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Otters at the top of the food chain and feeding largely on fish are likely to be especially vulnerable to the effects of bioaccumulating pollutants. This research reports the first data on mercury levels found in hairs of river otters (Lutra lutra) from Iran. Between June and December 2007, we collected museum and recent collections of river otter hair. These samples were collected from several provinces of three major regions of Iran. The mean of mercury concentration for all samples (recent and museum) was 5.819±1.557 mg/kg with 95% confidence interval for the mean. The concentrations of Total Hg (THg) in hair ranged from 0.293 to 12.382 mg/kg. No significant variation among the sample regions existed. A comparison of THg concentrations between two decades (1986-1996 and 1996-2006) showed that these differences were significant (p

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The zooplankton diversity of Helleh estuary, Busheher, Persian Gulf, and its relationship with some characteristics of water quality was investigated. Samples were taken using plankton net (mesh size of 140 µm) with vertical towing from 5 fixed-stations in mid-season from summer 2011 to spring 2012 for one year period. The mean (±SE) of biodiversity indices of Simpson, Shannon-Wiener, and Margalef were, respectively 0.84±0.10, 3.01±0.20, and 1.90±0.10 in summer; 0.63±0.06, 2.20±0.20 and 1.87±0.08 in autumn; 0.73±0.04, 2.22±0.10 and 1.43±0.10 in winter; and 0.87±0.01, 3.44±0.30, and 2.38±0.30 in spring. The seasonal zooplankton similarity based on Jaccard’s and Sørensen’s coefficients were highest (0.61 and 0.76) for summer-autumn, 0.56 and 0.72 for autumn-spring while these value were lowest for winter-autumn (0.27 and 0.43) and spring-winter (0.30 and 0.47). In addition, there were significant correlation between zooplankton density with salinity, dissolved oxygen and chlorophyll a, Simpson and Shannon- Wiener with temperature, and Margalef with pH.

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Age structure, growth and mortality index of 661 specimens of spirlin, Alburnoides eichwaldii, from Shirood River in Mazandaran Province were studied during April 2011 to March 2012. The average total length, weight and age of the specimens were 68.33 ± 16.92 mm, 4.9 ± 3.2 g and 1.32 ± 0.86 years, respectively. The fish were in the age range of 0⁺ to 3⁺, of which the 0⁺ year specimens dominanted the age groups in the river. The largest specimen was 111.4 mm in length and a weight of 15.5 g. Comparing total length and weight of fish showed significant differences various ages (P < 0.05). Based on Pauly formula, population growth pattern was negatively allometric (b = 2.94). Based on von Bertalanffy growth equation using the FiSAT program, L_∞, K and t₀ were 12.08, 0.55, and -0.47, respectively. The growth performance index was up to 3.65.  Mortality indices for the fish were calculated as 2.41, 1.19 and 1.22, respectively for the total (Z), natural (M) and fishing (F). Considering the ecological, biological and ornamental value of spirlin as well as its vulnerabilty to serious environmental degradation, such studies may be useful in the protection of the species.

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  Parameter estimation of the nonlinear Muskingum model is a highly nonlinear optimization problem. Although various techniques have been applied to optimize the coefficients of the nonlinear Muskingum flood routing models, but an efficient method for this purpose in the calibration process is still lacking. The accuracy of artificial bee colony (ABC) algorithm is investigated in this paper to optimize the coefficients of nonlinear Muskingum model. The performance of this algorithm was compared with other optimization techniques. For evaluating the ability of the ABC algorithm, several statistical criteria such as sum of the square error, sum of the absolute error, mean absolute error and mean relative error were used in the present study. ABC is an intelligent algorithm, which can effectively overcome the prematurity and slowed convergence speed of the traditional evolution algorithms. It determines the best parameter values in terms of the sum of square residual between the observed and routed outflows. The simulation results show that the performance of ABC algorithm with the sum of the square of the deviations between the computed and observed outflows (SSQ) of 35.62 m3 s-1, the sum of the absolute value of the deviations between the computed and observed outflows coefficients (SAD) of 23.2 m3 s-1, the mean absolute errors between the routed and observed outflows (MAE) of 1.05 m3 s-1 and the mean relative errors between the routed and observed outflows (MRE) of 2.9% is comparable to those of other algorithms. Thus ABC provided an efficient way for parameter optimization of the nonlinear Muskingum model.

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Abstract Urban parks and green spaces as a part of the urban structure must be design according to the necessities of urban life and fulfillment of the citizens requirements. The citizens requirements include wide variety environmental, social, cultural, economical and physical aspects. All cities potential spaces and their natural values must be consider to sustainable fulfillment of the citizens requirements. One of the most important natural values in cities are rivers and their surrounded valley that always very interested for Authorities and urban planners to convert to urban green space.. Rehabilitate and planning of these rivers and rivers valleys is mainly done base on recreational development and sustainable development objectives. Therefore their suitable ecological conditionse is very important. Base on above consideration, the principle criteriaes for urban river valleys ecological evaluation base on sustainable landscape design, wereinvestigated. In this project, case research method by use of compound solution has been used. Results of this research reveals that landscape elements in Darabad river valley could be divided in four categories including 1-watery surfaces 2-topography 3-vegetation cover 4-artificial elements and the first priority in permanent ecological landscape restoring of this river valley is connected to preservation and restoring of the river and vegetation cover in the river floor and side gardens. Keywords: sustainable development, river valleys, urban environment, park

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Based on the macro-invertebrate community and physico-chemical indices, water quality of the Tajan River in 6 stations along 80 km of the river length was assessed. Monthly sampling was conducted for one year (September 2011 to August 2012), using a surber with 30.5 × 30.5 cm dimensions and a 60μ mesh net for the benthic invertebrates sampling. The identified macro-invertebrates belonged to 31 families, 12 orders and 5 classes, the highest and the lowest abundance of which belonged to Psychodidae and Chironomidae, respectively. Based on Hilsenhoff Family Biotic Index, the research stations were classified into 4 qualitative categories, viz. excellent, good, fair, and fairly poor. Stations 1 and 5, respectively, showed the highest and lowest HFBI index. The highest and the lowest values for the Shannon–Weiner index were recorded in station 1 and station 2, respectively. The results of physicochemical parameters indicated  reduced dissolved oxygen in the stations 2 and 5, and increased TDS in station 2 and 1 and increased nitrite and ammonium in station 3. Results of Spearman correlation coefficients between biotic indices and physicochemical variables revealed significant relationship between DO, TDS, EC, PO₄ and water flow with HFBI and Shannon-Weiner indices. This study showed, generally pollution in stations 2 and 5 has reduced water quality in these station's.

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Due to its nature, water resources, in addition to giving life to a land and its creatures, can be the source of differences between countries and nations with common resources and cause great losses. In this regard, a new field of research called hydro politics has been created that surveys these issues. Considering the climate situation of the Middle East and the widespread limitation of water resources in this region, the purpose of this study is to investigate the hydro political situation of Iran's joint watersheds with neighbors with emphasis on the Tigris and Euphrates, especially the Arvandrud River. Using the descriptive-analytical method, first, the resources were reviewed systematically, and then the situation of water resources in the area was identified and studied using spatial analysis. Surveys were conducted on three large scales in the Tigris and Euphrates basins, the middle scale in the Karkheh and Karun basins, and the local scale in the Arvandrud River joint area. Studies have shown that the hydro political situation in the region will become tenser with the control of water by upstream countries and due to the very high population growth and water consumption in Iraq. Also, due to Iraq's limited access to open waters and its very small and unsuitable coastline for maritime transport, there is a potential for tension in the region in the future

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Background: Global warming and climate change are widely indicated as important phenomena in the 21st century that cause serious impacts on the global water resources. Changes in temperature, precipitation and evaporation are occurring in regions throughout the world, resulting in changes including, runoff, streamflow and groundwater regimes, reduced water quantity and quality.
Materials and Methods: Relying upon thirty years of base data (1965–1994), three global circulation models (GCM), namely GISS, GFDM and CCC, are utilized to assess impact of climate change to groundwater recharge rates between years 2010 to 2050 for the Guelph region of the Grand River Basin in Canada. The resulting groundwater recharge rates for alternative soil layers are used to assess water balance conditions, and ultimately, the percolation rate to the groundwater using the Visual-HELP model.
Results: While the climate change impact assessment indicates that evaporation will increase and percolation will decrease during summer, increased percolation is indicated in winter due to additional freeze/thaw dimensions of climate change. The net effect is that the impact of climate change, based upon use of GCM models, is expected to increase groundwater recharge rate by 10% on average (7% for CCC, 10.6% for GISS and 12% for GFDM) in future.                                  
Discussion and Conclusions: According to the results of this research in the Guelph region, the monthly average percolation rate is higher with climate change; (i) the percolation rate is increased during winter due to freeze/thaw effects, while (ii) it is decreased during summer due to higher evaporation rate.

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The River’s End is a fictional work with a dream-like structure. In this article we analyze this story and its meaning-making structure through a Freudian approach. This reading includes two layers: (1) the overt or surface structure of the story; (2) the covert or deep structure of the story. In the overt layer, it is demonstrated that the story has a conceptual structure and its events are narrated in a disorganized plot in which the causality and time sequence are distorted. In the covert layer, we have distinguished between metaphoric and hidden plot. In the metaphorical plot, the symbols of the narrative of The River’s End have been identified and two symbols of Zāyandeh-Rood and Gāvkhuni as two prevalent feminine symbols which are related to the return to the womb are analyzed. Many of the characters then based on their relationship to these two symbols are psychoanalyzed. In the hidden plot the relationship between the narrator with the pleasure principle and death principle are analyzed to unravel the unending suspension of the narrator in the procedures of fate, repetition, and movement toward death is defined.

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Aims: Karun River, which is the largest river in Iran, represents a unique ecosystem. However, increased anthropogenic activities result in the formation of this river is seriously affected by a large range of pollutants especially the heavy metal pollutants which may be toxic to human and aquatic fauna. Therefore, there is a need for continuous monitoring of pollution levels in the river.
Materials & Methods: In this study, water, sediment, and algae samples were collected from six different stations along the course of the river in September 2015 to investigate the quality of Karun’s River in terms of heavy metals (Pb, Zn, Cr, and Cd) at the basin of drinking water treatment in Ahwaz and Mollasani cities. After drying and digestion of samples, heavy metal concentrations were determined using an atomic absorption spectrophotometry (Perkin Elmer-Analyst 300).
Findings: The highest concentration of trace metals was found in sediment samples with Zn having the highest mean concentration values in all stations. The heavy metal concentrations in the downstream indicated an increase in the pollution load due to the flow of water from upstream to downstream of the river resulted in the movement and accumulation of all contaminants to the river in the downstream; hence, there was the highest concentration
of metals in basin of the Kut Abdollah treatment (downstream) and the lowest in Mollasani (upstream).
Conclusion: Comparison of the concentration of metals in the sediments with some universal standards including EPA3050 and the criterion of sediments quality standard from NOAA and Canadian Environment Agency showed that the concentration of chromium and cadmium in stations was higher than the allowable limit of EPA3050 standards and some environmental standards of Canada among all metals. Since algae samples have been able to accumulate a significant amount of heavy metals, therefore, these are suitable bio-indicators to determine the concentration of heavy metals in this aquatic ecosystems.

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The present study aims at applying different methods for predicting spring inflow to the Amir Kabir reservoir in the Karaj river watershed, located to the northwest of Te-hran (Iran). Three different methods, artificial neural network (ANN), ARIMA time se-ries and regression analysis between some hydroclimatological data and inflow, were used to predict the spring inflow. The spring inflow accounts for almost 60 percent of annual inflow to the reservoir. Twenty five years of observed data were used to train or calibrate the models and five years were applied for testing. The performances of models were compared and the ANN model was found to model the flows better. Thus, ANN can be an effective tool for reservoir inflow forecasting in the Amir Kabir reservoir using snowmelt equivalent data.

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Zab basin is in the south part of Urmia Lake. The little Zab River in northwestern Iran rises at the Piranshehr mountains and flows from the northwest to the southeast to join Iraq through Alan passage. The river basin contains many ancient settlements. Based on pot sherds it can be inferred that this basin has been a residential zone since the prehistoric period. A noteworthy feature of this basin is the presence of Uruk pottery, including the beveled-rim bowl, at 5 sites in Zab basin. This pottery has not been seen either in the northwest of Iran or in the higher regions of Hamadan. For the first time this material is identified in the Little Zab basin. This pottery belongs to the late Uruk period, i.e. late fourth millennium BC. Geographical position and settlement patterns could be signs of commercial and cultural relations between societies of Northwestern Iran and northern Mesopotamia in late Chalcolithic.
 

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The Zab river basin is locate in south of west Azarbaijan and north of Kurdistan province with total area equals 3527 km 2 .This river is flowing in the tectonic vally and slope instabilities occur frequently in center of this basin.Annually ,occurs of landslide and other type of mass movements cause of damages for roads , habitats and agriculture lands. This paper has attempted to evaluate and recognize these natural hazards and finally prepare hazard maps by applying Anbalagan method.The method of research in this paper are recognition and verify of landslide in field and determination of cause of their occurrence.The second stage is preparing factor maps and finally drawing slope instability zonation map.

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Abstract The complex three-dimensional flow characteristics in river bends necessitates the use of a three-dimensional numerical model. The numerical model used in this paper is called SSIIM (Sediment Simulation In Intakes with Multiblock option).The 3D model already has showed satisfactory results in related applications. In this study, SSIIM is applied to study the variation of channel bed under steady flows in a 180 mild curved open-channel with sandy bed. Bed roughness was calibrated to ks  4.5 d90  6.25d50 . Comparison of results showed good agreement between the computed and measured bed topography. The model simulated both the point bars near the inner bank and the scour holes near the outer bank. In addition, the positions of these phenomena are in fair agreement with the measured data. Numerical results show some dependencies on the grid size. In addition, deviations of model from the experimental data as well as uncertainties in numerical modeling are discussed.

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Hirmand River is originated from Afghanistan and the people's life in Sistan is depended on it. The increasing and reduction of Hirmand water flowing toward Sistan (Iran) from one hundred years ago have already caused problems in political relation between Iran and Afghanistan in local and national levels. This research wants to find the increasing and reduction reasons of Hirmand water toward Sistan and effect of it on political relationship between Iran and Afghanistan .Drought and reduction of flowing water from Afghanistan have caused reduction in water flowing toward Sistan and also caused water crises in this area. However , over past one hundred years the Afghanis separated various canals from Hirmand and built many dams over it , have consumed a large amount of water and also the rate of flowing water toward Sistan has reduced ..

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Lotic systems are rapidly changing due to anthropogenic impacts, making it crucial to note the diversity and abundance of Odonates for effective conservation of these running waters. Our study aimed to assess and compare the Odonate communities in two adjacent rivers, Medjerda and Cheref, in Souk Ahras, northeastern Algeria collected during the period from January 2022 to August 2023. In total, 27 species belonging to 7 families and 17 genera were recorded, with three rare species in Numidia, and three Maghrebian endemic species, including Gomphus lucasii (Selys, 1850) listed as “Vulnerable” in the IUCN Mediterranean Red List. Coenagrion mercuriale (Charpentier, 1840), a locally endangered species, was abundantly present in the Medjerda River. Additionally, the presence of the desert species Trithemis kirbyi (Selys, 1891) in Medjerda confirms their northward expansion within Algeria. The Libellulidae were the most dominant family with 11 species. Our findings revealed no significant differences in terms of biodiversity indices (Richness, Simpson, Shannon, & Pielou's evenness) between the two rivers. However, significant dissimilarities were observed in Odonate assemblages likely due to habitat and environmental variations. Many factors, such as water pumping, overgrazing, untreated wastewater, and riverbank development, which influence Odonate species, were observed in the two rivers. Consequently, an urgent conservation plan should be put in place to preserve water resources and biodiversity in the region. This study highlights the need for continued monitoring and conservation efforts, especially for rare and threatened species in the face of increasing anthropogenic pressures on these aquatic ecosystems.

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During late nineteenth century, Khuzistan was considered to be the most fertile land of Persia which at one time had yielded $ 50 million if calculated on 1962 price index. Many British officials presented in Iran and India office have recorded the abundance of water through a network of five rivers and canals, making Khuzistan a fertile ground for major staple and cash crops. At the time when the general populace was affected by the famine, Khuzistan stood unaffected. But thoroughly and gradually Khuzistan had faced deplorable condition owing to the British policy and power struggle. With the opening of the Karun River, the British influence had reached to the extent that they started interfering in the appointment of governors and granting of Khuzistan developmental projects to French, Dutch or Germans. The present article highlights the increasing influence of British in the political and economic affairs of Iran especially Khuzistan which was considered to be the 'second Egypt' next to Seistan. They had even assisted by the principle Arabs and Bakhtiaris tribes of Khuzistan as well as the influential trading and commercial figures to sabotage the irriga-tion project which could hamper the water flow to Karun River, a back bone for their commercial interest. In the first quarter of 20th century the British policy in Khuzistan proved detrimental to their vested interest.

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Analysis of land use changes in the areas around of large dams specially in the top of dam building and hydrology network is the main subject to evaluate environmentally effects. In this paper, analysis of dam effects in Sattarkhan Dam of Ahar city has been studied. Due to this dam supporting water in order to using in agriculture, drinking water activities and to support water for lands under dam construction areas, have considerable effects in the environment. In this study using results of reorganization of changed areas and unchanged areas from satellite images and to combine them with building and other equipments, rate and extent al effects analyzed in land use were determined. The results of this research in GIS environment as thematic maps presented, indicate that in covered Sattarkhan Dam have two direct and indirect effects in its around. Th/e changes of grounds and agricultural levels to building and water surface is the directs of very high injured and changes of dry farm land and bear land to gardens developments of urban areas is the indirect effects and has low and very high injured indexes respectively.

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Aim: Landslide classification using a fractal model at the Tajan river basin in northern Iran is the study intended as a new approach based on 142 landslide information data set.
Materials & Methods: The obtained results were interpreted using the Depth–Number (Dp–N) fractal model and a fairly wide set of information available for each landslide class, consisting of Digital Elevation Model (DEM), rainfall, landuse, geology (lithology and fault) and drainage network data.
Findings: The log–log plot shows five classes for depth (weakly, moderately, highly, strongly, and extremely magnitude) which shows that the extremely magnitude landslides have depths higher than 19.95 m in the NE, middle, western, and SE parts of the Tajan basin. The strong (5-19.95 m) and high (2.4-5 m) magnitude landslides happened in the northern, NE, western and NW parts. The results, which were matched up to landuse, drainage network, DEM, and fault allocation patterns revealed an affirmative correlation between landslide classes and the particulars in the area. In addition, the coefficient of determination, R2, for each population shows that the classification has been done correctly using the Dp-N fractal model. Amounts of P-value obtained from paired samples t-test and ANOVA showed that the separated categories are in incongruity with each other and are significantly different (sig=0.000).
Conclusion: Results show that separating the populations of landslides based on a parameter as magnitude and the difference between the populations’ magnitude of landslides should be considered in landslide susceptibility zonation.

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Aims: Preventing rangeland degradation and conserving them is a challenging task that necessitates targeted changes in rangeland policy and management systems. Planning should aim for the optimal utilization of rangelands while meeting the needs of stakeholders. One of the most crucial measures involves adopting a systemic approach to rangeland management, encompassing all resources, livelihood potentials, and income generated from rangelands through multi-purpose use. To effectively manage rangelands, it is crucial to take a comprehensive approach that considers all resources, livelihood opportunities, and income generated from these areas through multi-purpose use. This involves adopting a systemic approach to rangeland management, encompassing the identification and utilization of non-sustainable potentials within the content of multi-purpose exploitation of rangelands. Such an approach can have a significant impact on reducing the livelihood dependence of pastoralists. Since numerous factors influence its successful implementation in rangeland management, particularly in the summer season, this research was conducted to investigate the influential drivers affecting the development of multi-purpose management in the summer rangelands of Mazandaran Province, utilizing a future studies approach.
Materials & Methods: This descriptive-applied study employed a survey method. The study population comprised experts, deputy heads of departments, and members specializing in rangeland management. Through purposive judgment sampling, 50 individuals were selected from these populations within the natural resources domain in Sari, Mazandaran Province. Data was collected using a researcher-developed questionnaire, and the Cross-Impact Analysis technique was applied to analyze 21 extracted indices from individual and group interviews. The MicMac software facilitated this analysis.
Findings: The study revealed that the primary influential drivers for the advancement of multi-purpose rangeland management included “decentralization and stakeholder participation in the implementation process of multi-purpose plans,” “The results indicated that the indicators “ decentralization and stakeholder participation in the implementation process of multi-purpose plans,” “ generation of new employment prospects and strengthening of rural income potentials,” “ establishment and fortification of rural cooperatives and organizations,” “ governmental support and assistance,” and “ trust-building communication between stakeholders and the government” were the most significant drivers with the highest coefficients of 607, 596, 585, 585, and 564, respectively. These indicators influenced the multi-purpose utilization of the studied region’s rangelands.
Conclusion: Based on the obtained results, the paramount recommendation of this study, employing a forward-thinking approach, is the development of a long-term vision document encompassing economic, socio-cultural, and environmental dimensions. This strategic move is poised to catalyze the transformation of the multi-purpose rangeland management system in Mazandaran Province.