Ramin Salmasi; Mohsen Farahbakhsh; Hossein Asadi
Abstract
There is critical need for a practical indicator to assess the potential of phosphorus (P) movement from a given site to surface waters, either via surface runoff or subsurface drainage. The Degree of P Saturation (DPS), which relates a measure of P already adsorbed by a soil to its P adsorption capacity, ...
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There is critical need for a practical indicator to assess the potential of phosphorus (P) movement from a given site to surface waters, either via surface runoff or subsurface drainage. The Degree of P Saturation (DPS), which relates a measure of P already adsorbed by a soil to its P adsorption capacity, could be a good indicator of that soils P release capacity. For our country soils, there is not any report for DPS calculating. This study aimed to develop techniques of calculating the DPS for calcareous soils of western Azerbayjan, Uremieh Lake sub-watershed, obtaining DPS levels for calcareous soils, and evaluating DPS by use of soluble P as indicator of P runoff potential. For this purpose, 30 surface soil samples with widely P contents were selected and after determining some of general physico-chemical properties, useing of four measures of soil available P and four indices of P sorption capacity, sixteen different forms of DPS were obtained. Significant correlation was obtained between soluble P and different forms of DPS in this study. Threshold P concentration between four extractants, were obtained for Olsen, Mehlich-3, and Soltanpour ones, except in calculations with Mg as P adsorbed contributor in range of 0.4-33 percent, with 8.14 mean, and for FeO extractant, only in calculations with Ca + Mg as adsorbing one was obtained that was equal to 1.3 percent. Degree of P saturation in soils with higher than threshold P concentration values are sustainable to P runoff via surface runoff or leaching, and as a result eutrophication intensification, and for control this phenomenon should apply management practices with regard to different situations of watershed.
Payam Ebrahimi; Jamileh Salimi Kochi; Mohsen Mohseni Saravi
Abstract
SWAT is a continuous, physically based and distributed hydrologic model which all several hydrological processes like discharge, sediment yield nitrogen are simulated for each one of it. The purpose of this study is to test the efficiency of the Soil and Water Assessment Test (SWAT) and its applicability ...
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SWAT is a continuous, physically based and distributed hydrologic model which all several hydrological processes like discharge, sediment yield nitrogen are simulated for each one of it. The purpose of this study is to test the efficiency of the Soil and Water Assessment Test (SWAT) and its applicability as a flow simulator, and using SWAT-Cup software and the SUFI2 algorithm as a means to calibrate and validate Neka Watershed in Mazandaran Province. Four indices were used to assess the goodness of calibration, viz., P-factor, R-factor, R2 and Nash-Sutcliffe (NS). Runoff data (1995-2004) of four hydrometery stations were used for calibration and (2005-2009) for validation of this watershed. The results of these values for flows at four stations for calibration process in Ablo, Pain zarandin, Karkhane siman and Sefid chah were 0.85, 0.78, 0.78, 0.89 for P-factor; 2.55, 2.03, 1.71, 2.43 for R-factor; 0.76, 0.62, 0.69, 0.71 for Nash-Sutcliffe and 0.71, 0.82, 0.76, 0.63 for R2. The results of validation were 0.87, 0.88, 0.72, 0.72 for P-factor; 3.61, 2.24, 3.56, 1.78 for R-factor; 0.74, 0.66, 0.58, 0.64 for Nash-Sutcliffe (NS) and 0.81, 0.68, 0.73, 0.61 for R2 respectively. In general, the results showed that SWAT could be a proper tool for simulating the flow rate values of the Neka Watershed.
Ebrahim Karimi Sangchini; Majid Ownegh; Amir Sadoddin; Nasser Tahmasebipuor; Hossein Rezaee
Abstract
This article describes a research aiming to investigate factors affecting community participation and to predict community acceptance of vegetation-based management scenarios in the Hable-rud River Basin. The Hable-rud River Basin which is a transboundary basin is extended between Tehran and Semnan provinces ...
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This article describes a research aiming to investigate factors affecting community participation and to predict community acceptance of vegetation-based management scenarios in the Hable-rud River Basin. The Hable-rud River Basin which is a transboundary basin is extended between Tehran and Semnan provinces in Iran. In this research, vegetative management scenarios include: the current condition, terracing, saxaul plantation, riparian restoration, forage growing, bunch seeding, contour furrowing, tree plantation, grazing exclusion, seeding, drill seeding, orchard development, and agroforestry. Through an interview with the stakeholders of the basin, a predefined questionnaire was completed for each respondent separately. Validity and reliability of the questionnaire were tested. On the basis of Cochran formula, 379 respondents were chosen in a stratified sampling scheme among the local communities of the basin. The factors influencing people's participation in various districts of the basin were investigated. The community acceptance level of watershed management actions was quantified using binomial probability distribution. Financial support policies of the government were identified as the most effective factor in community participation for the study area that attained the highest value in the viewpoint of people living in Sorkhe and Ivanakey districts. Community participation was evaluated in four forms including support by heart, labor support, financial support, and labor and financial support. The analysis indicates that scenarios of agroforestry and orchard development have the highest level of labor and financial support. Central Firoozkooh and Central Damavand districts have maximum labor and financial support level. The results of the binomial distribution analysis show that scenarios of agroforestry and orchard development have highest preferences among the local communities of the Hable-rud river basin. The results of this research can be used by managers and decision makers to promote soil and water resources protection as well as to promote the adoption of management actions at the watershed scale.
Narges Ghasemiamin; Nasim Arman; Hossein Zeinivand
Abstract
Land use involves exploitation type of land for resolving human different needs. Land use changes is the result of interaction between human and affective factors on environment which is considered in spatial and temporal scale. Awareness of land use rates and its change in time is one of the most important ...
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Land use involves exploitation type of land for resolving human different needs. Land use changes is the result of interaction between human and affective factors on environment which is considered in spatial and temporal scale. Awareness of land use rates and its change in time is one of the most important factors in planning and management. By knowing rate of land use changes time scale, forecasting feature changes will be possible and do appropriate act. In this research, 2014 land use map was prepared by RS with Kappa coefficient of 0.88 and overall accuracy of 0.86 which has high accuracy. For investigating each effective factor on land use in CLUE-S model logistic regression was used and for assessment of logistic regression, ROC curve was used. After determination of demand ratio according to past changes, land use map of 2025 was prepared. Assessment of CLUE-S model showed its high accuracy (Kappa coefficient is 0.88). Also, the results demonstrated that the most land use change are related to forests and ranges to farmlands, as range and forest lands decreases 28.12 and 82.20 present respectively and farmlands increases 10.33 percent until 2025.
Mohammad NazeriTahrudi; Yousef Ramezani
Abstract
Estimating return period of hydrological processes such as flood flow, maximum discharge, drought and etc, is related directly to selecting a suitable probability distribution function. With selecting a proper distribution function, estimated return period will be more close to actual data and error ...
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Estimating return period of hydrological processes such as flood flow, maximum discharge, drought and etc, is related directly to selecting a suitable probability distribution function. With selecting a proper distribution function, estimated return period will be more close to actual data and error will be reduced. So, it should be tried to select the best probability distribution function. In this study, using daily discharge of western rivers of Urmia Lake, as well as the annual mean method, the data of the drought volume of these rivers were extracted. Several distributions from each of the continuous distributions, such as the continuous distribution of generalized maximums and wakeby, the continuous non-zero Erlang distribution, the continuous Johnson SB distribution, and the continuous boundary of Normal distribution for fitting the data of the dry volume of the western rivers Lake Urmia was used in the 38-year statistical period. Anderson-Darling and Kolmogorov-Smirnov tests used to compare results of each distribution. Also correlations between the data obtained from the sample data and statistical models computed. The results of the frequency distribution of the data of the three rivers showed that among the distributions of the continuous group, the advanced statistical distributions of Wakeby and Johnson SB had the best distribution and also had better performance than the conventional statistical methods.
Behnoush Farrokhzadeh; Sepideh Choobeh; Hamid Nouri; Massoud Goodarzi
Abstract
In addition to climate change, the land use changes as an ancillary factor affects flooding. Thus evaluation of impacts of climate change and land use change (together) on flood situation in the coming decades will open a new way to deal with this phenomenon. In this research, to study the effects of ...
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In addition to climate change, the land use changes as an ancillary factor affects flooding. Thus evaluation of impacts of climate change and land use change (together) on flood situation in the coming decades will open a new way to deal with this phenomenon. In this research, to study the effects of climate change on 2020s in Balighloo Chai Watershed, HadCM3 under A2 and B1 senarios was downscaled with LARS-WG. Results showed an increase between 8.78 to 12.86 percent in average of annual rainfall in 2020s. Average annual temperture increases 0.66 °C in 2020s. After examining past hanges in land use, two scenarios were developed to predict the impact of land use changes on the runoff in the coming decades: the first scenario assumes a constant in current land use and the second scenario assumes continuation of changes rate during past decades in the future. Results showed a decrease between nine percent in rangelands and five percent increase in agricultural lands area respectively in 2020s. In order to simulate the hydrologic system in the coming decades, HEC-HMS model was calibrated and validated using data of past period, and was used with new curve number, impersive area and hytograph estimated for the future decades. Then the coming decades predicted hydrographs were compared to the past ones. Results showed an increase in peak flow and flood volume in April while they will decrease in March, May and June. If land use change occures with climate change, this increase will be intensified.
Alireza Arabameri; Kalil Rezaei; Mohammadhossein Ramshet; Kourosh Shirani
Abstract
Landslide susceptibility and its risk assessment is the main part of landslide risk mapping. In this study, landslide susceptibility of Oliya's Padena in Semirom is mapped using artificial neural network. A total of 23 factors in relation to landslide in the region were initially characterized. The spatial ...
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Landslide susceptibility and its risk assessment is the main part of landslide risk mapping. In this study, landslide susceptibility of Oliya's Padena in Semirom is mapped using artificial neural network. A total of 23 factors in relation to landslide in the region were initially characterized. The spatial location of landslide events was then determined by field study as well as aerial photo analysis. AHP analysis tends to 14 out of 23 parameters as the important factors for further steps. A total of 72 (70%) and 31 (30%) out of 103 detected landslide events in the study area were selected as training and validation data for neural network analysis, respectively. A multilayer perceptron back propagation algorithm with sigmoid as activation function was developed. The best topology was determined by using conventional criteria including mean square error, root mean square error, maximum absolute error and correlation coefficient. Results show that a 14-4-1 array is the optimum topology for landslide susceptibility zoning in the region. The weight of each input layer was estimated by frequency ratio. In order to map landslide, ROC graph and area under curve indices were used and the accuracy of output map was computed. Results from validation shows that area under curve for the obtained model is about 0.938 (93.8%) that is considered as high resolution prediction group. According to this study, a total of 29.61 square kilometers (93.25%) of the landslide areas is categorized in very high and high susceptible groups.
Reza Chamanpira; Mohammad Roughani
Abstract
Evaluation is a fundamental tool for implementation of projects, and is used as a tool to assess their effectiveness. In areas with no evaluation, assessment is difficult. A practical method for overcoming to this problem is basin simulation using mathematical models. This research was implemented in ...
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Evaluation is a fundamental tool for implementation of projects, and is used as a tool to assess their effectiveness. In areas with no evaluation, assessment is difficult. A practical method for overcoming to this problem is basin simulation using mathematical models. This research was implemented in Dadabad Watershed in Lorestan, followed by impact assessment of watershed management operations on basin behavior change on reducing watershed area floods. Mapping and determining the volume of the built structures and their number, status, and characteristics constituted the first step of the research. The HEC-HMS mathematical model was then employed to estimate flood volumes. Results of simulations and comparison of the observed and simulated hydrographs indicated that the model had the required efficiency for simulating the Dadabad Watershed and was very sensitive to the parameters of curve number and initial loss. The capability of the storage ponds in storing runoff was then determined through calculating their volumes. The behavior of floodwater for the various return periods was simulated to determine the response of the watershed to design storms by applying the changes that had happened in the input part of the model. Results indicated that the water storage ponds could collect and store more than 80 percent of the runoff resulting from rainfalls with return periods of 2 and 5 years. In return periods of 10, 25, 50 and 100 years, 63.4, 54.3, 38.8 and 28.6 percent of the runoff stored in the ponds respectively, and the rest left the watershed from its outlet. In general, the water harvesting systems in the Dadabad Watershed could store 236645 m3 of runoff.
Aghdas Sotoudehnia; Majid Mahmoodabadi; Majid Fekri
Abstract
Due to low plant cover in arid and semi-arid regions, surface gravel cover (SGC) plays an important role in soil erosion control. The aim of this study is to investigate the effect of SGC and slope gradient on splash as well as interrill erosion in two contrasting soils. For this purpose, a constant ...
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Due to low plant cover in arid and semi-arid regions, surface gravel cover (SGC) plays an important role in soil erosion control. The aim of this study is to investigate the effect of SGC and slope gradient on splash as well as interrill erosion in two contrasting soils. For this purpose, a constant rain was simulated on two soils namely sandy and cropland with different aggregate size distributions at four slope gradients including 0.5, 2, 5 and 10 % and five levels of SGC including 0, 5, 10, 20 and 40 % each at three replicates. Through producing a rain intensity of 35 mm/h for 35 min duration on a 0.35 m by 0.35 m test area, both splash (downward, upward and the total splashed material) and interrill erosion rates were measured. Result showed that with increasing SGC in both soils, the downward, upward and the total average splash increased, significantly. However, the downward splash rate was higher than the upward splash rate. With increasing SGC from 0% (control) to 5, 10, 20 and 40 %, the downward splash rate decreased for the sandy soil by 12.9%, 25.3%, 35.7% and 47.7%, and for the cropland soil by 13.9%, 25.4%, 37.0% and 49.4%, respectively. Regarding the interrill erosion rate, the corresponding reduction percentages for the sandy soil were 13.5%, 26.4%, 33.3% and 46.4% and for the cropland soil were 12.9%, 30.7%, 37.3% and 45.9%, respectively. Moreover, nonlinear increases in the interrill and splash erosion rates were found at steeper slopes. Due to lower cohesion and greater detachability of sandy soil, it exhibited higher erosion rates than those for the cropland soil. The findings of this study revealed that in the presence of SGC, both splash and interrill erosion rates will reduce, significantly.
Leila Gholami
Abstract
In severely eroded areas, especially steep slopes, establishment of vegetation cover is not possible. The application of organic and inorganic amendments can therefore improve the conditions leading to establish vegetation cover through playing an effective role in runoff control. Accordingly, in the ...
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In severely eroded areas, especially steep slopes, establishment of vegetation cover is not possible. The application of organic and inorganic amendments can therefore improve the conditions leading to establish vegetation cover through playing an effective role in runoff control. Accordingly, in the present study, woodchips as a soil organic amendment was applied to control runoff variables including time to runoff, runoff volume and coefficient. For this purpose, three levels of woodchips treatment of 0.5, 1.0 and 1.5 kgm-2 were used in three replications at in 1 m2- plot scale. The plots were located in 30% slope in accordance with field conditions under simulated rainfall of 60 mmh-1 and duration of 15 min. The results showed that application of woodchips in 0.5, 1.0 and 1.5 kgm-2, time to runoff increased 97.50, 192.38 and 203.31%, respectively. The runoff volume decreased 35.23, 55.11 and 60.43% and runoff coefficient also decreased 42.43, 67.40 and 72.14% in three levels of woodchips treatments, respectively. The results of GLM showed that woodchips treatment had a significant increasing effect on time to runoff (p≤0.01) as well as a significant decreasing effect on runoff volume and coefficient (p≤0.05). The application of woodchips as a conservation treatment on the soil surface showed that this amendment can be used for runoff control especially where large quantities of woodchips are simply available.
Seysd Mostafa Tabatabaei; Hossein Khozeymehnezhad; Abolfazl Akbarpour; Peyman Varjavand
Abstract
Deposition of density current the main threats reservoir and its watershed numerous areas of application.In this study Six types of vegetation arrangement similar impact convergent, divergent similar, parallel, z(ed) shape, zigzag and checkered studied the density current control is completed. The experiments ...
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Deposition of density current the main threats reservoir and its watershed numerous areas of application.In this study Six types of vegetation arrangement similar impact convergent, divergent similar, parallel, z(ed) shape, zigzag and checkered studied the density current control is completed. The experiments were performed in a channel length of 10 meters. Made of plastic and the covering vegetation was three meters. Then density current speed in 6 sections 0.5 and 4 meters between the Vegetation was measured after coating. Experiments with 3 Slope bed 0, 1 and 2%, with a salt concentration of 40 and 80 g/l was repeated. The results show if there are vegetation in front of density currents, the speed of the front reduces consequently. Also results showed that vegetation leading to an average of 21-59 per cent density current. After passing density current vegetation Density current rate rises at one point that this speed is not impressive and always density current Substrate without vegetationis also affected.
Aliakbar Noroozi; Ziaoddin Shoaei
Abstract
Wind erosion is one of the important processes of desertification in arid and semi-arid regions. This process causes destruction in the land, soil and water resources and etc. Dust phenomenon is one of the major consequences of wind erosion in the world and Iran, particularly in the west and south west ...
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Wind erosion is one of the important processes of desertification in arid and semi-arid regions. This process causes destruction in the land, soil and water resources and etc. Dust phenomenon is one of the major consequences of wind erosion in the world and Iran, particularly in the west and south west of the country. Therefore, the present study aimed to identify areas of dust generation potential in the Khozestan, Iran using the combination of statistical methods, remote sensing and modeling. The statistical results showed that the most frequent occurrence of this phenomenon happened between 2008 and 2009. Most dust events happened in the seasonal scale, late spring and early summer and in the monthly scale, happened in May, June and July. Dust detection on satellite images and study their concentration using indicators AOD and BTD represents the greatest concentration of dust in the west and south west regions of the Khuzestan province, since 80 percent of these dust occurred in these zones. Tracking of dust showed that during the warm period, most dust happened from north west-south east and west-east and during the cold period, especially at the end of period, the northern-southern dust affected the province. The assessment of land use change showed the reduction in the irrigated areas, vegetation and arid lands increased in 2015, especially for the half of area of western Khuzestan. These features and physiographic features such as erodible formations, saline soils and marshy, low soil moisture and high changes in land use, indicates the presence of dust prone areas and potential for west and southern province.
Hossein Kheirfam; Behzad Kheirfam; Yaaghoub Azhdan; Saleh Hossein
Abstract
Variability analysis of river sediment transport in different temporal and hydrological conditions is important in hydraulics and hydrological science and engineering. Otherwise, behavior analyzing of the riverian systems at the different temporal conditions is necessary in managerial decisions to control ...
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Variability analysis of river sediment transport in different temporal and hydrological conditions is important in hydraulics and hydrological science and engineering. Otherwise, behavior analyzing of the riverian systems at the different temporal conditions is necessary in managerial decisions to control and reduce sediment transport. However, knowledge about the type and amount of sediment in watersheds in various temporal and hydrological conditions is limited. Therefore, this study aimed to investigate the variability of bed and suspended load and bed to suspended load ratio. The 6-years period (1998-2003) data of bed and suspended load (g l-1) and discharge (m3 s-1) were collected from Yazdekan station of Qotour Chay River. The analyses also were carried out in Excel 2007 software. The results indicate that discharge increasing caused that the suspended load was increased and the bed to suspended load ratio was decreased at all seasons. As well, the lowest and highest bed and suspended load transport were occurred at the winter and spring, respectively. Amounts of minimum, maximum and median bed to suspended load ratio at spring, summer, autumn and winter were 5.02, 563.99 and 27.34%; and 0.075, 2034.91 and 135.80%; and 28.31, 659.15 and 184.94%; and 28.96, 457.61 and 169%, respectively. Also, during the study period the bed to suspended load ratio was varied about 0.7 up to 2034%. Therefore, using indirect methods to estimate sediment is not accurate because of complex behavior of sediment particularly bed load and bed to suspended load ratio with discharge. By and large, it is necessary that daily bed load measuring in sediment gauges.
Maryam Rostami; Forood Sharifi; Mohammad Hossein Mahdian; Samaneh Arvandi
Abstract
Nowadays, we see the growth and development of several models for the design of water supply systems, flood estimation, allocation and use of water resources, runoff and wastewater management in urban areas and management of aquatic ecosystems. Understanding the water yield and water demand is one of ...
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Nowadays, we see the growth and development of several models for the design of water supply systems, flood estimation, allocation and use of water resources, runoff and wastewater management in urban areas and management of aquatic ecosystems. Understanding the water yield and water demand is one of the main components of decision making for the management of resources, watersheds and phenomena such as drought. The lack of a system that supports correct decision making and timely decisions is entirely evident for management of surface waters and drought risk in the country. For creating of fetus system, it is necessary reviewing and assessing the water yield in the country. In this study, the 7th order basin in the Markazi province, that is located in the semi-arid climate, are simulated and analyzed with using rainfall, evaporation and discharge data by using of AWBM and SFB models. The main objectives of this research are included of extracting physical parameters of the model, conversion of rainfall point data into regional data using different methods and routine, analysis of calculated evaporation and evapotranspiration and aggregated of data for simulating the 7th order basin and estimation of potential surface water yield Markazi province.
Sohrab Moradi; Soleiman Mohammadi Limaei
Abstract
This study was carried out with the aim of feasibility evaluation of the application of multi-objective game-theory model for settling balance between economic and environmental concerns in land use optimization as well as to facilitate the respective decision-makings in Zemkan basin, located in the ...
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This study was carried out with the aim of feasibility evaluation of the application of multi-objective game-theory model for settling balance between economic and environmental concerns in land use optimization as well as to facilitate the respective decision-makings in Zemkan basin, located in the west of Kermanshah Province. The bi-objectives of multi-objective game-theory model are minimizing the destructive effects on the environment (less erosion and sediments) and maximizing the economical incomes resulted from different land uses (more net present value). The IRS-P6 Satellite images were used for recognition of different land uses and the areas of these land uses were determined using GIS tools. In this study, the environmentalists (player 1) and Zemkan basin users (player 2) were selected as environmental and economical players, respectively. In this study, an integration of game theory, multi-objective optimization and geographic information system was used in land use optimization of Zemkan basin in order to set balance between economic development and environmental effects. The results of multi-objective game-theory model indicated that after several rounds of bargaining and moderating the objectives between players, Nash equilibrium would be resulted. Within Nash equilibrium limits, the mean of erosion and sediment ranges from 4296 to 4300 thousands m3 per year and net present value, also ranges from 47050 to 47068 million Rials for economic player. Comparing with Pareto optimality, which is the result of classical multi- objective model, Nash equilibrium offered more satisfactory solutions based on decision makers’ priorities. The results also suggest that the game theory model can be applied in many other issues concerning environmental management. The future researches may concentrate on developing a third objective like social concerns so that three-objective games would be applied instead of bi-objective ones.
Ali Jafari; Rasool Mahdavi; Arash Malekian; Hamid Gholami; Ahad Habibzadeh
Abstract
Groundwater is a major source of water. The management of these resources is very important answer for increasing drinking, agricultural and industrial water demands. Management measures need knowing the spatial and temporal behavior of groundwater. According to anomalous use of groundwater resources ...
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Groundwater is a major source of water. The management of these resources is very important answer for increasing drinking, agricultural and industrial water demands. Management measures need knowing the spatial and temporal behavior of groundwater. According to anomalous use of groundwater resources in this region and considering floods due to precipitation regime with severe rainfall, there is a need to investigate Hydro-geomorphological characteristics of quaternary deposits of Jam Plain. In this research, exploration-geophysical surveys of quaternary deposits within the Jam Plain was investigated. For this purpose, graphical methods, geo-electric sections draw, and preparing iso-resistance to different depths maps, reviews exploratory piezometer wells drilled within the Jam Plain by drawing the logs through the provision of wells and subsurface levels between wells; and finally, hydro-geomorphology relations of quaternary deposits were studied. Results showed that the minimum alluvial depth starts from 30 m in north-western margin at a distance of 500 m east of Jam Forest Park and its maximum depth of 95 m is in the north-western margin of the aquifer and 450 m south of Mehrbagh oil and gas well. The highest hydraulic conductivity coefficient of 2.5 m/day in Jam Plain belongs to Gachi well and its minimum of 1.06 m/day is related to Faramarzi well. Investigating the trend of changes of hydraulic conductivity coefficient showed that its rate in the eastern part of the study area was 2-2.5 m/day and decreases to 1-1.5 m/day in the western parts and in the north to south direction it decreases from 2-2.5 to 1-1.5 m/day. The spatial trend of changes in the coefficient of transmission capacity from east to west to the middle of the plain is approximately constant and is located on the floor of 180-200 m2/day, but in western areas it has fallen to 50-90 m2/day. The changes of this coefficient showed no significant changes in the north to south direction till the middle of the plain. But, decreased in the southern parts, which is the result of the reduction of the thickness of alluvium in these areas. Results demonstrated that 4810, 2186 and 5282 ha of the study area belongs to mountainous, hill and plateau and the middle areas between the plains and the mountains units.
Seyed Vahid Shahoei; Jahangir Porhemmat; Hossein Sedghi; Majid Hosseini; Ali Saremi
Abstract
Soil and Water Assessment Tool (SWAT) is a continuous and semi-distributive model which can simulate the hydrological processes in basins on daily, monthly and yearly time scales through a wide range of information such as physical data of basins (soil, land use, slope) as well as weather information ...
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Soil and Water Assessment Tool (SWAT) is a continuous and semi-distributive model which can simulate the hydrological processes in basins on daily, monthly and yearly time scales through a wide range of information such as physical data of basins (soil, land use, slope) as well as weather information such as precipitation, temperature, wind, relative humidity, solar radiation and connectivity to geographic information systems (GIS). In this research, the monthly runoff of Ravansar Sanjabi basin (1260 ), in Kermanshah Province of Iran is simulated through SWAT hydrological model. Runoff simulation is done in a period of nine years from 2002 to 2010, where the first seven years of this period (2002-2008) is selected as a calibration period by using 14 various parameters and the two end years (2009 to 2010) as a validation period of model. The results of simulations during the calibration and validation periods are evaluated through two statistical indices namely Nash–Sutcliffe coefficient (NSE) and coefficient of determination (R2). According to compared simulated and observed monthly flow hydrographs and also calculated statistical coefficients, the SWAT model has acceptable results in simulating monthly runoff during both calibration and validation periods, so that the NSE and R2 coefficients are calculated equal to 0.7, 0.8 and 0.81, 0.9 for calibration and validation periods, respectively.
Mehdi Sepehri; Seyyed Abbas Atapourfard; Alireza Ildoromi; Hamid Nori; Saba Goodarz; Mohammadmehdi Artimani; Morteza Solgi
Abstract
Peak flow estimation is one of the major issues in water resources and flood management that have basic role in the design of hydraulic structures and biomechanics activities in basins. So that a proper assessment has a basic role in the success of administrative works. In this paper, using artificial ...
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Peak flow estimation is one of the major issues in water resources and flood management that have basic role in the design of hydraulic structures and biomechanics activities in basins. So that a proper assessment has a basic role in the success of administrative works. In this paper, using artificial intelligence methods (MLP Neural Network, the mixture of SOFM with MLP, the mixture of FCM with ANFIS) to estimate Yalfan River’s peak discharge in hydrometer local station. For these models, eight variables have been considered as the inputs that includes rainfall amount in the occurrence time of flood, rainfall of five days ago from occurrence of flood, curve number of the basin (CN), basic discharge and finally peak discharge are considered as the output. In the artificial intelligences after preprocessing of the data, the optimal structure of the models are determined with input and output data, evaluation criteria and trial and error. At the end, the MLP model had better performance compared to ANFIS+FCM, MLP+SOFM, GRNN models.
Touraj Sabzevari; Mehdi Karami Moghadam
Abstract
Time-area hydrograph and Clark’s methods are commonly used for prediction of runoff in catchments. In the both methods, the Time-Area Diagram (TAD) of the catchment is needed. In this study, two methods for estimation of Dimensionless Time-Area Diagram (DTAD) are introduced. In the first method, ...
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Time-area hydrograph and Clark’s methods are commonly used for prediction of runoff in catchments. In the both methods, the Time-Area Diagram (TAD) of the catchment is needed. In this study, two methods for estimation of Dimensionless Time-Area Diagram (DTAD) are introduced. In the first method, called geometric method, a hyperbolic function for the geometry of the catchment is assumed. Furthermore, travel time is assumed to be proportional to an exponent ( ) of flow distance to outlet. It was shown that the resultant DTAD equation is equal to USACE (1990) equation when is one. In another method, called Nash-TA, DTAD equation was derived as a function of Nash model parameters. The two developed methods were applied to Ajay catchment, in India, and Kasilian, Jafarabad, Shourandika catchments, located in Iran, and the results were compared to those obtained from the kinematic wave method. The efficiency coefficients for geometric method with being 0.6 and for the Nash-TA method were 0.971 and 0.955, respectively. The efficiency coefficient for geometric method in cases of =1, 1.5, 1.67 were 0.824, 0.484 and 0.161, respectively. The efficiency of the geometric method ( =0.6) and the Nash-TA method was satisfactory.
Maryam Hosseinpour; Ahmad Fatehi Marj
Abstract
Drought is one of the natural disasters impacting on socio-economic of the society during short, mid and long terms. Continuously monitoring and evaluating of droughts, which are accounted for the main object of the present study, can affectively alleviate drought impacts helping to come up with a drought ...
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Drought is one of the natural disasters impacting on socio-economic of the society during short, mid and long terms. Continuously monitoring and evaluating of droughts, which are accounted for the main object of the present study, can affectively alleviate drought impacts helping to come up with a drought risk management plan. In this research, the spatial variation of meteorological drought was analyzed for the first half of the hydrological year 1392-1393. Drought indicators used in this study were SPI and PN and their results were compared through the prepared maps. Results indicated that spatial variations of the rainfall have been considerable in some provinces which has led to severe droughts whereas, other provinces have received more precipitation compared to normal situation. In addition to variation of drought intensity, its spatial extension has been changing significantly. In this regard, the drought intensities have been decreasing in North Khorasan, Razavi Khorasan, Alborz, and Tehran province with regard to the SPI classification namely -2.5
