Hydrogeomorphology
Alireza Ildoromi; Mehdi spehri
Abstract
In this researchlandslide sensitivity was zoned using statistical models intheKurdistan Dam watershed and the most appropriatemodel was introduced.First, the studied area was determined and with field observations, the number of 9 landslides was recorded and a landslide distribution map was prepared. ...
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In this researchlandslide sensitivity was zoned using statistical models intheKurdistan Dam watershed and the most appropriatemodel was introduced.First, the studied area was determined and with field observations, the number of 9 landslides was recorded and a landslide distribution map was prepared. In the next step, the factors affecting the occurrence of landslides including geology, rainfall, land use, distance from the river, distance from the fault, slope and height were identified and then a map of these factors was prepared. To determine the rateof each of the effective factors in the occurrence of landslides, the map of each information layer of the effective factors is integrated with the distribution map of the landslide and using AHP, BWM and FUCOM statistical modelsseparate information layers are weighted and By overlapping different layers, the final landsliderisk zoning mapswere prepared and compared.The results showed that land use in AHP and BWM methods and rainfall lines, in addition to land use inFUCOM method have the greatest effect and the criteria of heightdistance from the fault and slope respectively in the three AHP, BWM and FUCOM methods have the least effect on the occurrence of landslidestheresults showed that the lithological variable has a great role on the occurrenceof landslides in the studied area.In generalthe results showed that in AHP and BWM methods, the numberof required pairwise comparisons increases significantly with the number of compared parameters, and in this case, the uncertaintyof opinions increases, which shows the superiority of the FUCOM method over It showswell in other ways.
Hydrogeomorphology
Alireza Ildoromi; nasrin hassanzadeh; fariba hedayetzadeh
Abstract
Sustainable quality of rivers water has become one of the main concerns in developing countries, so monitoring the water quality of these resources for various uses is essential to formulate a public health and environmental management policy. The purpose of this study is to evaluate the water quality ...
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Sustainable quality of rivers water has become one of the main concerns in developing countries, so monitoring the water quality of these resources for various uses is essential to formulate a public health and environmental management policy. The purpose of this study is to evaluate the water quality of Karun and Dez river systems in Khuzestan province and to analyze the suitability of their water quality for drinking and agricultural purposes. To this end, various techniques, indicators and statistical analyzes are used to evaluate spatio-temporal changes in the interpretation of large and complex datasets of 12 water quality parameters collected from the Karun and Dez river basins over a period of 17 years (2003-2019).Evaluation of the trend of water quality changes in the study period also showed that according to WQI, the water quality of Karun and Dez rivers from 2003 to 2007 are in the category of "very poor"and "poor", and from 2008 to 2018 in the "unsuitable" and "very poor"category, respectively. Regarding irrigation parameters, the lack of a clear trend in their values can indicate the lack of effect of river water quality from natural factors and their obedience with human factors. Overall, this study highlights the importance of using water quality indicators that provide a simple interpretation of monitoring data to help improve water quality, because based on these indicators and PCA, it can be concluded that related human activities along the banks of the Karun and Dez rivers, especially in recent years, affect their water quality.
hydrogeology
Alireza Ildoromi
Abstract
The purpose of this study is to simulate and sedimentation status of Ebro River of Ekbatan Dam in Hamedan using GSTARS 2.1 mathematical model.For this purpose, they measure the hydrodynamic part of the sediment from the water and hydrometry of the measuring station Ebro and data on water level cultivar ...
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The purpose of this study is to simulate and sedimentation status of Ebro River of Ekbatan Dam in Hamedan using GSTARS 2.1 mathematical model.For this purpose, they measure the hydrodynamic part of the sediment from the water and hydrometry of the measuring station Ebro and data on water level cultivar changes in 2006 and cross-sectional geometric data collected in 2006 and 2019 and sediment transport equations in 13-year production period have been used.Studies show that the cross section of the river is changing from V-shaped to U-shaped from 2005 to 2019..Examination of sedimentation rate during 13 years (2006-2019) shows that the cross-sectional level of the river is about 24.6 cm and using Wyang's sedimentary relationships changed by 22.8 and 20.2 cm, respectively, which indicates a good agreement of the model in the evaluation and Simulation of cross-sectional change due to erosion and sedimentation.Studies show that the values of slope and velocity in the middle of the study area are less than the beginning and more than the end, so the amount of sediment in the middle is more than the beginning and less than downstream of the region.It is recommended to use FLUVIAL 12 and HEC-RAS methods to select and apply the most practical method.
Fariba Darabi; Alireza Ildoromi
Abstract
Rainwater harvesting is a way to develop the utilization of water resources in arid and semi arid regions with the aim of increasing the quantity and quality of water resources. The purpose of this study was to determine the factors influencing the location of areas susceptible to the construction of ...
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Rainwater harvesting is a way to develop the utilization of water resources in arid and semi arid regions with the aim of increasing the quantity and quality of water resources. The purpose of this study was to determine the factors influencing the location of areas susceptible to the construction of a rainwater harvesting network (RWH) in the Siahkhore Watershed of Kermanshah using multi-criteria decision making (MCDA) and ANP network analysis. The results of the rainwater harvesting potential map show that poor classes with 2.96, relatively poor 35.49, average 26.06, relatively good 29.2 and good with 6.29 of the catchment area are included. and it indicates that the middle and relatively good and good middle classes with the highest percentage of area level with 61.55%.Field observations and results from the ROC curve show that most of the 115 rainwater harvesting plots are located in areas that are topographically and hydrologically appropriate, all of which are in relatively good, good, and moderate areas. And it represents a very good evaluation of the ANP model. Over 89% of rainwater harvesting sites are in the middle and relatively good and good classes It was found that the combination of Analytical Hierarchy Process (ANP) technique and GIS are useful tools for planning rainwater collection at basin and sub-basin scale.
mehran mohammadpanah moghadam
Abstract
1-IntroductionAt present, it is important to accurately predict the hydraulic parameters of flow and sediment for better operation and management of rivers.Today, quasi-two-dimensional mathematical models have been widely used as an optimal and efficient solution in the hydraulics of river flow and sedimentation ...
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1-IntroductionAt present, it is important to accurately predict the hydraulic parameters of flow and sediment for better operation and management of rivers.Today, quasi-two-dimensional mathematical models have been widely used as an optimal and efficient solution in the hydraulics of river flow and sedimentation Zahiri et al. (2018). Mathematical models are one of the most important and accurate tools for predicting the amount of sedimentation in riverbeds and dam reservoirs, which are based on the equations governing the phenomena affecting the transfer, sediment accumulation. Gholami,et al. (2017). Raeisi et al. (2019), in examining the temporal phenomena of the sediment measurement curve and comparing it with several statistical methods to estimate the suspended sediment load of Gamasiab watershed, showed that the time series model of the transfer function compared to other models used has higher performance. Lai et al. (2019) in a study of the capacity of current and sediment transfer with 3D model for open surface channels showed that the model of good simulation between flow and sediment for forecasting is presented and is well matched with experimental data.In the present study, an attempt has been made to examine and determine the most appropriate models for estimating the suspended sediment load of the watershed of Hamedan River by using different models.2-MethodologyAbshineh basin is located in the southeast of Hamedan city and its river regime is under the semi-humid cold mountainous snow-rainy and permanent climate.In this study, the amount of sediment yield of Hamedan Abashineh dam watershed using USBR models, the middle curve of the categories Seasonal measurement curve and FAO method were estimated and while direct sampling of suspended load, the selected model by logarithmic conversion error correction method (CF1, CF2) and GS + model were statistically analyzed and evaluated.3-Results and DiscussionExamination of CF1 and CF2 correction coefficients shows that the FAO method has evaluated the amount of suspended sediment over time better than the two linear USBR methods and the intermediate method with the least amount of error.In the model without data segmentation, the FAO method with the lowest relative error percentage and the mean power of the second error was selected as the optimal method, and the similar hydrological period method was selected as the most inappropriate method for estimating suspended sediment in the basin. The results show that the USBR method follows the normal distribution to some extent and the FAO method follows the perfectly normal distribution.The results of data analysis in Kriging method show that the regression line fitted in USBR method is not well adapted and could not provide a complete analysis of sediment observation data. However, in the FAO method, it is observed that the computational data have a high and good agreement with the fitted regression line.The results showed that FAO method, due to considering more parameters in boundary conditions and the lowest amount of correction coefficients of CF1 and CF2, estimates the amount of suspended sediment with the least amount of error compared to other methods over time with more acceptable accuracy and efficiency.Also, the results of the Gs + model show that the FAO method calculates suspended sediments more accurately in terms of tons per day and has more fit and consistency with the observed sediment values, and the USBR method has the least fit.4- ConclusionThe output results of Gs + model and comparison of suspended load estimation in models show that FAO method due to more compatibility and accuracy, more accurate sedimentary fit with observational data and with least error, as the best model and USBR method with matching and fitting Less with observational data in the next degree and similar hydrological period with the highest relative error percentage of 100.34 and low correlation coefficient were selected as the most inappropriate method for estimating suspended sediment in the basin.Reviews show that hydrological models had different results than each other. So that in the model without data segmentation, FAO method compared to other methods with the lowest percentage of relative error and the average power of the second error as the optimal and appropriate method of moreaccuracy and efficiency for estimating suspended sediment in a modified form in the Abshineh basin Hamedan.
Sahar Forotan; Alireza ILdoromi; Hamid Nouri; Matab Safari Shad
Volume 6, Issue 20 , December 2019, , Pages 1-20
Abstract
1- Introduction Land use change is a hydrological challenge for urban watershed management that effects on the management methods through surface runoff changes. Remote sensing, GIS techniques and satellite imagery can be used to improve and accelerate the management of natural resources and urban areas. ...
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1- Introduction Land use change is a hydrological challenge for urban watershed management that effects on the management methods through surface runoff changes. Remote sensing, GIS techniques and satellite imagery can be used to improve and accelerate the management of natural resources and urban areas. This study investigates on the relationship between urban development and runoff values using hydrological modeling, GIS and remote sensing. First, the land use maps of the city of Asad abad were prepared using TM and ETM + sensors of Landsat 5 and 7 in May, 1992, 2002 and 2014. For supervised classification and estimate of surface runoff were used maximum likelihood method and Resources Conservation Service National (NRCS-CN) respectively. The maps of land use, curves number and runoff amount were calculated and plotted. The results showed that surface runoff has been increased about 15.8 % due to increase of 4/59 % of urban land use. Management of atmospheric precipitation and surface runoff from watersheds that are a factor in collecting and transporting hazardous pollutants while passing through streets, streets and other urban areas. Risk management is inevitable in relation to public health and urban environmental resources. Increasing the impenetrable levels caused by urbanization and construction of the building on permeable soils, naturally, has decreased the permeable levels of the basin, which is capable of absorbing part of the rainfall, and thus has increased the total amount of runoff in the city. One of the important issues of urban development is the change in surface runoff. So that the delay time of the hydrograph and the base time of the flood is reduced and, consequently, with an equal volume of flood, the peak flood discharge with urban development will be more than the pre-development, in addition, the runoff coefficient also increases (Amir Ahmadi, 2011:92). Regarding the management and optimization of watersheds, accurate prediction of outflow runoff can be very effective in optimizing watershed management to prevent regional flood rebound. Despite the nonlinear relations, the uncertainty and the lack of clarity and the characteristics of time and place variables in the flow systems, none of the proposed statistical and conceptual models have been able to be considered as a superior and capable model in order to accurately model rainfall and runoff. To be known. Remote sensing and GIS technology is one of the most effective and efficient technologies for environmental change and resource management that provides updated information for management purposes (Janson, 2012: 86). Therefore, this tool can be used to study urban development. Considering the previous studies and the importance of the phenomenon of physical development of the city and increasing the impenetrable levels on the relations of rainfall, urban runoff is very important with regard to the urban development process using an efficient tool such as remote sensing along with hydrological models (GIS Special Website, 2014: 1) The city of Asadabad is also no exception because of the increase in inertia levels following the expansion of the city. The location of the city is such that it has spread in three watersheds, and this form of expansion, as well as the lack of such a study, requires the study of urban runoff and The impact of urban development on production runoff in the area is doubled. The present study attempts to investigate the physical development of Asadabad in 1992, 2002, 2014 and its effect on runoff rainfall relations. 2- Methodology The city of Asad Abad, in the area of 1195 km2, forms 6.1% of the area of Hamedan province. The average elevation is 1607 meters.The Annual rainfall is between 350 and 500 mm (Aka Iran,2014:1). In this study, the relationship between urban development with distributed hydrological modeling of the integrated approach of remote sensing and geographic information system was used. Landsat satellite data was used to detect land cover changes (Kavosi and Vatan khah, 2013:4). The SCS method estimates runoff in unobstructed watersheds according to rainfall and the characteristics of the watersheds. Basically, this method will be valid when runoff is due to rainfall, and it is not effective at a time when snowfall. The American Conservation Survey (CNS) Curve Number (CN) method is one of the most common methods for estimating and forecasting flood volume and runoff and flood altitude (Mahdavi, 2009: 86). In this research, the average monthly long-term average was calculated in inches. Then, layer the point rainfall in Arc GIS, and digital calls and using IDW interpolation was to be the second (Javadi, 2011: 59). To estimate the runoff of the study area, we calculated the weighted mean of runoff. For this purpose, the data was transmitted from the descriptive table in the Arc GIS software to the Excel environment (Zhang, 2014: 956). After calculating the total runoff heights, the values obtained were retrieved in millimeters in the tables and graphs. In this research, all of the above was done in three periods of time, 1992, 2002, and 2014, we tried to use the results of 1992 and 2014 to review the changes and to use the 2002 changes to verify. So the results are presented every three times. 3- Results Land use classification maps in Arc GIS software procurement and since the purpose of assessing changes in three different periods, a guide map has been changed for better. After the land use was extracted in the time periods studied, the area of each user and the percentage of the area of each user were calculated. Generally between the years 1992 and 2014 in the area of other Land use 5.45% (equivalent to 63.9 square kilometers) declined. The urban and non-urban usage map was extracted from the land use classification map for three periods of the study, in three periods of 1992, 2002, and 2014, which were obtained in the Arc GIS environment. After extraction of urban and non-urban when the study area and the percentage of urban and non-urban area was calculated in Excel. In order to better understand the relations between runoff rainfall in the study area, rainfall, runoff height was calculated and presented according to the curve number. The results of the study of the impact of urban development on runoff variations are presented at the time of study. By changing the type of use, including the change in area in each polyglone, the calculated CN values will vary in the polyhedron, which results in changes in the runoff height in each polyhedron. By changing the type of use, including the change in area in each polyglone, the calculated CN values will vary in the polyhedron, which results in changes in the runoff height in each polyhedron. According to the results, between 1995 and 2014, urban land increased by 4.95% (equivalent to 57.7 km2), and in the period from 2002 to 2014, urban land increased by 42.3% (equivalent to 127 / 40 sq. Km), and in this period the construction rate has been higher than the previous period. However, urban runoff runoff from 2002 to 2014 increased by 11.29% over the period from 1992 to 2002. Urban development is not the only one in metropolises. It is also important in a small city such as Assadabad. Because it will affect the relations of runoff precipitation. If the runoff height, which is a small number in the city, would be 350 m 3, this volume of runoff in a small town is significant and sometimes dangerous. 4- Discussion and conclusion In the present study, we tried to investigate the impact of urban development on runoff using remote sensing and its integration with GIS. Finally, it was found that using remote sensing; we can consider the variation of runoff from urban development with an accurate precision. It was also determined that urban development in addition to rainfall has been effective on runoff due to the increasing urban use that is related to construction development, industrial development and road construction development. In general, the use of remote sensing because of the cost reduction of field operations, and especially because of the reduction in the time needed to analyze the issues, can be considered as possible solutions to improve the level of water resources management. In addition, using this tool, this opportunity is created for researchers and executives to evaluate different management scenarios (which cannot be executed in a short time without heavy cost), and by analyzing the results, the best Made a decision. It is suggested to use different methods of runoff estimation and compare their results with the results obtained in this study as well as a hydrological model to study the runoff rainfall relationships and compare its results with the results of this study.In order to better study land use changes (especially urban development studies), in different years, it is necessary to use a satellite data format that is also available on a given date. To study more precisely, the relationships between rainfall runoff and time intervals increase. And the last suggestion is to use long-term returns to better predict and understand the impact of urban development on runoff variations.
Mahin Naderi; Alireza Ildoromi; Hamid Nouri; Soheila Aghabeigi Amin; Hossein Zeinivand
Volume 5, Issue 16 , December 2018, , Pages 61-79
Abstract
Abstract Intr4oduction Changing the environmental conditions of a natural ecosystem influences the hydrological responses such as flooding and the extent of erosion and sedimentation of the area. One of the models used to investigate the effect of land use change and climate change on runoff is SWAT ...
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Abstract Intr4oduction Changing the environmental conditions of a natural ecosystem influences the hydrological responses such as flooding and the extent of erosion and sedimentation of the area. One of the models used to investigate the effect of land use change and climate change on runoff is SWAT model which is a hydrological simulator and a continuous and semi-distributive time-space model with a physical base. Understanding the relationship between land use change and its causative factors and its secondary effects on hydrologic regimes provides essential information for land use planning and sustainable management of natural resources. Investigating the amount and trend of the changes and its effect on the hydrological processes in the basin is a way to predict the state of future changes and provide more effective plans for the sustainable development of the water resources in the basin. The construction of the Garin Dam in the Garin Basin, the risk of filling the sediment reservoir with sediment, reducing its useful life due to seasonal floods, and the effect of basin land use and climate change were the reasons for choosing this area for this research. The purpose of this study was to study the land use and climate change in the studied watershed and determine the effect of these changes on the runoff rate of this watershed in order to better it correctly. Garin Dam is located in the Zagros in the province of Hamedan. It includes the catchment area of the Sarab Gamasiab River to the Garin Reservoir Dam and its area is up to the 22,000 m2. The Garin land basin is mainly mountainous and its range of height ranges from 1833.9 to 3429.2229 m above sea level. Materials and Methods SWAT model input data included climatic and hydrological data (daily precipitation, maximum and minimum temperature, relative humidity, wind speed, dew point, and solar radiation). In this study, the ten year data of Nahavand synoptic station was uased. Topographic maps, digital elevation model (DEM), soil and land use were also used as the input of the model. A digital elevation model (DEM) was extracted using a topographic map of 1: 250,000 of the Garin River basin. SWAT CUP software was used for the calibration and validation of the SWAT model. The calibration data was from the years 2002 to 2007, but the validation data was from 2008 to 2010. In order to determine the degree of the sensitivity of the flow parameters in the SWAT model, SUFI2 software SWAT CUP were used and the sensitivity of the selected 24 parameters were measured. The Elimination of the parameters which had less sensitivity, was based on the calibration process. According to the P-value and T-Stat criteria, the sensitivity of the parameters were determined. The land use maps of 1986, 2000, and 2014 were prepared at the previous stages, and the Markov chain and the CA Markov filter were used to map the land use in 2042. In this research, the outputs of the Hadcm3 model were used to predict Garin's future climate. In addition, the SDSM statistical method was used to fine-scale the output of the general atmospheric circulation models. The SWAT model was also used in the range of calibrated parameters to simulate runoff caused by climate change in Garin basin under two A2 and B2 scenarios. After micro-sampling, the SWAT model was converted and t analyzed for the scenarios. Then, the results of the model implementation with different scenarios and the results of model implementation with the current climate conditions were compared Results and Discussion Regarding the results of the statistical indices, NS index was 0.95. P and R factors were respectively 0.47 and 0.03, and the coefficient of determination (R2) for observed and simulated floodguns was 0.6. Accordingly, the results were confirmed in the calibration phase. The validation phase was conducted to verify the correctness of the selection of the parameters during the calibration period between 2008 and 2010. Given that the Nashatcliff coefficient for Garin's catchment area at the calibration and validation stages were respectively 0.95 and 0.66, , the results were satisfactory and the SWAT model was able to simulate surface runoff in Garin River Basin. In general, due to an increased forest use, an increased permeability and water drainage to the surface and deep water aquifers, and an increased evaporation and transpiration, the amount of runoff has decreased. Regarding the results of temperature, rainfall, and runoff of the next period, it can be seen that in months when rainfall is reduced and the temperature increased, the amount of runoff in the coming period also decreases. The main reasons for this discrepancy can be attributed to the difference in the intensity of land use change as well as the extent of the altered land area, which, given the mountainous nature of the area in the Garin land basin, can be compared to other areas with flat lands with agricultural uses. It is concluded that the effect of climate change in the Garin dam basin is greater than the change in land use due to its mountainous nature. Conclusion The results of the study of the effect of land use change on runoff in the Garin basin indicated that there was a daily and monthly decline in the amount of runoff. The results of the study of the effect of climate change on runoff in the Garin western basin also indicated that there was a daily and monthly decline in the amount of runoff. In both A2 and B2 scenarios, the monthly average temperature, especially in the first and last months of the year, had an increasing trend and rainfall decreased in the spring and winter. It can be attributed to the increased temperature and evaporation, and decreased rainfall. It can also be seen that there was a decline in the average monthly runoff in January, February, April, May and December, with a decreased rainfall, but there was an increase in the average monthly runoff in June, July, August and September, with an increased rainfall. In addition, the effect of land use change on the reduction of runoff in the upcoming period is lower compared to the change effect under A2 and B2 scenarios. It will affect the climate change of the runoff more flatly and the reduction of runoff is more affected by climate change. According to the information obtained from these predictions, it is possible to properly manage the watershed and adopt appropriate management measures in accordance with the conditions of this watershed, prevent unauthorized land use changes, and reduce the damage caused by the phenomenon of the climate change.
Mahin Naderi; Alireza Ildoromi; Hamid Nouri; Soheila Aghabeigi Amin; Hossein Zeinivand
Volume 5, Issue 14 , June 2018, , Pages 23-42
Abstract
Introduction
In a natural ecosystem, changing the environmental conditions of that ecosystem influences hydrological responses such as flooding and the extent of erosion and sedimentation of the area. One of the models used to investigate the effect of land use change and climate change on SWAT runoff, ...
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Introduction
In a natural ecosystem, changing the environmental conditions of that ecosystem influences hydrological responses such as flooding and the extent of erosion and sedimentation of the area. One of the models used to investigate the effect of land use change and climate change on SWAT runoff, the SWAT model is a hydrological simulator and a continuous and semi-distributive time-space model with a physical base. Understanding the relationship between land use change and its causative factors and its secondary effects on hydrologic regimes provides essential information for land use planning and sustainable management of natural resources. Investigating the amount and trend of the changes and its effect on hydrological processes in the basin is a way to predict the state of future changes and provide more effective plans for sustainable development of water resources in the basin. The construction of the Garin Dam in the Garin Basin and the risk of filling the sediment reservoir with sediment and reducing its useful life due to seasonal floods and the effect of basin land use and climate change on the reason for choosing this area for this research. The purpose of this study was to study the land use and climate change in the studied watershed and determine the effect of these changes on the runoff rate of this watershed in order to better manage it.
Study of Area
Garin dam dam is located in the province of Hamedan and is located in the mountain range of Zagros mountains. This area includes the catchment area of Sarab Gamasiab River to the Garin Reservoir Dam and its area is up to the 22,000-square-meter Garin Garin Dam, the Garinland basin is mainly mountainous and its range of elevation ranges from 1833.9 to 3429.2229 meters above sea level.
Materials and Methods
SWAT model input data include climatic and hydrological data (daily precipitation, maximum and minimum temperature, relative humidity, wind speed, dew point and solar radiation), which is ten years in the study of statistics related to the synoptic stations Skinheads Became Topographic maps, digital elevation model (DEM), soil and land use are also needed as model inputs. A digital elevation model (DEM) was extracted using a topography map of 1: 250,000 Garin River basin. Calibration and validation of the SWAT model in SWAT CUP software. The study used calibration data from 2002 to 2007 and 2008 to 2010 for validating the model. In order to determine the degree of sensitivity of flow parameters in the model SWAT using SUFI2 software SWAT CUP sensitivity analysis for 24 parameters election, the results of the sensitivity analysis on the Elimination of parameters that has the less sensitive they are, the calibration process decision It is accepted. According to the P-value and T-Stat criteria, the sensitivity of the parameters is determined. Land use maps of 1986, 2000, and 2014 were prepared in the previous stages, and the Markov chain and the CA Markov filter were used to map the land use in 2042. In this research, the outputs of the Hadcm3 model were used to predict Garin's future climate. In this research, the SDSM statistical method was used to fine-scale the output of the general atmospheric circulation models. The SWAT model was used in the range of calibrated parameters to simulate runoff from climate change in Garin basin under two scenarios A2 and B2. After micro-sampling, the SWAT model was converted and the model was analyzed for the scenarios. Then, the results of model implementation with different scenarios and the results of model implementation with the current climate conditions were compared
Discussion and results
Regarding the results of statistical indices, NS index is equal to 0.95, P factor and R factor were respectively 0.47 and 0.03 respectively, and the coefficient of determination (R2) for simulated and simulated floodguns was 60 / 0. Accordingly, the results were confirmed in the calibration phase. The validation phase was conducted to verify the correctness of the selection of parameters during the calibration period for the period 2008-2010. Given that the Nashatcliff coefficient for Garin's catchment area at calibration and validation stage was equal to 0.95 and 0.66, respectively, the results were satisfactory and the SWAT model was able to simulate surface runoff in Garin River Basin. In general, due to increased forest use due to increased permeability and water drainage to the surface and deep water aquifers and increased evapotranspiration, the amount of runoff has decreased. Regarding the results of temperature, rainfall and runoff of the next period, it can be seen that in the months when rainfall is reduced and the temperature increased, the amount of runoff in the coming period also decreases. The main reasons for this discrepancy can be attributed to the difference in the intensity of land use change as well as the extent of the altered land area, which, given the mountainous nature of the area in the Garinland basin, can be compared to other areas with flat lands with agricultural uses. It is concluded that the effect of climate change in the Garin dam basin is greater than the change in land use due to its mountainous nature.
Conclusion
The results of the study of the effect of land use change on runoff in the Garin basin indicate that the amount of runoff is decreasing daily and monthly in this catchment area. Also, the results of the study on the effect of climate change on runoff in the Garinwestern basin indicate that the amount of runoff is daily and monthly in this catchment area. Considering that in both scenarios A2 and B2 the monthly average temperature, especially in the first and last months of the year, has an increasing trend and rainfall has decreased in the spring and winter, this decrease can be attributed to the increase in temperature which Following this, evaporation also increases and decreases in rainfall in this catchment area. Regarding the results, it can be seen that the average monthly runoff in months when rainfall decreased in January, February, February, April, May and December, and in the months when rainfall increased As of June, July, August and September, the amount of runoff will increase compared to the current period. It is also observed that the effect of land use change on the reduction of runoff in the upcoming period is lower compared to the change effect under A2 and B2 scenarios and will affect the climate change of the runoff more flatly and the reduction of runoff is more affected by climate change. According to the information obtained from these predictions, it is possible to properly manage the watershed and adopt appropriate management measures in accordance with the conditions of this watershed and to prevent unauthorized land use changes and reduce the damage caused by The phenomenon of climate change.
Mahtab Safari Shad; Mahmoud Habibnejad Roshan; Karim Solaimani; Alireza Ildoromi; Hossein Zeinivand
Volume 4, Issue 10 , June 2017, , Pages 81-98
Abstract
Climate change has altered the earth’s hydrologic cycles, especially its temporal and spatial distributions. Therefore, prediction of its future changes is very important. This study investigated the effects of climate change onthe precipitation, minimum temperature, maximum temperature, and runoff ...
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Climate change has altered the earth’s hydrologic cycles, especially its temporal and spatial distributions. Therefore, prediction of its future changes is very important. This study investigated the effects of climate change onthe precipitation, minimum temperature, maximum temperature, and runoff in three sub watersheds in Hamadan, Bahar Watershed. To this end, the WETSPASS model was used to estimate runoff and the LARS-WG model was used to predict climate variables between the years of 2014 and 2043. The results showed that the HadCM3 model with the largest weighting coefficient and the lowest error has the highest efficiency in simulation of precipitation and temperature. According to the scaled down measurements, in the next period, the average minimum and maximum temperatures will respectively increase up to 1.22 ºc and 0.9 ºc and the total rainfall will decrease about 8%. The results of the impact of the climate change on the future of the watershed's hydrology showed that runoff volume for all three sub-watersheds under the A2 scenario and the first and second sub-watersheds under the B1 scenario is going to decrease. For the third sub-watersheds, in contrast, it is going to increase. In addition, while total runoff input to plain will decrease by 36 % under A2 scenario, it will increase by 8 % under B1 scenario which will affect the watershed's water resource system changes. The remarkable thing is the reduction in rainfall in the winter and in the spring, disassembling the temporal distribution of the rainfall, and increasing the temperature. Accompanied by land use changes, it can have a significant negative effect on the future water resources management.
