Somayeh Taheri; Hasan Ahmadi; Jamal Ghodousi; ُSadat Feiznia; Shahram Khalighi Sigaroudi; Mohamad Hossein Ramesht
Abstract
subsidence in urban areas poses significant risks to infrastructure, including buildings, roads, railways, pipelines, sewage systems, and wells. Therefore, assessing its potential is crucial. This study models the subsidence risk in Karaj city using Geographic Information Systems (GIS) and the Weight ...
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subsidence in urban areas poses significant risks to infrastructure, including buildings, roads, railways, pipelines, sewage systems, and wells. Therefore, assessing its potential is crucial. This study models the subsidence risk in Karaj city using Geographic Information Systems (GIS) and the Weight of Evidence (WoE) model. To achieve this, we created maps of factors influencing subsidence, such as slope, alluvial thickness, groundwater fluctuations, aquifer layering, particle size, and permeability. These maps were then compared with recorded subsidence data to determine the weight of each factor's influence. By integrating the effects of these factors, a Subsidence Index (SI) map was generated and categorized using the Success Rate Curve (SRC), identifying five sensitivity zones from very sensitive to very low sensitivity. The effectiveness of the WoE model was evaluated, revealing that the subsidence sensitivity prediction map covers 93.64% of actual occurrences. Results indicated that aquifer layering positively influences subsidence development, with the highest impact arising from alluvial deposits with good permeability and fine particles. This factor, with a weight of 3.72, demonstrates significant influence among all evaluated parameters. In terms of thickness, the most significant subsidence occurred in alluvial deposits exceeding 200 meters. Areas experiencing groundwater level declines of over half a meter annually markedly contributed to subsidence. Additionally, slopes of less than two degrees were identified as the most susceptible to subsidence. Thus, while many areas in Karaj are relatively safe, the threat is notably higher in the southern and southwestern parts, requiring special attention in urban management.
Saeid Khosrobeigi Bozchelui; Arash Malekian; Alireza Moghaddam Nia; Shahra,m Khalighi
Abstract
Flood is one of the most devastating natural disasters, causing financial and human losses each year. At the same time, many rivers in Iran's watersheds lack complete and accurate statistics and information. On the other hand, estimating the flow of floods is one of the most important factors for the ...
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Flood is one of the most devastating natural disasters, causing financial and human losses each year. At the same time, many rivers in Iran's watersheds lack complete and accurate statistics and information. On the other hand, estimating the flow of floods is one of the most important factors for the design and implementation of water structures. In such cases, one of the appropriate solutions to estimate the maximum flow rate with different return periods is flood analysis. In order to conduct the present study, 55 hydrometric stations with a common statistical period of 20 years were considered to perform the work after the statistical deficiencies were eliminated. Then, based on the distribution of the third type of Pearson logo with the lowest error rate and the highest number of first rank as the most suitable fit function, the amount of discharge in different return periods was estimated. The following information was collected on the types of physiography, land use, climate and geology variables. After collecting information about all independent variables using Gamma test, the most important variables affecting the maximum instantaneous flow, including area, drainage density, maximum 24-hour rainfall and watershed environment, were selected and modeled using methods. Random forest modeling and support vector modeling were performed and their efficiency was determined based on statistical indicators With an efficiency coefficient of 74 to 83%, the error of 3.05 to 32.11 m3 and the coefficient of explanation of 76 to 91 are more accurate than the random forest model.
Amir Hossein Parsamehr; Ali Salajegheh; Shahram Khalighi; Khaled Ahmadaali
Abstract
Aim: The aim of this study is to propose an approach for modeling spatiotemporal changes in rainfall that can be used as input for rainfall-runoff models.Research Method: To achieve this, rainfall data from four rain gauge stations in the Paskouhak catchment were used. Five parameters, including elevation, ...
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Aim: The aim of this study is to propose an approach for modeling spatiotemporal changes in rainfall that can be used as input for rainfall-runoff models.Research Method: To achieve this, rainfall data from four rain gauge stations in the Paskouhak catchment were used. Five parameters, including elevation, slope, aspect, longitude, and latitude, were identified. The different combinations of these five parameters were prioritized using the gamma test in WinGammaTM software. After the use of different regression models, the best model was selected based on evaluation criteria such as R2, RMSE, and the Taylor diagram. A raster map of a selected rainfall event was drawn in the Arc GIS environment. Finally, using the proposed approach of relative equations, the spatiotemporal changes in rainfall were modeled.Results: The results showed that using a second-degree nonlinear model and parameters of elevation and latitude, it is possible to accurately obtain the spatial distribution of rainfall in the form of a regular pixel grid (100 square meters) with high precision (R2=0.917 and RMSE=0.2277).Conclusion: In different rainfall events in small catchment areas, the variation in rainfall in each pixel is almost constant relative to other pixels, including the rain gauge station, the proposed approach in this study can model the spatiotemporal changes of each rainfall event as a three-dimensional matrix in the study area. The approach can be valuable in predicting potential flood events and in water resource management and planning. However, further research is required to validate the results and test the approach in other areas.
Esmatullah Ghaljaee; Shahram Khalighi-Sigaroodi; Alireza Moghaddam Nia; Arash Malekian
Abstract
Reliable estimation of precipitation is one of the most essential needs in water resources management. However, in many parts of the world, especially in Iran, the lack of time and place of rainfall data is very noticeable. Therefore, the use of satellite information is one of the ways to compensate ...
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Reliable estimation of precipitation is one of the most essential needs in water resources management. However, in many parts of the world, especially in Iran, the lack of time and place of rainfall data is very noticeable. Therefore, the use of satellite information is one of the ways to compensate for the lack of information. The purpose of this research is to compare the accuracy of rainfall information of TRMM-3B42 and PERSIANN-CDR products on a daily scale. The products of these two satellites are available daily for free in the pixel size of 0.25 degrees. The daily rainfall of 12 stations in the southern slopes of Alborz in a statistical period of 2000-2014 was used. The results show that these two satellite products are not the same in different statistical parameters, so that CDR and 3B42 have estimated 100% and 25% more rainfall events than the stations, respectively. Also, PERSIANN satellite is significantly superior to 3B42 in terms of RMSE, POD and CSI parameters, but on the other hand, it is weaker in terms of Bias and FAR parameters. Therefore, the selection of the desired satellite product should be based on the proper parameters.
Reza Bagheri; Mehdi Ghorbani; Shahram Khalighi Sigaroudi; Amir Alambeigi
Abstract
Water deficit caused by climate change due to the extent and magnitude of the social and economic damages it causes, is one of the most dangerous natural disasters that causes irreparable damage to the agricultural and water resources of the country. In other words, it has devastating effects on the ...
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Water deficit caused by climate change due to the extent and magnitude of the social and economic damages it causes, is one of the most dangerous natural disasters that causes irreparable damage to the agricultural and water resources of the country. In other words, it has devastating effects on the productive, economic, social and environmental sectors. The purpose of this study was to analyze the components of resilience and present a model of resilience of the local community in the face of climate change. The statistical population of the study consisted of rural community of Nodushan watershed which was used for sample size of Cochran formula and 100 people were surveyed based on a researcher-made questionnaire. The Resilience Component Analysis Questionnaire was used. Data were analyzed using SPSS25 and LISREL8.8 software. To investigate the fit of the resilience component measurement model, the data was analyzed used LISREL software. The results showed that among the resiliency indices, the indicators of "local networks" and "financial and infrastructure" with 91 percent and 84 percent path coefficients were better than other indices, respectively. "Compatible management status" and "risk-taking" with 10 percent and 8 percent path coefficients, respectively, are not appropriate. Also, results showed that the goodness-of-fit indices had values and confirmed the resilience dimension measurement model with the data. Therefore, it can be acknowledged that the results of this study can in actions and can be effective in promoting and adopting climate change crisis mitigation mechanisms to create resilience in the local community.
S.Mahdi Taghipour; Shahram Khalighi Sigaroodi; Amir Alambaigi
Abstract
All rural and nomadic communities reside in natural watershed areas and, based on the specific climatic and geological conditions that each catchment area has, they are useful for living. Today, there is a danger to the livelihoods of non-residents as well as climate change caused by human activities, ...
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All rural and nomadic communities reside in natural watershed areas and, based on the specific climatic and geological conditions that each catchment area has, they are useful for living. Today, there is a danger to the livelihoods of non-residents as well as climate change caused by human activities, in other words, global warming due to the burning of fossil fuels. Accordingly, in this study, using the indices defined in the natural, social, physical, human and economic parameters, we examine the amount of five effective capital in the capacity of watershed adaptation to the climate change phenomenon in the three villages of Haji Abad, Gisur and Noodat Pashang In Gonabad city. In this study, due to climate homogeneity, 3 villages in the dry climate of Gonabad city have been selected. In this research, based on the questionnaire, the size of each of the five indicators and the organized interviews with the target groups in the three villages of the desert region were 3.13, 3.39, 3.14, 3.26, 7.2 was calculated. Also, using the Freeman test, it was found that there is a significant difference between different capital, which, respectively, social, human, physical, natural and economic, have the greatest impact on the capacity of aquaculture adaptation, so it is better to solve The watershed problem has used social and human capital to inflate other (physical, natural, and economic) capital
Farhad Zolfaghari; Hossein Azarnivand; Hassan Khosravi; Gholamreza Zehtabian; Shahram Khalighi Sigaroodi
Abstract
Any Changes in a dry land surface ecosystem will be affected by the climate near the ground or microclimate in the vertical plane. In recent decades' wetland drying cause to reduced vegetation significantly. Assessing Zabol synoptic station statistics shown an increased temperature of this place. It ...
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Any Changes in a dry land surface ecosystem will be affected by the climate near the ground or microclimate in the vertical plane. In recent decades' wetland drying cause to reduced vegetation significantly. Assessing Zabol synoptic station statistics shown an increased temperature of this place. It seems that there has a direct relationship between the changes in land surface vegetation and increases the ambient temperature. The situation ground roll on microclimate has been investigated to illustrate this relationship. In this study we compare and assessment temperatures at depth of 5cm and surface and height about 150 cm and heat fluxes and energy in three microsites with different vegetation cover. The distance between the experiment microsites is about 20 km, and the elevation difference is less than 10 meters. Microsite A with the total vegetation average about 65%, B microsites 20% and microsites C with 100% bare soil. It evaluated the equation ρc_p z_a (dT_air)/dt to investigate the role and effects of vegetation on the ground surface. Data analyzes showed temperatures in the period of study at the C microsites were higher than other microsites. It seems the lack of vegetation in microsites C has a major role in the higher air temperature. In micro site C At 00:30 Am (local time) the air temperature was 3.2ºC higher than microsite A and B. The results showed there is a direct relationship between the vegetation cover percentage and air temperature because of different soil heat fluxes and surface temperature.
Mohammad Bashirgonbad; Alireza Moghaddam Nia; Shahram Khalighi Sigaroodi; Mohammad Mahdavi; Emmanuel Paquet; Michel Lang
Abstract
There are many methods for estimating the maximum flood discharge including frequency analysis methods and risk study of hydraulic structures based on flood frequency analysis is often sensitive to the observations and selected statistical distribution that cause errors in design. Since heavy rainfalls ...
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There are many methods for estimating the maximum flood discharge including frequency analysis methods and risk study of hydraulic structures based on flood frequency analysis is often sensitive to the observations and selected statistical distribution that cause errors in design. Since heavy rainfalls are the main cause of floods and the rainfall records are longer than flow records, hence long-term records of rainfall at rain gauge stations of Bakhtiary basin in a 66-year period and the 58-year records of daily maximum discharge were used in this study. In this research, peak and maximum daily flows were estimated by using hydro-climatic methods of Agregee and Gradex. Then, the results obtained from the simulation based on hydro-climatic approach for the different return periods were compared with those of classical statistical techniques of Gumbel and Generalized Extreme Values (GEV). The results showed that using additional information like rainfall data plus hydrometric data in hydro-climatic methods gives better estimates rather than frequency analysis methods. Because each three evaluation criteria of Root Mean Squared Error (RMSE), Nash–Sutcliffe efficiency (NSE) coefficient, Kling-Gupta efficiency (KGE) coefficient confirm performance of hydro-climatic methods in comparison with Gumbel and Generalized Extreme Values (GEV) distributions. Finally, a peak to volume ratio extracted from the 26 major flood events detected at Tang-e panj hydrometric station within the hourly discharge records was used to transform the cumulative distribution function of daily discharge into peak discharge.
M Zare; Aliakbar Nazari Samani; shahram khalighi; javad bazrafshan; mohsen hasan joury
Abstract
Land use Changes have recently been increasing due to anthropogenic and climatic factors. Natural resources management critically needs land use maps and simulation of its changes for understanding the interaction and relationship between humans and natural phenomena, as well as for making premium decisions. ...
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Land use Changes have recently been increasing due to anthropogenic and climatic factors. Natural resources management critically needs land use maps and simulation of its changes for understanding the interaction and relationship between humans and natural phenomena, as well as for making premium decisions. Accordingly, present study has dealth with simulation of future changes land use of Kessillian watershed. Hence, land-use and land cover maps of the catchment was prepared by using multi-period Landsat images captured in 1986, 2000, and 2011. Then, applying cellular automaton and Markov model, the land-use/land cover condition in 2011 was predicted 0.9 using ROC. Thereafter, this model was run for simulating land-use/land cover changes in 2030. According to the results of detection and simulation of changes, forest land reduction trend will continue but the area of rangelands and inhabited areas will expand. Agricultural lands will not seriously change due to steep slope and low fertility after several consequent plantings. In most cases, maximum changes occurred around the forest and rangeland areas and changes will decrease far from these margins. Markov model can precisely show the land changes in the area via time period and can anticipate the future of them. Therefore, this model can be applied in order to manage the land.
bahram choubin; SHahram KHalighi Sigaroodi; Arash Malekian
Abstract
Predicting climate trends, especially forecasting rainfall, provides managers of different fields withsuitable tools so that considering these predictions; they can devise future-state policies. At thisstudy, after selecting the most effective climate indices applying PCA method, the effects of largescaleclimate ...
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Predicting climate trends, especially forecasting rainfall, provides managers of different fields withsuitable tools so that considering these predictions; they can devise future-state policies. At thisstudy, after selecting the most effective climate indices applying PCA method, the effects of largescaleclimate signals in seasonal rainfall of basin Maharlu - Bakhtegan were investigated bothsimultaneously and by delay through statistical methods (Pearson correlation and cross-correlationcoefficient) and by applying stepwise regression model, regression equation for forecasting rainfallwas offered. The results showed that in cross-correlation between the time series of SPI (dependentvariable) at time (t) and climate signals (independent variable) at time (t-k), only SOI indexconcurrently has a significant relationship with rainfall, whereas, most of indices turned significantwith standardized precipitation index with different lag times. In season to season study of thesignals with the standard precipitation index using Pearson's correlation coefficient it was found thatclimate signals of spring and summer are not significantly correlated with SPI. Representationcoefficients (R2) and standardized regression effect (Beta) in stepwise regression model showed thatsimultaneous and with season to season delays signals (for example: SPI index of autumn with fourprevious seasons indexes) at method Pearson correlation have higher relationship with seasonalstandardized precipitation index than the cross-correlation in time (t-k), (which signals of allseasons given is delay together with than SPI of all seasons) show.
Leila Fazel Dehkordi; Hossein Azarnivand; Mohammad Ali Zare Chahouki; Farhad Mahmoudi Kohan; Shahram Khalighi Sigaroudi
Abstract
To identify an appropriate index for monitoring and evaluation of drought, rainfall data obtainedfrom meteorological stations of Ilam Province from 2000 to 2011 and MODIS satellite images with16-day intervals were collected and processed. The Standardized Precipitation Index (SPI) wascalculated based ...
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To identify an appropriate index for monitoring and evaluation of drought, rainfall data obtainedfrom meteorological stations of Ilam Province from 2000 to 2011 and MODIS satellite images with16-day intervals were collected and processed. The Standardized Precipitation Index (SPI) wascalculated based on rainfall data; therefore, the rainfall data were used for measuring SPI andsatellite images were used for calculating NDVI. Also, the percentages of canopy cover in rangetypes were selected from the information of the National Evaluation of rangelands in differentclimatic zones. The correlation between SPI and NDVI and also canopy cover and NDVI wasexamined. The relationship between vegetation index (NDVI) and SPI was determined byregression. The results of SPI showed that in 2000 a severe drought and in 2006 a medium wetoccurred in rangelands of Ilam Province. NDVI value variations have as well confirmed it. Theresults showed that NDVI and life form (annual forb and annual grass) has the highest percentage ofcorrelation. Also examining of result showed that most correlation of SPI and NDVI was in 3 and 6-months intervals. Evaluation of regression models performance in range types described thatmodels in 3 and 6- months intervals was suitable for monitoring drought. The result of regressionconfirmed that NDVI was an appropriate index for monitoring and assessment of drought.
Reyhaneh Masoudi; Gholamreza Zehtabian; Hassan Ahmadi; Shahram Khalighi sigarudi
Abstract
Desertification is a major problem in many countries. International efforts have been considered to combat and prevent this phenomenon. The most important cases of these measures are the United Nations Convention to Combat Desertification. In this study, IMDPA model and GIS were used to assess desertification ...
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Desertification is a major problem in many countries. International efforts have been considered to combat and prevent this phenomenon. The most important cases of these measures are the United Nations Convention to Combat Desertification. In this study, IMDPA model and GIS were used to assess desertification phenomena in Kashan Plain. Some indices of Climate and water criteria were selected to consider for each condition of the region. Final desertification intensity was calculated based on geometric average of the selected criteria and their indices. The numerical value was classified in 5 classes including non-significant, low, medium, severe and very severe and desertification intensity map was drawn using GIS in the studied period. According to the results, among the studied indices, the groundwater level depletion, EC and Transu aridity index with 3/82, 3/04 and 3/01 numerical values are the most effective factors. The threshold of ground water level, EC and Transu aridity index were determined respectively: more than50 cm/year, 2250-5000((μmohs)⁄(cm)) and 0/05-0/2. Also, the case study has classified in medium class of desertification with DS=2/4. Regarding the determined thresholds were specified the sensitive areas, and the required equipment are proposed to install on these areas for observing the thresholds.
Shahram Khalighi Sigarodi; Mohammad Rostami Khalaj; Mohammad Mahdavi; Ali Salajegheh
Abstract
Large impervious surfaces and man-made waterways are the characteristic of urban area. Increasing urbanization and rapid growth of cities in recent decades towards the upstream watershed, has been severely affected on rainfall-runoff processes in urban area. Therefore, to computer models in order to ...
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Large impervious surfaces and man-made waterways are the characteristic of urban area. Increasing urbanization and rapid growth of cities in recent decades towards the upstream watershed, has been severely affected on rainfall-runoff processes in urban area. Therefore, to computer models in order to illustrate these processes the proper design or assessment of urban drainage systems has special attention. The purpose of this study is simulation and validation the volume of runoff and calibrated SWMM model in small urban area. Required parameters of the model using land use maps, DEM of study area, and field inspection were calculated. For calibration and validation process model, corresponding to three event rainfall runoff measured at the output of the basin and was compared with runoff simulated by the model. The results showed there is good agreement between simulated and observed runoff discharge and depth. There is a little difference between simulated and observed for runoff rate but this difference is more than acceptable value (NS>0.5). NS value for the first, second and third event is the, 0.69, 0.85 and 0.52 respectively. This performance represents that the SWMM model is effective in the study area and this model can be used for in appropriate designs, and evaluate network systems in urban drainage.
Sadegh Tali-Khoshk; Mohsen Mohseni Saravi; Mahadi Vatakhah; Shahram Khalighi-Sigarodi
Abstract
Because of insufficient factors including facilities, budget, human resources as well as time watershed operation is not applicable throughout the basin. As a result, watershed operation should be performed in the sub-basins in which is more affectionate and the risk frequency of some events such as ...
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Because of insufficient factors including facilities, budget, human resources as well as time watershed operation is not applicable throughout the basin. As a result, watershed operation should be performed in the sub-basins in which is more affectionate and the risk frequency of some events such as destruction, degradation; physical and financial damage and also flooding are considerably high. In addition, due to hydrometric stations, defects or the lack of stations in some areas, some efforts have been made experts recently to assess and consequently introduce some novel and reliable methods for prioritizing on the basis of current data obtained from sub-basins features of different geographical regions. In current study, the utilization possibilities of neuro-fuzzy technique and SCS in HEC-HMS model that have different potential to examine a wide range of advantageous and disadvantageous in making various decisions were studied. To determine the prediction accuracy of these methods, the rate of flow and sediment output of Taleghan sub-basins were taken over one year. The results of these methods were then compared with the maximum two-year return period flow observations. Our results revealed that in making prioritization, neuro-fuzzy as compared with the SCS method can produce the best prediction as long as the coefficients of errors, efficiency compared to the observational data and predictions are taken into account.
Hossein Eslami; Ali Salajagheh; Shahram Khalighi sigaroudi; hasan Ahmadi; Shamsollah Ayoubi
Abstract
Rainfall erosivity is the ability of rainfall to detach the soil particles. This study was conducted to evaluate spatial variability of rainfall erosivity indices in Khouzestan Province. The point data of indices (EI30, AIm, KE>1 and Onchev indices) in 74 stations were used to generate spatial erosivity ...
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Rainfall erosivity is the ability of rainfall to detach the soil particles. This study was conducted to evaluate spatial variability of rainfall erosivity indices in Khouzestan Province. The point data of indices (EI30, AIm, KE>1 and Onchev indices) in 74 stations were used to generate spatial erosivity maps through deterministic and geostatistical interpolation methods (Radial Basis Functions, Inverse Distance Weighted, Kriging and Cokriging). Results indicate that cokriging have least error and most correlation with determining coefficient of 0.89, 0.89, 0.48 and 0.49 for EI30, AIm, KE>1 and Onchev indices. Based on the correlation relationships between the basins specific sediment yield (in basins dominating the sedimentation stations) and mean indices of EI30, AIm, KE>1 and Onchev, EI30 index with correlation coefficient of 0.98 (P<0.01) is selected as the appropriate rainfall erosivity index. Based on the prepared map on the basis of Cokriging method with secondary variable of maximum mean monthly rainfall, the east and northeastern regions presented the highest values of EI30 index, while the southern and western regions showed the lowest values of EI30 index. The annual rainfall erosivity (EI30) ranged from 404 to 3064 Mj.mm.ha-1.h-1.y-1.
ali shahbazi; Shahram khaliqi sygarodi; Arash Malekian; Ali Salajegheh
Abstract
In order to decrease the risks associated with the management of urban watersheds, the use of proper methods is an essential task to estimate the runoff with a high degree of confidence. Time of concentration is one of factors that impacts on peak discharge and runoff volume. The objective of this study ...
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In order to decrease the risks associated with the management of urban watersheds, the use of proper methods is an essential task to estimate the runoff with a high degree of confidence. Time of concentration is one of factors that impacts on peak discharge and runoff volume. The objective of this study is to select the best method among the empirical formulas for estimating the time of concentration. In this study, for determination of actual time of concentration, the field method based on measuring the travel time by using floating-object method was employed. To select the best empirical formula of the time of concentration, the statistical criteria including percentage Relative Error (RE), Root Mean square error (RMSE), Average percentage Relative Error (RME), Nash - Sutcliffe criteria (NS) and determination coefficient were used. Then, differences among the estimations obtained from empirical equations were compared with the actual values. The results of this study based on comparison of the relative error in each interval showed that in the reach No. 2, empirical formulas of California, Chow, Carter and Federal Aviation, with percentage error of 2.7, 2.9, 4.4 and 4.4 have showed the best estimation, respectively. The equation proposed by Kirby with percentage error of 1 in the reach No. 3, the equation of Ventura with percentage error 8.5 in the reach No. 9 and the equation of rational hydrograph with percentage error 4.8 in the reach No. 10 have showed the best estimates. Therefore, it is recommended to use the empirical formula that has the lowest percentage of error for areas with features similar to the studied reaches. In general, the results show that only rational hydrograph method in all of the reaches has the lowest error and then provides the most proper estimates compared than others.
Samaneh Razavizadeh; Ali Salajegheh; Shahram Khalighi Sigaroudi; Mohammad Jafari
Abstract
Land use change is one of the main factors in the process of changing the regime of flood in watersheds. Taleghan watershed has been subjected to many land use changes over years, which probably effects on flood characteristics of Taleghan River. In present study the effects of land use change on some ...
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Land use change is one of the main factors in the process of changing the regime of flood in watersheds. Taleghan watershed has been subjected to many land use changes over years, which probably effects on flood characteristics of Taleghan River. In present study the effects of land use change on some parameters including peak flow, volume and flood base time, in part of Taleghan basin, was investigated by using Geographical Information System (GIS) and HEC-HMS model. Land use maps of 1987 and 2002 were prepared and integrated with soil hydrological groups and pasture conditions maps in GIS with the aim of providing of CN map. Then by using curve number and SCS unit hydrograph in sub basins and also Muskingum routing method, HEC-HMS model was calibrated and validated, for 10 incident rainfall - runoff views. Results of the simulation showed that due to the changes in land use (the reduction in the level of agricultural lands and increases in pasture areas), peak flow and flood volume in 2002 than in 1987 showed the average reduction of 46% and 34%, respectively. The evaluation of base time of flood showed no change in the parameter in flood hydrograph at the study period. On the whole the results showed that the trend of land use changes have the positive effect on reducing flood productions in study area.
Asghar Zare Chahouki; Ali Salajegheh; Mohammad Mahdavi; Sharam Khalighi; Said Asadi
Abstract
A flow-duration curve (FDC) illustrates the relationship between the frequency and magnitude of streamflow. Applications of FDC are of interest for many hydrological problems related to hydropower generation, river and reservoir sedimentation, water quality assessment, water-use assessment, water allocation ...
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A flow-duration curve (FDC) illustrates the relationship between the frequency and magnitude of streamflow. Applications of FDC are of interest for many hydrological problems related to hydropower generation, river and reservoir sedimentation, water quality assessment, water-use assessment, water allocation and habitat suitability. This study was carried out in 11 selected watersheds with common characteristics such as the 20 years period, the minimum land use change and similar annual water volume through all watersheds in 3 province of: Yazd, Semnan and Markazi which are located in central zone of Iran to regional flow duration curve. It was extracted Q5, Q10, Q20, Q30, Q40, Q50, Q60, Q70, Q80 and Q90 from 11 Hygrometric stations as a dependent variable were derived from flow duration curve. The flow duration curve is regionalized by using morphoclimatic characteristics of the drainage basin. Using multiple regression techniques, the geographic variation of each parameter of the best fitted flow duration model is explained in terms of the drainage area, length of longest flow, Stream slope, mean annual areal precipitation, course from the divide of the basin to the site of interest. The regionalized nonlinear regression equations are successfully used to flow duration curves at other locations within the hydrologically homogeneous regions of center of Iran. A cross-validation Nash–Sutcliffe Efficiency procedure was used to evaluate best fitting of the regional model in ungauged watershed.
