Saeid Afkhamifar; Amirpouya Sarraf
Abstract
Today, due to the importance of sustainable groundwater management, groundwater level modeling and forecasting are used to assess and evaluate water resources. The purpose of this study is to evaluate the performance of two models of Extreme Learning Machines (ELM) and Artificial Neural Network (ANN) ...
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Today, due to the importance of sustainable groundwater management, groundwater level modeling and forecasting are used to assess and evaluate water resources. The purpose of this study is to evaluate the performance of two models of Extreme Learning Machines (ELM) and Artificial Neural Network (ANN) and the combination of two models with wavelet transmission algorithms (W-ELM and W-ANN), which ultimately to increases the predictive power and optimization of input weights (the weights between the input and hidden layers) of models, Quantum Particle Swarm Optimization algorithm (QPSO) has been used. Also, in this study, the data of Ground Water Level of observation wells (GWL), precipitation (P) and average temperature (T) of Urmia Plain aquifer with a time series of 36 years (1981 – 2017) which were collected on monthly scale, are used. Also, in order to evaluate the performance of models, correlation coefficient (R), Root Mean Square Error (RMSE) and Mean Absolute Error (MAE) were used. In this regard, 80% of the data (September 1981 to August 2010) are used for training section and 20% of data (September 2010 to August 2017) used for the test section of models. Based on the results of this study, the hybrid model of W-ELM-QPSO with correlation coefficient (R) 0.991, 0.983 and 0.975, respectively for periods of one, two and three months in the test section, have a better performance than other models and also in addition to predicting power, this model has a high speed in terms of training and testing speed than other models.
Behnam Farid Gigloo; Ebrahim Omidvar
Abstract
Ephemeral Gully (EG) erosion is one of the most destructive types of water erosion, which contributes significantly to land degradation. EG erosion prediction is necessary to assess the magnitude of soil loss and to implement the appropriate conservation measures. The aim of current study was to ...
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Ephemeral Gully (EG) erosion is one of the most destructive types of water erosion, which contributes significantly to land degradation. EG erosion prediction is necessary to assess the magnitude of soil loss and to implement the appropriate conservation measures. The aim of current study was to evaluate the efficiency of EGEM model for EG erosion prediction in Ghoorichay Watershed, Ardabil Province, Iran. For this purpose, a number of 17 EG erosion was identified and monitored between the years 2014 to 2016. The morphological characteristics and erosion rate of EGs were measured and recorded after seven effective rainfall events. In order to calculate the EG erosion, EGEM model requires four major categories of input data, including identification information, watershed data, soil data, and rainfall data. The model has two major components: hydrology and erosion. The runoff induced by a rainfall event in each gully catchment was determined by the Natural Recourses Conservation service (NRCS) Curve Number (CN). The result of EGEM model performance evaluation showed that the eroded soil volume and cross-section were predicted with a determination coefficient of 0.96 and 0.89, respectively. Sensitivity analysis revealed that the curve number was the most sensitive parameter, so that, with a 10% increasing and decreasing in CN, the volume of soil loss varied 22.98 and -18.92%, respectively. It can be concluded that EGEM model was suitable for event-based EG erosion prediction in Ghoorichay Watershed and it can be recommended for studying and planning on EGs in similar watersheds.
Mosayeb Heshmati; Mohammad Ghaietury; Mahmood Arabkhedri; Yahya Parvizi
Abstract
Forest and land use change has many negative consequences including increased flooding, erosion, sedimentation and dust storms. The aim of the research was thus to investigate the effects of land use change in Zagros forests on erodibility and sedimentation via soil quality reduction in some forests ...
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Forest and land use change has many negative consequences including increased flooding, erosion, sedimentation and dust storms. The aim of the research was thus to investigate the effects of land use change in Zagros forests on erodibility and sedimentation via soil quality reduction in some forests of Kermanshah Province, Iran. In order to achieve this aim, in the first step, afforest area and its adjacent rain-fed farm (which is developed during recent 10 years a result of forest land change), were selected and 35 soil samples were collected from the surface layer (0-20 cm). Then, the physico-chemical analyses were done on the soil samples. In the next step, soil erodibility factor was calculated and sediment yield was assessed using portable rainfall simulator. The results showed that six key properties of soil including soil aggregate stability, bulk density, organic carbon, total nitrogen, total absorbable potassium and cation exchange capacity were significantly (p<0.05) influenced by land use type. Additionally, in all tested samples, the total clay and silt content was about 80%, which resulted in the formation of soil with heavy texture. Subsequently soil erodibility factor (K) and sediment yield intensity in rain-fed farm was found significantly (P<0.05) higher than those of forest. According to the results and the role of Zagros forest ecosystem on water harvesting, aquifer recharge, flood and dust control, the current trend of changing forest landuse to arable lands accompanying improper tillage practice, crops residue burning and heavy machinery traffic in nearby rain-fed farms, cause accelerating global warming, increasing runoff coefficient and evaporation as well as water scarcity in future.
Samane Arvandi; Forood Sharifi; Ali Shahnazari
Abstract
Water is a major factor in food production and sustainability of ecosystems. The need for water resources is increasing. Due to the scarcity of water and also aridity in many regions, development of new technologies to meet the plant water needs is important at plant establishment and specifically at ...
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Water is a major factor in food production and sustainability of ecosystems. The need for water resources is increasing. Due to the scarcity of water and also aridity in many regions, development of new technologies to meet the plant water needs is important at plant establishment and specifically at the development stage. Development of new technologies is a key for solving the problem of water shortage. Steam condensation in soil (using renewable energies) is a new and developing method that has the potential of increasing water efficiency. In this method, the steam transfers directly to the root zone and increases the moisture content of the soil. The purpose of this study was to investigate the efficiency of evaporation-condensation irrigation system in increasing water use productivity and evaluating performance of this technology in moisture absorption of various soils improved using organic matter. In order to increase water condensation, the produced steam, conveyed into steam chambers and after distillation, it increases the moisture content of the soil. In this study, a number of experiments were conducted on small flumes. Results showed that the moisture condensation of the soil with organic matter 11% higher than that of soil without organic matter. Then, with the possibility of increasing the moisture with this method, the experiments were carried out in larger pots. The result of analysis of variance of soil texture, steam temperature and organic matter interactions showed that these three parameters had no significant effect on soil moisture increase. Based on the results, the soil with medium texture, 35% organic matter and steam at 45 °C in coated conducting tube showed better results than other treatments. The steam blown into vapor tubes in flume and pots was at two temperatures of 45 and 55 °C that 30°C was selected for planting. After determining the proper temperature and selecting soil texture, plant cultivation was carried out by evaporation-condensation irrigation method. Then the water consumption was compared with greenhouse and field planting. Selected soil for cultivating lettuce under controlled conditions and with evaporation-condensation irrigation, was designated to be medium and in combination with 35% organic matter and coated conducting tube at steam temperature of 30°C. The results of this study showed that after harvesting and full growth of lettuce in all three conditions, production per 1 m3 of water for lettuce in evaporation-condensation irrigation, greenhouse and field was 1250, 333 and 75.5 kilograms, respectively. Water use efficiency was investigated in all treatments and the results showed that there is a significant difference between different irrigation methods (P≼0.01), and the highest water use efficiency resulted from evaporation-condensation irrigation method. The consumed water during the growing period in the greenhouse was approximately 4 times that of evaporation-condensation irrigation method and in the field was about 21 times that of condensation irrigation, which indicates a significant reduction in water use. By examining dry matter the weight of lettuce in all three methods, the results showed that in all samples taken from condensation irrigation, greenhouse and field, the average dry matter was 12.5% and average water was 87.5%, which indicated the same quality of the product in all three methods.
Ali Mohammad Ghaeminia; Mohammadali Hakimzadeh Ardakani
Abstract
With regards to the wind erosion phenomenon importance, it is vital to quick identification of areas that are sensitive to dust removal and wind erosion processes. In this research, a lightweight and efficient device is designed, fabricated and evaluated in order to create conditions for applying constant ...
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With regards to the wind erosion phenomenon importance, it is vital to quick identification of areas that are sensitive to dust removal and wind erosion processes. In this research, a lightweight and efficient device is designed, fabricated and evaluated in order to create conditions for applying constant wind stress on soil particle surfaces and measuring erosive particles. The production of wind power by a blower and measuring the amount of loose and unstable particles that were harvested in the reservoir with the highest efficiency were the principles of designing the device. The prototype of the device was designed using components and parts, and the device was evaluated in the field. The device is usable by a user in the field without the need for a power generator and the weight of the particles collected in the tank indicates the relative erodibility of the test site to the wind. Using the air filter bag (tank), it was possible to achieve a minimum loss of fine particulate matter and has been reduced the measure of less than the actual amount of land erosion. The result of the comparison of the sensitivity of soil sensitivity to erosion by the device in desert lands of northern Yazd-Ardakan Plain with the height of winding of the soil with the installation of the index showed that this device has good capability (R2= 0.57) in the rapid detection of areas susceptible to wind and without measuring physical and chemical properties of the soil, there is an early identification of wind erosion-sensitive land. This device does not actually simulate the natural processes of wind erosion created by the particle saltation, but using it, a new index can be obtained for assessing soil erodibility and subsequently identified the location of dust emissions.
Behzad Hessari; Kamran Kamran
Abstract
Considering the importance of Lake Urmia, the purpose of this research is to survive the human activates on the trend of surface water and groundwater changes in the Urmia plain. For this purpose, the changes in input and output discharge, aquifer drainage and land use changes in the Urmia Plain were ...
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Considering the importance of Lake Urmia, the purpose of this research is to survive the human activates on the trend of surface water and groundwater changes in the Urmia plain. For this purpose, the changes in input and output discharge, aquifer drainage and land use changes in the Urmia Plain were studied on the basis of nine hydrometric stations data (during 1973-1903) and information of 74 piezometers and using satellite images. The test used for trend analysis was Mann-Kendall nonparametric test with considering the effect of autocorrelation. According to the results, the trend of input discharge from the Nazlou-Chay, Rouzh-Chay and Barandoz-Chay sub-basins to the Urmia Plain was decreasing and the negative trend of outlet discharge related to the Rouzh-Chay, Shahr-Chay and Barandoz-Chay sub-basins was significant at 95% confidence level. Comparison of the results the difference between discharge average during after and before 1995 (the year which in it the lake begins to dry) showed that at all stations except Ghassemlou, there is a significant difference between average discharge during these two periods. The value of the statistic (Z = -2.18) indicates a significant decreasing trend at 95% confidence level for the drainage volume of the aquifer reservoir. The results of this study showed that discharge to Lake Urmia in all seasons had a decreasing trend during the studied period and serious actions should be done to manage water resources in the region.
Mozhdeh Mohamadi; Jafar Mamizadeh; Eghbal Ehsanzadeh
Abstract
Surface water collection networks are responsible for collecting, transporting and directing runoff to the nearest acceptable outlet. In this research, simulation and evaluation of Ilam City runoff system with the ASSA mathematical model developed by the Autodesk Inc. was carried out. In the present ...
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Surface water collection networks are responsible for collecting, transporting and directing runoff to the nearest acceptable outlet. In this research, simulation and evaluation of Ilam City runoff system with the ASSA mathematical model developed by the Autodesk Inc. was carried out. In the present research, the entire study area, which includes in-city and outsides, was divided into 46 sub-basins. The physical properties of each sub-basin were determined using the ArcGIS software and field investigation. Within the Ilam City there are four main channels that lead the runoff of sub-basins out of the city. The runoff from sub-basins was calculated using three methods of rational, modified rational and SWMM. The results of the study showed that the collecting system only had a flood transfer ability during the two year return period and during the return periods greater than five years the major part of the main channels in the city were waterlogged and damaged.
Ghasem Mortezaii; jafar lotfi; shahram khalighi sigarodi; mohsen saravi; Aliakbar Nazari Samini
Abstract
In recent years, Kurdistan Province has faced a dramatic decline in groundwater levels. In this research, the time interval between the occurrence of meteorological drought and hydrological drought was determined for the necessary measures to cope with the drought caused by the lack of surface water ...
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In recent years, Kurdistan Province has faced a dramatic decline in groundwater levels. In this research, the time interval between the occurrence of meteorological drought and hydrological drought was determined for the necessary measures to cope with the drought caused by the lack of surface water and underground water resources. Therefore, the hydrological drought situation in Kurdistan Province was evaluated using Groundwater Resources Index (GRI) and Streamflow Drought Index (SDI) and compared with meteorological drought indicators. The GRI and SDI time series for the 30 years of studied period of 1982-2014 was inter-compared. The GRI showed the highest percentage of frequency of normal period. According to the results of Man-Kendall test, in all time scales, SDI has a higher variability than the meteorological drought indicators. Knowing the interval between the occurrence of meteorological drought and hydrological drought will help managers to cope with the drought caused by a shortage of surface water resources in the interior ministry, The Markov chain model used to predict the current state of a system with regard to the previous state in the statistical period showed good performance. According to the results of the study, on average, the probability of dry, wet and normal periods in the stations was 31, 29, and 40 percent, respectively. This means that in most cases, the region is in normal climatic condition, while the likelihood of wet and dry conditions is very similar. Also, SPEI with12 and 24 months’ time scales have the highest correlation with GRI index at 3 months lag-times, which showed the effects of meteorological drought on groundwater level even after two years or more. By considering the results of this study, the executive directors of water in the province can mitigate the effects of the crises caused by the hydrological droughts.
Payam Amouzegari; Mostafa Panahi; mir khalagh mirnia
Abstract
Groundwater resources are the most important source of fresh water in the world. In Iran which is located in the arid and semi-arid region, mismatch of consumption needs with rainfall time along with climate change has increased the demand for groundwater. Excessive extraction of groundwater in the Alashtar ...
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Groundwater resources are the most important source of fresh water in the world. In Iran which is located in the arid and semi-arid region, mismatch of consumption needs with rainfall time along with climate change has increased the demand for groundwater. Excessive extraction of groundwater in the Alashtar Watershed reduced the water level in the aquifer of the plain and water resources of this area have faced a negative balance. Due to the inherent limitations of the country's water resources and increasing the split between supply and demand, the use of economic instruments and the establishment of the water market for optimal allocation of groundwater is a necessity. Accordingly, this study in order to determine the market price of groundwater with the aim of accurately identifying the local markets for groundwater and also measure the views of local water market operators about some of the strategies for advance the water market designed and implemented. The statistical population in this research was all rural exploiters are the main reservoirs of groundwater in the basin who contribute to the buy and sale of these resources. Regarding market prices in the study area, the average price of groundwater was 1,749 Rials per cubic meter, and the total value of groundwater was estimated as 555,307.5 Milion Rials. The results showed that in 103 villages there is a market for the buy and sale of groundwater. Those villages that have a local groundwater market, 76% of the villages have been established by creating popular organizations and the water regulatory council and 43% of the villages by create a bulletin board agreed to facilitate the buy and sale of groundwater resources.
Saeed Arab; Yasamin Segar; Mehdi Naderi khorasgani; Mohammad Asadi; Parvin Kia
Abstract
In a watershed, we can investigate the relationship between geomorphometric factors and sediment index. Digital Terrain Model (DTM) derived from DEM, has a high ability to receive, process, store, manage and monitor information for a catchment area. With the help of DTM in a watershed we can calculate ...
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In a watershed, we can investigate the relationship between geomorphometric factors and sediment index. Digital Terrain Model (DTM) derived from DEM, has a high ability to receive, process, store, manage and monitor information for a catchment area. With the help of DTM in a watershed we can calculate the sediment index (power stream, sediment transport and wetness) and some geomorphometric factors such as total length and slope along drainage, length and slope of straight drainage, drop coefficient, sinuosity and downstream elevation and its mapping. Bahadorbeyg Basin with an area of 216.69 km2 on northern pediment slopes of Alvand in Hamedan Province was selected for this study. First, the drainage rating was managed in DTM and the sediment index map along with the map of some geomorphometric factors (interpolation method) with four ranks and 30 focus points. Runoff and sediment discharge factors were proposed as a point estimator from the combination of sediment index with mean runoff and sediment discharge of the hydrometric station. In a complete regression model between sediment index (dependent variable) and some geomorphometric factors along with partial runoff and sediment discharge (independent variables), statistical relationships were significant at the level of 0.01 and 0.025. Results showed that the partial runoff and sediment discharge, the slope along drainage (total and direct), the drainage straight length, the downstream elevation and sinuosity are the most important factors affecting the sediment index, respectively. Finally, according to a time-series function (23 and 24 years old), the variation trend of runoff discharge had downward pattern in the basin and did not match with sediment discharge.
Ata Amini; Jahangir Porhemmat; Hossein Sedri
Abstract
Virtual water concepts and water productivity are considered as powerful tools for analyzing issues related to water resource management. This research was conducted to use the indicators of physical and economic productivity of water, in water resources management in Talvar Watershed, Kurdistan, Iran. ...
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Virtual water concepts and water productivity are considered as powerful tools for analyzing issues related to water resource management. This research was conducted to use the indicators of physical and economic productivity of water, in water resources management in Talvar Watershed, Kurdistan, Iran. The data from field observation, meteorological and climatic, water resources, agriculture, irrigation and watershed management were collected. The crop area of the irrigated products in the watershed was identified and their cultivation percentage was determined. Data on the growth of these products and their water consumption were calculated using CROPWAT software and field data. Using the results of data analyzing, management indicators such as physical productivity and economic productivity of products were calculated. Results showed that five crops of wheat, potato, barley, alfalfa and clover make up more than 93% of the irrigated products area of the watershed. It was found that the potato and wheat were with highest and lowest physical efficiency, respectively. The potato is with highes productivity as 3.46 and wheat was with lowest one as 0.43 kg m-3. Despite of low physical efficiency for wheat, the major part of water consumption in this crop was from green water, while the potato is using the lowest rate of green water. In terms of economic productivity, barley and potato products were with most net economic benefits. The results of this research can lead to proper management and appropriate water resources in the basin.
Atefeh Davari Dolatabadi; Akbar Ghazifard; Kourosh Shirani; Farzad Heidari Morche khorti
Abstract
East of Isfahan City, especially around Segzi Plain is one of the desert areas of the country that due to the flatness and soils sensitivity to wind erosion, there is high susceptibility to wind erosion. The aim of this study is to evaluate the possibility of using saline water of Segzi Plain and its ...
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East of Isfahan City, especially around Segzi Plain is one of the desert areas of the country that due to the flatness and soils sensitivity to wind erosion, there is high susceptibility to wind erosion. The aim of this study is to evaluate the possibility of using saline water of Segzi Plain and its effect on the soil strength properties, crust formation and its stability against wind erosion. In order to conduct this research, five soil samples with different textures were collected from top soil surface and were transferred to the laboratory along obtained saline water sample from surface aquifer. After determining some of the physical and chemical properties of samples, they were examined in wind tunnel with specified velocity for soil erosion tests. The first soil sample was flooded with saline water and the rest were treated with either spraying of undiluted saline water or spraying of diluted saline water with 2 to 1, 1 to 1 and 1 to 2 ratios of saline water to water. In this regard, parameters such as salinity of saline water, erosion threshold velocity of dried treated soil samples, maximum dry density, thickness, strength and sieve analysis of the crusts were determined. The results indicated that, as the salinity of saline water increases, the strength, thickness and maximum dry density of forming crust and wind erosion threshold velocity also increases in the model. Analysis of variance used to investigate the effects of soil texture, salinity of saline water, crust thickness and threshold velocity to control wind erosion showed significant difference in 1% level. Sample C1 with the highest percentage of fine grains had threshold velocity of 11 m.s-1, but sampleE1 with the lowest percentage of fine grains had threshold velocity 6.23 m.s-1. The presence of a high amount of sodium makes restrictions on the possibility of using saline water as mulch scientifically and practically but the results showed that the use of saline water can increase the density of dirt roads.
Hamzeh Noor; Ali Bagherian Kalat; Aliakbar Abbasi
Abstract
Rangeland exclusion is one of the watershed management methods that is applied for range rehabilitation. However, most rangeland hydrology studies have been focused on exclusion effects on soil loss at plot scale, whereas their effects on sediment yield at micro-watershed in seasonal and annual scales ...
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Rangeland exclusion is one of the watershed management methods that is applied for range rehabilitation. However, most rangeland hydrology studies have been focused on exclusion effects on soil loss at plot scale, whereas their effects on sediment yield at micro-watershed in seasonal and annual scales have rarely been considered. The present study was conducted in two sub-watersheds under exclosure and open grazing treatments, with area of 1.0 and 1.1 ha, respectively, in Sanganeh Watershed, Khorasan Razavi Province, Iran. Runoff and sediment associated with 56 storm events occurred during 2006 to 2016 were estimated at the main outlet of the watershed. The results showed the significant decreasing effect of exclosure treatment on sediment yield at micro-watershed scale (p≤0.05). So that, 582% decrease in sediment yield was obtained in exclosure treatment compared to open grazing. Results also showed seasonal and annual variations of exclosure on hydrological processes so that, maximum and minimum differences in sediment yield among study treatments were founded. The results of this study suggest that livestock grazing management during sensitive seasons as well as rangeland exclosure, if its social problems are resolved, is a practical solution to reduce watershed sedimentation.
Mostafa Baniasadi; Mojtaba Palouj
Abstract
Policymakers in the field of water resource management in the country have been seeking solutions for water issues through technical engineering, water transfer, damming, and constructional projects. However, the main problem of water resources in the country is the existence of bad and undesirable governance ...
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Policymakers in the field of water resource management in the country have been seeking solutions for water issues through technical engineering, water transfer, damming, and constructional projects. However, the main problem of water resources in the country is the existence of bad and undesirable governance and the inefficient management system. Inappropriate institutional arrangements, fragmented management, lack of transparency, and lack of stakeholders’ involvement in management are among the characteristics of the current water resource governance system in the country. The purpose of the present study is to design of good governance on groundwater resources at the basin of Arzuiyeh Plain. To this purpose, using the analytical method of grounded theory, interviewing experts and pundits, and conducting relevant analyzes, the pattern of good governance of water resources was developed. The most important results and suggestions of this pattern include the development of appropriate institutional arrangements at the basin, integrated management at the macro level to basin level, transfer of management to the stakeholders at the basin, stakeholders’ participation in monitoring and implementation and reform of the rules and the legal system.
Jamal Mosaffaie; Amin Salehpour Jam
Abstract
Evaluation of the impacts of past watershed projects provides useful insights for future projects. In this study, the hydrology and water resources status of Akujan Catchment of Qazvin Province has been the object of the study in which the effects of various measures of watershed managements were evaluated. ...
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Evaluation of the impacts of past watershed projects provides useful insights for future projects. In this study, the hydrology and water resources status of Akujan Catchment of Qazvin Province has been the object of the study in which the effects of various measures of watershed managements were evaluated. For this purpose, the changes of water resources discharge, increased infiltration, water storage, peaks and volumes of catchment floods, were compared before and after the implementation of watershed management projects. Results showed that 114000 m3 more runoff storage has been carried out by watershed management operations that 20.1% of this volume was related to the structural operations and 79.9% of it was due to biological and biomechanical projects of the catchment. Results of the flood analysis indicated that the role of structural measures in the change of time of concentration is low and even negative. Therefore the reduction of the peak flow and flood volume at the outlet of the catchment is due to the implementation of biological and biomechanical measures which reduces the peak flows by 42.7, 25.4, 20.8, 17.1, 15.3 and 13.8% and flood volumes by 41.8, 24.8, 20.2, 16.5, 14.8 and 13.3% respectively for the return periods of two, five, 10, 25, 50 and 100 years. Another observation is that the effect of watershed management practices on the reduction of flood peak and volume decreases when the return period of flood is increased.
Farzad Heidari; Razieh Saboohi
Abstract
This research was carried out aiming to investigate positive and negative aspects of watershed practices and their effects on quantity and quality of water resources in Budejan River basin. This river is one of the main branches of Shour-Dehaghan River and its area plays an important role in supplying ...
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This research was carried out aiming to investigate positive and negative aspects of watershed practices and their effects on quantity and quality of water resources in Budejan River basin. This river is one of the main branches of Shour-Dehaghan River and its area plays an important role in supplying water for lower lands. In this regard, meteorological data, hydrology and other information and maps were collected. The volume of dam reservoirs and the amount of rainfall within two years of the project were measured by field studies and hydrology studies were carried out by field measurement and assessment of hydrologic conditions of the basin. Results showed that the water content generated by these practices is enough to recharge groundwater. Construction of dams tended to decrease water flow rate and reduced the destructive effects of seasonal flood and with increasing water infiltration rate, it has increased aquifer recharge in the study area. The low volume of dam reservoirs has not caused irregularity in water supply of downhill lands. However, the lack of proper management of these operations and the excessive development of gardens and agricultural lands, due to the ease of access to water, overshadow positive results of watershed practices and offset it by a very high cost.
Saeed Nabipay Lashkarian; Mahmood Arabkhedri; Samad Shadfar
Abstract
Accelerated soil erosion and the production and transfer of large amounts of sediment are considered as one of the most important issues in many parts of Iran. Having enough knowledge on soil erosion and sediment production as well as identification of critical areas are necessary in order to reduce ...
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Accelerated soil erosion and the production and transfer of large amounts of sediment are considered as one of the most important issues in many parts of Iran. Having enough knowledge on soil erosion and sediment production as well as identification of critical areas are necessary in order to reduce the adverse effects of this problem through soil and water conservation measures. Due to lack of gauge stations in the outlets’ of small watersheds, empirical models are considered as the proper tools for estimating soil erosion and sedimentation. One of these methods which was developed based on Meditranean sediment data, is the Factorial Scoring Model (FSM). Towards this, the main objective of this research is to compare estimated vs. observed sediment yields in some selected regions of Iran. For this purpose, 58 small chatchments equipped by reservoirs in their outlets were selected in Semnan, Central, Isfahan, Chaharmahal and Bakhtiari, West Azarbaijan, Lorestan, Fars, Golestan and Khorasan Razavi Provinces. The comparison of the results showed that all estimates of the original model (before calibration) are several times bigger than observed values obtained by surveying (0.44 to 459.44 t.km-2.y-1). In order to correct the model coefficients for Iran, calibration was performed in two scenarios; once using all data and in the second secenario after allocating data into three geographic regions, which in both cases resulted in significant improvement of estimates. The Nash‐Sutcliffe Efficiency coefficient for all catchments was 0.39, and for Central, Zagros and Northeast regions were 51.1, 0.66 and 0.78, respectively. Based on obtained findings, the application of original FSM must be avoided in study areas. Instead, we strongly recommend using calibrated models based on observational values for different geographic regions.
Reza Talaei; Arash Mohammadalizadeh
Abstract
The southern areas of Ardebil Province have clay sedimentary rocks and many damages have been made because of new landslide occurrence or reactivation of old landslides every year. The clay sedimentary layers are related to the Upper Red Formations to the Neogene period in the study region. The clay ...
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The southern areas of Ardebil Province have clay sedimentary rocks and many damages have been made because of new landslide occurrence or reactivation of old landslides every year. The clay sedimentary layers are related to the Upper Red Formations to the Neogene period in the study region. The clay minerals could be the main reason of the landslide occurrence because of swelling and shrinkage characteristics of soils. This research was carried out to test the hypothesis of the effect of clay expansive soils in slope instability. This area extends to 164500 ha, and 11.91% of it found to be affected by landslides. 32.8% of the whole area of the clay sedimentary rocks had experienced landslides. Minimum percentages of sand, silt and clay particles in the soil samples are 0.0, 23.4 and 8, and the maximum values are 39.9, 72 and 54.5, respectively. Minimum liquid limit of samples is 36.7% and its maximum is 67.66. The plastic limit of the samples also varies between 19 and 33.13%. Soils have a pH above 8. The cation exchange capacity above 30.41 milligrams per 100 grams of soil, which reaches up to 76.52, is one of the main characteristics of the soils in the region. The swelling potential rates of the soils of landslide area have been classified to four respective zones indicating the low, medium, high and very high swelling potential using physical and chemical properties of soils and based on different methods. At least 80% of the soil samples in the area have a swelling potential with medium to high intensity and 87.2% of them are located in zones of high and very high landslide hazard. The expansive clay soils are one of the main causes of landslide occurrence in the region.
Soghra Malekpurlarki; Zohre Khorsandi kouhanstani; Mohammad Faraji
Abstract
Conservation and utilization of water resources are principles of sustainable development of each country. Surface waters or rivers are one of the most important water resources which have important role in supplying water demands in different sectors such as agriculture, industry, drinking water and ...
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Conservation and utilization of water resources are principles of sustainable development of each country. Surface waters or rivers are one of the most important water resources which have important role in supplying water demands in different sectors such as agriculture, industry, drinking water and energy. Shavoor River which is one of the effective rivers in Shoosh City is important due to its quality in water urban and agricultural usages. Land use and its changes have important effects on river water quality. In this research, the effect of land use change is investigated in water quality of Shavoor River in 1985-2015. For this reason, land use maps of 1985 and 2015 were prepared by satellite imageries and land use changes were investigated. Results showed an increase in residential and agricultural lands and a reduction in rangelands and forests. Also, the changing trend of water quality factors in Shavoor River was studied with Mann-Kendall test and graphs. Results demonstrated that the changes overall trend of Hco3, Cl, TDS, EC, Ca, Mg and So4 were increasing in the period. According to meaningful changes of parameters, it can be concluded that the increase in residential and agricultural lands and reduction in rangelands and forests cause the water quality of Shavoor River in the study period.
moslem dehdari far; Mohammad Faraji; Mohammad salehi veisi; Jahangir Ehsani
Abstract
Rock behavior varies with different erosions, which depends on the inherent and environmental characteristics of the rock. In other words, some petrological units are susceptible to erosion and have sediment production potential. This study is conducted to investigate the sensitivity to erosion and resistance ...
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Rock behavior varies with different erosions, which depends on the inherent and environmental characteristics of the rock. In other words, some petrological units are susceptible to erosion and have sediment production potential. This study is conducted to investigate the sensitivity to erosion and resistance of rock formations of Fars group (Mishan limestone, Aghajari sandstone and Gachsaran Anhydrite) and Asmari formation using Selby method in Behbahan, Gachsaran, Deylam and Dehdasht areas. Results of analysis of ANOVA variance based on the comparison of 81 samples from 4 types of rocks showed that there was a significant difference between the rocks (p= 0.05).In general, the Asmari limestone with scoring mean of 66.72-70.99 is the most rock resistant based on theSelby method. Mishan, Aghajari limestone, Gachsaran Anhydrite will be in the next ranks, respectively.
