Seyed Ahmad Hosseini
Abstract
Sediment dams are built with multi-purpose goals including flood control, erosion, sedimentation and aquifer feeding. These dams, with the aim of controlling the sediment from transferring part of it to the reservoirs of the dams in the downstream, and by causing a delay in the surface runoff, they control ...
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Sediment dams are built with multi-purpose goals including flood control, erosion, sedimentation and aquifer feeding. These dams, with the aim of controlling the sediment from transferring part of it to the reservoirs of the dams in the downstream, and by causing a delay in the surface runoff, they control a part of the flood and feed the aquifer of the area. Improper design or lack of optimal implementation of these structures causes the reduction of useful life and sometimes premature destruction of these structures. Evaluating the function and technical performance of such plans with the aim of improving and managing the system is of special importance. For this reason, in this article, a number of sediment dams implemented in Abdanan City of Ilam Province were investigated and evaluated. This research was conducted in the form of hydraulic simulation and comparison of the current situation with the conditions before the implementation of the project, in a section of the waterway about seven kilometers long. It should be mentioned that six stone and mortar dams have been built during the last decade. The results of the hydraulic simulation of the flooding of waterways and constructed structures showed that, based on the discharge with a return period of 100 years, the average overflow width of the construction dams is about 25% larger than the required value and the length of the stilling basin is about 40% less than the required value. In general, in all construction dams, the length of the stilling pond is not chosen correctly, so that the short length of the stilling pond has caused the hydraulic jump to leave the pond or to form at its end. Due to the high flow speed in the area of the hydraulic jump, erosion and destruction in the end zone of the calm pond has intensified, which has been extended to the upstream side and the main structure of the sediment dam. Based on the hydraulic simulation of the flood and the relative comparison of the results in the conditions before and after the construction of the dams, it was found that the constructed dams have a positive effect on the parameters of flow speed, flow strength and flow shear stress, which are all factors that aggravate erosion in the waterway. So that for discharge with a return period of 25 years, the speed, power and shear stress parameters of the flow have decreased by 23, 29 and 27%, respectively, during the research period. Therefore, the average reduction of these parameters locally and at the construction site of the six dams was estimated as 73, 85 and 82%, respectively. In general, according to the field visits and investigations, the implementation of the plan has been effective in controlling floods and sediments, and in case of annual protection and repair, its effects will be doubled.
Pouya Allahverdipour; Yaghob Dinpashoh
Abstract
Introduction
In recent years and decades, due to minor changes and challenges in sufficient and high-quality water resources, sustainable water resources have been the subject of various studies and research. The lack of safe and high-quality water resources is a major obstacle to sustainable development. ...
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Introduction
In recent years and decades, due to minor changes and challenges in sufficient and high-quality water resources, sustainable water resources have been the subject of various studies and research. The lack of safe and high-quality water resources is a major obstacle to sustainable development. For this reason, understanding the processes of the water cycle is very important and requires accurate information about hydrological phenomena. Runoff from water transfer is one of the main sources meeting various water demands, including agriculture, industry, and domestic use. The allocation of water resources to these sectors is planned based on runoff data at different times. A significant portion of precipitation in the hydrologic cycle is converted into runoff due to watershed characteristics. Considering the issue that the Lake Urmia Basin is shrinking, identifying the water resources of this basin and its sub-basins is crucial.
Materials and methods
The Ajichai Basin is one of the sub-basins of Lake Urmia. In this study, rainfall data from the Tabriz synoptic station and runoff data from the Nahand hydrometric station were used. The aim of this research is to model the daily rainfall-runoff of the Ajichai Basin using intelligent machine learning models, including Artificial Neural Network (ANN), Support Vector Machine (SVM), Gene Expression Programming (GEP), and Random Forest (RF). Seventy percent of the data was used for training, and 30% was used for testing the models. Statistical measures such as the Coefficient of Determination (R²), Root Mean Square Error (RMSE), Nash-Sutcliffe Efficiency (NSE), and Willmott Index (WI) were used to evaluate the performance of the models.
Results and discussion
The results of this research showed that all models performed very well in simulating rainfall-runoff in the Ajichai Basin. According to the obtained results, the GEP model, with R² equal 0.84, RMSE equal 0.024 m³/s, NSE equal 0.864, and WI equal 0.968, was the most accurate in modeling rainfall-runoff in the Ajichai Basin. Based on scatter plots and time series analysis, the GEP model demonstrated higher accuracy than other models in predicting rainfall-runoff values with a high correlation.
Conclusions
According to the results, all the investigated models showed good capability in modeling daily rainfall-runoff in the Ajichai Basin. The findings of this research highlight the strong performance of machine learning models in rainfall-runoff modeling. In general, due to the high accuracy of intelligent models, particularly the GEP model, in predicting daily rainfall-runoff, it is recommended to apply these methods to hydrological problems. Additionally, for future research, it is suggested that intelligent methods and data mining techniques be used to model the precipitation-runoff process in different basins separately for drought-affected and wet years.
Seyed Hamidreza Sadeghi; Raoof Mostafazadeh; Amir Sadoddin
Abstract
Assessment of suspended sedimentgraph (SG) and rating loops are important tools for analyzing the behavior of watersheds and successful implementation of watershed management measures in reducing sediment. However, the development and analysis of SGs and rating loops and influencing factors need more ...
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Assessment of suspended sedimentgraph (SG) and rating loops are important tools for analyzing the behavior of watersheds and successful implementation of watershed management measures in reducing sediment. However, the development and analysis of SGs and rating loops and influencing factors need more attention in watershed-scale. Therefore, the present study aimed to conduct the analysis of 13 observed and simulated sedimentgraphs (SGs) during October 2011 and November 2012, in Galaz-Chai Watershed with an area of 103km2 located in West-Azarbaijan Province, Iran. Towards this attempt, the SG of observed events was derived using instantaneous unit sediment graph (IUSG) concept, and the effects of different land uses were investigated. Also, the variation and patterns of the simulated sedimentgraphs (SGs) and rating loops were plotted and interpreted with the respective land use types. Based on the results, an early peak occurred in SGs with respect to the observed hydrograph peak rates and consequently had clock-wise pattern. Increase in falling limb of hydrograph could be attributed to the participation of sediment production from agricultural land in watershed upstream. The model predicted SGs with good accuracy according to the Nash-Sutcliffe criterion (70%). Analysis of results indicated that the type and distribution pattern of different land uses had significant effect on the shape of SGs and sediment rating loops.
Mohammad Rostami Khalaj; Ali Salajeghe
Abstract
Rainfall-runoff modeling is on of runoff estimation techniques and an appropriate tool for studying hydrological processes, water resources evaluation and watershed management. But the complexity and the non-linear nature of rainfall-runoff process and not being known factors affecting it and generally ...
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Rainfall-runoff modeling is on of runoff estimation techniques and an appropriate tool for studying hydrological processes, water resources evaluation and watershed management. But the complexity and the non-linear nature of rainfall-runoff process and not being known factors affecting it and generally on discharge at watershed outlet, modeling has become more difficult. Therefore, using the methods that have additionally dynamic, development capability, conceptual structure and user friendly is essential. Therefore, in this study for rainfall-runoff modeling were used system dynamics methods in the Kardeh dam basin of Mashhad. The proposed model includes 6 reservoir including snow storage, canopy storage, impervious storage, surface soil storage, subsurface storage and groundwater storage. The input data required includes average daily precipitation and temperature. To calibrate the model daily discharge data from basin outlet in the period from 1998 to 2008 and for evaluation the discharge from 2009 to 2012 were used. The results of sensitivity analysis showed temperature parameters are more sensitive and have considerable impact on discharge and peak flow. Also the results indicate that the simulated stream flow pattern is quite similar to that observed and Nash-Sutcliffe coefficient obtained in the evaluation period between 0.57-0.67 which represents that the system dynamics methods is high ability to rainfall-runoff modeling.
Saeed Najafi; Habib Nazarnejad; Hedieh Mohammadnezhad
Abstract
Since most of soil erosion studies in the watersheds are conducted by consultant and executive companies (as contractors) using the semi-quantitative MPSIAC model under the supervision of provincial natural resources and watershed administrations (as employers), so in this study, the results and findings ...
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Since most of soil erosion studies in the watersheds are conducted by consultant and executive companies (as contractors) using the semi-quantitative MPSIAC model under the supervision of provincial natural resources and watershed administrations (as employers), so in this study, the results and findings of the aforesaid studies in West Azerbaijan Province were considered. Analysis of the studies showed that in the last three decades a total of 76 watersheds of the province with an approximate area of 4100 km2 have been studied in terms of soil erosion and sediment yield states using the MPSIAC Model. Estimated mean annual soil erosion was 13.95, 16.30, and 15.59 t.ha−1.yr−1 for northern, central, and southern sections, respectively. Meanwhile, based on the model, the mean sediment yield of mentioned sections has been calculated equal to 5.39, 5.64, and 6.09 t.ha−1.yr−1. Nevertheless, a detailed investigation based on the resistance of different lithology units to erosion in the studied watersheds, as well as land use and vegetation cover as the two most important factors of the MPSIAC Model showed less reliability of the reported results. It seems one of most important reasons for such unreliable results refers to one of the most important weaknesses of the MPSIAC model which estimation of the soil erosion is depended on the estimated amounts of sediment yields and sediment delivery ratio. According to our findings, it can be concluded and suggested that the Forests, Rangelands, and Watershed Management Organization should replace the MPSIAC Model, with USLE family models, especially RUSLE, at least in estimating the soil erosion, in the services description of consultant and executive companies. Implementation of this change should also be taken seriously by the provincial natural resources and watershed management administrations.
Mohammad Gheitury; Mosayeb Heshmati; Mohammad Roughani
Abstract
Water resources scarcity is the negative impact of climate change, which is more severe in arid and semi-arid regions, including Iran. However, harvesting water through micro-catchment is one of the possible issues for combating this problem. This research was conducted in Kaboodeh-Olya Village to compare ...
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Water resources scarcity is the negative impact of climate change, which is more severe in arid and semi-arid regions, including Iran. However, harvesting water through micro-catchment is one of the possible issues for combating this problem. This research was conducted in Kaboodeh-Olya Village to compare the effects of three different micro catchment systems on runoff harvesting and increasing soil moisture. The experimental plots were constructed at a 20% hill slope in northern direction. Research was carried out in randomized experimental block with tree replications. Micro catchments were constructed in rhomboid-shape (1.7×1.7 m) and treatments included plastic with pebble pavement (PPP), compacted surface soil with crop residue (CSCR) and control plot (CP) which was a natural surface soil. The harvested runoff from each plot was stored in a container with 100 litter capacity at the downward. The valium of overland flow was measured after each rainfall occurrence. Results demonstrated that harvested runoff rates through PPP, CSCR and CP were 88, 44 and 16 percent, respectively indicating significant effects (p<0.05) of both PPP and CSCR on runoff harvesting. Furthermore, the effective rainfall for triggering runoff at the PPP, CSCR and CP were 0.8, 1.5 and 3.4 mm that significantly was lower in PPP. Consequently, in limited CSCR building, the SSS can be used for maximum runoff harvesting and soil moisture storage.
amir moradinejad; Amir Hamzeh Haghabi; Mojtaba Saneie; Hojatola Yonesi
Abstract
Sediment entering lateral intakes depend on flow pattern in intake entrance. Using a structure in front of the intake entrance can change this pattern and as a result the entering sediment. One of the effective methods to change pattern and manage sediment entering lateral intake is using skimming wall. ...
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Sediment entering lateral intakes depend on flow pattern in intake entrance. Using a structure in front of the intake entrance can change this pattern and as a result the entering sediment. One of the effective methods to change pattern and manage sediment entering lateral intake is using skimming wall. By removing sediments from intake entrance, the skimming wall reduces the volume of sediments entering the intake. To direct the flow towards intake and increase skimming wall efficiency, a spur dike is used on the opposite side of the intake. The length and angle of the spur dike were 0.25B and 60° and was located at distances 2b from intake center. In this study, the effect of skimming walls angle with the bank, a combination of spur dike and skimming walls and discharge changes on controlling sediments entering the intake, intake ratio and bed topography were investigated experimentally. The effect of the skimming walls with three angles (β1=10, 14, and 18 degrees) and a combination of skimming walls and spur dike on opposite sides of the intake was investigated. Conducting dimensional analysis, non-dimensional ratios were extracted and test variables were specified. Results showed that in the case of having a skimming wall combined with spur dike, the amount of sediment entering the intake has decreased to 81%, 78.5% and 76% on average in walls with an angle of 10, 14 and 18 degrees respectively. The combination of using skimming wall and spur dike has a superior effect on reducing enterance sediments to intake than employing skimming wall alone, namely about 15% for three angles.
Hooshmand Safari; Aliashraf Jafari
Abstract
Most of Iranian rangelands are located in arid and semi arid areas, therefore, drought resistance is an important issue in this regions' plants. Drought resistance variation of forage yield for 11 genotypes of Elymus hispidus was examined in complete block design with three replications under normal ...
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Most of Iranian rangelands are located in arid and semi arid areas, therefore, drought resistance is an important issue in this regions' plants. Drought resistance variation of forage yield for 11 genotypes of Elymus hispidus was examined in complete block design with three replications under normal and dryland farming system, in Islam Abad Gharb, Kermanshah, Iran, during 2004-2006. Significant variation (p<0.01) for forage yield were observed between with and without tension environments and between genotypes. Drought resistance indices of genotypes were measured for dry matter forage yield (Yp) of irrigated and dryland (Ys) conditions, like sensitivity to stress index, Tolerance (Tol), Mean Productivity (MP), Drought Tolerant Index (DTI), Harmonic Mean (HM) and Geometrical Mean of Productivity (GMP). Variance analysis of drought resistance indices showed that genotypes had significant variation at 1% level for DTI, MP and Yp and at 5% level for HM and GMP. Significant variation for SSI, Tol and Ys were not observed among genotypes. The indices of MP, GMP, HM and DTI showed the significant positive correlation with Ys and Yp, therefore selection for drought resistance were performed based on this indices. Also, the results of mean productcomparision of Ys, Yp and drought resistance indices by Duncan method at 5% level showed that genotypes 890-5 and 890-6 has higher drought resistance value and can be introduced as a suitable genetic material for rangeland reclamation or breeding programs for drylands in Kermanshah province. This results were confirmed by claster and principle component analysis.
Majid Soufi; Hossein Esaei
Volume 2, Issue 2 , July 2010, , Pages 73-82
Abstract
Gully erosion is more important than both rain splash and sheet erosions due to both higher sediment productions. Estimation of the volume of gully erosion requires some indices that could be measured easily in the field. This research aims to present simple models to estimate the volume of gully erosion ...
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Gully erosion is more important than both rain splash and sheet erosions due to both higher sediment productions. Estimation of the volume of gully erosion requires some indices that could be measured easily in the field. This research aims to present simple models to estimate the volume of gully erosion with minimum cost. After determining influenced regions, using anecdotal, historical and field surveying, two regions in each modified Dumartin climate zone and region, three representative gullies were selected. Then, morphometric and edaphic characteristics such as length, depth, top and bottom width, clay, silt, sand, Ca, Na and Mg percentages of the gullies were measured both in their heads and cross sections in 25, 50 and 75% of their length from the headcut. The volume of gully erosion was calculated by the sum of partial volumes in each gully. The results revealed that gullies were initiated and developed in two arid and semi-arid climates on the loess sediment with little cohesion. Gully widening is higher than deepening and silt has an important role in it. Statistical analysis indicated that linear relationship with R2 of 0.86 is more suitable than power relationship with R2 of 0.54 for estimation of the volume of gully erosion. Results indicated that the volume of the gullies had a significant linear relationship with gully length, depth and top width in 0.01 level. Results also, revealed that gully length with 86% interpretation of changes in gullies volume and had the most impact among the variables. These results prove that suggested comments in literature using gully length to sediment yield estimation in EGEM is applicable in the northeast of Iran.
Majid Khazaei; Mohammad Reza Mirzaei
Abstract
Prediction in hydrology is as estimation of hydrological and meteorological conditions in a specific interval time. In this regard, understanding the relationship between precipitation and runoff is necessary for water resources optimal management. The purpose of this study was to compare different models ...
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Prediction in hydrology is as estimation of hydrological and meteorological conditions in a specific interval time. In this regard, understanding the relationship between precipitation and runoff is necessary for water resources optimal management. The purpose of this study was to compare different models of artificial neural networks (two type of ANNs: RBF and MLP) and time series models (ARMA) to discharge estimation in a part of the Taleghan watershed, using monthly flow discharge data for a period of 30 years between 1977 and 2007. Among the different ARMA models, a model with a lowest error and akaike (AIC) criterion was selected as an optimal model. Using trial and error method, ANNs were designed by specifying the number of hidden layers and neurons in each layer, sigmoidal transfer function, training function, weight/bias learning function and performance function. Using trend analysis, Halt-Winters and Box-Jenkins (ARMA) methods, time series analysis showed that ARMA (2, 2) (R= 0.77) and Halt-Winters (R=0.72) presented more accurate results. In general, it could be concluded that ANNs models produced more accurate predictions of flow discharge than time series approaches. Also, the results revealed that the MLP model (average R=0.83) produced more accurate predictions of flow discharge than RBF model (average R=0.81). Assessment of accuracy of all models based on RMSE and R showed that the model 1 (with RMSE= 6.45 and R= 0.86) obtained with a network architecture of 4-20-1 configuration. Model 1 used the input vector consisting of antecedent monthly discharge with one to four time lag.
Seyed Hamid Reza Sadeghi; Seyedeh Laleh Razavi; Mohammad Mahdavi
Volume 1, Issue 2 , July 2009, , Pages 78-86
Abstract
Many different runoff prediction methods are being used among which SCS model has been applied throughout the globe. It is therefore very important to evaluate the circumstances and input specifications under which such models could be applied. The present study was conducted to investigate the role ...
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Many different runoff prediction methods are being used among which SCS model has been applied throughout the globe. It is therefore very important to evaluate the circumstances and input specifications under which such models could be applied. The present study was conducted to investigate the role of rainfall main characteristics on accuracy of SCS model in runoff prediction for Kasilian and Darjazin watersheds. For this purpose, the simultaneous rainfall-runoff data were selected and the storm runoff was estimated using determining rainfall characteristic, providing Curve Number map and calibrating the model. In order to determine the effects of rainfall characteristics on model output, the standardized values of regression coefficient (β) of the best fitted multiple regression, developed between rainfall circumstances and maximum storage index coefficient, were determined. The results of the study showed the depth, maximum rainfall in concentration time, maximum 30 minutes intensity, 2nd quartile and 1st quartile have the highest rate of effectiveness on model output respectively.
Amir Samadi Tabrizi; Hamid Reza Peyrowan; Ahmad Motamed
Abstract
This study is about the relation between erodibility rate and plasticity features ofNeogene Marl deposits of Gatchab and Gitcha in southeast of Garmsar. The erosions alfeature of Neogene sediments are rill, gully and waterway shapes. The depth of soilsampling for rill and waterway types is from surface ...
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This study is about the relation between erodibility rate and plasticity features ofNeogene Marl deposits of Gatchab and Gitcha in southeast of Garmsar. The erosions alfeature of Neogene sediments are rill, gully and waterway shapes. The depth of soilsampling for rill and waterway types is from surface to 30-centimeter thickness and forgully one is from head cut and all outcrop of gully bank. The engineering analyses forsediments include liquid limit, plastic limit and plastic index and engineeringgranulometry. On the basis of engineering classification of soil, the sediment ofGatchab and Siahkoh mountains are fine grained soils with low to very low degreecohesive, consequently low plastic limit and low internal consistency. The comparisonof the results between marl units of Gatchab and Gitcha area have shown the M2 unithas low plasticity and high sensitive to erosion to other units M1 and M2. By the way,the M1 unit is high resistance to water erosion in comparison to M3 unit. From allaspect, Abundance of the lime and clay particle amounts is positive effects ondecreasing of sensitivity rate to erosion of Neogene deposits. The above mentionedresults base on plasticity features of Neogene deposits confirmed by field witness.
Mohsen Shariatjafari; Mohammad Hadi davoudi; Mehrdad Safaee; Afshin Partovi
Abstract
The establishment and development of fast-growing trees with effective root systems and avoidance of deforestation are effective ways for slope stability and to reduce landslides. Soil reinforcement and reduction of erosion by tree root systems are influenced by physiological and ecological characteristics ...
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The establishment and development of fast-growing trees with effective root systems and avoidance of deforestation are effective ways for slope stability and to reduce landslides. Soil reinforcement and reduction of erosion by tree root systems are influenced by physiological and ecological characteristics of roots. In this research, root reinforcement of Diospyros lotus, one of dominant species in the forests of northern Iran, was investigated by reinforced soil sampling and laboratory testing. Based on the results, shear strength of reinforced soil is related to two factors of root density and diameter. Evaluating test results by RDR and RDDI indexes showed that soil cohesion and shear strength of reinforced soil by Diospyros lotus roots increased by 207 and 350 percent respectively compared to unreinforced soil and this process has an effective role in Soil reinforcement and massive erosion control, especially in shallow landslides.
Shabanali Gholami; Masoumeh Nasiri
Abstract
Human life is affected by different hydrological events such as floods, water storage, droughts, water pollutions, avalanche and etc. that the risk range of these events depends on the behavior of hydrological variables and watersheds characteristics. Lack of correct data and information or inadequate ...
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Human life is affected by different hydrological events such as floods, water storage, droughts, water pollutions, avalanche and etc. that the risk range of these events depends on the behavior of hydrological variables and watersheds characteristics. Lack of correct data and information or inadequate correct data is the important factor affects on regognition of the behavior of hydrological variables and watershed charactristics. In this regard, there are different models which could follow watershed characteristics and estimate or simulate runoff and sediment load and other water balance factors in watershed. SWAT model is one of the important hydrological models. In this research, Atrak River monthly runoff was simulated using this model based on collected data in Maraveh Tappeh watershed, Gholestan province, Iran. Required information such as topography, land use, pedologyand also, hydrological and meteorological data such as daily rainfall, temperature, relative humidity and runoff have been collected. To determine important and sensitive parameters, sensitivity analysis has been performed using one parameter at a time (OAT) method. The results indicated that curve number, channel hydraulic conductivity, surface runoff lag coefficient, base flow alpha factor and soil evaporation compensation factor have the most influence on different parts of water balance. Calibration and validation of the model were performed using the SUFI2 algorithm for the periods of 1994 to 1999 and 2000 to 2008, respectively The simulation accuracy using Nash-Sutcliffe and coefficient of determination were 0.54 and 0.54 for the calibration period and 0.46 and 0.46 during the validation period, respectively. So, it can be concluded that the performance of the SWAT model for estimating monthly flow is quite good.
Mansour Mehdizadeh Youshanloei
Abstract
Computation and estimation of flood discharge is necessary in hydraulic structure planning and flood control projects. The precise estimation of runoff and flood discharge needs comprehensive data of the amount and condition of rainfall and design precipitation. Rainfall Depth-Area-Duration curves (DAD) ...
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Computation and estimation of flood discharge is necessary in hydraulic structure planning and flood control projects. The precise estimation of runoff and flood discharge needs comprehensive data of the amount and condition of rainfall and design precipitation. Rainfall Depth-Area-Duration curves (DAD) of each region, are used to estimate the optimal precipitation. In this research, these curves were provided for 1, 3, 6, 9, 12, 18 and 24 hours intervals and their relations were studied for Northern parts of Western Azerbaijan province. Eleven maximum and pervasive storms were selected to draw the cumulative rainfall graph. There are adequate recorded and non-recorded rain gauges in the region. Mass curves were prepared for non-recorded stations using relations between rainfall gradient and altitude in the isohyets maps. Results showed that the maximum rainfall for 1 km2 is related to 18 h rainfall with 42 mm and its minimum is related to 1 h rainfall with 4.29 mm. Also, 9 and 12 h curves indicated no difference in different areas. Comparing 18 and 24 h curves indicated that the amount of precipitations are equal in small areas and 18 h curve is above 24 h curve in wast areas that could be related to the shortage of rainfalls with 24 h duration.
Jafar Dastoorani; Ali Fazlollahi; Ali Salajeghe; Ghasem Dastoorani
Volume 2, Issue 3 , October 2010, , Pages 133-142
Abstract
Effective discharge (Qeff) that transports the most of suspended sediment in rivers and controls the bed conditions is an important criterion for evaluating the quality of water. Qeff usually has 1.5 years recurrence interval on the yearly maximum flood data series. For examining similarity between Qeff ...
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Effective discharge (Qeff) that transports the most of suspended sediment in rivers and controls the bed conditions is an important criterion for evaluating the quality of water. Qeff usually has 1.5 years recurrence interval on the yearly maximum flood data series. For examining similarity between Qeff and Q1.5 in ten stations of Daryacheh Namak Drainage Basin, at first the probability density function (pdf) of daily flows and sediment rating curves was plotted, after that probability density function of suspended sediment was constructed by multiplying the coefficient of sediment rating curves with pdf of daily flows. Then its recurrence interval was estimated by Vibul's method. The results showed that there are not any similarities between Qeff and Q1.5, and the ratio of Qeff to Q1.5 ranged from 1.03 to 16.8. Therefore more research is required to reach more certain result.
Hossein Kheirfam; Seyed Hamidreza Sadeghi
Abstract
Measurment of river sediment transport in different temporal and hydrological conditions is important in hydraulics, hydrology and soil and water conservation science and engineering. Bed load is rarely measured because of difficulties and low efficiency of conventional samplers. The present study was ...
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Measurment of river sediment transport in different temporal and hydrological conditions is important in hydraulics, hydrology and soil and water conservation science and engineering. Bed load is rarely measured because of difficulties and low efficiency of conventional samplers. The present study was carried out in order to design a bed load sampler based on the conditions prevailing in the mountainous rivers flumes. The sampler with dimensions of 120 cm length, 60 cm height and 60 cm width was designed and subsequently fabricated. The accuracy of sampler was evaluated through comparing the bed loads estimations made by the designed equipment and those measured by collecting the whole discharged runoff to a 300 liters water tank installed at the outlet flume and with the help of statistical criteria. The t-test, relative erorr (RE) and relative bias (RBIAS) criteria were then used for statistical analyses. The results showed that the mean mesured bed load by water tank and designed sampler were 0.00635 and 0.0064 gl-1, respectively with no siqnificant differece (p<0.0763). In overall, the designed sampler had a high accuracy and efficiency in river bed load measurement with relative erorr and relative bias of about 8.5% and 0.107, respectively.
Mojtaba Saneie
Abstract
Spur dikes are used widely to prevent outer bank river bends and path-modification river projects. Local scouring in spur dile nose is due to contraction and strong eddy is among the important problems occurring in designing Super dikes. Experimental study has been done on effect of length and alignment ...
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Spur dikes are used widely to prevent outer bank river bends and path-modification river projects. Local scouring in spur dile nose is due to contraction and strong eddy is among the important problems occurring in designing Super dikes. Experimental study has been done on effect of length and alignment of minor spur dike to reduction of main spur dike scouring. In order to do this study a shorter spur dike was used in two stages, one perpendicular and one angled to flow channel direction. By non dimensional parameters, contraction ratio L/B=0.3, 0.35, 0.4, 0.45, (L=length of spur dike, B=width of channel), Length ratio L’/L=0.5, 0.6, 0.7, (L’= length of minor spur dike) and distance ratio x/L=0.5, 1, 1.5, 2, 2.5 have been studied. Scour depths at nose of minor and main spur dike have been measured. Data collection were fitted by regression analysis and a relation for reducing scour depth at nose of first spur dike is provided, with and without minor spur dike.
Mahshid Souri; Khadijeh Tork; Omolbanin Bazrafshan
Abstract
Site selection is the most significant and fundamental process in dam construction. Site selection of dam is one of the most important and effective steps of project implementation. Optimal site selection impacts on reducing the costs of dams establishing. Today, this matter is considered by managers ...
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Site selection is the most significant and fundamental process in dam construction. Site selection of dam is one of the most important and effective steps of project implementation. Optimal site selection impacts on reducing the costs of dams establishing. Today, this matter is considered by managers and decision makers. So, different methods apply to site selection. Different parameters are important in text of site selection such as the sub-basins characteristics and hydraulic characteristics. This research determined the optimal location of stone–mortar dams implementation based on nine effective criteria in ten sub-watersheds in Yakhlaqan Makoo region. In this research, criteria weighting was done by AHP method. Then in order to implement stone-mortar dams, Priority of sub-watershed is identified by TOPSIS and VIKOR methods. According to the results, efficient criteria of stone-mortar dams site selection were the catchment area and channel length with 0.191, 0.204 weights. While, the road distance and villages distance were the inefficient criteria with 0.033 weights. The results of both methods identified sub-basins D1, D and H as suitable sub-basins to site selection. The purpose of this research was introduction of the decision support system techniques in identifying and ranking suitable sub-basins in the feild of stone-mortar dams' site selection.
Marzieh Hajimohammadi; Abolfazl Azizian; Bagher Ghermezcheshmeh
Abstract
Knowledge of climate variabilities and their behavior in future periods and their effects in various fields has great importance especially in strategic and macro planning in water resources. This study aims to evaluate the effect of climate change on hydrological condition of the Kan Watershed. For ...
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Knowledge of climate variabilities and their behavior in future periods and their effects in various fields has great importance especially in strategic and macro planning in water resources. This study aims to evaluate the effect of climate change on hydrological condition of the Kan Watershed. For this purpose the HadCM3model under the A2 emission scenario and also statistical downscaling model (SDSM) were applied for temperature and rain variables simulation. Then, SWAT model was used for monthly runoff simulation and SUFI-2 algorithm was used in SWAT-CUP software pack for calibrating and uncertainly analyzing. The performance of SDSM model was evaluated base on MBE and NRMSE parameters, the result indicated that temperature variable was simulated more accurate than of precipitation. The result of the predicting temperature in period (2011-2040) compare with the base period (1961-2001) showed the maximum and minimum temperature will increase by 1.3 and 0.8 °C, respectively. Also, the rainfall will decrease by 3-4 percent for all of selected stations. The most rainfall reduction will be for spring. While in some months of winter an increase of precipitation was predicted. The result of calibration and validation of SWAT model agreed well with the observed data, so that Nash-Sutcliff efficiency coefficient, as objective function, was 0.82 and 0.71, in calibration period (1983-1991) and validation period (1992-1996) respectively. Finally, results of runoff prediction showed an increase in winter and a decrease in other seasons based on climate scenarios. Overall, according to obtained results runoff will decrease by seven percent for future period.
Ali Shojaeian; Sara Amouzegar; Sajjad Jokar
Abstract
The morphological and geomorphological characteristics of rivers are constantly changing due to their continuous nature. In this research, the geomorphology of a part of Karun River in relation to the changes leading to meandering has been studied using satellite data and with a "descriptive-analytical" ...
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The morphological and geomorphological characteristics of rivers are constantly changing due to their continuous nature. In this research, the geomorphology of a part of Karun River in relation to the changes leading to meandering has been studied using satellite data and with a "descriptive-analytical" methodology. For this purpose, first the cell values of different bands of TM images (related to 1991) and ETM (related to 2002 and 2010) were weighted using fuzzy hierarchical analysis method to detect the bands showing the most changes compared to other bands. Then, from the weighted bands, the main components of the corresponding bands TM 1991 and ETM 2010 (as the beginning and end years of the studied period) were extracted and finally, by defining the fuzzy membership of the changes, the regions with the highest amount and intensity of changes in five The floor is provided. The results show that bands 7 and 5 show the most weight changes (river area) among the other bands for the images of 1991, 2002 and 2010, respectively. On the other hand, the fuzzy membership function of the changes showed that the maximum changes with intensity of zero to 20%, with values of 149 square kilometers including 48.3% and also the minimum changes with intensity of 80 to 100% with values of 8.2 square kilometers including 2.6% of the total study area. Therefore, from the study area of Karun, an area of eight square kilometers (about 3% of the total area evaluated) has experienced the intensity of changes above eighty percent and about 20% of the area with an intensity factor of fifty percent or more, prone to meandering or about to.
Seyed Hamidreza Sadeghi; Roghayeh Alipour; Hasan Fereydoni; Fatemeh Zahra Enayati; Alireza Pakravan; Reza Yaghoti; Mitra Moradnezhad; Fatemeh Esmailzadeh Ashini; Fatemeh Abdolbaghi; Sahar Mousavian; Reza Chamani; Marjan Bahlekeh; Hamed Beigi
Abstract
Extended abstract
Introduction
Today, the destruction of natural resources has increased the possibility of shortages and crises of resources needed for human well-being. Therefore, to prevent further land degradation, it has become necessary to develop effective policies and strategies. In this regard, ...
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Extended abstract
Introduction
Today, the destruction of natural resources has increased the possibility of shortages and crises of resources needed for human well-being. Therefore, to prevent further land degradation, it has become necessary to develop effective policies and strategies. In this regard, significant costs are spent every year on protecting natural resources and controling their degradation in the form of studies and executive projects, which in most cases do not meet the desired standard and require a comprehensive and systematic plan. In this regard, the country's watershed management faces many problems and challenges, which must be addressed by new approaches to comprehensive watershed management, taking into account all effective and influential aspects of watersheds.
Materials and methods
In this research, first, a review of the detailed-executive studies of the Daftabad Watershed in South Khorasan Province, Iran was conducted with the aim of identifying the problems of the watershed. Also, the necessary visits were made to understand the watershed as much as possible. Then, a list of the problems and challenges of the region was prepared and placed in a fishbone diagram. The study evaluated the six pillars of comprehensive watershed management, viz., legal, policy, economic, social, cultural, and knowledge, and addressed their position in the watershed management ladder.
Results and discussion
The research evaluation shows that although research studies and a watershed management unit have been included in the watershed, the failure to implement a watershed health and sustainability approach has caused the Daft Abad Watershed to be placed on the research-implementation rung of the watershed ladder. The research assessment shows that current approaches to managing the Daftabad Watershed face serious challenges. Several factors, including inappropriate management patterns, climate change, lack of active participation of local communities, lack of investment, lack of exploitation of economic opportunities and capabilities of the region, and existing socio-economic issues, have exposed this watershed to serious vulnerability. Also, the lack of assessment of the various needs of the population, especially the needs of women in different age groups, has led to the lack of various solutions for population management in the short- and long-term. On the other hand, utilizing the economic capabilities of the Daft Abad Watershed, especially in agriculture and barberry cultivation, to produce products, market the produced products, and expand ecotourism can reduce general poverty and strengthen the economy of local communities. In this regard, utilizing the economic capabilities of watersheds in order to produce products, market the produced products, and expand ecotourism can reduce general poverty and strengthen the economy of local communities. In general, by observing the approaches mentioned in this research and promoting detailed executive studies, the current trend of watersheds can be improved, and the waste of water and soil resources, the continuous migration of people to larger cities, and environmental problems can be reduced. Therefore, this program requires the active participation of all stakeholders, including the government, the private sector, non-governmental organizations, and local communities in the design and implementation. Strengthening the participation of local communities, policy-making and planning that is appropriate for the health and sustainability of the area investing in various sectors and infrastructure, supporting vulnerable groups, as well as paying attention to Indigenous knowledge and local experiences, along with using scientific and specialized knowledge, can significantly contribute to the success of this program.
Conclusions
This study emphasizes the need for a comprehensive and participatory approach, providing solutions for improving the management of the Daftabad Watershed. The results can serve as a model for managers and policymakers in natural resource and watershed management, highlighting the need for holistic and inclusive strategies to ensure sustainable development and resilience. Accordingly, it is recommended that managers and planners at various levels of management, while paying significant attention to the participation of local communities, prioritize the evaluation, monitoring, and measurement of the effects of implemented projects so that in the long-term, they can simultaneously preserve and restore healthy watersheds and prevent the migration of watershed residents to neighboring cities and the emergence of numerous problems in those cities.
Sattar Chavoshi; Mohammad Reza Yazdani; Abdorasoul Telvari
Volume 1, Issue 3 , October 2009, , Pages 153-159
Abstract
Flood risk estimation is one of the most important subjects for Hydrologists. The main objective of flood risk estimation is study on past events in order to determine the following flood risk. There are various methods for flood risk estimation. Rainfall- runoff and empirical equations are the most ...
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Flood risk estimation is one of the most important subjects for Hydrologists. The main objective of flood risk estimation is study on past events in order to determine the following flood risk. There are various methods for flood risk estimation. Rainfall- runoff and empirical equations are the most recently used methods. In these methods, rainfall is the main parameter influencing flood mechanism. In this research, spatial distribution of rainfall pattern in Esfahan province is studied. Esfahan province with 10.5 million ha area is located in central part of Iran with different topography, climate and ecological condition. A number of 203 rainguages, located in the study area and nearby, were studied. Recorded data of 32 years, from 1968-2000 and a total number of 1654 storm events with less than 1 hour to 72 hours duration were investigated and three index events, i.e. widespread and maximum events, were used. The common methods of geostatistics like kriging, Co-kriging, IDW and TPSS were applied to interpolate the recorded points to non-observed ones. Results showed a low correlation between rainfall and elevation in the study area. Among the studied interpolation methods, kriging showed the best results, from which the Gussian and Spherical models best fitted to the observed points. In order to gain best results, it is recommended to add the number of rainfall gauge sites according to the World Meteorological Organization (WMO) standards. Also, grouping the study area into homogeneous regions and studying DAD in each homogeneous region is advised.
Ali Jafari; Davood Nikkami; Esmail Abbasi; Fateme Tavakoli Rad
Abstract
Improper land use management has inverse impacts on available resources. To reduce these environmental and economic effects of soil erosion, there is a need for proper watershed plans. Land use optimization is of the solutions for achieving sustainable development and reducing the loose of resources. ...
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Improper land use management has inverse impacts on available resources. To reduce these environmental and economic effects of soil erosion, there is a need for proper watershed plans. Land use optimization is of the solutions for achieving sustainable development and reducing the loose of resources. The main objective of this research was determining the optimal level of land use to increase the income of residents and reducing the effect of erosion in the Sana Dam Watershed. To apply an optimal pattern of land used for minimizing soil erosion and maximizing land income by a multi-objective programming model, optimal scenarios were chosen proportion to the shape of objective functions and constraints. For this purpose a linear programming model was used for three different scenarios of a) present land use conditions b) present land use condition with some applied land use management and c) standard land use conditions according to principles and scientific criteria. The results showed that present land use is not in optimal level and should be changed. Also, results demonstrated that the amount of soil erosion could be decreased by 5.3, 31.7 and 43.4 percent and the amount of net income could be increased by 47.73, 242.57 and 242.57 percent by land use optimization in present land use conditions, present land use condition with some applied land use management and standard land use conditions, respectively.
Ahmad Mokhtari; kourosh shirani; Navid Moslemzadeh
Abstract
Extended abstractIntroductionSegzai plain, 40 kilometers from Isfahan city, with an area of about 40,000 ha, is considered a serious threat to this historical city. This plain, which until a few decades ago was a relatively prosperous reed and meadow, has now become a huge danger in terms of nature destruction ...
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Extended abstractIntroductionSegzai plain, 40 kilometers from Isfahan city, with an area of about 40,000 ha, is considered a serious threat to this historical city. This plain, which until a few decades ago was a relatively prosperous reed and meadow, has now become a huge danger in terms of nature destruction and environmental pollution. Two natural and human factors play a role in the desertification of this region. Among the natural factors are low rainfall, high evaporation, the presence of limiting layers in the soil and strong winds and from human factors, excessive grazing and overgrazing of livestock as well as bush-cutting, rapid population growth and excessive exploitation of existing resources decline Underground water and most importantly, exploitation of surface mines, especially gypsum mines, can be mentioned. The main goal of this research was to evaluate the effectiveness of the SEBAL model for estimating the actual evaporation and transpiration of the Segazi Plain, considering the arid and semi-arid location of the region using the landsat 8 image. Materials and methodsTo do this research, first, landsat 8 images were processed. Extraction of required information from satellite images in this research was done during three main stages, i.e. pre-processing, processing and post-processing. In other words, in the pre-processing stage, after performing atmospheric, geometric and other necessary corrections, the image was referred to the ground. In the area of data processing, different highlighting methods and statistical analyzes and remote sensing were done in order to achieve the information layers of the plan. In order to evaluate the results in the image processing stage, the post-processing of the data based on various analyzes was used to evaluate the reliable layers in terms of accuracy and precision. After that, the SEBAL algorithm was implemented. first the amount of net radiation (Rn) was calculated according to the temperature of the earth's surface and vegetation and the amount of energy reaching the earth, then the heat flux of the soil (G) was obtained to determine the amount of transfer capability The heat into the soil was determined, then it was determined to calculate the amount of sensible heat flux (H), which determines the loss of energy from the soil to space. Finally, after determining the sensible heat flux, evaporation and transpiration were calculated. The SEBAL algorithm calculates the energy balance equation in order to calculate the actual evaporation and transpiration of the plant. Results and discussionSurface albedo parameters (the highest and lowest weighted values are around 0.85 and 0.16), soil surface temperature (the highest and lowest weighted values are around 326 and 299 degrees Kelvin), NDVI vegetation index (the highest and lowest weight values related to areas with good vegetation close to +1 and related to water and water bodies close to -1), the amount of net energy reaching the surface of the earth (the highest and lowest weight values are about 703 and 210 Wm-2, soil heat flux (the highest and lowest weight values are about 130 and 35 Wm-2), sensible heat flux (the highest and lowest weight values are about 323 and 23 Wm-2 , momentary evaporation and transpiration (the highest and lowest weight values are about 0.842 and 0.225 mm) and daily transpiration evaporation (the highest and lowest weight values are about 20.2 and 5.4 mm) are among the most important effective parameters in this Sabal algorithm which were investigated in this research. Changes in actual transpiration evaporation (the highest weight values about 0.85 mm and the lowest weight values about 0.16 mm). The obtained results showed that the SEBAL model has well predicted evaporation and transpiration in areas that have vegetation, mostly agriculture and gardens, so that the amount of water loss through evaporation has been predicted close to the values found in the eastern synoptic station of Isfahan (airport Shahid Beheshti) is registered. ConclusionThe amount of error obtained in SEBAL calculation was 0.1%. The amount of real momentary evaporation and transpiration has been calculated in the range between 0.22 and 0.84 mm, according to the weather conditions of the region and the temperature of the air near the surface (27 to 50 degrees) and the amount of evaporation and transpiration recorded by the Penman-Monteith equation (30.0 mm in the east of Isfahan synoptic station), this value is in a reasonable range. Comparing the outputs of Sabal model with the amount of evaporation and transpiration obtained in the same station, which shows the root mean square error (RMSE) value of 0.1, indicates the suitability of this algorithm in calculating evaporation and transpiration in Segazi region. Considering the growing need of the country to prevent the wastage or excess consumption of water in the agricultural sector, either through changing the cultivation pattern or changing the irrigation methods, the application of the developed tool of the Sabal algorithm in this research can provide valuable information to the experts and managers of the water sector put agriculture. The results obtained from this implementation of this research showed that remote sensing has a good potential for estimating actual evapotranspiration (ETA) by having different algorithms such as SEBAL algorithm and minimum ground information.
