲۰۱۳) and Chezgi (۲۰۱۵). The proposed method can accurately be used to select the suitable sites for construction of underground dams through detailed and accurate surveys and by considering the effective factors

Abstract Shallow water table is an important problem in arid and semi-arid regions. Since it causes reduction of agricultural yield; therefore, water table fluctuation is necessary to be monitored in irrigation and drainage fields. These conditions are intensified for arid and semi-arid countries, such as Iran, which saline groundwater are main water resources. These problems increased in sugarcane industrial farm that covered large area in Khuzistan province, Iran. Therefor, it is necessary to determine water table in sugarcane field during growing season. Regarding the purpose, it is important to evaluate water table fluctuations in each farm continuously. There are some problems to achieve this purpose like spending time and financial supports. So, computer models are developed to solve the problems. Water table can be simulated in different farm conditions, even before designing an agricultural unit, using the models. This research was conducted to evaluate two models: DRAINMOD and SWAP in order to estimate water table levels in Amirkabir Agro-industry farms located at latitude between ۳۱˚ ۱۵’ to ۳۱˚ ۴۰’ and longitude between ۴۸˚ ۱۲’ to ۴۸˚ ۳۰’, Khuzistan. Regarding the aim, water table data were collected from a ۲۵ ha-farm. In order to evaluate the results, four statistics criteria root mean square error (RMSE), modeling efficiency (EF), coefficient of residual mass (CRM) and coefficient of determination (R۲) were used. The calibration results of soil physics parameters for SWAP and DRAINMOD revealed that in both models, the parameters n and Alpha had the most variations compared to other parameters. In calibration stage, the amount of R۲ for DRAINMOD model was ۸۷. This result showed that there was a good correlation between field and simulated data. The result of R۲ for SWAP and ENDRAIN models were ۸۳ and ۹۳, respectively. RMSE values for DRAINMOD, SWAP and ENDRAIN were ۱۲.۴۲, ۱۰.۴۶ and ۱۱.۶۳ cm, respectively. So, in calibration stage, SWAP had more accuracy compared to other models to determine water table. The CRM values were obtained as -۰.۰۲۸, -۰.۰۲۲ and -۰.۰۶۱ cm for DRAIMOD, SWAP and ENDRAIN, respectively. Then, all three models lead to overestimate of water table. The results of EF were ۰.۸۳, ۰.۸۵ and ۰.۸۸ for mentioned models, respectively. Validation results of DRAINMOD model revealed that RMSE, CRM and R۲ were ۱۳.۱۹ (cm), -۰.۰۰۸ and ۰.۸۵, respectively. These statistical criteria were found to be ۱۷.۰۰ (cm), ۰.۰۲۰ and ۰.۸۲ for SWAP. These parameters were obtained as ۲۸.۱۰ (cm), ۰.۶۰۳ and ۰.۸۲ for ENDRAIN model. The results of EF were ۰.۸۴, ۰.۷۵ and -۲.۸۰ for DRAINMOD, SWAP and ENDRAIN models, respectively. These results showed that ENDRAIN had no efficiency to determine water table. SWAP and DRAINMOD had good efficiency to simulate water table. Thus, DRAINMOD had overestimate error and SWAP and ENDRAIN had underestimate error. DRAINMOD is recommended as a better model according to higher coefficient of determination and lower error value.

Abstract One of the most important issues to be considered in trapezoidal channels is the effect of side slope effects on the shear stress and jump characteristics including energy loss, jump length and conjugate depths ratio which have been studied in this study. For this purpose, at first, model has been calibrated by using an experimental results published for trapezoidal channel of ۴۵ degree side slope, the RGN model was selected from the turbulent models, and then the model for different hydraulic conditions (Froude number between ۱.۵ to ۱۲) and two slopes of ۶۰ and ۷۵ degrees has been performed and the results have been obtained. Due to the shear stress importance, which is usually not investigated in experimental researches, in this study the distribution of bed shear stress has been calculated in all three channels side slopes, and also the hydraulic jump characteristics. The results of this study on the three side slopes show different behavior of hydraulic jumps and shear stress in trapezoidal channel of ۴۵ degree side slope, in which the asymmetry of jump is very tangible and the shear stress concentration is observed on the left side of the channel wall. Comparison of the shear stress results show a significant reduction in shear stress after jump which the maximum amount of this reduction is related to the trapezoidal channel of ۴۵ degree side slope. It was also found that by increasing the side slope the amounts of shear stress and the sequent depths ratio increase, and the amounts of energy loss and length of jump decrease.

Abstract In this research, the changes in groundwater table and the volume of water reservoirs of the Kuhpayeh Segzi and southern Mahyar aquifers during the years ۱۹۸۱-۱۹۸۲ to ۲۰۱۲-۲۰۱۳ were investigated. For this purpose, the average level of aquifers' water table was calculated using the Thiessen method. The mean values of the groundwater table obtained from the Kuhpayeh Segzi and southern Mahyar aquifers were recorded as the average level of groundwater table in the Gavkhouni wetland during a ۲۲-years statistical period. Then, changes in the groundwater table and the water volume of Kuhpayeh Segzi and southern Mahyar aquifers, as well as the average changes of the above mentioned parameters were calculated for the wetland area. The trend of groundwater table changes was examined using the Mann-Kendall method. Finally, a hydrodynamic gradient map and field observations were applied to analyze the the interaction of the wetland and its leading aquifers. The results showed that the groundwater table in the Kuhpayeh Segzi and the southern Mahyar aquifers has decreased ۲.۷۵m and ۱۲.۸۳ m, respectively and the water volume of the aquifers was reduced by ۱۶۰ m۳ and ۳۰۰ m۳ per year, respectively, until the end of the statistical period studied. The results of Mann-Kendall test also showed a significant decrease in the level of groundwater table in the studied aquifers during the study period. In general, the level of groundwater and the volume of water resources in the wetland area has declined were ۷.۸ m and ۲۲۹ million m۳, respectively. Also, the results indicated that the Gavkhoni wetland had a nutritional role for the aquifers surrounding during ۲۲ years.

Abstract Introduction:
Water consumption has been rising during the last five decades across the globe because of population growth, higher standard of living, and economic development. Water resources limitations in Iran has led to the emergence of sustainable water resource management. To deal with the complex and interlinked water challenges, we need knowledge about the quantity and quality of water in the watersheds through water balance investigation. Evaluating available water resources is a prerequisite step in the water resources management to avoid adverse environmental impacts. Water balance investigations, as a tool for quantitative evaluation of water resources, is a prerequisite step in water resources management process. However, we have faced to some problems with water balance calculations such as: it is costly and time-consuming to provide reliable data for a large area and the estimation methods of water balance components rely on the methods that would not be appropriate for Iran's meteorological, hydrological and hydrogeological conditions. For example, in many cases, the empirical methods and mathematical models used in Iran were developed in other countries with different climates.

Methods:
Water balance models have been developed over multiple timescales (hourly, daily, monthly and yearly) and different spatial resolutions and varying degrees of complexity. Water balance models were ?rst developed in the ????s by Thornthwaite. With the increasing use of water balance models to address hydrological problems, a considerable amount of efforts has been devoted to the development of such models and techniques. A variety of models have been considered, ranging from relatively complex conceptual models to complex physical based models. Previous studies showed that using conceptual water balance models rather than process-based models or data-driven models have some advantages. Process-based models require high resolution, in both space and time, data and data-driven models may not remain valid in changed climatic conditions. Therefore, we focus on distributed and semi-distributed mathematical conceptual models. After evaluation different models, we introduce and classify some models that have relative advantages for being applied in Iran. These models have at least one of the following properties: they are conceptual models, some of them have been used for different regions, and some of them have been used for dry and semi-arid areas, and they use a simple method for water balance calculation, or their code, software or graphical interface are available freely.

Results:
To choose and modify an appropriate water balance model for Iran's watersheds, we should consider a simpler one especially when there are usually uncertainties about the model parameters and input data due to sparse data and lack of knowledge about the natural systems. We investigated different models especially models that have a fewer number of parameters for calibration and consider hydrological spatial variability in a water basin. Considering these facts, it seems the model developed by Portoghese et al. could be a good choice for the most arid and semiarid regions in Iran, after necessary corrections and modifications. The modified model was successfully implemented in different watersheds in Razavi Khorasan province. The model results, such as runoff, actual evapotranspiration, and deep percolation were in agreement with other studies, and consistent with the basin hydrological process.

Abstract Introduction: Alluvial rivers always change their hydraulic geometry to achieve a balance between water discharge, input and output sediment. Hydraulic geometry focuses specifically on the evolution of the river form and how the bed and channel influence this evolution. The morphology of alluvial rivers has led to the creation of two concepts: (۱) at-a-station hydraulic geometry and (۲) downstream hydraulic geometry (Julien, ۲۰۱۵). Downstream hydraulic geometry is defined by the top channel width (W), average flow depth (h), mean flow velocity (V), and slope of the flow energy (S) under bankfull conditions. Downstream hydraulic geometry as a function of hydraulic parameters and bed conditions, including flow rate, median size of bed particles and the Shields parameter is paramount to determine the state of a river. Therefore, various relationships have been derived based on various methods to estimate the channel hydraulic geometry, include: empirical relationships based on collected fields observation and theoretical relationships based on governing equations such as flow rate, resistance to flow, secondary flow and sediment transport in alluvial river. Result of theoretical derivations indicated reasonable agreement with field observations and regime equations. In recent years, intelligent data driven methods is used as new methods for predicting and estimating the parameters of complex hydraulic models. One of the common methods is the Group Method of Data Handling (GMDH) with self-organization approach, which has the ability to solve complex non-linear problems with higher accuracy and simpler structure. In GMDH method the coefficients of the polynomial are found by a Least Square Estimation (LSE) method. It is possible that combined the GMDH methods and optimization algorithms. By doing this, a hybrid method will be created. In this method an optimization algorithm used to calibrate the weights of each neuron in GMDH rather than LSE method and so the hybrid methods may have better performance. The GMDH method is combined with artificial intelligence and optimization techniques such as harmony search (HS) optimization method. Harmony search algorithm (HS) is one of the optimization methods that used to solve nonlinear problems, which was introduced in ۲۰۰۱ by Geem et al. based on a metaheuristic technique. The advantages of this algorithm are less computations to find a solution, fast convergence and significant ability to achieve the optimal solution due to the appropriate structure. HS algorithm has become one of the most used optimization algorithms because can be used for both continuous and discrete problems. Since the GMDH algorithm has a self-organizing approach and its structure is initially unclear, the Harmony search algorithm is used to train and optimize the weights in the structure of each neuron in the GMDH network. In fact, the objective of HS sub model is to determine the optimal weights in short time to achieve the optimal GMDH structure and minimize the cumulative error between the measured and computed data sets. Methods: In this study, to predict and improve the accuracy of the relations of the downstream hydraulic geometry in alluvial channels the GMDH model and a hybrid intelligent model based on the combination of GMDH and HS optimization algorithm that called GMDH-HS developed in the MATLAB software. Before using the developed models to predict and improve the accuracy of downstream hydraulic geometry in alluvial channels, it is necessary to check the accuracy of their results. Typically, researchers use the Mackey and Glass standard time series to verify the accuracy of developed models. Therefore, the validation of the developed models was done using the Mackey-Glass time series and calculated the verification results of the models for the two prediction methods by the CE, RMSE, MSRE, MPAE and RB criteria. To evaluate the developed models, ۸۸۰ data series were collected from previous research. This data set include a wide range of field and laboratory measurement data. From this collection, ۴۹۸ series were used to train and ۳۸۲ remaining data series employed to test models. The results of GMDH and GMDH-HS are compared with observed data. Also, the intelligent models results are compared with theoretical equations proposed by Lee and Julian (۲۰۰۶). Results: Evaluate the performance of developed models using statistical indices CE, MSRE, MAPE, RMSE, RB and R۲ indicate satisfactory performance of both models in predicting the downstream hydraulic geometry alluvial channels. A closer examination and comparison of the results of the two models showed that the hybrid GMDH-HS model had a much higher performance in predicting hydraulic geometry. Also, the comparison of the statistical indices obtained from the results of both developed models with the theoretical relationships presented by Lee and Julein (۲۰۰۶) suggests the very satisfactory performance of the hybrid intelligent model GMDH-HS in predicting the downstream hydraulic channel geometry in alluvial channels.

Abstract Heavy metals are hazardous pollutants that are usually produced by industrial waste water and enter the aqueous environment. In this experiment, three doses of adsorbent, rice husk and Activated carbon, nine Initial concentrations of lead metal, three different pH and four contact times were used to remove lead ions from the aqueous environment. Investigation of the equilibrium time at different concentrations showed that with decreasing initial concentration of the solution, the time of equilibrium for both adsorbents decreased. The time of equilibrium for both adsorbents was equal and its value was ۳۰ minutes. Investigation of adsorption efficiency at different concentrations showed that by decreasing the initial concentration of the solution, the adsorption efficiency increased for both adsorbents and get close together. The best removal of lead by two adsorbents of rice husk and activated carbon was obtained at ۷۷.۴ and ۹۴.۴%, respectively, at pH=۶ and adsorbent mass=۱ g/L. Activated carbon had the higher ability to lead remove from the aqueous environment. The fitting of Langmuir and Freundlich adsorption isotherm models showed that the adsorption process followed both the Freundlich and Langmuir isotherms, but the Freundlich isotherm is fitted better than the Langmuir isotherm.

Abstract Many processes amplify the nitrate contamination in the groundwater. In addition to economic losses caused by further utilization of nitrate fertilizers, nitrate leaching from agricultural lands imposes irreparable damages to the environment .Biochar has been recently used as an optimal method to decrease the leaching of soil nutrients. To meet this purpose, the present study was carried out to investigate the effect of using Biochar on the decrease of nitrate leaching from soil as well as the effect of changes (including increase and decrease) of dispersivity coefficient and absorption isotherm coefficient on the break through curve and nitrate distribution profile. The HYDRUS-۱D model was used to simulate the variations of the break through curve (BTC) and nitrate distribution profile in different points of the soil depth Biochar hydraulic parameters were measured in the lab. The results showed that increasing the value of Biochar adsorption isotherm decreases the output nitrate concentration and causes the nitrate BTC moves to the right side (Retardation). The results also showed that the increase of the Biochar dispersivity coefficient decreases the reduction rate of output nitrate concentration and causes nitrate BTC moves to the left side. The results also showed that the presence of the Biochar layer can decrease the content of nitrate distributed at the end of the column by about ۶۱%. The transfer velocity of pollutants into the soil depth also decreased with the increase of the Biochar adsorption and decrease of dispersivity coefficient meaning that the solutes exit later and less from the soil column when the biochar layer is used. The results of momentum analysis showed that the value of output pollutant mass from the column in the case of non-Biochar is ۱۵.۳۶ (mg/cm۳×h) while in the case of using Biochar is ۱۳.۷۸ (mg/cm۳×h) indicating a ۱۰.۳% reduction of output pollutant from the column. In all treatments, this value was lower than the control treatment meaning that the Biochar, can absorb contaminants in all conditions from the aquatic environment and reduce the contaminant percolation to the soil depths.