IRANIAN JOURNAL OF ECOHYDROLOGY
Year:2018 | Volume:5 | Issue:3 |Papers Count:25

River bank erosion imposes sever damages to the adjacent lands annually and changes the river morphology considerably. In this study, the effectiveness of the Vetiver grass root system in enhancement of the soil shear strength and reducing the river bank erosion is examined. Several experiments were carried out to find the effect of Vetiver grass root system on soil cohesion and internal friction angle. Also, variations of morphological characteristics of Vetiver grass root system including RAR, RDR, RDDI and RLD in different depths have been investigated as well as the lateral and vertical distribution of roots. Three different spacing between Vetiver grass plants have been studied and the optimum distance has been proposed. The results showed that Vetiver grass root system increases the soil cohesion and internal friction factor upto 104% and 83%, respectively. Also, it was found that soil cohesion and internal friction factor are best correlated with RAR and RDR, respectively. Finally, an attempt was made to compare the Vetiver grass with several native trees. It was concluded that Vetiver grass is more suitable than common plants and can be considered as an alternative for river bank protection against erosion.

Estimating aquifer hydrogeological parameters is essential for the studies or management of groundwater resources. There are several different methods such as pumping test, simulation or modeling of groundwater, geophisical modeling to estimate these parameters. Although analysis and evaluation of pumping test data is the best way to achieve this purpose, it is costly, time consuming and the gained results are from limited points. Malekan plain aquifer is one of the marginal plains of Urmia Lake which suffered more ground water declination and Salinization in last decades and it needs qualitative and quantitative management. In this study, artificial neural networks, fuzzy logic and random forest models have been used to estimate the transmission of aquifers and the performance each of these models has been investigated. Inputs of presented models included related geophysical and hydrogeological variables to transmissivity such as transverse resistivity (Rt), electric conductivity (EC), alluvium thickness (B), and hydraulic conductivity (k). Based on the results of all models, random forest model has higher accuracy and ability to predict transmissivity parameter. According to this model, electrical conductivity (EC), aquifer environment (A) and hydraulic gradient (H) parameters were identified as the most important parameters to predict the transmissivity, respectively.

Environmental Flows describes the timing, quality, and quantity of water flows required to sustain ecosystems, human well-being and livelihoods that depend upon them. A review of the present status of environmental flow methodologies revealed the existence of 4 differentiated methodologies. The main purpose of this paper is to assess common methods of environmental flow requirements. According to the standards of the Ministry of Energy of Iran, Tennant introduced as the base method for determining the environmental flows. This method together with wetted perimeter method with three different ideas is applied to the SefidRud. Also, the habitat simulation method, which is a part of the ecological method, is applied to SefidRud River too. Huso Huso fish was chosen as the species river target in this research study. The advantages and limitations of the above mentioned methods are presented as a part of results. 20% and 30% of the annual average flows are suggested for maintaining river health in poor and good conditions, respectively. The combined simulation method habitats and the maximum curvature of the wetted perimeter are recommended as a native method for SefidRud River to determine the minimum ecological flow and improve the ecosystem of the studied river.

In this study, the use of genetic optimization algorithm (GA), Particle Swarm(PSO), the ant colony for continuum (ACOR)and differential evolution (DE), to develop and improve the performance of ANFIS were investigated. the monthly maximum temperatures in Isfahan during the period of 64 years (1951-2014), was simulated and analyzed. At first in a sensitivity analysis, the best entries for each prediction period (1 month, 1, 2 and 3 years) were selected. Then, the maximum temperature hybrid models by ANFIS-GA, ANFIS-PSO, ANFIS-DE, ANFIS-ACOR and ANFIS were examined. The performance of each model with regard to R2, RMSE and MAE were evaluated. The results showed that the ANFIS-GA, as the most appropriate model, increased ANFIS performance in R2 to by 0. 06, 0. 07, 0. 08 and 0. 12 and RMSE by 0. 09, 0. 09, 0. 16 and 0. 1, respectively, in 1 month and 1, 2 and 3 year. After, ANFIS-DE and ANFIS-PSO, respectively, had the best forecasting accuracy. On the other hand, ANFIS showed highest error and lowest R2, as the weakest model. The results showed that the proposed models, which use global search techniques and avoid being trapped in local optimum, could improve the performance of ANFIS favorably. Therefore, these models can be used in other areas related to hydrology and water resources.

One of the natural characteristics of the Gamasiab River is the probability of occurrence of the flood and its hazard. Hydrological studies under climate change conditions are required to organize and manage it. Because of the necessity of using CMIP5 series models in new researches due to their high accuracy and lack of research using these models in our country, in the present study, four models of CMPI5 series and two scenarios RCP2. 6 and RCP8. 5 were used for the near future (2049-2020 AD) and the far future (2070-2099 AD). The results show the annual rainfall in five stations would vary from 52. 8 to-31. 6 percent according to the scenarios and different time periods. The average minimum and maximum monthly temperature at Kermanshah station increases to 2. 75 ° C and 2. 15 C° , and at Hamadan station, increases to 3. 43 C° and 4. 26 C° , respectively according to different scenarios. The SWAT model was used to simulate the hydrologic regime. The results while confirming the effectiveness of the SWAT model for simulating of river discharge, showed that changes in runoff rate using the output of the CSIRO-k3. 6. 0 model under different scenarios would indicate a change from 17. 8 to-42. 3 percent.

For better understand of hydrogeochemical processes in the Salmas plain aquifer, this study adopted graphical methods and multivariate statistical techniques to analyze groundwater samples. The results of the Piper diagram and expanded Durov diagram reveals that the major groundwater type is Ca-(Mg)-HCO3 and mixing groundwater type exists in southeast of the Salmas plain. Hierarchical Cluster Analysis (HCA) identified five classes of groundwater type (HC1 to HC5). The hierarchical cluster analysis is able to show the influence of nitrate concentration in classification while the graphical methods cannot. The Stiff diagrams of five classes (HC1 to HC5) show three different sources of groundwater samples. The HC1 to HC3 classes indicate groundwater with limestone and dolomite origin. In HC4 class, Na+ and Clˉ are the dominate ions in groundwater samples and shows saline waters. The HC5 shows mixing groundwater. Using Factor Analysis (FA), we identified three factors that accounted for 85. 03% of the total variance of the dataset. Factors 1 and 2 are reflected the natural hydrogeochemical processes and factor 3 is anthropogenic in the Salmas plain.

Lack of sustained access to water resources will lead to social disputes and economic disruption. This issue is currently one of the serious problems in Sarkhoon watershed, Hormozgan province. In this regard, the WQI method and the Man-Kendall test have been used to determine the water quality class andto observe the trend in the studied variables, respectively. The results showed that a significant and definite decrease in the quality and level of groundwater in the Sarkhoon plain. The obtained trend for declining water level in the plain had a coefficient of variance of 0. 03 and S-Mann-Kendall statistic of-277 at 99. 9% significance level. The slope of trend obtained for water level drop and the increase in WQI values, which indicates a decrease in water quality, were-33. 3 and-42. 3, respectively. The reported values for the slope of trend represent a decrease of 33 centimeters and an increase of 3/4 WQI unit per year.

The current study aims to prioritize of spatial flooding of Maharlo Sub-watersheds using morphometric parameters and VIKOR decision model. So, to select 13 morphometric parameters including slope, drainage density, stream frequency, constant of channel maintenance, drainage texture rate, ruggedness number, circularity ratio, compactness coefficient, relief ratio, stream length, form factor, elongation ratio, and coefficient of shape, and 1 climatic parameter including rain have been used to determine the weight of the parameters of the AHP. The results showed that the morphometric parameters such as slope and drainage density, and the climatic parameter of the rain, with values of (0. 206, 0. 165 and 0. 134) had the most weight and effect on flood event, while the least weight and consequently the least effect on the coefficient is related to shape (0. 122) factor. Also, for prioritizing used from 53 sub-watersheds based on VIKOR decision model. The results showed that sub-watershed 34 based on prioritization of flood first ranked (0. 082), The second sub-watershed 31 (0. 110) and sub-watershed 12 third ranked (0. 129) given specialty, which must have to be prioritized for management operations. While sub-watershed 42 has the last ranked (1) in prioritization of flood, which is indicate low sensitivity to flood events.

Flood is among the most important environmental hazards, broadly threatening human societies and their assets. In this research, by integrating the Rational model to estimate peak runoff into Marand basin flood hazard on a sub-basin scale, assessments are accomplished using remote sensing and GIS. After determining the runoff coefficient land cover/use layers were taken from satellite images of the Sentinel 2A, and the slope map was derived from the ASTER DEM 30m and soil hydrological groups, using the specified amount of rainfall hamely intensity in mode of 1-hour peak runoff was calculated. Using linear membership function in fuzzy logic model, integrating prepared this peak runoff and elevation lines between zero and one were fuzzy and then by applying multiple weight tangles to each of these two layers we collected their results, and the flood hazards distribution map was prepared. With the implementation of prepared risk map in fifth grade the classes include very low-risk, low risk, medium, high and very high risk with the results of GIS partnership or PGIS and entering this information into the confusion matrix. The accuracy of prepared maps was determined to be about 87. 83%.

Surface water is an important source for drinking water, which are under environmental and anthropogenic stresses. There are several evidences confirming that forest cover positively affects water quality. However, little quantitate information is available regarding the impacts of forest canopy cover on purification of drinking water quality in Iran. To achieve this, we selected several forested catchments with different ground canopy cover in Tang-e-Shool forest located in the Fars province and Water Quality Index (WQI) were measured by using physicochemical parameters. The production function of water quality service was also estimated by taking into account other characteristics of the forested micro catchments. Our results showed that the WQI in 30% crown cover is in a good quality scale. Also with an increase of 1% in the crown cover, WQI will improve by 0. 8% and an increase of 1% in the area of the micro catchment causes a decline of 0. 14 percent of WQI. Also, Aghajari Formation has a negative effect on WQI compare to Asmari. According to this study increasing the crown cover to protect water quality by up to 30%, will minimize treatment costs and the waters provided by these forests can be used for human drinking purposes.

The present paper briefly describes heavy metals from various aspects, the sources of production and the negative effects of these metals on human health, the standards and regulations of various agencies to comply with the permissible limits and finally, it also explores the methods of purification, separation and removal of these elements. Regarding treatment methods, a wide range of processes and disadvantages and advantages of each of the old types to the new technologies has been investigated, including chemical precipitation, coagulation-flocculation, flotation, ion exchange, electrochemical treatment, membrane filtration and adsorption. In this regard, absorption is considered as a simple but efficient approach, and has been specifically addressed and sorbents have been studied including active carbon, carbon nanotubes, graphene oxides and biosorbents. Today, nanoscale materials have shown significant applications in the treatment of aquatic environments, due to their unique features such as high surface area, large active sites and high absorption capacity. In this regard, magnetic nanoparticles of iron oxides are considered as cost-effective, high-efficiency and environmentally friendly adsorbents.

Years ago nitrate pollution in water and soil has been a major concern in the world's environmental issues. Nitrogen-containing compounds in the environment can cause new problems, such as river eutrofication and a dangerous disease called methemoglobinemia and other disorders in human health. One of the most important wastewater treatment goals is the removal of nitrogen, which is carried out by chemical, physical and biological processes that biological methods of nitrogen removal are more efficient and economical. Nitrification is one of the main processes for the removal of nitrate in water, a process that requires no oxygen, in which bacteria use from nitrate as an electron receiver to obtain energy for growth. Solid-phase denitrification process is an emerging technology which has received increasing attention in recent years. It uses biodegradable polymers as both the carbon source and biofilm carrier for denitrifying microorganisms this process is a promising technology for the removal of nitrate from water and wastewater. In the future, more attention can be devoted to the simultaneous removal of nitrate and other pollutants from water by Solid-phase denitrification, thereby ensuring the health of the environment and human.

In this study, an entirely fuzzy optimization model is presented for conjunction use of surface and groundwater. Groundwater level in Astaneh-Koch Esfahan Aquifer was simulated using the GMS Model, while its results were used as a constraint in optimization model. Then, Kumar and Jayalakishimi fuzzy optimization methods were solved by applying the GAMS software. Maximum water supply shortage in Kumar method for left-side of Sangar was in 2009 that 58. 36% of demands was satisfied. Also this value in the right-side was calculated about 56. 76% in 2008. In the Jayalakishimi method, the maximum water supply shortage was obtained in 1998 and 2014 that 66. 5% and 60. 96% of demands for left and right-side are satisfied, respectively. On the other hand, for this method, in the situation of total maximum shortage for left and right sides of Sangar channel, supply percentage of water needs was about 65. 9% in 1998, while for the Jayalakishimi method, it was obtained about 66. 5% in 1998. Also in the current situation, the supply percentage in the worst conditions is 54%. Regarding consideration of uncertainties, the proposed fuzzy optimization model can be applied to manage the conjunctive water supply for agriculture.

Flow modeling in rivers is very complicated due to their meandering path. Therefore, the use of an accurate numerical model for predicting flow pattern and the effects of flow turbulence is necessary. Furthermore, choosing the type of turbulence model can be effective in simulating and studying flow properties. Different types of turbulence models can be used in SSIIM numerical model. In this study, with the aim of investigating the efficiency of turbulence models, three different kindes of k-Ԑ turbulence model, including the standard type, based on water velocity and RNG, are used to simulate flow characteristics in different points of a 45 degrees cross-section from a steep bend located on the Doab Samsami river. Comparing the measured values of the velocity component with the results of the model indicated that the standard k-Ԑ model for determining the vertical component of velocity and k-Ԑ model based on water velocity for the longitudinal component of the velocity are best models in accuracy, respectively and generally the ability of all mentioned the turbulence models evaluated well. Moreover, exact consideration of bed roughness and roughness of the channel bank in the numerical model can have a significant effect on the accuracy of the model results.

In this research, the hydrogeochemical situation of Kashan aquifer, its pollution to nitrate and nitrite and their mechanism were studied. For this purpose, 42 water samples from the aquifer were prepared and analyzed. The results showed that chloride and sulfate are predominant anions and sodium and calcium are dominant cations. The results about the permitted range of TDS, pH, Na+, K+, Cl-, SO42-, NO3-, NO2-, Ca2+ and Mg2+ variables showed that respectively, 97. 61%, 40. 47%, 100%, 97. 61%, 95. 23%, 38. 09%, 95. 24%, 83. 34% and 95. 23% of region water resources have unauthorized status according to WHO and ISIRI standards. Correlation between NO3-with Na+, K+, Ca2 +, Mg2+, Cl-, SO42-, NO2-, TDS and EC was 0. 68, 0. 50, 0. 63, 0. 52, 0. 64,-0. 34, 0. 32, 0. 64, 0. 64, respectively. other results showed that nitrate varied between 1. 86 to 1034 and had an average of 118. 76 mg/lit. Also, 40. 49%, 21. 42% and 38. 9% of the samples for nitrate were slightly polluted, polluted and highly polluted, respectively. For more precise investigation of aquifer contamination, based on WHO recommendation, the combined results of nitrate and nitrite showed that 95. 23% of the samples had a non-allowable concentration. Therefore, only small parts of the aquifer in the south, southwest and west have acceptable situation.

The Curve Number Model (SCS-CN) is in conventional mode is based on the linear relationship between initial absorption (Ia) and potential maximum retention (S) of the catchment but this model has been modified to consider non-linear Ia-S relation. The objective of this study is to compare the conventional curve number and modified curve number (non-linear Ia-S relation) models in flood hydrograph estimation in five Galikesh, Nodeh, Tamer, Vatana and Kechik catchments (37 rainfall-runoff events in calculation and selection of 14 events for results comparison in validation step). The root mean square error (RMSE), Nash-Sutcliff (NSE) and peak discharge estimation error (PEP) criteria were used for results comparison. Investigation of RMSE and NSE and PEP criteria shows that the application of modified curved number model (non-linear Ia-S) in all events of validation step improves the estimations of flood hydrograph and peak discharge in comparison with conventional curve number model (SCS-CN), therefore the results indicated that in studied catchments, the modified curve number model (non-linear Ia-S) has improved the conventional curve number SCS-CN model.

Lack of appropriate allocation Environmental Flow, has been disrupts the vital activities of aquatic organisms, reduces communication between ecosystems, access to suitable areas for spawning and migrating aquatic. In this research, the environmental demand of Gharasoo River at the siahab station hydrometry was investigated at the entrance to the Gorgan Gulf. Were evaluated of In order to obtain the ecological requirement of Gharasoo River in Golestan province hydrological methods of Tenant, Tessman, Arkansas, Physical Habitat Simulation Model (PHABSIM) for species Capoeta capoeta gracilis. The findings of this research show method of Tenant by taking 30 % annual average flow for the spring and summer seasons, 10 % annual average flow for autumn and winter seasons suggests respectively quantities 0/57 and 0/19 cms. Methods of Tessman, Arkansas and Physical Habitat Simulation model Provide estimates environmental water requirement in equal order 0/856, 1/22, 1/63 cms. Also, there was a lot of difference among between the results of estimating the minimum required water requirement for the river using hydrological methods and providing minimum habitat conditions for indicator species using habitat simulation method and as regards the ecological and habitat conditions of the river are a completely dynamic situation.

The increase in the world's population, the use of more than fossil fuels, landuse change, the increasing expansion of industrial activities to provide the welfare and needs of the planet's population has led to gradual changes in the climate after the Industrial Revolution The Earth is the most significant of which is the increase in the average temperature in Korea, the increase of extreme climatic phenomena such as floods, storms, rising sea levels, melting of polar ice and Drought. In this research, SDSM model was used for quantitative estimation and investigation of climate change in Karaj region. The simulation results, on average, in the scenario A2, in the first periods(2020-1999), second(2021-2050) and third(2051-2080) for rainfall were about 0. 1, 0 and 0. 2mm in comparison with the base period and in the case of temperature is about 0. 1, 0. 4 and 0. 2C, respectively, relative to the base period of increase. Under scenario B2, the time periods mentioned for rainfall were about 0, 0. 1 and 0. 2 millimeters, respectively, and about 0. 2, 0. 1 and 0. 1 centigrade, respectively Shows the increase relative to the base period. Changes in rainfall will lead to significant changes in the quality and quantity of water resources, which require careful planning in order to utilize water resources.

In order to model groundwater flow, numerical and analytical methods can be utilized. In this paper, the effects of different parameters on leaky aquifer were investigated using mathematical model and separation of variables method. This aquifer is located adjacent to the river and the flow rate falls across the border. Comparison of hydraulic head changes shows that over the time the water level changes decreases in the aquifer and the aquifer adapts itself to the new conditions. Groundwater level decrease with rises in hydraulic conductivity. Reducing hydraulic conductivity has a greater effect than increasing it on the aquifer. Also, the groundwater head rises by increasing the recharge rate and over time, these changes are more evident. Outflow changes are greater than inflow changes. In addition, the presented analytical solution is compared with those results obtained from MODFLOW. This comparison showed that the analytical solution presented in this research is very efficient.

Drought phenomena may cause unpredictable changes under influence of climate change and there are indexes for its evaluation. In this research, firstly, base period’ s drought (1998-2017) was evaluated in 3, 6, 12 and 24-month time series in synoptic stations of Ilam and Dehloran, located in Ilam province, through using monthly precipitation data. Then, monthly precipitation of future period (2018-2037) were studied through using daily data of precipitation, minimum temperature, maximum temperature and radiation via using downscaling LARS-WG Model under Hadcm3 General Circulation Model and A2 and B1 Regional Scenarios. Then, SPI drought index was evaluated for future period in desired time series. Results of drought evaluation in base period in Ilam Station represented that 2008-2014 period had been a relatively humid period. It also represented timid period in Dehloran Station at beginning of period. Evaluation of drought in future period based on A2 and B1 Scenarios presented there will be a mostly drought period in Ilam Station between 2025 to 2035. Also, there will be a complete drought period in Dehloran Station from 2019 to 2021. Also, results represented that duration of drought and timid periods are increasing and their severity will be decreased by increase of statistical period.

One of the major consequences of climate change is the increasing severity of drought. Drought is a recurring natural phenomenon that is associated with a shortage of available water resources in a large area over a given period of time. In recent years, the increasing frequency of occurrence of extreme climatic phenomena such as floods and droughts, along with global warming evidence, has led to an increase in attention to climatic issues. In this research, by preparing climatic statistics of two stations in Bojnourd and Assadi, the drought condition of Bojnoord plain has been investigated according to drought indices SPI, RAI and PN. Then, using Piper and Wilcox diagram, the quality of groundwater resources has been compared during drought and wet periods. The results of the survey indicate that the Bojnourd plain has been in drought situations in recent years. The results show that the quality of water resources during the wet period was mostly mixed and sweet water, but in the drought period, the water type was more than the mixed and saline water. The results also show that in the drought period more than 50 percent of wells in saltwater conditions were unsuitable for agriculture.

In most of the factories, one of the most important and practical devices is the type of cooling towers which are used to release extra heat from processes in various industries to the environment. This study is an overview of novel ways on the effect of different type’ s nanofluids on the thermal performance and reduce the amount of flowing water down the cooling tower. Nanofluids can improve thermo physical properties such as heat capacity& thermal conductivity coefficient and increase density & viscosity in comparison to base fluid. The dispersion of the nanoparticle increases the surface tension of the nanofluid and increases the resistance to water evaporation. So in this paper study influence of ZnO/water, nonporous graphene, AL2O3/ water, TiO2/water, CuO/water with the different concentration in order to improve cooling tower performance. It was found that by using nanofluids, cooling range, cooling tower characteristic (TC), volumetric heat transfer coefficient and efficiency are enhanced in comparison to water. For example, TC enhanced by 21. 5% and 22. 5% for ZnO/water nanofluid with concentration of 0. 02 wt% and 0. 05 wt%, respectively. In continue, results of sensitivity analyses that has been carried out in investigations, are discussed.

The purpose of this research is to analyze the decrease of surface moisture and source of dusts in Hamoon-Hirmand Basin of Sistan and Baluchestan province. In order to achieve the objectives of this paper, WEAP software was used to simulate subsurface flow drops and then, by applying water resource management scenarios, the subsurface flow loss rate was simulated by 2031. Using the hierarchical analysis method, the best option among the scenarios was selected and the area under study under this scenario at the end of the year is 29 cm below the subsurface flow rate and the total unsecured amount for various criteria such as drinking, agriculture And the environment is equal to 804. 183 million cubic meters. The wind speed in the study area is greater than the velocity threshold of the particles (more than 400 cm / s), so the area is capable of producing dust. The HYDRYS-1D model has been used to analyze the soil moisture content reduction in this paper. The obtained results indicate a decrease in soil moisture content in each year. It was concluded that the reduction of soil moisture content is closely related to the subsurface flow rate and the potential for dust.

This study survived the factors affecting on water demand in agricultural and domestic consumption, amount of water demand and income and price elasticities in household sector in the north of Sistan and Baluchestan. For this purpose, we used the Stone-Greay utility function in the household sector and considered quantitative and qualitative factors influencing the optimal water resources management in agriculture using the Logit model. The results of water demand function estimation in household sector showed that the demand for per capita in general condition was equivalent to 61. 5 cubic meters per year and the extera consumption per capita in this case was 26. 8 cubic meters. Also, income and price elasticities of household water demand in this case were equal to 282. 0 and 373. 0 respectively, indicating that the demand for water was less tangible than price; Income stretch is less than one, indicating the necessity of water. The results of estimation of the optimum water consumption model showed that the most effect was on the work experience and history variables and then the variables of using fertilizers and chemical pesticides, type of communication channels, irrigation methods, education and education level had the most effect on optimal use of agricultural water resources.

The semi-tropical plant of saffron, due to low water requirement and high income, has a special place in the cultivating pattern of arid and semi-arid regions such as Torbat Heydarieh region of Khorasan Razavi. In this research was carried out to determine the potential and actual evapotranspiration rate and the most suitable model for estimating evapotranspiration of saffron in Torbat Heydarieh (the world's saffron producing pole). The results of comparison of different methods with FAO method as standard and basic method showed that Blaney-Criddle, Genesis and Hargreaves methods were more accurately than other methods. A comparison of the results of the FAO method with other methods was performed using Chi-square test. The amount of annual water requirement of saffron in the climate of Torbat Heydarieh using the FAO method was 1731 m3 / ha. Since in the Hargreaves-Samani equation, for the calculation of evapotranspiration, only two factors are necessary for temperature and solar radiation, and it is possible to determine the factors in most weather stations, the overall result of this research is that, in the estimation of initial and Rapid need for a saffron plant in the region can be used.