mohsen Tavakoli - Academia.edu (original) (raw)

Papers by mohsen Tavakoli

Journal of Watershed Management Research, Apr 10, 2021

Most of our country is located in arid and semiarid climate which have high soil erosion and sedi... more Most of our country is located in arid and semiarid climate which have high soil erosion and sediment production, therefore, the study of soil erosion and sediment yield and also evaluation of the effective factors on sediment production are very important in proper management of a watershed. The aim of present study is the efficiency evaluation of MUSLE model in sediment estimation in the storm scale and also its modeling based on storm and runoff characteristics in four sub-basins of Doviraj River watershed in Ilam Province, which finally an optimized model is given for estimation of sediment resulted from the storm. Two storms in different dates (2012.11.22 and 2013.1.30) are used in this research. Results indicate appropriate correspondence in calibration stage between the observed and estimated sediment yield in four sub-basins. But, in validation stage, a high difference between observation and estimation in 1, 2 and 3 sub-basins was observed compared to the 4th sub-basin. The...

Journal of Water and Soil Science, 2021

1 Katholieke Universiteit Leuven Hydraulics Division, Kasteelpark Arenberg 40, BE-3001 Leuven (Be... more 1 Katholieke Universiteit Leuven Hydraulics Division, Kasteelpark Arenberg 40, BE-3001 Leuven (Belgium), Tel. +32 16 321658, Fax +32 16 321989, E-mail: Thomas.Vansteenkiste @bwk.kuleuven.be 2 Flanders Hydraulics Research, Flemish Government, Berchemlei 115, BE-2140 Antwerp (Belgium) 3 Vrije Universiteit Brussel Department of Hydrology and Hydraulic Engineering, Pleinlaan 2, BE-1050 Brussels (Belgium)

Wind erosion is considered as one of the main processes of land degradation in different parts of... more Wind erosion is considered as one of the main processes of land degradation in different parts of the world. Among the most effective ways to control wind erosion is to cover land surface with natural vegetation area. In this study, 3 replica soil samples were collected, at a depth of 0-3 cm, from various land uses in Dehloran, Ilam Province, Iran. Physical and chemical characteristics of soil samples were determined in the laboratory to allow the application of the ENVI_met Headquarter model commonly used to design biological windbreak. The threshold friction velocity (TFV) is the basic parameter for effective construction of a windbreak. To determine its values, a wind tunnel test was conducted. Based on simulation results with the pattern designed with Prosopis juliflora species, it was observed that the wind speed decreased in front of the windbreak but returned to the initial speed at a larger distance behind the windbreak. Therefore, the designed windbreak for this species is ...

Arabian Journal of Geosciences, 2021

Climate change has been regarded as the most important cause of land degradation in the world by ... more Climate change has been regarded as the most important cause of land degradation in the world by changing the precipitation pattern. The purpose of the current study was to evaluate the impact of climate change on soil erosion by RUSLE model in Gol-Gol catchment in the west of Iran. To do so, first, simulation of meteorological factors, such as precipitation and temperature, was performed using climate change models based on the recorded meteorological data for future periods up to the end of current century. Second, considering the use of the RUSLE model, the erosion status of the catchment was simulated based on the R parameter extracted from the current state of the meteorological parameters. Third, this calibrated model was used to simulate erosion based on the meteorological values of future periods and the difference between the erosion rate and its increase or decrease. The results showed an increase in temperature and a decrease in precipitation and, consequently, a decrease in erosion rate in the Gol-Gol watershed, Ilam, Iran. The average annual decreases of erosion results for the periods of 2040s, 2070s, and 2099s, in the RCP8.5 scenario, were 56%, 59.2%, and 64.1%, respectively, whereas, in the RCP4.5 scenario, it would be 23.5%, 29.7%, and 24.02%, respectively. Besides, in the RCP2.6 scenario, the erosion results would decrease by 6.2%, 4.05%, and 1.4%; in the A2 scenario, we had 26.9%, 27.2%, and 49.5%; and in the B2 scenario, the results were 0.34% and 7.77%, respectively. Besides, a 13.7% decrease was witnessed over the baseline period.

Journal of Hydrology, 2012

Phase 2 of the Distributed Model Intercomparison Project (DMIP 2) was formulated primarily as a m... more Phase 2 of the Distributed Model Intercomparison Project (DMIP 2) was formulated primarily as a mechanism to help guide the US National Weather Service (NWS) as it expands its use of spatially distributed watershed models for operational river, flash flood, and water resources forecasting. The overall purpose of DMIP 2 was to test many distributed models with operational quality data with a view towards meeting NWS operational forecasting needs. At the same time, DMIP 2 was formulated as an experiment that could be leveraged by the broader scientific community as a platform for testing, evaluating, and improving the science of spatially distributed models. This paper presents the key results of the DMIP 2 experiments conducted for the Oklahoma region, which included comparison of lumped and distributed model simulations generated with uncalibrated and calibrated parameters, water balance tests, routing and soil moisture tests, and simulations at interior locations. Simulations from 14 independent groups and 16 models are analyzed. As in DMIP 1, the participant simulations were evaluated against observed hourly streamflow data and compared with simulations generated by the NWS operational lumped model. A wide range of statistical measures are used to evaluate model performance on both run-period and event basis. A noteworthy improvement in DMIP 2 was the combined use of two lumped models to form the benchmark for event improvement statistics, where improvement was measured in terms of runoff volume, peak flow, and peak timing for between 20 and 40 events in each basin. Results indicate that in general, those spatially distributed models that are calibrated to perform well for basin outlet simulations also, in general, perform well at interior points whose drainage areas cover a wide range of scales. Two of the models were able to provide reasonable estimates of soil moisture versus depth over a wide geographic domain and through a period containing two severe droughts. In several parent and interior basins, a few uncalibrated spatially distributed models were able to achieve better goodness-of-fit statistics than other calibrated distributed models, highlighting the strength of those model structures combined with their a priori parameters. In general, calibration solely at basin outlets alone was not able to greatly improve relative model performance beyond that established by using uncalibrated a priori parameters. Further, results from the experiment for returning DMIP 1 participants reinforce the need for stationary data for model calibration: in some cases, the improvements gained by distributed models compared to lumped were not realized when the models were calibrated using inconsistent precipitation data from DMIP 1. Event-average improvement of distributed models over the combined lumped benchmark was measured in terms of runoff volume, peak flow, and peak timing for between 20 and 40 events. The percentage of model-basin pairs having positive distributed model improvement at basin outlets and interior points was 18%, 24%, and 28% respectively, for these quantities. These values correspond to 14%, 33%, and 22% respectively, in DMIP 1. While there may not seem to be much gain compared to DMIP 1 results, the DMIP 2 values were based on more precipitation-runoff events, more model-basin combinations (148 versus 51), more interior ungauged points (9 versus 3), and a benchmark comprised of two lumped model simulations. In addition, we propose a set of statistical measures that can be used to guide the calibration of distributed and lumped models for operational forecasting.

Finds and Results from the Swedish Cyprus Expedition: A Gender Perspective at the Medelhavsmuseet, 2010

Background and Objective: The purpose of this study is to investigate the relationship between tr... more Background and Objective: The purpose of this study is to investigate the relationship between trend of soil salinity, land use and climatic factors in the region of Shadegan, Khuzestan. Method: In this study, using principal component analysis and 54 samples of soil, soil salinity maps were prepared for the years 1990, 2006 and 2015. In the next step, land use maps of the region for the mentioned years have been prepared using satellite images and trend changes are determined. On the other hand, changes in climatic factors (temperature and precipitation) for the period of 1990-2015 were evaluated. Findings: Results showed that, reducing precipitation and increasing temperature caused increasing soil salinity during 25 years and also agricultural land and irrigation by saline water increases the salinity of the soil. Discussion and conclusion: Locating Hoor al-Azim wetland in the western part of the region, although it has fresh, brackish and saline water, it may have negative effec...

A popular method for climate change prediction are General Circulation Models which are at coarse... more A popular method for climate change prediction are General Circulation Models which are at coarse spatial resolution and must be downscaled. In this study, observed data of temperature, precipitation and potential evapotranspiration over a base period under two emission scenarios in three time intervals were used to implement SDSM as a downscaling tool for HadCM3 model output. From another standpoint, MPEH5 model predicts data under three emission scenarios for three future periods. Results indicated that all parameters would increase in comparison to the base period. Predictions for all periods under all emission scenarios indicated an increasing trend for all parameters, although it is predicted almost as constant precipitation trend for the future. According to predictions by both models, the greatest increase has been estimated for 2080s under A2 scenario. In SDSM model, the greatest increases in mean monthly temperature would be respectively 6.9, 4.5, 6.2 °C for July and for po...

This research investigates the changes of soil properties in Dasht -e Abbas plain due to the Kark... more This research investigates the changes of soil properties in Dasht -e Abbas plain due to the Karkheh water transfer to this plain. In this study, the maps of groundwater level changes before and after the utilization of irrigation system were prepared. Furthermore , to investigate the changes of soil characteristics, soil samples were collected from vari ous project implantations and control areas and their parameters were determined and compared. The results showed that the groundwater level has been increased more than 15 meters during the study period and the depth of groundwater in some areas reached t o less than 5 meters. The results indicated that the highest salinity belonged to the network coverage areas and evaporating zone having a saturation extract electrical conductiv ity of 10.62 and 9.26 ds/m respectively, while dry land areas have the lowest salinity with electrical conductivity of 0.8 - 4.0 ds/m. The results further demonstrated that the water transfer of Karkheh D...

Land Degradation & Development, 2021

Natural Resources Forum, 2019

Climate change involves increasing atmospheric carbon dioxide concentration which is driven by an... more Climate change involves increasing atmospheric carbon dioxide concentration which is driven by anthropogenic emissions. Afforestation, which is the establishment of forests on previously non‐forested lands, could be a suitable climate change mitigation strategy. The aim of this research is to evaluate the carbon sequestration capability of the Eucalyptus and Prosopis species in the Reza‐Abad afforestation park in western Iran. For this aim, three stands of any species were selected. For quantitative assessment, a transect was implemented at the length of 100 m. In trees located of transects, the general characteristics of species were measured. Also, for estimating the amount of litter, a sample plot has been measured at the center of the quadrate. These samples were taken from the afforested area, the control area inside the afforested area and another control area outside. In each stand, species were selected randomly and one‐eighth of the whole stand was taken for calculating the percentage of carbon and aerial biomass. Then the aboveground organs were weighted and after the transfer of different plant organs to the laboratory, the conversion factor of carbon sequestration of the plant organs was determined individually by combustion method. Also, soil samples were also collected from two depths of 0–15 and 15–30 cm in each of the cultivated and control parts. The results showed that there is a significant difference between the species and Prosopis has higher carbon sequestration than Eucalyptus. The carbon sequestration among different organs showed a significant difference, carbon sequestration was 19.24 t/ha for Eucalyptus and 18.43 t/ha for Prosopis. After an economic calculation, it was concluded that afforestation has a positive effect on the reduction of atmospheric carbon dioxide. Hence, these results allow decision makers to change land use from desert area to forest, and planting the Prosopis species is more recommendable than Eucalyptus for afforestation in such areas which are economically profitable.

Frontiers of Earth Science, 2019

Investigation of the relationship between catchment hydrology with climate is essential for under... more Investigation of the relationship between catchment hydrology with climate is essential for understanding of the impact of future climate on hydrological extremes, which may cause frequent flooding, drought, and shortage of water supply. The purpose of this study is to investigate the effects of climate change on extreme flows in one of the subcatchments of the Ilam dam catchment, Iran. The changes in climate parameters were predicted using the outputs of HadCM3 model for up to the end of the current century in three time periods including 2020s, 2050s, and 2080s. For A2 scenario, increases of 1.09°C, 2.03°C, and 3.62°C, and for B2 scenario rises of 1.18°C, 1.84°C, and 2.55°C have been predicted. The results suggest that for A2 scenario, the amount of precipitation would decrease by 12.63, 49.13, and 63.42 and for B2 scenario by 47.02, 48.51, and 70.26 mm per year. Also the values of PET for A2 scenario would increase by 51.18, 101.47 and 108.71 and for B2 scenario by 60.09, 89.86, and 124.32 mm per year. The results of running the SWAT model revealed that the average annual runoff would decrease by 0.11, 0.41, and 0.61 m3/s and for B2 scenario by 0.39, 0.47, and 0.59 3/s. The extreme flows were then analyzed by running WETSPRO model. According to the results, the amounts of low flows for A2 scenario will decrease by 0.02, 0.21 and 0.33 3/s and for B2 scenario by 0.19, 0.26 and 0.29 3/s in the 2020s, 2050s and 2080s, respectively. On the other hand, the results show an increase of peak flows by 11.5, 19.1 and 48.7 3/s in A2 scenario and 11.12, 25.93 and 48.1 3/s in B2 scenario, respectively. Overall, the results indicated that an increase in return period leads to elevated levels of high flows and diminished low flows.

Arabian Journal of Geosciences, 2019

Drought as one of the natural phenomena and one of the greatest climate problems has been of cent... more Drought as one of the natural phenomena and one of the greatest climate problems has been of central importance and investigated as a matter of necessity. In recent decades, Iran and especially Ilam province faced drought problem and this research was conducted with the aim of predicting drought in Ilam (semi-arid region) and Dehloran (arid area) stations, as well as evaluating the efficiency of the neural network. In this study, the data of temperature, precipitation, relative humidity, wind speed, and monthly sunny hours in the period of 1983–2013 were used to calculate the standardized precipitation index (SPI) and moving average of 3, 5, and 7 years. Also, artificial neural network was employed for monitoring the drought in Ilam (semi-arid region) and Dehloran (arid region) stations. Accordingly, the artificial neural network (ANN) was modeled after determining the best input composition and the best number of data using the backpropagation algorithm and C-Sharp programming language. Then, the possible future drought was predicted in both stations. The architecture of network was optimized in form of 5-30-1, 5 neurons in input layer (precipitation, temperature, relative humidity, wind speed, and sunny hours); 30 neurons in the hidden layer and a neuron in the output layer (SPI) after training and repeated errors. In order to evaluate ANN performance in climate elements simulation, four designed models were investigated using different learning functions and the number of variously hidden neurons and the error was calculated using MAE, RMSE, and R2 indices. The results showed that in the stations, bipolar sigmoid function pattern and updating weights by the method of the moment were introduced as the optimal model, due to the lowest error rate and highest correlation between input and output data. Then, outputs of the program were compared with observed SPI. The results of statistic method and output of network showed that the stations entered a prolonged drought phase from 1996–1997 to 2012. Although the stations showed short periods of wet year, the trend of these droughts has continued so far, with the difference that the severity of droughts in Dehloran station (Arid region) was higher and in this long period of drought, short, 7-, 5-, and 3-year droughts occurred and it was completely consistent with the definition of drought.

Arabian Journal of Geosciences, 2019

Wind erosion is one of the important aspects of land degradation in arid and semiarid regions. Th... more Wind erosion is one of the important aspects of land degradation in arid and semiarid regions. The study of wind erosion variations is very important in choosing and designing biological and mechanical practices for wind erosion control. This research investigates the threshold velocities and soil loss across five different land uses by wind tunnel testing. According to the results, the highest threshold friction velocity (TFV) was related to Ziziphus nummularia natural forests and then agricultural land, rangelands, planted Prosopis juliflora forests, and sand dunes, respectively. Also, the most dust concentration and soil loss was related to sand dunes and then reduced in rangelands, planted P. juliflora forests, agriculture, and Z. nummularia natural forest land uses, respectively.Results of principal components analysis showed three main components controlling the TFV as PC1, PC2, and PC3 with quotas of 51.6%, 20.9%, and 9.7%, respectively (PC1 imposes the largest contribution into TFV). PC1 is composed of the following components: organic matter, Mg, Ca, silt, saturation moisture content, and soil compressive strength. In general, it can be concluded that, among the factors affecting wind erosion, texture, moisture content, and organic matter of the soil have the most significant effects on soil resistance to erosion.

Journal of Watershed Management Research, Apr 10, 2021

Most of our country is located in arid and semiarid climate which have high soil erosion and sedi... more Most of our country is located in arid and semiarid climate which have high soil erosion and sediment production, therefore, the study of soil erosion and sediment yield and also evaluation of the effective factors on sediment production are very important in proper management of a watershed. The aim of present study is the efficiency evaluation of MUSLE model in sediment estimation in the storm scale and also its modeling based on storm and runoff characteristics in four sub-basins of Doviraj River watershed in Ilam Province, which finally an optimized model is given for estimation of sediment resulted from the storm. Two storms in different dates (2012.11.22 and 2013.1.30) are used in this research. Results indicate appropriate correspondence in calibration stage between the observed and estimated sediment yield in four sub-basins. But, in validation stage, a high difference between observation and estimation in 1, 2 and 3 sub-basins was observed compared to the 4th sub-basin. The...

Journal of Water and Soil Science, 2021

1 Katholieke Universiteit Leuven Hydraulics Division, Kasteelpark Arenberg 40, BE-3001 Leuven (Be... more 1 Katholieke Universiteit Leuven Hydraulics Division, Kasteelpark Arenberg 40, BE-3001 Leuven (Belgium), Tel. +32 16 321658, Fax +32 16 321989, E-mail: Thomas.Vansteenkiste @bwk.kuleuven.be 2 Flanders Hydraulics Research, Flemish Government, Berchemlei 115, BE-2140 Antwerp (Belgium) 3 Vrije Universiteit Brussel Department of Hydrology and Hydraulic Engineering, Pleinlaan 2, BE-1050 Brussels (Belgium)

Wind erosion is considered as one of the main processes of land degradation in different parts of... more Wind erosion is considered as one of the main processes of land degradation in different parts of the world. Among the most effective ways to control wind erosion is to cover land surface with natural vegetation area. In this study, 3 replica soil samples were collected, at a depth of 0-3 cm, from various land uses in Dehloran, Ilam Province, Iran. Physical and chemical characteristics of soil samples were determined in the laboratory to allow the application of the ENVI_met Headquarter model commonly used to design biological windbreak. The threshold friction velocity (TFV) is the basic parameter for effective construction of a windbreak. To determine its values, a wind tunnel test was conducted. Based on simulation results with the pattern designed with Prosopis juliflora species, it was observed that the wind speed decreased in front of the windbreak but returned to the initial speed at a larger distance behind the windbreak. Therefore, the designed windbreak for this species is ...

Arabian Journal of Geosciences, 2021

Climate change has been regarded as the most important cause of land degradation in the world by ... more Climate change has been regarded as the most important cause of land degradation in the world by changing the precipitation pattern. The purpose of the current study was to evaluate the impact of climate change on soil erosion by RUSLE model in Gol-Gol catchment in the west of Iran. To do so, first, simulation of meteorological factors, such as precipitation and temperature, was performed using climate change models based on the recorded meteorological data for future periods up to the end of current century. Second, considering the use of the RUSLE model, the erosion status of the catchment was simulated based on the R parameter extracted from the current state of the meteorological parameters. Third, this calibrated model was used to simulate erosion based on the meteorological values of future periods and the difference between the erosion rate and its increase or decrease. The results showed an increase in temperature and a decrease in precipitation and, consequently, a decrease in erosion rate in the Gol-Gol watershed, Ilam, Iran. The average annual decreases of erosion results for the periods of 2040s, 2070s, and 2099s, in the RCP8.5 scenario, were 56%, 59.2%, and 64.1%, respectively, whereas, in the RCP4.5 scenario, it would be 23.5%, 29.7%, and 24.02%, respectively. Besides, in the RCP2.6 scenario, the erosion results would decrease by 6.2%, 4.05%, and 1.4%; in the A2 scenario, we had 26.9%, 27.2%, and 49.5%; and in the B2 scenario, the results were 0.34% and 7.77%, respectively. Besides, a 13.7% decrease was witnessed over the baseline period.

Journal of Hydrology, 2012

Phase 2 of the Distributed Model Intercomparison Project (DMIP 2) was formulated primarily as a m... more Phase 2 of the Distributed Model Intercomparison Project (DMIP 2) was formulated primarily as a mechanism to help guide the US National Weather Service (NWS) as it expands its use of spatially distributed watershed models for operational river, flash flood, and water resources forecasting. The overall purpose of DMIP 2 was to test many distributed models with operational quality data with a view towards meeting NWS operational forecasting needs. At the same time, DMIP 2 was formulated as an experiment that could be leveraged by the broader scientific community as a platform for testing, evaluating, and improving the science of spatially distributed models. This paper presents the key results of the DMIP 2 experiments conducted for the Oklahoma region, which included comparison of lumped and distributed model simulations generated with uncalibrated and calibrated parameters, water balance tests, routing and soil moisture tests, and simulations at interior locations. Simulations from 14 independent groups and 16 models are analyzed. As in DMIP 1, the participant simulations were evaluated against observed hourly streamflow data and compared with simulations generated by the NWS operational lumped model. A wide range of statistical measures are used to evaluate model performance on both run-period and event basis. A noteworthy improvement in DMIP 2 was the combined use of two lumped models to form the benchmark for event improvement statistics, where improvement was measured in terms of runoff volume, peak flow, and peak timing for between 20 and 40 events in each basin. Results indicate that in general, those spatially distributed models that are calibrated to perform well for basin outlet simulations also, in general, perform well at interior points whose drainage areas cover a wide range of scales. Two of the models were able to provide reasonable estimates of soil moisture versus depth over a wide geographic domain and through a period containing two severe droughts. In several parent and interior basins, a few uncalibrated spatially distributed models were able to achieve better goodness-of-fit statistics than other calibrated distributed models, highlighting the strength of those model structures combined with their a priori parameters. In general, calibration solely at basin outlets alone was not able to greatly improve relative model performance beyond that established by using uncalibrated a priori parameters. Further, results from the experiment for returning DMIP 1 participants reinforce the need for stationary data for model calibration: in some cases, the improvements gained by distributed models compared to lumped were not realized when the models were calibrated using inconsistent precipitation data from DMIP 1. Event-average improvement of distributed models over the combined lumped benchmark was measured in terms of runoff volume, peak flow, and peak timing for between 20 and 40 events. The percentage of model-basin pairs having positive distributed model improvement at basin outlets and interior points was 18%, 24%, and 28% respectively, for these quantities. These values correspond to 14%, 33%, and 22% respectively, in DMIP 1. While there may not seem to be much gain compared to DMIP 1 results, the DMIP 2 values were based on more precipitation-runoff events, more model-basin combinations (148 versus 51), more interior ungauged points (9 versus 3), and a benchmark comprised of two lumped model simulations. In addition, we propose a set of statistical measures that can be used to guide the calibration of distributed and lumped models for operational forecasting.

Finds and Results from the Swedish Cyprus Expedition: A Gender Perspective at the Medelhavsmuseet, 2010

Background and Objective: The purpose of this study is to investigate the relationship between tr... more Background and Objective: The purpose of this study is to investigate the relationship between trend of soil salinity, land use and climatic factors in the region of Shadegan, Khuzestan. Method: In this study, using principal component analysis and 54 samples of soil, soil salinity maps were prepared for the years 1990, 2006 and 2015. In the next step, land use maps of the region for the mentioned years have been prepared using satellite images and trend changes are determined. On the other hand, changes in climatic factors (temperature and precipitation) for the period of 1990-2015 were evaluated. Findings: Results showed that, reducing precipitation and increasing temperature caused increasing soil salinity during 25 years and also agricultural land and irrigation by saline water increases the salinity of the soil. Discussion and conclusion: Locating Hoor al-Azim wetland in the western part of the region, although it has fresh, brackish and saline water, it may have negative effec...

A popular method for climate change prediction are General Circulation Models which are at coarse... more A popular method for climate change prediction are General Circulation Models which are at coarse spatial resolution and must be downscaled. In this study, observed data of temperature, precipitation and potential evapotranspiration over a base period under two emission scenarios in three time intervals were used to implement SDSM as a downscaling tool for HadCM3 model output. From another standpoint, MPEH5 model predicts data under three emission scenarios for three future periods. Results indicated that all parameters would increase in comparison to the base period. Predictions for all periods under all emission scenarios indicated an increasing trend for all parameters, although it is predicted almost as constant precipitation trend for the future. According to predictions by both models, the greatest increase has been estimated for 2080s under A2 scenario. In SDSM model, the greatest increases in mean monthly temperature would be respectively 6.9, 4.5, 6.2 °C for July and for po...

This research investigates the changes of soil properties in Dasht -e Abbas plain due to the Kark... more This research investigates the changes of soil properties in Dasht -e Abbas plain due to the Karkheh water transfer to this plain. In this study, the maps of groundwater level changes before and after the utilization of irrigation system were prepared. Furthermore , to investigate the changes of soil characteristics, soil samples were collected from vari ous project implantations and control areas and their parameters were determined and compared. The results showed that the groundwater level has been increased more than 15 meters during the study period and the depth of groundwater in some areas reached t o less than 5 meters. The results indicated that the highest salinity belonged to the network coverage areas and evaporating zone having a saturation extract electrical conductiv ity of 10.62 and 9.26 ds/m respectively, while dry land areas have the lowest salinity with electrical conductivity of 0.8 - 4.0 ds/m. The results further demonstrated that the water transfer of Karkheh D...

Land Degradation & Development, 2021

Natural Resources Forum, 2019

Climate change involves increasing atmospheric carbon dioxide concentration which is driven by an... more Climate change involves increasing atmospheric carbon dioxide concentration which is driven by anthropogenic emissions. Afforestation, which is the establishment of forests on previously non‐forested lands, could be a suitable climate change mitigation strategy. The aim of this research is to evaluate the carbon sequestration capability of the Eucalyptus and Prosopis species in the Reza‐Abad afforestation park in western Iran. For this aim, three stands of any species were selected. For quantitative assessment, a transect was implemented at the length of 100 m. In trees located of transects, the general characteristics of species were measured. Also, for estimating the amount of litter, a sample plot has been measured at the center of the quadrate. These samples were taken from the afforested area, the control area inside the afforested area and another control area outside. In each stand, species were selected randomly and one‐eighth of the whole stand was taken for calculating the percentage of carbon and aerial biomass. Then the aboveground organs were weighted and after the transfer of different plant organs to the laboratory, the conversion factor of carbon sequestration of the plant organs was determined individually by combustion method. Also, soil samples were also collected from two depths of 0–15 and 15–30 cm in each of the cultivated and control parts. The results showed that there is a significant difference between the species and Prosopis has higher carbon sequestration than Eucalyptus. The carbon sequestration among different organs showed a significant difference, carbon sequestration was 19.24 t/ha for Eucalyptus and 18.43 t/ha for Prosopis. After an economic calculation, it was concluded that afforestation has a positive effect on the reduction of atmospheric carbon dioxide. Hence, these results allow decision makers to change land use from desert area to forest, and planting the Prosopis species is more recommendable than Eucalyptus for afforestation in such areas which are economically profitable.

Frontiers of Earth Science, 2019

Investigation of the relationship between catchment hydrology with climate is essential for under... more Investigation of the relationship between catchment hydrology with climate is essential for understanding of the impact of future climate on hydrological extremes, which may cause frequent flooding, drought, and shortage of water supply. The purpose of this study is to investigate the effects of climate change on extreme flows in one of the subcatchments of the Ilam dam catchment, Iran. The changes in climate parameters were predicted using the outputs of HadCM3 model for up to the end of the current century in three time periods including 2020s, 2050s, and 2080s. For A2 scenario, increases of 1.09°C, 2.03°C, and 3.62°C, and for B2 scenario rises of 1.18°C, 1.84°C, and 2.55°C have been predicted. The results suggest that for A2 scenario, the amount of precipitation would decrease by 12.63, 49.13, and 63.42 and for B2 scenario by 47.02, 48.51, and 70.26 mm per year. Also the values of PET for A2 scenario would increase by 51.18, 101.47 and 108.71 and for B2 scenario by 60.09, 89.86, and 124.32 mm per year. The results of running the SWAT model revealed that the average annual runoff would decrease by 0.11, 0.41, and 0.61 m3/s and for B2 scenario by 0.39, 0.47, and 0.59 3/s. The extreme flows were then analyzed by running WETSPRO model. According to the results, the amounts of low flows for A2 scenario will decrease by 0.02, 0.21 and 0.33 3/s and for B2 scenario by 0.19, 0.26 and 0.29 3/s in the 2020s, 2050s and 2080s, respectively. On the other hand, the results show an increase of peak flows by 11.5, 19.1 and 48.7 3/s in A2 scenario and 11.12, 25.93 and 48.1 3/s in B2 scenario, respectively. Overall, the results indicated that an increase in return period leads to elevated levels of high flows and diminished low flows.

Arabian Journal of Geosciences, 2019

Drought as one of the natural phenomena and one of the greatest climate problems has been of cent... more Drought as one of the natural phenomena and one of the greatest climate problems has been of central importance and investigated as a matter of necessity. In recent decades, Iran and especially Ilam province faced drought problem and this research was conducted with the aim of predicting drought in Ilam (semi-arid region) and Dehloran (arid area) stations, as well as evaluating the efficiency of the neural network. In this study, the data of temperature, precipitation, relative humidity, wind speed, and monthly sunny hours in the period of 1983–2013 were used to calculate the standardized precipitation index (SPI) and moving average of 3, 5, and 7 years. Also, artificial neural network was employed for monitoring the drought in Ilam (semi-arid region) and Dehloran (arid region) stations. Accordingly, the artificial neural network (ANN) was modeled after determining the best input composition and the best number of data using the backpropagation algorithm and C-Sharp programming language. Then, the possible future drought was predicted in both stations. The architecture of network was optimized in form of 5-30-1, 5 neurons in input layer (precipitation, temperature, relative humidity, wind speed, and sunny hours); 30 neurons in the hidden layer and a neuron in the output layer (SPI) after training and repeated errors. In order to evaluate ANN performance in climate elements simulation, four designed models were investigated using different learning functions and the number of variously hidden neurons and the error was calculated using MAE, RMSE, and R2 indices. The results showed that in the stations, bipolar sigmoid function pattern and updating weights by the method of the moment were introduced as the optimal model, due to the lowest error rate and highest correlation between input and output data. Then, outputs of the program were compared with observed SPI. The results of statistic method and output of network showed that the stations entered a prolonged drought phase from 1996–1997 to 2012. Although the stations showed short periods of wet year, the trend of these droughts has continued so far, with the difference that the severity of droughts in Dehloran station (Arid region) was higher and in this long period of drought, short, 7-, 5-, and 3-year droughts occurred and it was completely consistent with the definition of drought.

Arabian Journal of Geosciences, 2019

Wind erosion is one of the important aspects of land degradation in arid and semiarid regions. Th... more Wind erosion is one of the important aspects of land degradation in arid and semiarid regions. The study of wind erosion variations is very important in choosing and designing biological and mechanical practices for wind erosion control. This research investigates the threshold velocities and soil loss across five different land uses by wind tunnel testing. According to the results, the highest threshold friction velocity (TFV) was related to Ziziphus nummularia natural forests and then agricultural land, rangelands, planted Prosopis juliflora forests, and sand dunes, respectively. Also, the most dust concentration and soil loss was related to sand dunes and then reduced in rangelands, planted P. juliflora forests, agriculture, and Z. nummularia natural forest land uses, respectively.Results of principal components analysis showed three main components controlling the TFV as PC1, PC2, and PC3 with quotas of 51.6%, 20.9%, and 9.7%, respectively (PC1 imposes the largest contribution into TFV). PC1 is composed of the following components: organic matter, Mg, Ca, silt, saturation moisture content, and soil compressive strength. In general, it can be concluded that, among the factors affecting wind erosion, texture, moisture content, and organic matter of the soil have the most significant effects on soil resistance to erosion.