Reza Chamani; Seyed Hamidreza Sadeghi; Mehdi Vafakhah; Maryam Naghdi
Abstract
Drought is one of the natural disasters related to climate and one of the most important threats to human survival leading to adverse effects on social, economic, and environmental sustainability. In this study, it has been tried to evaluate the changes in reliability, resilience, and vulnerability of ...
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Drought is one of the natural disasters related to climate and one of the most important threats to human survival leading to adverse effects on social, economic, and environmental sustainability. In this study, it has been tried to evaluate the changes in reliability, resilience, and vulnerability of the Chalous Watershed under the influence of drought in the period of 1982-2017. In this vein, rainfall data of nine stations were interpolated using invers distance squared method to the whole watershed. The SPI drought index was then determined through determining the mean and standard deviation of the data. To calculate Rel, Res and Vul indices, the mean value of SPI Index was used. By calculating the geometric mean value of these indicators, the general health status of the watershed was determined and quantified. The results showed that the SPI Index in this period varied between -1.43 and 2.25. Drought index had a similar pattern to that of rainfall with an increasing trend at the end of the period. The watershed health assessment also showed that the indicators of reliability, resilience, and vulnerability were found 0.5, from 0.23 to 0.62 and from 0.06 to 1, respectively. The geometric mean of these indices was also ranged between 0.19 and 0.58. The overall health condition of the Chalous Watershed based on the dynamics of drought index with a mean index of 0.45 was classified as “moderate”. The findings of the current research will play an important role in explaining the methods of adaptive management of the watershed.
Milad Hatefi; Seyed Hamidreza Sadeghi
Abstract
The present study was conducted to make a brief prioritization based on a combined index for flood potential, water stress, rainfall erosivity index and drought severity at province scale in Iran. To accomplish this, the initial country-wide available data were initially collected. The raw data were ...
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The present study was conducted to make a brief prioritization based on a combined index for flood potential, water stress, rainfall erosivity index and drought severity at province scale in Iran. To accomplish this, the initial country-wide available data were initially collected. The raw data were mined and then standardized to neglect differences in units and magnitudes. The standardized data were ultimately analyzed using geometric mean. According to the results, Khozestan, Alborz and Kermanshah Provinces with respective combined indices of 0.61, 0.59 and 0.58 stood at the first priority in viewpoint of water and erosion indicators. Furthermore, the results of the study showed that southwestern provinces of the country were the most sensitive areas owing to high probability of extreme events and as a result, high amount of water resources loss and erosion potential. So that, implementation of soil and water resources management strategies in aforesaid provinces seems to be vital.
Seyed Hamidreza Sadeghi; Fahimeh Mirchooli; Zeinab Hazbavi; Abdulvahed Khaledi Darvishan; Mohsen Khorsand
Abstract
Measuring soil erosion and sediment yield using different methods is necessary to achieve integrated and reliable information from amount of soil loss. In this regards, the application of new and up-to-date innovative methods is required and important to facilitate the measurements, which leads to increase ...
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Measuring soil erosion and sediment yield using different methods is necessary to achieve integrated and reliable information from amount of soil loss. In this regards, the application of new and up-to-date innovative methods is required and important to facilitate the measurements, which leads to increase the accuracy. However, there is no enough information for the efficiency assessment of innovative techniques. An optic scanner method therefore was used in the present study to measure soil particles detached/transported by splash/runoff. Then, the obtained results were compared with two traditional methods. Including rillmeter and paraffin, which were applied for the measurement of rill erosion in the laboratory. For this study, first a clay loam soil was poured in experimental plots with 30×40 cm dimensions and slope of 20%. The study plots were then exposed to sheet erosion under simulated rainfall intensity of 50 mm h-1 with duration of 20 minutes. In the next stage, two simulated rainfall intensities of 90 and 100 mm h-1 with duration of 20 and 80 minutes, were applied, respectively. The output runoff and sediment were collected and measured. Consequently, the results of optic scanner were compared with sediment measurements and also rillmeter and paraffin methods. Average soil erosion amount at the intensity of 90 mm h-1 with duration of 20 minutes based on optic scanner, rillmeter and paraffin were 283.30±79.73, 35.8±49.27, and 45.93±9.22 gr, whereas average soil erosion amount at the intensity of 100 mm h-1 with duration of 80 minutes were 377.94±274.22, 41.5±45.71, and 46.20±11.45 gr, respectively. According to the results, it was clear that the results of optic scanner was significantly different from other methods and overestimated soil erosion.
Seyed Hamidreza Sadeghi; Zeinab Hazbavi; Mehdi Gholamalifard
Abstract
Developing an understandable and comprehensive conceptual model for watershed health assessment is one of the main priorities of many various managerial and policy making projects in the world including the mega project on the integrated watershed management of Iran. Towards this, the present study as ...
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Developing an understandable and comprehensive conceptual model for watershed health assessment is one of the main priorities of many various managerial and policy making projects in the world including the mega project on the integrated watershed management of Iran. Towards this, the present study as the pioneering research in the country has been conducted to customize the reliability, resilience and vulnerability (RelResVul) conceptual model based on hydrological data to assess watershed health. To this end, firstly the long-term data of discharge of the Shazand Watershed that located in Markazi Province was prepared and the flow duration curve was accordingly derived. Secondly, the appropriate thresholds of low and high flow discharges as prerequisites for watershed health assessment were applied to the RelResVul conceptual model. Hence, the reliability (Rel), resilience (Res) and vulnerability (Vul) indicators were calculated for four node years of 1986, 1998, 2008 and 2014. Finally, the general health state of the Shazand Watershed and its different sub-watersheds was zoned on the basis of two low and high flow discharge criteria through the geometric integrating of the mentioned indicators. The results showed that for the four study years respectively, 59, 53, 68 and 66 % of the watershed in terms of low flow discharge as well as 19, 22, 54 and 38 % of the Shazand Watershed in terms of high flow discharge were situated beyond relatively healthy state. The watershed health index assessment indicated the moderate and relatively healthy states with improving trend for low flow discharge criterion and moderate healthy state with constant trend for high flow discharge criterion. In addition, the results were verified the spatial changeability of watershed health state in different sub-watersheds for the study years.
Shirko Ebrahimi Mohammadi; Seyed Hamidreza Sadeghi; Kamran Chapi
Abstract
In this study, the seasonal variations of discharge and concentrations of soluble nitrite, nitrate, ammonium, orthophosphate and potassium and also the concentrations of these substances during baseflow and rainfall runoff in the seasonal and perennial rivers entering the Zarivar Lake were investigated. ...
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In this study, the seasonal variations of discharge and concentrations of soluble nitrite, nitrate, ammonium, orthophosphate and potassium and also the concentrations of these substances during baseflow and rainfall runoff in the seasonal and perennial rivers entering the Zarivar Lake were investigated. The results showed a great variation of discharge in the spring than the other months because of frequent rainfalls and the maximum discharge in this season. Despite the differences of the stream lake behavior and also the different nature of nutrients, generally, nutrients concentrations have different seasonally significant so that the maximum concentrations and the maximum concentration variations of soluble nitrite, nitrate, orthophosphate and ammonium were seen in summer. The results of the inter and intra storm variability analysis of nutrient concentrations indicated a significant differences between nitrite and nitrate during and between storm events with sig=0 and sig
Seyed Hamidreza Sadeghi; Mohsen Zabihi
Abstract
Rainfall erosivity factor is the first noticeable point in soil erosion issues that plays very important role in detachment of soil particle from the origin bed. Hence, investigation of rainfall erosivity factor trend is necessary in decision-making and planning in order to manage soil and water resources. ...
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Rainfall erosivity factor is the first noticeable point in soil erosion issues that plays very important role in detachment of soil particle from the origin bed. Hence, investigation of rainfall erosivity factor trend is necessary in decision-making and planning in order to manage soil and water resources. However, studies on various aspects of erosivity like trend and in interaction with precipitation and SPI index have not been attended well. The present study therefore aimed to investigate the rainfall erosivity factor trend based on the Fournier index in 28 stations throughout North-Khorasan Province during the period of 1987 to 2006 by using the Mann-Kendall test. In addition, the SPI and precipitation trend were comprehensively investigated for better characterization of erosivity trend analysis. Results showed that Noushirvan, Faruj, Ayerqayeh and Gholaman stations had decreasing trend and other study stations (71.85%) had increasing trend in the modified Fournier erosivity index. The SPI and precipitation in the study area indicated that most of the stations (89.28%) excluding Khartot, Noushirvan, Faruj and Ayerqayeh had increasing trend. The maximum and the minimum values of modified Fournier erosivity index with 70.97 and 33.44 mm were also assigned to Darkesh and Abiary Bojnourd stations, respectively.
Saeed Najafi; Seyed Hamidreza Sadeghi; Tobias Heckmann
Abstract
Comprehensive watershed management programs need to take into account the sediment and related process in sediment management paradigm. Whilst, the dominant processes on sediment yield has not been considered in watershed scale yet. Accordingly, sediment connectivity is an emerging concept in sediment ...
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Comprehensive watershed management programs need to take into account the sediment and related process in sediment management paradigm. Whilst, the dominant processes on sediment yield has not been considered in watershed scale yet. Accordingly, sediment connectivity is an emerging concept in sediment management that has been accounted in recent years to investigate the sediment transfer from different sections of watersheds. Sediment connectivity is defined as the integrated transfer of sediment across all possible sources to all potential sinks in a system over the continuum of detachment, transport and deposition processes. The structural connectivity is therefore a concept derived from sediment connectivity which investigates potential of sediment particles displacement across a watershed on the base of anatomy of watershed's system. Naturally, identifying sectors with similar sediment connectivity patterns support applying similar and integrated sediment control mitigation strategies. The present research was planned to investigate the structural sediment connectivity in Taham Watershed in Zanjan Province for year 2014. To calculate the structural sediment connectivity, the Digital Elevation Model (DEM) and C Factor layers were used and the results were assessed according to field observations and surveying in several times. The results of the validity of the structural sediment connectivity map showed there were acceptable agreement between Field Index of Connectivity (FIC) and Index of Connectivity (IC). In addition, IC map with respective max, min and mean values of 1.02, -8.24 and -5.95, showed 32 percent of the study area had a high structural sediment connectivity that generally have been dispersed in western parts of the study area. Regarding to rapid appraisal and being low cost of IC calculation as well as identification of primary sediment sources, the structural sediment connectivity is a very useful concept for sediment management of watersheds of Iran.
Seyed Hamidreza Sadeghi; Aliakbar Davudirad; Amir Sadoddin; Shahla Paimozd
Abstract
Today, land degradation is inevitable due to growing population and corresponding demands, and also economic development, unscientific and illogical utilization of resources. Monitoring and identification of factors affecting is therefore essential for controlling and management of land degradation in ...
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Today, land degradation is inevitable due to growing population and corresponding demands, and also economic development, unscientific and illogical utilization of resources. Monitoring and identification of factors affecting is therefore essential for controlling and management of land degradation in an area. However, such important issues have been less considered by experts and managers. To this end, the present study aimed to analyze the trend and identifying the important affecting factors on land degradation in the Shazand Watershed, Iran, based on the Environmental Sensitive Area Index (ESAI) for significant changes due to a variety of uses, management and industrial development from 1986 to 2014. According to the ESAI maps in five year nodes of 1986, 1998, 2008 and 2014, some 16.56, 33.39, 42.32 and 49.52 percent of the study area were in critical condition of land degradation, respectively. Based on the results, the process of land degradation in the region was increasing and land degradation was considerable in the periods leading up to 1998 and 2014. The sensitivity analysis on factors influencing land degradation in the study area also revealed that the role of vegetation, anthropogenic and managerial factors on ESAI changes were more than other factors and therefore could moderate or intensify the land degradation.
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.
Mahbobeh Kiani Harchegani; Seyed Hamidreza Sadeghi; Hossein Asadi
Abstract
Water erosion comprises major processes of the detachment, entrainment, transport and deposition. Sediment washed out from the watershed is composed of different particle sizes. The particle size distribution of sediment is a significant factor influencing detachment and transport processes. However, ...
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Water erosion comprises major processes of the detachment, entrainment, transport and deposition. Sediment washed out from the watershed is composed of different particle sizes. The particle size distribution of sediment is a significant factor influencing detachment and transport processes. However, the changeability variables of particle size distribution under different flow conditions have been less considered. Accordingly present study was therefore planned to evaluate the changes in particle size distribution of effective sediments by laser diffraction in initial unsteady and mature steady flow conditions in laboratory scale for a type of soil that was collected from Koudir region in Mazandaran Province. Towards this attempt, rainfall simulation experiments with intensities of 30, 60, and 90 mm h-1were conducted in a set of 1 × 6 m plot with varying slopes of 5, 15 and 25% based on governing condition in the north region of the a soil type and in three replications. The results showed that the sediment concentration is influenced by the slope more than by the rainfall intensity in runoff different conditions. In addition, the results explained significant levels of (p<0.05) for particle of 10 in slope of 5% and in rainfall intensities of 60 and 90 mm h-1 in steady and unsteady flow conditions. While particle of >2 micron had a significant different (p<0.05) in slope of 5% and in rainfall intensity of 30 mm h-1. In this regard, variable of D50 had very complex behavior in slopes and different rainfall intensities but D90 was not influenced by slopes and rainfall intensities in confidence level of 90% in steady and unsteady flow conditions because of inability flow in moving particles of >63 micron and especially variable of D90.
Pari Saeidi; Seyed Hamidreza Sadeghi; Abdulrasul Telvari
Abstract
Sediment graph is an important tool for soil and water resources management of watersheds. It is therefore important to find an appropriate procedure to simulate sediment graph data in different watersheds with inadequate and unreliable suspended sediment data. However, achieving simple procedures based ...
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Sediment graph is an important tool for soil and water resources management of watersheds. It is therefore important to find an appropriate procedure to simulate sediment graph data in different watersheds with inadequate and unreliable suspended sediment data. However, achieving simple procedures based on easily accessible data has been less considered. Hence, the present study was conducted in Galazchai Watershed in West-Azerbaijan Province, Iran, with an area of some 103 km2 to investigate the ability of synthetic sediment graph development by using hydrograph. Towards this attempt, a databank of 18 storm events occurred during autumn 2011 and spring 2014 was developed and corresponding total and direct hydrographs and sediment graphs were prepared. All total and direct sediment graph components were simulated using corresponding hydrograph components with the help of different bivariate regression models and the best performed model was ultimately determined by applying different criteria. The results showed that the simulation of different total sediment graph components was possible using hydrograph components except for base time and ordinates of 50 and 75 percent of peak. Direct sediment graph simulation results also verified the simulation ability of all components except for ordinates of 75 percent of peak. According to the results, simulation of temporal components with the lower relative errors had better performance than the other components. So that, for total sediment graph, the lowest relative estimation and validation errors for time to peak were 48.86% and 45.65%, respectively. Also, the best performed model developed for the direct sediment graph base time had the lowest relative estimation and validation errors of 23.03% and 21.75% and the highest coefficient of efficiency of 0.93.
Saeed Najafi; Seyed Hamid Reza Sadeghi
Abstract
Many on-site and off-site problems occurred due to irregular human use of natural resources leading to increasing sediment loads in watersheds. Understanding relative importance and source of erosion and sediment is essential for effective control of aforesaid problems. Today's, there are different techniques ...
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Many on-site and off-site problems occurred due to irregular human use of natural resources leading to increasing sediment loads in watersheds. Understanding relative importance and source of erosion and sediment is essential for effective control of aforesaid problems. Today's, there are different techniques for determining sediment sources. However, the evaluation of their relative agreement has been less considered. Towards his attempt, the present study aimed to compare the results of fingerprinting, soil erosion feature map and direct field measurements of soil erosion. According to the results of fingerprinting technique, the red gysiferouse marl geological unit with 85 percent contribution in sediment yield was most important sediment source. It was in the same line with that reported from soil erosion feature map with code of CS23R41G42. The results of field measurements also showed that the red gysiferouse marl geologicalunit with soil erosion rate of 34.4 t ha-1 and 14023 t annual erosion had the highest proportion in sediment yield. Other geologic units viz. young alluvial deposits and old alluvial clastic lied in second and third orders. These were also consistent with those of fingerprinting technique. Totally, the differences in the results of fingerprinting technique, soil erosion feature map and field measurement techniques referred to their quantitative or qualitative approaches and not considering sediment delivery ratio concept and other sediment transition processes. It clearly confirmed the necessity of simultaneous use of all aforesaid techniques to get access to reliable results.
Seyed Hamid Reza Sadeghi; Sudabeh Gharemahmudli
Abstract
Awareness of particle size distribution of river bed material plays an important role in studies of the organizing and analysis behavior of rivers. The traditional separation of particle sediments needs a lot of cost, time and fieldwork. Therefore, new methods such as image processing separation, is ...
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Awareness of particle size distribution of river bed material plays an important role in studies of the organizing and analysis behavior of rivers. The traditional separation of particle sediments needs a lot of cost, time and fieldwork. Therefore, new methods such as image processing separation, is essential for studies on particle size distribution of riverbed sediments. It is necessary to maintain standards in reach to the goals and to justify the adoption of a new separation technique. Accordingly, the resolution of the camera is very important for standard image processing. However, it has not been considered, yet. Hence, the present study aimed to analyze the accuracy of the particle size distribution of bed sediments using the image processing of image taken by cameras with different resolutions. For this purpose, variety of cameras were applied to provide images with different resolutions. The direct samplings and measurement was also conducted for comparison purposes. The results showed that cameras with 3 and 10 megapixel resolutions had the highest and the lowest consistency with observed data with respective correlation coefficients of 0.65 and -0.51 for coarse sediment. The cameras with resolutions of 16 and 18 megapixel also had the highest and the lowest agreement with the observed data with correlation coefficients of 0.88 and 0.69 for fine-grained sediments, respectively. In principle, the results suggested that the most appropriate camera for image processing purposes born 10 to 16 megapixels of resolution. However, coarse-grained sediments ranged from 10 to 107 mm in diameter with the respective highest and the lowest standard deviation and mode of 98.455 and 89.7, and 21 and 14. The fine-grained sediments also ranged from 10 to 57 mm in diameter with the highest and the lowest standard deviation and mode of 33.143 and 17.10, and 12 and 48, respectively.
Haniyeh Asadi; Hamid Reza Moradi; Seyed Hamid Reza Sadeghi; Abdolrasoul Telvari
Abstract
The proper application of instantaneous unit hydrograph theory is very efficient for watershed with lack of rainfall data. Therefore, the present study has been conducted to evaluate the efficiency of Clark instantaneous unit hydrograph modelwith the help of geographical information system in regenerating ...
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The proper application of instantaneous unit hydrograph theory is very efficient for watershed with lack of rainfall data. Therefore, the present study has been conducted to evaluate the efficiency of Clark instantaneous unit hydrograph modelwith the help of geographical information system in regenerating flood unit hydrograph in Kasilian watershed in Mazandaran province. The comparative evaluation is conducted between the 3h-unit hydrographs simulated using Clark model and the one obtained from averaging the observed ones. This comparison is made with the help of statistical criteria viz. relative error, root mean square of error, coefficient of efficiency and bias. It verified high level of compatibility between two unit hydrographs using the Clark model and the hydrograph obtained by averaging the observed data.
Morteza Dehghani; Ali Karami Khaniki; Seyed Hamid Reza Sadeghi
Abstract
One of the main objectives of hydrology is rainfall–runoff forecasting process for determination of flood hydrograph at the outlet of a watershed. The aim of this study was to investigate the consistency, accuracy and reliability of time–area and Clark instantaneous unit hydrograph models ...
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One of the main objectives of hydrology is rainfall–runoff forecasting process for determination of flood hydrograph at the outlet of a watershed. The aim of this study was to investigate the consistency, accuracy and reliability of time–area and Clark instantaneous unit hydrograph models for estimating the shape, peak discharge, time to peak, base time and volume of flood resulting from a rainfall with certain intensity and duration. For this purpose, the topographic map of Bazoft watershed was digitized by using R2V package, the digital elevation model (DEM) and isochronal prepared with the ILWIS software. Finally, the flood hydrographs were estimated by Clark and time-area models for six selected storm events. The computed hydrographs then compared with those obtained by measured data an outlet of the basin. The results showed that while both methods have some errors, the Clark model gives a better estimation of outlet hydrograph in comparison with time-area model. The amount of relative error for peak discharge for Clark and Time- Area methods were 23.3% and 32.8%, respectively.
Seyed Hamid Reza Sadeghi; Gholam Reza Shojaee; Hamid Reza Moradi
Volume 2, Issue 3 , October 2010, , Pages 143-149
Abstract
The intensity and type of soil erosion are functions of climatic, topographic, soil and land use characteristics. The role of land use is more than others due to the human impacts. In order to study the relationship between land use change and soil erosion, the Manderijan watershed located upstream of ...
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The intensity and type of soil erosion are functions of climatic, topographic, soil and land use characteristics. The role of land use is more than others due to the human impacts. In order to study the relationship between land use change and soil erosion, the Manderijan watershed located upstream of Zayandehrud dam basin, comprises 23000 ha, was selected. The satellite images of MSS1979, TM1990, TM1998 and ETM2002 were used to map land use as well as soil erosion features during the study periods. The relationship between the existence as well as areas of each particular soil erosion feature and land use was also investigated using regression and Chi-square analyses. The results of the study verified a significant relationship between areas of land uses and soil erosion features. The moderate sheet erosion was further related to the land use changes in particular in the form of cubic regression equation having the determination coefficient of less than 81% and relative error of below 39.65%. The Chi-square analysis was also certified the insignificant relationship between existence of each particular soil erosion feature and land use whereas the relationship between land use and soil erosion areas could be significantly approved. The results of the study therefore can be utilized for proper management of the area through devoting necessary attention into the land uses.
Seyed Hamid Reza Sadeghi; Bahar Salavati; Abdolrasoul Telvari
Volume 2, Issue 2 , July 2010, , Pages 111-115
Abstract
Population ever increasing and consequent demands in recent decade have encouraged farmers to utilize unsuitable and marginal lands such as forests and ranges for agricultural purposes. However, these lands have high soil erosion potential and low productivity and their proper management is therefore ...
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Population ever increasing and consequent demands in recent decade have encouraged farmers to utilize unsuitable and marginal lands such as forests and ranges for agricultural purposes. However, these lands have high soil erosion potential and low productivity and their proper management is therefore a vital task. In the present study, the land use areas have been evaluated in Garan watershed in Kordistan Province, Iran, from 1995 to 2002 by using three digitized images and corresponding changes have been then assessed. The effects of land use changes on changing annual runoff were ultimately evaluated with the help of moving average and hydrological regime analyses. The results of the study revealed that the variation in water discharge thoroughly followed the annual rainfall oscillation which itself affected land allocation to different land uses.
