Ziba Kounani; Alireza Ildoromi; hossien zenivand; Hamid Nouri
Abstract
1-Introduction Due to the importance of climate change and the effects it can have on runoff, developing a suitable model for simulating the present and future conditions of the catchment areas is of great importance (Rajabi et al, 2012). Nowadays, the LARS-WG and SDSM models are used to downscale environmental ...
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1-Introduction Due to the importance of climate change and the effects it can have on runoff, developing a suitable model for simulating the present and future conditions of the catchment areas is of great importance (Rajabi et al, 2012). Nowadays, the LARS-WG and SDSM models are used to downscale environmental parameters in climate change studies nowadays. Studies show that the SDSM model has less uncertainty and a more complex simulation process, and the LARS-WG model with simpler process and faster performance is more efficient (Aghashahi et al., 2012). Considering that many of Iran's watersheds lack hydrometric stations, it is of great importance to use those methods that can estimate the amount of runoff obtained from the rainfall. Therefore, the present study aimed to investigate the role of climate change in estimating runoff from the Silakhor-Rahimabad basin of Lorestan using a rainfall-runoff model (SIMHYD). 2-Methodology Silakhor-Rahimabad basin is in the catchment area of Dez Dam in Borujerd, Lorestan Province, which is located between N 33º 45¢ and 34º 7¢ and E 48º 29¢ and 48º 57¢. First, the baseline data including observation data of minimum temperature, maximum temperature, precipitation and sunshine during the period 1990-2014, and rainfall-runoff data including evaporation, rainfall and flow data, which were available, were received from the General Department of Aerology and Regional Water Authority of Lorestan Province, respectively. In this study, the daily data from Borujerd metrological synoptic station were used as the basis because they were complete and the elevation of the station was equal to the average of other stations’ elevations. For the evapotranspiration variable, the mean daily data from Rahimabad, Borujerd, and Silakhor stations were used, the mean daily data from the six rain-sensing stations for the rainfall variable. Moreover, Rahimabad hydrometric station at the outlet was used as the base station to observe the runoff variation in the basin. 3-Results and Discussion The results of the evaluation of criteria show that the LARS-WG model has a good ability to simulate rainfall parameters, minimum temperature, and maximum station. The simulated precipitation is in good agreement with the observed values (Table 1 and 2). After assuring the ability of the LARS-WG model to produce the rainfall data, minimum and maximum temperatures of Silakhor-Rahimabad Basin, the output of the HADCM3 model was downscaled under the scenarios A2 and B1, the parameters were predicted and compared with their values in the period 1990-2014 (Figures 2, 3 and 4). The results of the LARS-WG model indicate a decreasing trend of precipitation and temperature rise under both scenarios A2 and B1 for the period 2046-2065. The average amounts of annual rainfall predicted under the scenarios A2 and B1 are 451.445 and 4.420 mm, respectively. If the annual rainfall is 453.8 mm in the base period, the study area will observe a decrease in precipitation from 51.0 to 20.7 percent. The results obtained in the SDSM model under the two climate scenarios A2 and B2 for the future period indicate that the average air temperature is increasing and in the period 2050, the monthly average temperature, compared to the 1990-2014 period, increases in most months of the year. Also, rainfall has a decreasing trend in this period (Figure 5). Investigations show that the model efficiency has a direct correlation with the recharge coefficient, infiltration coefficient and soil moisture storage capacity. The effects of climate change on runoff are presented in Figures 9-16. In the period 2046-2065, the amount of runoff in the studied basin will decrease compared to the 1990-2014 period. This decrease in runoff rate can be attributed to the increase in temperature, followed by an increase in evaporation and a decrease in rainfall. Regarding the study of temperature and rainfall for the future period and monthly runoff, it is observed that the amount of runoff will decrease in the future period. 4-Conclusion In recent decades, the increase in greenhouse gases and thereby, the rise in temperature, have made Earth’s climate system imbalanced and caused massive climate change in most parts of the planet. Therefore, it seems necessary to apply climate predictions in national macro plans, especially in relation to natural disasters. The results indicate the decrease in precipitation and temperature rise in both SDSM and LARS-WG models. Also, in the present study, the SDSM model showed more variations than the LARS-WG model. Finally, the results obtained in both statistical downscaling models indicate the decreased amount of runoff in the studied basin is in the future period. In the study of the effect of climate change on runoff in the studied area, according to the values of Nash-Sutcliff coefficient and the coefficient of determination obtained at the calibration step (0.63 and 0.779, respectively) and the verification step (0.61 and 0.61, respectively), it is observed that the SIMHYD model has acceptable performance in the studied basin. These results are consistent with the findings of Aghashahi et al. (2012), Rajabi et al. (2013), Zolgharnein et al. (2013), Zhang et al. (2014).
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.
Mahnaz Karami Jozani; Alireza Ildoromi; Hamid Nouri; Abdollah Pernia
Abstract
IntroductionThe Climate forecasts show that climate change will change the hydrological cycle. The purpose of this study was to assess the effect of climate change on the Gorganrood- Ghareh Sou watershed in Golestan province using two generic oocytes of HadCM3 and ECHAM4 and the LARS-WG model according ...
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IntroductionThe Climate forecasts show that climate change will change the hydrological cycle. The purpose of this study was to assess the effect of climate change on the Gorganrood- Ghareh Sou watershed in Golestan province using two generic oocytes of HadCM3 and ECHAM4 and the LARS-WG model according to the three scenarios of A2, B1 and A1B for the period of 2011-2030. The results showed that discharge has insignificantly decreased in two stations of Tamar and Arazkooseh in the studied watershed. In addition, changes in the minimum temperature and rainfall have a more significant effect on river discharge changes in the watershed. The results also indicated a decrease in the discharge rate in all scenarios of two models of general circulation of the atmosphere in the future period relative to the base period.Many of the environmental problems of our age, including floods, storms, droughts, and the like are all rooted in global climate change. The study of the effects of climate change on water resources is an important issue that has been considered in recent years. For example, Kling et al. (2012) examined variations in runoff in the Danube watershed under the influence of changing scenarios. The results showed that most models predicted precipitation increase and runoff reduction for future years. Rajabi (2013) investigated the effect of changes on Ghareh Sou runoff in Kermanshah province in the coming decades and its results showed that in the coming periods, the average rainfall of the watershed reduced. Singh et al. (2013) evaluated the performance of artificial neural network in a small watershed in India based on RMSE and R criteria. The results showed that the neural network model had an acceptable performance in the study of climate change in the region.MethodologyGorganrood watershed-Ghareh Sou is in the southeastern part of the Caspian Sea with an area of 13061 km2. The average annual rainfall is about 300 mm to 1000 mm, and the annual average temperature varies from about 7.5 to 17 ° C. In this study, the seasonal and annual data series of minimum and maximum parameters of temperature, precipitation and annual discharge of the year and non-parametric tests were used to determine the trend direction and correlation of the studied parameters. In order to investigate the effect of variation on discharge, the data from B1, A2 and A1B scenarios of the HadCM3 model and B1, A2 and A1B scenarios of ECHAM4 model were used. In addition, Lars statistical model was used for calibration of the data, after calibrating and validating it for the simulation of rainfall-runoff, The output of the Lars statistical model was introduced into the neural network model and the changes in the discharge rate were investigated in the course of 2030-2011 (near future). In order to evaluate the performance of the model, the statistical index of the coefficient of explanation and the mean squared error were used.ResultsThe annual variations in discharge at two stations of Tamar and Arazkooseh showed that precipitation on both stations of Arazkooseh and Tamar was significant at 99% probability level. But it had less effect on rainfall than river discharge. The studies showed that during the last 30 years in the study area, the maximum temperatures and precipitation, had insignificantly increased. The minimum temperature had a significant increase in most of the studied time series. Also, the climatic parameters had a more significant effect on rainfall than the minimum temperature.The results of the climate simulation showed that the average temperature for the HadCM3 for 2011-2030 period would increase with all scenarios. The results of the HadCM3 model showed that precipitation is rising in all scenarios. But in the ECHAM4 model, the precipitation in the A2, B1 scenarios will decrease, but in A1B scenario it will increase. In HadCM3 and ECHAM4 models, the highest precipitation rates are respectively for A2 and A1B scenarios.Discussion and ConclusionThe results of the two HadCM3 and ECHAM4 models indicated an increase in precipitation (except for scenario A2 and B1 in the ECHAM4 model) and increase in temperature in the Gorganrood-Ghareh Sou watershed. Moreover, the changes in minimum temperature will be higher than maximum temperature. Discharge will decrease in both climatic models. The results showed that the greatest decrease in the amount of discharge in both climates models and in all three scenarios was in September. The results of the changes in the discharge rate at the two hydrometric stations of Tamar and Arazkooseh indicated that although the changes were not significant in any one, the decrease in discharge rate during the period at the Tamar station was more pronounced than that of the Arazkooseh station. The results showed that the LARS meteorological model had a high potential for generating daily data.
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.
