Saeid Khosrobeigi Bozchelui; Arash Malekian; Alireza Moghaddam Nia; Shahra,m Khalighi
Abstract
Flood is one of the most devastating natural disasters, causing financial and human losses each year. At the same time, many rivers in Iran's watersheds lack complete and accurate statistics and information. On the other hand, estimating the flow of floods is one of the most important factors for the ...
Read More
Flood is one of the most devastating natural disasters, causing financial and human losses each year. At the same time, many rivers in Iran's watersheds lack complete and accurate statistics and information. On the other hand, estimating the flow of floods is one of the most important factors for the design and implementation of water structures. In such cases, one of the appropriate solutions to estimate the maximum flow rate with different return periods is flood analysis. In order to conduct the present study, 55 hydrometric stations with a common statistical period of 20 years were considered to perform the work after the statistical deficiencies were eliminated. Then, based on the distribution of the third type of Pearson logo with the lowest error rate and the highest number of first rank as the most suitable fit function, the amount of discharge in different return periods was estimated. The following information was collected on the types of physiography, land use, climate and geology variables. After collecting information about all independent variables using Gamma test, the most important variables affecting the maximum instantaneous flow, including area, drainage density, maximum 24-hour rainfall and watershed environment, were selected and modeled using methods. Random forest modeling and support vector modeling were performed and their efficiency was determined based on statistical indicators With an efficiency coefficient of 74 to 83%, the error of 3.05 to 32.11 m3 and the coefficient of explanation of 76 to 91 are more accurate than the random forest model.
Maryam Asadi; Arash Malekian; Ali Salajegheh
Abstract
GCM models are widely used to assess climate change on a global scale, but outputs of these models are not sufficient and accurate to assess climate change at local and regional levels. Therefore, in this study, SDSM model was used for micro-scaling of CanESM2 model data and climate conditions of Semirom ...
Read More
GCM models are widely used to assess climate change on a global scale, but outputs of these models are not sufficient and accurate to assess climate change at local and regional levels. Therefore, in this study, SDSM model was used for micro-scaling of CanESM2 model data and climate conditions of Semirom region based on three scenarios of RCP2.6, RCP4.5 and RCP8.5 in the period 2020 to 2100. The results of model evaluation based on NCEP database showed that the model was more accurate in estimating and predicting temperature data especially mean temperature. Comparison of observation and simulated data of temperature and precipitation of GCMs in the baseline period (1980 to 2005) based on NCEP predictor variables showed the mean correlation of precipitation data of 0.52, mean temperature of 0.88, maximum temperature of 0.80 and minimum temperature of 0.70 for validation and verification periods. The results of the estimation of precipitation variations in different scenarios also predicted a decrease of at least 7.24% and a maximum of 18.55% for the time period of 2020 to 2100 compared to the baseline period (1980-2005). The results of precipitation prediction also show the changes of precipitation pattern. The comparison of the scenarios also shows that the RCP2.6 scenario as the most optimistic scenario has the least rainfall while the RCP8.5 scenario predicts the highest rainfall reduction. Examination of the predicted changes in temperature also shows an increase for the mean, minimum and maximum temperatures,
Zahra Noori; Arash Malekian
Abstract
Groundwater is important water resource supply, especially in arid and semi- arid regions. Increased utilization of the ground water aquifer leads to significant reduction in the storage of reservoirs. This study evaluates the hydrogeological drought in Garmsar plain using Groundwater Resource Index ...
Read More
Groundwater is important water resource supply, especially in arid and semi- arid regions. Increased utilization of the ground water aquifer leads to significant reduction in the storage of reservoirs. This study evaluates the hydrogeological drought in Garmsar plain using Groundwater Resource Index (GRI). First, we used 17 piezometric wells data over 2001-2011 statistical period to calculate GRI in the beginning, middle and end of the period. So, we used different interpolation method including geostatiscal method ordinary kriging (OK), simple kriging (SK) and deterministic methods including inverse distance weighting (IDW) to prepare the maps over three periods. The mean absolute error (MAE) and root mean square error (RMSE) indices were used to evaluate the accuracy of simple kriging, ordinary kriging and IDW classification based on the drought maps. The results showed that the values of MAE and RMSE criteria for simple Kriging is better than the other methods and indicates the suitability of this method for zoning GRI. According to the results, the most severe hydrogeological drought in Garmsar plain was at the end of 2011, that 91.16 % of the study area was suffered from severe drought. SPI was used for considering the effects of meteorological drought in the time scale of 3, 6, 9, 12, 24 and 48 months on groundwater. The correlation between SPI and GRI showed long-term timescale of 48 monthly has the greatest correlation with groundwater level.
Esmatullah Ghaljaee; Shahram Khalighi-Sigaroodi; Alireza Moghaddam Nia; Arash Malekian
Abstract
Reliable estimation of precipitation is one of the most essential needs in water resources management. However, in many parts of the world, especially in Iran, the lack of time and place of rainfall data is very noticeable. Therefore, the use of satellite information is one of the ways to compensate ...
Read More
Reliable estimation of precipitation is one of the most essential needs in water resources management. However, in many parts of the world, especially in Iran, the lack of time and place of rainfall data is very noticeable. Therefore, the use of satellite information is one of the ways to compensate for the lack of information. The purpose of this research is to compare the accuracy of rainfall information of TRMM-3B42 and PERSIANN-CDR products on a daily scale. The products of these two satellites are available daily for free in the pixel size of 0.25 degrees. The daily rainfall of 12 stations in the southern slopes of Alborz in a statistical period of 2000-2014 was used. The results show that these two satellite products are not the same in different statistical parameters, so that CDR and 3B42 have estimated 100% and 25% more rainfall events than the stations, respectively. Also, PERSIANN satellite is significantly superior to 3B42 in terms of RMSE, POD and CSI parameters, but on the other hand, it is weaker in terms of Bias and FAR parameters. Therefore, the selection of the desired satellite product should be based on the proper parameters.
Mehrnoosh Ghadimi; Nadia Hajihasani; Arash Malekian; Ebrahim Moghimi
Abstract
Sub-basin prioritization and morphometric characterization analysis is one of the efficient and low-cost tools in identifying flood hazards. The purpose of this study is to Prioritize the flood potential of watershed sub-basins using morphometric parameters, combines of model statistical correlation ...
Read More
Sub-basin prioritization and morphometric characterization analysis is one of the efficient and low-cost tools in identifying flood hazards. The purpose of this study is to Prioritize the flood potential of watershed sub-basins using morphometric parameters, combines of model statistical correlation and multi-criteria decision making systems. 17 morphometric parameters including slope, elevation, curvature, Ruggedness number, elongation coefficient, circularity coefficient, equivalent rectangle, drainage density, Stream Length, coefficient Permeability, concentration time, duration-intensity of precipitation, land cover, land use, geology, Bifurcation Raito, Length of overland flow were studied. the relationship between parameters and weighting results showed that in AHP in climate and Morphotopography (slope, height, curvature, number of roughness) was one of the important factors of flooding. In ANP method, slope and concentration time (0.11) duration-intensity of rainfall (0.12) has become one of the most important factors in flooding. Ranking in AHP method showed that the sub-basins of Imamzadeh Davood, Taloon and Doab to Respectively with the highest score (0.74, 0.50, 0.38) and in the ANP method with the highest score (0.97, 0.51, 0.48) in the sub-basins of Imamzadeh Davood, Talun and Sangan They are located in the first to third places and the intensity of flooding in them is higher than other sub-basins. According to the results, relationship between the equivalent rectangle (width) and the circularity showed a strong correlation between these two variables.
Maryam Rostami; Ali Salajegheh; Forood Sharifi; Arash Malekian; TAYYEBEH MESBAHZADEH
Abstract
AbstractPrecipitation plays an important role in climatic, water, energy and biogeochemical cycles. Several global and regional data sets currently provide historical estimates of this variable over Iran, including the MWEP and WFDEI forcing datasets and production of some institutions such as MOHC, ...
Read More
AbstractPrecipitation plays an important role in climatic, water, energy and biogeochemical cycles. Several global and regional data sets currently provide historical estimates of this variable over Iran, including the MWEP and WFDEI forcing datasets and production of some institutions such as MOHC, SMHI and IITM. All these datasets provide data with different resolutions based on gage stations, satellite Images and models output. In this study, we do an inter comparison between these data sets during 1990- 2008. We also validate all ten data sets against independent ground station observations over 30 second-order basins of Iran. MSWEP and WFDEI have an acceptable compatibility with observational data on different spatial and temporal resolutions. RMSE and Bias are 5.68, 6.34 and 0.58, 2.75 for these two datasets during 228 months, respectively. However, it is needed that MSWEP improves in the western and northwestern parts of the country and WFDEI in June and September months. Our findings in this research provide valuable guidance for a variety of stakeholders, including rainfall- runoff and land-surface modelers, watershed management studies and data providers.
Setareh Bagheri; Reza Tamartash; Mohammad Jafari; Mohammad Reza Tatian; Arash Malekian
Abstract
Plain ecosystem is highly vulnerable to environmental changes, and drought is the most famous ecosystem change driver that is difficult to identify after its occurrence. In this research, to study the slope of vegetation changes against drought, the NDVI index of MODIS images and the SPI index from 2001 ...
Read More
Plain ecosystem is highly vulnerable to environmental changes, and drought is the most famous ecosystem change driver that is difficult to identify after its occurrence. In this research, to study the slope of vegetation changes against drought, the NDVI index of MODIS images and the SPI index from 2001 to 2016 were used and the map of vegetation changes against drought with five drought stress classes included very low classes, Low, moderate, high and very high, so that a suitable assessment of the drought can be made at specified time scales. The results of slope pattern of spatial change of vegetation against drought showed that across the plain vegetation changes have declined, and from east to west of Qazvin plain, the slope of vegetation changes and land susceptibility to drought have been reduced. So that the most percentage of area in a one-month drought related to the drought class is very low, but in droughts of 3, 6, 9, 12, 24 and 48 months, the highest percent of the area belonged to moderate and high drought classes. The results of this study, the determination of the level of vegetation changes in against drought in the past years and prediction of these changes in the future years, can be used in the planning and optimal use of resources, control changes in the future.
Sahar Zakeri Anaraki; Gholamreza Zehtabian; Hassan Khosravi; Hossein Azarnivand; Arash Malekian
Abstract
Intergovernmental Panel on Climate Change report shows that the world average temperature has increased to 0.6 ° C ± 0.2 ° C in the twentieth century. Therefore, long-term prediction of climate variables and the consideration of measures to mitigate the adverse effects of climate change ...
Read More
Intergovernmental Panel on Climate Change report shows that the world average temperature has increased to 0.6 ° C ± 0.2 ° C in the twentieth century. Therefore, long-term prediction of climate variables and the consideration of measures to mitigate the adverse effects of climate change is evident. The SDSM model was used to downscale observation data of the minimum and maximum temperatures of the Vazvan Meyme station in Isfahan province. The CanESM2 global model data under new emission scenarios: RCP2.6, RCP4.5, and RCP8.5 are used to predict the near future (2006-2036), mid-term (2037-2078) and far-away future (2079-2100). The studies show the ability of the SDSM model to model maximum and minimum temperatures in the base period. The results of this study necessary indicate that as we get closer to the 21st century, the minimum and the maximum temperatures increase in the area of study. The average maximum temperature changes will have the highest increase under the RCP8.5 scenarios in the (2079-2100), in July, which will reach 7.9 ° C. The average changes in minimum temperature show the highest increase in August under the RCP8.5 scenarios. Therefore, considering that this temperature increase in future periods will affect the status of the study area, water resources, and natural resources. Planners and authorities of the relevant departments will take the necessary measures, such as measures to correct irrigation systems, methods for reducing evaporation and improving the cultivation system, to adjust the damage caused by heating or adapt to the new climatic conditions.
sahebe Karimi; Sharareh Pourebrahim; Ali Salajegheh; Arash Malekian; Michael Strauch; martin volk; felix witing
Abstract
Environmental flow (EF) is the quantity, quality and timing of water needed for ensuring the sustainability of aquatic ecosystems. The Karaj River is one of the five protected rivers in Iran. It provides drinking water for the cities of Tehran and Alborz, water needed for agriculture, and is also an ...
Read More
Environmental flow (EF) is the quantity, quality and timing of water needed for ensuring the sustainability of aquatic ecosystems. The Karaj River is one of the five protected rivers in Iran. It provides drinking water for the cities of Tehran and Alborz, water needed for agriculture, and is also an important power supply source for the country. While the river has fulfilled for a long time environmental requirements of downstream areas, this has been threatened in recent years by increasing demands of the rapidly growing population in Tehran and Karaj. In the present study, we tried to find an acceptable environmental flow range by using Flow Duration Curve (FDC) and Indicators of Hydrological Alteration and compared the results with the Tennant method which has been officially used by the Energy Ministry of Iran. Results are presented in monthly resolution and at the scale of sub-watersheds to provide a spatio-temporal EF analysis that can be used in watershed management planning. Based on the results, highest and lowest amounts of EF were calculated by FDC-Q95 and Tennant methods, respectively. For instance, the monthly mean Q95 in last gauge (Sira-Karaj) equals 5.75 m3/s, while the mean value estimated by Tennant is just 2.35 m3/s. Eventually, this study suggests a range of the EF values obtained by the FDC method as the upper monthly threshold and the Indicators of Hydrological Alteration as lower monthly threshold for Environmental Flow in Karaj River.
mina pouresmaeel; ali salajegheh; Arash Malekian; amirreza keshtkar
Abstract
The complexity of the urban environment makes it difficult to consider all the vulnerable components of the urban. Hence, decision-making in urban environments is one of the most important issues in modern management. As a result, the purpose of this study is to investigate the urban vulnerability of ...
Read More
The complexity of the urban environment makes it difficult to consider all the vulnerable components of the urban. Hence, decision-making in urban environments is one of the most important issues in modern management. As a result, the purpose of this study is to investigate the urban vulnerability of Azimiyeh in Karaj to flood based on multi-criteria decision-making method. The statistical population includes specialists who had sufficient knowledge and experience in the field of vulnerability management in urban areas. To this research, first, comprehensive knowledge of the factors affecting the urban vulnerability to floods was obtained using library studies, and then, the results of the Delphi technique, , was shown that among the primary indices, a total of 11 effective indicators were selected and a map of each of them was prepared using ArcGIS software. Then, the urban vulnerability to floods was calculated using the TOPSIS method. The study area was divided into 13 sub-areas based on runoff directional pattern and field observations, and then the decision matrix was made according to 13 sub-areas and 11 indicators. The results showed the vulnerability of this region to floods, which among the studied sub-areas, in sub-areas No. 1 and 2 observed the highest of flood vulnerability and the lowest of it observed in sub-area No. 13. Causes of flood vulnerability in the region include a direct connection to the upstream catchment that has lithology impermeable and geologically impermeable, high-density of building and population, and lack of proportionate open spaces.
Majid Rahimi; Arash Malekian; Amir Alambeigi
Abstract
Water is a source of life, even when it is abundant. In the last few years, the unreal certainty of water services in Iran has caused institutional structures of water to be unsuitable and incompatible with environmental changes, and when water-related crises such as drought, flood occurrence and in ...
Read More
Water is a source of life, even when it is abundant. In the last few years, the unreal certainty of water services in Iran has caused institutional structures of water to be unsuitable and incompatible with environmental changes, and when water-related crises such as drought, flood occurrence and in the larger scale, climate change, are capable of flexibility and resilient in the face of these changes. In this regard, the recognition of the present governance system in the country is considered essential. Therefore, in this study, mode and regime of water governance were studied in one of the problem areas of water scarcity. In order to determine the mode of governance, questionnaires were used in two levels of the institution and local stakeholders. In order to determine the regime of governance, formal and informal institutional network analysis method was used in the Arsanjan, Neyriz, Kherameh and Estahban counties. The results of the governance mode showed that in ten sub-functions of governance under consideration, the more hierarchical mode has been observed. In addition, the results of the analysis of the institutional network also showed that the current governance regime in all four counties is a centralized (Rent-seeking) regime, which is considered a hierarchical governance mode feature. Finally, the combination of methods of governance and arrival to meta-governance is proposed.
jamileh salimi; Ali Salajegheh; Arash Malekian; Abdolmotalleb Rezaei
Abstract
Studying human and social dimension in the management of natural resources, including water resources has been accompanied by growth and development during past several decades. So, we require planning and policy making for the sustainable management of water resources for achieving human and ecological ...
Read More
Studying human and social dimension in the management of natural resources, including water resources has been accompanied by growth and development during past several decades. So, we require planning and policy making for the sustainable management of water resources for achieving human and ecological sustainability of water resources. Because of human and environmental components, managing the natural resources is very difficult and complicated. For effective management of water resources, cooperation of local beneficiaries is necessary. Accordingly, the social network analysis has been noted in the analysis of local stakeholders for sustainable management of water resources. The purpose of this study is social monitoring of local water beneficiaries network in Doroodzan watershed downstream using social network analysis. This analysis is based on trust and cooperation links and using quantitative and mathematical network indicators in macro-level. Based on the results, the density of local stakeholders of water resources in the relationship of trust and participation in the village of Kuh Sabz and Kare-Tawi was 68.8% and 66.2%, 60.1% and 55%, respectively, and the rate of reciprocity in these villages is 71.1% and 60.2%, respectively. . It is necessary to amplification social capital as main source of problem solving and sustainable water management realization.
Mahroo Dehbozorgi; Mohammad Jafari; Arash Malekian; Gholamreza Zehtabian; seyed rashid fallah shamsi
Abstract
In Iran, due to arid and semi-arid weather conditions the optimal use of limited water and soil resources has a particular importance. Land degradation is the result of incorrect policies in land management, which is a prominent example in the Bakhtegan watershed. Human factors, as well as climate changes ...
Read More
In Iran, due to arid and semi-arid weather conditions the optimal use of limited water and soil resources has a particular importance. Land degradation is the result of incorrect policies in land management, which is a prominent example in the Bakhtegan watershed. Human factors, as well as climate changes and the phenomenon of drought in recent years, have caused the area to be severely degraded in terms of water and soil resources and the life of Bakhtegan wetland has been subject to destruction. In this study, it was tried to identify natural and ecological factors as well as human parameters affecting the destruction and vulnerability of the area using fuzzy classification method and hierarchical analysis method (AHP) as well as the capabilities of GIS modeling, the data from the criteria and effective layers have been used and the level of vulnerability and land degradation has been determined. According to the results of the research, the level of land degradation and instability in the area has a large extent (48% of the area), However, the level of vulnerability in the central and downstream regions of the watershed and often in areas affected by human factors such as high population density, consumption of water in the agricultural sector, improper management of land use in the region, as well as dams and dike construction, has been increased. It was also concluded that human parameters have a more significant role in the degradation and vulnerability of the region compared to ecological and environmental factors.
hosein Saemipour; Arash Malekian; Mehdi Ramezan zadeh lasbuei
Abstract
Sustainable development will not be realized in any country unless social capital is reinforced. Accordingly, present study made an attempt to measure social capital of local beneficiaries network in traditional boundary of Telobine in Mayamei county, Semnan province through network analysis approach ...
Read More
Sustainable development will not be realized in any country unless social capital is reinforced. Accordingly, present study made an attempt to measure social capital of local beneficiaries network in traditional boundary of Telobine in Mayamei county, Semnan province through network analysis approach considering macro and micro level indexes. Besides, social powers and local leader playing critical role in sustainable development will be identified. Based on trust and participation ties, level of social capital was respectively moderate and weak and social capital of the village was estimated weakening . It can be argued that reinforcement of trust and participation in this village essential for faster knowledge and resource transfer and also for better unity of beneficiaries. It was as well revealed that Gh.Ar and Mo.Ar are core actors among Telobin traditional boundary beneficiaries. High authority and social influence of these actors contribute greatly to the establishment organizations and other beneficiaries toward rural sustainable development.
payam ebrahimi; Ali Salajegheh; Mohsen Mohseni Saravi; Arash Malekian; Amir Sadoddin
Abstract
One of the important criteria for quality of life is the health of the watershed. Researches in this field show that in Iran, a model for assessing the health of the watershed is not prepared. So, In this study, using the statistical data of 27 years (1990-2016) 5 environmental variables in the Taleghan ...
Read More
One of the important criteria for quality of life is the health of the watershed. Researches in this field show that in Iran, a model for assessing the health of the watershed is not prepared. So, In this study, using the statistical data of 27 years (1990-2016) 5 environmental variables in the Taleghan watershed in the province of Alborz is estimated using gene expression and Bayesian network techniques. By using the gene expression programming and the Bayesian network of each variable, the years from 1991 to 2006 selected as a training data and 2006 to 2014 as test data, and from 2014 to 2016 selected as validation period (predictive accuracy). In comparison, the estimation accuracy of the gene expression and Bayesian network, the mean correlation values of 5 variables are 0.87 and 0.78, respectively. In the case of the gene expression model, the values of the coefficient of determination in the training section were: 0.87 for discharge, sediment, 0.92, precipitation, 89.9, temperature 0.91 and evaporation 0.77, and also in the Bayesian network, the values were 0.73, 0.88, 0.78, 0.71 and 0.81. The amount of gene expression scheduling will have a high power in simulating future values, given the generation of a generation of 200,000 times. The results of this study indicate that the health state of the watershed with a score of 8 in 2016 has advanced cancer status, and according to the results of the model in 2017, it can be in the recurrence of cancer.
saeedeh joriz; Meghdad Jourgholami; arash malekian; maryam etehadi
Abstract
Land use changes can significantly affect the hydrology of a forest watershed. Ground cover is important to protect the soil against erosion. Timber harvesting has been changed the canopy cover and forest soil was exposed to the wind and water. Soil compaction and removing the forest floor in the skid ...
Read More
Land use changes can significantly affect the hydrology of a forest watershed. Ground cover is important to protect the soil against erosion. Timber harvesting has been changed the canopy cover and forest soil was exposed to the wind and water. Soil compaction and removing the forest floor in the skid trails was reduced the capacity of water absorption in mineral soils and thus reduced water infiltration, increased runoff, which caused to soil erosion. In order to measure the rate of sediments in two slopes and to study the effect of skid trails on the amount of sediments, the plot-level study was carried out in the Gorazbon district in Kheyrud forest in the control area and skid trail after skidding operations in the sample plot. The results showed that the most sediment value was 1.938 g. liter-1 in the skid trail with a 20-40 percent slope in the autumn and the lowest deposition was 0.103 g. liter-1 in the control area with a slope of 20-40 percent in the autumn. Type of Coverage (skid trail and control area), the season and the interactions between the cover and the season statistically have significant effect on the sediment yield, but the slope and the interactions between the slope and cover, as well as the interactions between the slope and season have no statistically significant effect on the sediment yield. Duncan’s test showed that there was a yield statistically significant difference between sediment yeild in different seasons and the autumn had the highest sediment
Aliakbar Nazari Samani; mahmoud samadi; arash malekian
Abstract
For developing of water resources a lot of different factors (such as: geological structure, faults, joints and geomorphological metrics) are important. This research tried to assess the effects of geomorphology on karstic water resources in central Elburz region. Geomorphometrics indices were prepared ...
Read More
For developing of water resources a lot of different factors (such as: geological structure, faults, joints and geomorphological metrics) are important. This research tried to assess the effects of geomorphology on karstic water resources in central Elburz region. Geomorphometrics indices were prepared in the form of separate layer in GIS and RS and were overlaid on the springs distribution map. To assess the relationship between springs frequency, discharge and geomorphology statistical analysis such as correlation and factor analysis were done. Results indicate a close relation between spring occurrence and hillslope curvature and TPI. Also the Pearson correlation coefficient of elevation and lineament density and drainage density was significant (P<0.01). According to results the discharge of springs are directly related to drainage density and indirectly related to elevation and lineament density. Moreover the fetor analysis on 17 variables revealed that the first six components had Eigen value of more than 1 and 73.5% of total variance was explained by them. Result indicated that for future developing such a geomorphology characteristics can give suitable information of water resources.
ali dastranj; ahmad nohegar; Arash Malekian; Hamid gholami
Abstract
Abstract Vulnerability assessment and vulnerability mapping, is an important strategy to management of karst water resources. Due to the geomorphology of karst developed in karst aquifers and other natural conditions Azhvan-Bisotun area, Emissions are rapidly and widely. The aim of this study is mapping ...
Read More
Abstract Vulnerability assessment and vulnerability mapping, is an important strategy to management of karst water resources. Due to the geomorphology of karst developed in karst aquifers and other natural conditions Azhvan-Bisotun area, Emissions are rapidly and widely. The aim of this study is mapping vulnerability Azhvan-Bisotun karst aquifer in Kermanshah province against surface contamination by using COP model. According to the aforementioned approach, the COP method considers three factors to assess the resource vulnerability: Overlying layers (O), Concentration of flow (C) and Precipitation regime (P). The results show that the vulnerability of the area between zero and 4.5, respectively, at the end of the five-class very high, high, medium, low and very low were classified. In general, the total area calculated parameters C, P and O have the most significant role in the vulnerability zone. The results demonstrate that COP is a useful method to assess the vulnerability of the test sites under consideration.
hosien شظهیه; omonabin bazrafshan; Abdolreza Bahremend; Arash Malekian
Abstract
The purpose of this study is the effects of the morphometric factors on peak discharge in 108 hydrometric stations in the southern watersheds, Iran. After homogeneous tests and random data, a time period (from 1983-1984 to 2013-2014 was chosen and used to choose the best probability distribution function. ...
Read More
The purpose of this study is the effects of the morphometric factors on peak discharge in 108 hydrometric stations in the southern watersheds, Iran. After homogeneous tests and random data, a time period (from 1983-1984 to 2013-2014 was chosen and used to choose the best probability distribution function. Overall, the 84 morphometric and geometric parameters were calculated in ARC GIS software. In this research, the structural equation modeling with the least approach in smart – PLS software was used to check the most effective factors on the annual maximum discharge. 18 variables were identified as effective factors on the maximum discharge. between more than 84 structures, the effect of the focus time structures, positive height ratio, miller slenderness ratio structures ,the main river- slope characteristics , elevation number and the main river-slope height properties are negative than can predict overall the %46 of the annual maximum discharge changes in the watershed areas of Iran s southern parts. These factors affect directly on the flood in the total focus time about %38 thus, the most effective factor on the flood discharge is the focus time factor that should be considered in the flood management in Iran s southern areas.
Fatemeh bahreini; Fatemeh Panahi; Mohammad Jafari; Arash Malekian
Abstract
The complexity of drought phenomenon hinders our full understanding of its impact. Field sampling, Geographic Information Systems, SPI and NDVI, EVI and SAVI indices derived from 16-day interval MODIS images during 2000-2015 were used to better understand the effects of drought on vegetation In recent ...
Read More
The complexity of drought phenomenon hinders our full understanding of its impact. Field sampling, Geographic Information Systems, SPI and NDVI, EVI and SAVI indices derived from 16-day interval MODIS images during 2000-2015 were used to better understand the effects of drought on vegetation In recent study, ground true map was prepared by sampling and field surveys and vegetation cover data was obtained from 32 sampling units in 320 plots over the entire study area. Then, the correlation between field sampling data and vegetation indices was estimated and vegetation cover models were produced for different indices. In this study, precipitation data of 14 stations within and around the study area were used and SPI was calculated at the same time scales with the vegetation indices to study the effect of drought on vegetation. The results showed that NDVI has had the highest correlation coefficient (R2=0.56) amongst the indices so it was selected for vegetation cover percentage mapping. Investigating NDVI rates and drought index in different temporal periods, 9-month SPI was found to have the best correlation with NDVI. On the basis of SPI analysis, it was found that the study area had the most severe drought in 2012 and the best wet condition in 2004. The similar trend was observed in NDVI. The comparison of classified images between 2004 and 2012 (with 42 % changes in poor vegetation) indicates the effect of drought on vegetation in the study area.
Fatemeh Einloo; Ali Salajegheh; Arash Malekian; Mohsen Ahadnejad
Abstract
Urbanization has led to development the impervious surfaces and subsequently changes in urban hydrology. The aim of this study is investigate the effect of land use change and urbanization on the changes of runoff peak discharge in Zanjan City Watershed, Iran. In order to, Landsat Thematic Mapper (TM) ...
Read More
Urbanization has led to development the impervious surfaces and subsequently changes in urban hydrology. The aim of this study is investigate the effect of land use change and urbanization on the changes of runoff peak discharge in Zanjan City Watershed, Iran. In order to, Landsat Thematic Mapper (TM) images and Aerial photos of 1956, 2000 and 2012 has been processed by using IDRISI Selva and Geographic Information System software and land use maps prepared in six land use class and the trend of land use changes and urbanization determined. To analysis the hydraulic and hydrology behavior of three periods of land use changes and urbanization on the changes of runoff peak discharge, Stormwater Management Model (SWMM) was used. After the SWMM model calibration based on observation rainfall-runoff events, the results of model calibration and verification, confirmed the accuracy of the model simulation. The results of land use change and urbanization trend of Zanjan City Watershed show that urban areas in 2012 compared to 2000 and 1956, respectively, has increase 22.59 and 923.88 percent and in 2000 compared to 1956 has been increased 543.06 percent. The results of SWMM model show that land use change and urban development has led to increase the runoff peak discharge, so that the average change in runoff peak discharge show that it increase in 2012 compared to 1956 and 2000, respectively, 96.85 and 475.52 percent and in 2000 compared to 1956, 194.288 percent increase in average of runoff peak discharge is observed.
Fatemeh Maghsoud; Mohammad Reza Yazdani; Mohammad Rahimi; Arash Malekian; ali asghar zolfaghari
Abstract
Overview, drought is effected an unusual dry period which is enough continued and causes imbalance in the hydrologic status, as depletion of surface water and groundwater resources. The purpose of this research is modeling meteorological drought prediction using Neural Network- Multi layer Perceptron, ...
Read More
Overview, drought is effected an unusual dry period which is enough continued and causes imbalance in the hydrologic status, as depletion of surface water and groundwater resources. The purpose of this research is modeling meteorological drought prediction using Neural Network- Multi layer Perceptron, parameters and climatic signals in three time scales include short, middle and long term in a rain-gauge station located at south plain of Qazvin Province. Three different scenarios were tested as inputs model. Optimal combination of variables was determinate by Gamma-Test after identification of input variables using cross-correlation. Results showed, influence of climatic signals increased and against the influence of meteorological parameters decreased when time scale were increased from short-term to long-term. MEI (Multivariate ENSO Index) and rainfall were introduced as the most effective climatic signals and meteorological parameter for each scale, respectively. Neural Network modeling which has hidden layer with enough neurons, Sigmoid Function in middle layer and linear function at output layer was used. The most appropriate of the number neurons was determined in each scenario and wasn’t observed significant correlation between increasing or decreasing the error and number of neurons. Finally, the most appropriate network structure was determined based on evaluation indexes in three scenarios and each time scale.
mahboobeh moatamednia; ahmad nohegar; arash malekian; maryam saberi anari
Abstract
One of the most important of hydrological computing in ecosystem is estimation of the relationship between rainfall and runoff. So that investigation occurred processes in it and the estimate of important outputs such as flood and sediment is considered one the most important mission of a watershed project. ...
Read More
One of the most important of hydrological computing in ecosystem is estimation of the relationship between rainfall and runoff. So that investigation occurred processes in it and the estimate of important outputs such as flood and sediment is considered one the most important mission of a watershed project. Because of variable spatial and temporal characteristics of incident in the water cycle and the nonlinear relationship and uncertainties, none of the statistical and conceptual models are able to be a better and capable model for that. But today using nonlinear networks as intelligent system for forecasting such complicated event can be efficient and effective in many problems of ecology. For this aim it is used variables such as precipitation, temperature, evartanspiration, relative humidity and discharges in daily scale over 42 years period and assessment 62 different suggested structures for surveying river flow in Amame representative watershed. For comparison it used Multi Layer Perceptoron (MLP) and Radial Basis Function (RBF).The results show that out of 6000 available models for estimation river flow model number 54 with 8-9-8-1 network structure and 8 types of input variable such as precipitation (Pt), precipitation with two lags (Pt-1 and Pt-2), temperature (Tt), evartanspiration (ETt), relative humidity (Rht), and discharge with two lags (Qt-1 and Qt-2) with Multi Layer Perceptoron method has the best function. The error of model was 0.03, 0.18 and 0.04 in training and 0.02, 0.14 and 0.02 for testing stage for MSE, RMSE and MAE, respectively.
majid kazemzadeh; arash malekian
Abstract
One of the most important dynamic ecosystems is river, awareness of spatio-temporal water quality changes of which is necessary. In this research, we studied the spatiotemporal water quality changes using three techniques of Cluster analysis (CA), Discriminant analysis (DA) and Principal Component analysis ...
Read More
One of the most important dynamic ecosystems is river, awareness of spatio-temporal water quality changes of which is necessary. In this research, we studied the spatiotemporal water quality changes using three techniques of Cluster analysis (CA), Discriminant analysis (DA) and Principal Component analysis (PCA) in the Aji-Chai watershed over 1981-2010. Applying clustering, we identified three homogeneities clusters. Stations which were labeled in the first cluster showed that they are located in the upstream of Aji-Chi River. In comparison with other stations, these stations showed better water quality and the lowest changeability. DA methods significantly determined the three functions which described about 73.50, 20.30 and 3.40% of total variances. In the other word, in general three functions described the 97.20% of the total variances. Also the DA methods revealed the HCO-3, SAR, Na+, SO42- and Ca2+ were the most important parameters affecting upon water quality, based on which it's possible to seperate homogenous clusters. Finally, the results of PCA showed that the first two factors were the most important factors of water quality changes in the Aji-Chai River Watershed. These factors described about 78.75 and 14.71% of the variances, respectively.
mohammad moazami; Sadat Feiznia; Majid Khayyat Kholghi; Arash Malekian
Abstract
Hydraulic conductivity is an important parameter for controling water flow through porous media. Hence, accurate estimation of this parameter is important for evaluating flow exchange between surface water and groundwater. In this study, 12 empirical formulae based on grain-size and 4 infiltration equations ...
Read More
Hydraulic conductivity is an important parameter for controling water flow through porous media. Hence, accurate estimation of this parameter is important for evaluating flow exchange between surface water and groundwater. In this study, 12 empirical formulae based on grain-size and 4 infiltration equations were used for estimating hydraulic conductivity on 3 sites in Jarmeh flood spreading system, Khuzestan Province. Results were evaluated using measured hydraulic conductivity by double rings infiltrometer. The results of the empirical formulae showed that 9 formulae were overestimated or underestimated and 3 formulae were close to measured values. Hazen formula gave the largest overestimation and Slitcher formula gave the largest underestimation and Shepherd formula is the best one. Generally, empirical formulae applicability requires the calibration of C coefficients. The results of the infiltration equations showed that all of 4 equations estimated hydraulic conductivity appropriately and there are no significant differences between them. Among the equations, Kastiakov and Green-Ampt were the best.
