Ramtin Sobhkhiz Foumani; Alireza Mardookhpour; Mohammadreza Fallah Ghavidel
Abstract
Extended abstractIntroductionToday, the estimation of the rainfall resulting from rainfall, especially in small basins with no statistics, is one of the main activities among hydrologists, and the estimation of the volume of runoff resulting from rainfall and the application of surface water collection ...
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Extended abstractIntroductionToday, the estimation of the rainfall resulting from rainfall, especially in small basins with no statistics, is one of the main activities among hydrologists, and the estimation of the volume of runoff resulting from rainfall and the application of surface water collection and containment methods, both in terms of water supply And it is very important in terms of flood prevention. In this research, by using the simulation of the conversion of rainfall to floods in a long statistical period of about 20 years between January 23, 2000 and September 23, 2021 in the Astana-Kochsafhan catchment area with HEC-HMS software, one of the main objectives of the selection effect The type of flow conversion hydrographs was checked on the amount of calculation error of the closed boundary flood. The main goal of this research was to investigate the importance of the dimensionless Muskingum coefficients in developing a flood distribution model in a computer simulator. Materials and methodsFor do this research, two types of models were used in extracting the flow hydrograph. The first model continued by using the integration of the general set of sub-basins until the stage where only 5 general sub-basins or 4 sub-basins in the upstream of the catchment area leading to the outlet of the range continued. The process of removing the sub-basins was done by combining the area and other physiographic parameters in the geographic information system environment and using the HEC_GeoHMS extension. Results and discussionIn addition to the principle of trending, by analyzing the results, it was found that each of the surface current conversion methods under known and more widely used titles have limitations, weaknesses and strengths that can be The title of local regressions was also considered for this transformation, the SCS method as the most well-known method, due to its lower limitation in models with local conventional scale in the limits of third-order watersheds, showed that the error of the obtained data It has been less than other cases. This amount of error was predictable in itself. Clark's method, which has a more structured approach, like Schneider's calculation method, calculates the error in its general form, as well as in the maximum values, moment of occurrence, volume, etc. slow In particular, Schneider's method is designed for large domains in its default. In this study, unlike the SCS method, in which the Nash function error number is 0.540 and the RMSE is 0.7, as well as the deviation percentage is 28.01, for the Clark method, the Nash function is 533. 0 and RMSE is 0.7 and the deviation percentage is 29.71. This calculation also confirms from the point of view of error measurement that one of the best criteria for observing the difference cannot be RMSE. In the model The detailed analysis of the trending effect, the error of 0.537 in the Nash function is very close to the figure calculated in the similar case (initial aggregated model). However, only this error measurement should not lead to the opinion that the creation of more detailed models cannot improve or destroy the structure of its numerical code. Because although the differences in measurement errors can be ignored in a certain way, the total amount of flow in the aggregated model was equal to 19672395 cubic meters. While the same parameter in the partial model has a difference of 277655 cubic meters. ConclusionIn general, separation of basic discharge with advanced methods such as WHAT cannot necessarily help to increase the correlation between observational data in a continuous model. On the other hand, calculating the discharges that leave the hydrographic network under the heading of deviation from the hydrographic network in the process of flood flows is the basic condition for reducing the model error, regardless of the type of hydrograph selected in the model.
Alireza Shokoohi; Reza Morovati
Abstract
The Lake Urmia is the 20th largest lake and the second hyper saline lake in the world. In recent years, the drying out of the Urmia Lake has attracted attention of many researchers. The main motivation of this study is to evaluate the role of drought in this disaster. For this purpose, Standardized Precipitation ...
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The Lake Urmia is the 20th largest lake and the second hyper saline lake in the world. In recent years, the drying out of the Urmia Lake has attracted attention of many researchers. The main motivation of this study is to evaluate the role of drought in this disaster. For this purpose, Standardized Precipitation Index (SPI) and Reconnaissance Drought Index (RDI) are employed. The data for analysis including precipitation and temperature was provided from two global databases: GPCC for precipitation and NCEP/NCAR for temperature. The study was performed at the time span of 1980-2010 and the results showed that the Lake Urmia basin has experienced a severely drought during 1999-2000. After this period and during eight subsequent years, the negative effects of this drought could not be reduced completely by near normal to wet condition of the basin. Moreover, another severely drought occurred at 2008. RDI value for the 1999 drought was found to be -2.23 which is related to the extremely dry condition. The value of SPI for the same region and same year was obtained as -2.13. This comparison for other severe and extreme cases shows that RDI is more sensitive than SPI at the tails of the phenomenon. It was also observed that after 2000, while the region, in terms of rainfall and drought conditions, is generally close to normal condition, the lake follows a continuous decreasing trend up to the present time. Therefore, one can conclude that in addition to drought, other factors contribute to the drying out of the lake. The results indicated that the anthropogenic effects are responsible to some percent in this disaster. Construction of reservoir dams for agricultural development and other activities for job creation purposes like constructing fish ponds has intensified this crisis. The span of these activities is concurrent to the periods which the drought indices show the fragile condition of the basin in terms of available water resources. This fact emphasizes the importance of drought monitoring as an inseparable part of an IWRM program to prevent a nationwide disaster.
Abdosaleh Rangavar; Gholamali Gezanchian; Hassan Angoshtari; Reza Ghafourian
Volume 1, Issue 4 , February 2010, , Pages 259-265
Abstract
The deposition of transported materials by flood water on soil surfaces in warm and arid region causes some changes in texture, structure, depth and fertility of the soil. According to the study of flood water spreading effect on physical and chemical characteristics of the soil, the study field of flood ...
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The deposition of transported materials by flood water on soil surfaces in warm and arid region causes some changes in texture, structure, depth and fertility of the soil. According to the study of flood water spreading effect on physical and chemical characteristics of the soil, the study field of flood water spreading of Jajarm in North Khorasan province was chosen. This area has located on alluvial fan with 0.75- 1% slop, 146.3 millimeter mean annual rainfall, arid and extra arid climate. For the period of 4 years (1995-1999), the soil samples were collected from recognizable A and C horizons and the depth of 0-30 centimeter (plow layer) from 7 profiles at three primary strips. The quantity of effective parameters on soil characteristics was determined in laboratory. This process was repeated after three times flood water spreading. Obtained data were analyzed: I) by t-student test to compare different properties of soil before and after flood spreading. II) by split plot procedure with three replicates to compare the whole effects at flood water spreading. The samples variance analysis showed that flood water spreading was effective on sand ratio, clay, organic matter, bicarbonate (p<0.05) and was effective too on Ca, Mg, Cl, Na, SAR and EC (p<0.01). There was a significant difference between the samples before and after spreading of flood water. Comparing the average mean of factors including soil salinity, Ca and Mg on A, C and plow layer before and after flood water spreading showed only different between plowing layers, also results showed that the sand to clay ratio and silt in a horizon were decreased. Flood water spreading had no more effect on the other soil characteristics.
Gholamreza Chamanpira; Gholamreza Zehtabian; Hassan Ahmadi; Arash Malekian
Abstract
Utilization of water resources, using a combination of simulation and optimization, are a useful and powerful set for specifying decision-making and management strategies. In this regard, MODFLOW mathematical model, as an efficient and cost-effective tool to evaluate different management options was ...
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Utilization of water resources, using a combination of simulation and optimization, are a useful and powerful set for specifying decision-making and management strategies. In this regard, MODFLOW mathematical model, as an efficient and cost-effective tool to evaluate different management options was used. After providing a conceptual model of the aquifer, requirement data were defined in different versions of the V. MODFLOW (V. 5.33) software. Then, the model was calibrated by the manual method that has higher accuracy than software techniques and validation operations were also carried out. In the simulation process, with the goal of water resource management, the results of modeling and calibration model were used to optimize the groundwater table level. In this study, a linear programming model was used for optimizing the management. Lingo software was used to implement this model and achieve the optimal management. The information needed to solve the problem, was based on the output of a simulation model and optimization options. Due to linearity of objective function, a multi-objective linear programming model was selected to solve the problem. General multi-objective optimization problem with n decision variables, m constraints and p objectives is presented in optimizing relationships. The objectives of the optimization problem were maximizing the profits of agricultural products and minimizing the use of aquifer water. Results indicated that the amount of yield and water use were different before and after optimization. . The amount of annual water consumption before optimization was 92.22 million m3 while after optimization was 75.51 million m3. In other words, the rate of water consumption was reduced by 18 prevent. Results also showed that annual water consumption in agriculture was 31.79 million m3 that shows 65.5 percent reduction compared to the present situation. The amount of benefits before optimization was 47, 798 million Rials, while after optimization it was 63,689 million Rials. In other words, the amount of total profit increased by 33.25 percent. Based on the scenario of a national document (pure water requirement), total profits increased by 15 percent.
Reza Siahmsnsour; Hossein Arzani; Mohammad Jafari; Seyed Akbar Javadi; Ali Tavili
Abstract
The fire is one of the factors that have effect on the natural cycle of ecosystem. This project was established to deal with the effect of the fire on quality features of habitat in the research site of rangelands plants of Zagheh Gorge.It was occur at Khoramabad northeast 35 Km with 33° 29" N, and ...
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The fire is one of the factors that have effect on the natural cycle of ecosystem. This project was established to deal with the effect of the fire on quality features of habitat in the research site of rangelands plants of Zagheh Gorge.It was occur at Khoramabad northeast 35 Km with 33° 29" N, and 48° 42" E, being at 1960 meters above the sea level. This study was formed by travel method, We Used Transects 200 m and plots 1 m that chose vegetation type and plants morphology Both Control area and treatment in Comparison Conclusion show that there are difference significant between canopy cover in the control area, and the fire (p<0.01). Also, after two years, there are not difference significant between organic matter, litter, pebble and rock (p<0.01). But there are significant difference between Soil Conservation level inside and outside of the fire area (p<0.01).This Statistics show that there are difference between the plant production of Class I and III in the control area and the fire with 30.32 and 5.54 in control area and 24.84 and 2.72 gr/m2 in the fire area (p<0.01). The Control area with 69.32 Percent of Canopy Cover is better than the fire area with 51.6(p<0.01) so, high percent of Canopy cover in the Control treatment caused heap of crucibles and numerous branches in this area. Forbs plants, decreased from 46.8 % in the control Canopy Cover area to 35.6 % in the fire area; whereas, grasses increased from 53.2 percent in the control area to 64.4 percent in the fire area. So, the fire is effective on increase of grasses and decrease of forbs.
Abolghasem Dadrasi Sabzevar; Ali Ghazanchian; Mohammad Namaki
Abstract
Social and economical evaluation of watershed management activities, is an important criterion for its validation. The main objective of present study was, identification and analysis of socio-economic impacts of watershed management operations implimented in Gosh village wich is located in 60 km north ...
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Social and economical evaluation of watershed management activities, is an important criterion for its validation. The main objective of present study was, identification and analysis of socio-economic impacts of watershed management operations implimented in Gosh village wich is located in 60 km north of Mashhad. The sample data of this study was consisted of 38 extension workers were randomly selected from the study area based on Cochran’s sampling methodology. The research instrument consisted of three parts in Likert scale. The validity of the questionnaire was analyzed and reliability coefficient was calculated for the questionnaire using Cronbach's alpha ratio of 0.745. These amounts showed that questionnaire has an acceptable ability for data gathering. Factor analysis was the major statistical method. The results offactor analysis indicated that socio-economic effective parameters are increasing garden and farm area, increasing qanats water discharge, increasing rangeland area, and preventing lands flood damages. These four factors, in general, had more than 60 percent of the total variance. Final results indicated that watershed management activities have improved qanats water discharge by flood control and aquifer rechrge and increased the area of Agricultural and garden lands. Also, conseving activities in rangelands caused improving of vegetation cover density and the area of rangelands.
Alireza Majidi; Gholamreza Lashkaripour; Ziaoddin Shoaei
Abstract
The swelling potential of fine-grained soils is one of effective parameters on soil mechanical behavior and erosion and fundamental data required for the design, construction and choosing construction materials. This paper presents a multi-layer perceptron (MLP) artificial neural network (ANN) model ...
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The swelling potential of fine-grained soils is one of effective parameters on soil mechanical behavior and erosion and fundamental data required for the design, construction and choosing construction materials. This paper presents a multi-layer perceptron (MLP) artificial neural network (ANN) model to prediction of the swelling potential of marl soils. Marl soil is a fine-grained soil. The Levenberg-Marquadt learning algorithm was used to train the networks. Existing models prediction of soil swelling potential based on physical and soil index parameters. The present study considers the effects of chemical factors on the behavior and characteristics of fine-grained soils along with the common soil index parameters. The model used physicochemical and mechanical test results from 60 marl soil samples taken from marl formations in the Neogene basin in central Iran (Tehran, Qom and Saveh regions). The models were designed to use different input data sets and structures to determine which soil properties and ANN structures correlate well with the swelling potential parameter. Electrical conductivity (EC) of saturated soil was a new input parameter used in addition to the physical and soil index parameters that include the atterberg limit, activity, content of the clay and silt, initial of porosity ratio and dry density. Values of RMSE, R2 and MCE (evaluation criteria) related to the best model with the physical parameters LL, PI, A, M, C and Yd0 are respectively 0.89, 2.3, 0.84, and for the best model with the physical parameters LL, PI, M, C, Yd0 and EC are respectively 0.92, 1.7, and 0.91.The results of the evaluation criteria models show that inclusion of EC improved the accuracy of the model. It was found that the accuracy of the generalizations and estimations of the ANN models was further increased by clustering data before the data division stage by k-means method to Compared with hierarchical method.
Mohammad Rasoul Rajabi; Ali Nasiri Khiavi; Mahin Kalehhouei; Sonia Mehri; Azam Mumzaei; Khadijeh Haji; Abdulvahed Khaledi Darvishan
Abstract
The present research aimed at presenting a new SWOT strategy for integrated watershed management of Asiabrood in Mazandaran Province. At first, the SWOT matrix and the tables identifying the strategic indicators of internal and external factors were formed and then internal and external evaluation matrices ...
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The present research aimed at presenting a new SWOT strategy for integrated watershed management of Asiabrood in Mazandaran Province. At first, the SWOT matrix and the tables identifying the strategic indicators of internal and external factors were formed and then internal and external evaluation matrices were analyzed. A new strategy used in the discussion of the weighting of SWOT strategies was based on the fact that the final value of each strategy was multiplied by the number of effective strengths and opportunities and the final results were analyzed based on these priorities. Based on analysis of strengths and weaknesses, nine strengths and eight weaknesses were identified. The suitable water quantity and quality with a weight of 0.444, low air temperature with a weight of 0.395, mineral water utilization with a weight of 0.288 and economic poverty with a weight of 0.493, respectively, were the most important strengths, weaknesses, opportunities and threats. According to the internal-external factors evaluation matrix in the SWOT model, the strategy of increasing the sense of satisfaction of residents, based on the conventional method and the new strategy, gave the highest value. With a careful look, it can be concluded that strengthening the sense of satisfaction between residents happens when People problems in different sectors of livelihoods, including economic, social and cultural, have been considered more and, by presenting correct programs, have increased satisfaction and reduced migration to urban areas. In general, it can be concluded that due to the problems and solutions presented in this study, proper and applied planning should be used to compensate for the weaknesses and to strengthen the strengths as much as possible in the development of Asiabrood watershed.
Mohammad NazeriTahrudi; Yousef Ramezani
Abstract
Estimating return period of hydrological processes such as flood flow, maximum discharge, drought and etc, is related directly to selecting a suitable probability distribution function. With selecting a proper distribution function, estimated return period will be more close to actual data and error ...
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Estimating return period of hydrological processes such as flood flow, maximum discharge, drought and etc, is related directly to selecting a suitable probability distribution function. With selecting a proper distribution function, estimated return period will be more close to actual data and error will be reduced. So, it should be tried to select the best probability distribution function. In this study, using daily discharge of western rivers of Urmia Lake, as well as the annual mean method, the data of the drought volume of these rivers were extracted. Several distributions from each of the continuous distributions, such as the continuous distribution of generalized maximums and wakeby, the continuous non-zero Erlang distribution, the continuous Johnson SB distribution, and the continuous boundary of Normal distribution for fitting the data of the dry volume of the western rivers Lake Urmia was used in the 38-year statistical period. Anderson-Darling and Kolmogorov-Smirnov tests used to compare results of each distribution. Also correlations between the data obtained from the sample data and statistical models computed. The results of the frequency distribution of the data of the three rivers showed that among the distributions of the continuous group, the advanced statistical distributions of Wakeby and Johnson SB had the best distribution and also had better performance than the conventional statistical methods.
Ali Talebi; Zahra Eslami; Abdolhossein Abbasi
Abstract
Identification of areas with high potential for flooding in the basin is one of the most important activities in flood control and reducing its damages. In this research, the possibility of prioritizing nine sub-basins from flooding point of view has been studied in Eskandari Watershed, using HEC-HMS. ...
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Identification of areas with high potential for flooding in the basin is one of the most important activities in flood control and reducing its damages. In this research, the possibility of prioritizing nine sub-basins from flooding point of view has been studied in Eskandari Watershed, using HEC-HMS. Also, the priorities of sub-basins were studied using flooding coefficient and peak discharge per unit area experimental methods. In order to run HEC-HMS model, plan rainfall with two, five, 10 and 50 years return periods were used. Flood hydrographs associated with each precipitation were calculated for each sub-basin, using the sequential removal method of sub-basins and removing CN in each sub-basin in each run of the model and their effect were computed in flood generation. Results showed that sub-basin I has the first priority is flooding potential, considering independent and depended sub-basins. Prioritization of sub-basins with two experimental methods had different results that are independent from a particular process. As E sub-basin had sixth priority in flooding coefficient method and third priority in the peak discharge estimating method. By comparing the prioritization of sub-basins in HEC-HMS model in different return periods, results showed that sub-basins prioritization in different return periods has specific process. Therefore, HEC-HMS model is more efficient compared to experimental methods in sub-basins prioritization in flooding.
Mehdi Mahbod; Saeedeh Safari; Mohammaf Rafie Rafiee
Abstract
Determining precipitation spatial pattern in a catchment is necessary for the calculation of hydrologic quantities such as runoff flow and soil moisture content. Sparse meteorological stations as well as spatial variability of precipitation are major obstacles for accurate spatial estimation of precipitation. ...
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Determining precipitation spatial pattern in a catchment is necessary for the calculation of hydrologic quantities such as runoff flow and soil moisture content. Sparse meteorological stations as well as spatial variability of precipitation are major obstacles for accurate spatial estimation of precipitation. The development of remote sensing technology and the possibility of using satellite precipitation products has facilitated attaining spatial precipitation patterns. However, low spatial resolution of satellite precipitation products highlights the need for downscaling methods. Nineteen predictive models were fitted using Regression Learner toolbox in MATLAB software. Annual TRMM precipitation data were downscaled from 2001 to 2017 using Normalized Difference Vegetation Index (NDVI), land surface temperature, land elevation and coordination. Models are divided into five general categories: Linear Regressions, Decision Trees, Support Vector Machines, Ensemble models and Gaussian Process Regression models. Comparing the downscaled TRMM data with gauges data, Boosted Ensemble model had the lowest root mean square error and highest correlation coefficient. On the other hand, two methods of Geographical Distance Adjustment (GDA) and Geographical Ratio Adjustment were compared for calibrating the downscaled precipitation. Smaller errors were obtained using GDA in all models.
Rohallah Taghizadeh Mehrjardi; Fereydoon Sarmadian; Mehdi Tazeh; Mahmood Omid; Norair Toomanian; Mohammad Javad Rousta; Mohammad Hassan Rahimian
Abstract
Recently, researchers are increasingly employed Digital Soil Mapping (DSM) techniques to overcome traditional soil mapping difficulties. Apparently, due to the large heterogeneity of soil environments, sampling may be the most important step in digital soil mapping studies. Therefore, in this research, ...
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Recently, researchers are increasingly employed Digital Soil Mapping (DSM) techniques to overcome traditional soil mapping difficulties. Apparently, due to the large heterogeneity of soil environments, sampling may be the most important step in digital soil mapping studies. Therefore, in this research, we employed three different sampling strategies including Latin hypercube, Fuzzy-K-Means and random sampling to achieve the best spatial distribution of soil samples in an area around 720 km2 located in Ardakan region, Yazd province, Iran. Auxiliary data that used in this study, were including terrain attributes, Landsat 7 ETM+ images and a geomorphologic surfaces map. Based on statistical criteria (i.e. mean and standard deviation), results showed that Latin hypercube is the best sampling method. For instance, in the selected points, the mean of wetness index is 18.19 which is the same as the mean of all area. Similarly, the mean of Multi-resolution Valley Bottom Flatness (MrRVF) in the points selected by Latin hypercube strategy is very similar to all area. Moreover, histogram of auxiliary data in selected points (samples) was more similar to histogram of auxiliary data in all area. Also, the results indicated that a good geographical coverage (Fuzzy-K-Means) does not adequately represent the distribution of the variables. Therefore, Latin hypercube is the best strategy to determine sample locations in our study area and hence, it is recommended that researchers apply Latin hypercube method in future digital soil mapping studies.
Rahim Kazemi; Samad Shadfar; Reza Bayat
Abstract
Information on the hierarchical importance of the factors influencing on the spatial distribution of springs in a watershed are required for the development of the water quality and quantity management plan. In this regard, we address the integration of GIS and decision support tools, for zoning prone ...
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Information on the hierarchical importance of the factors influencing on the spatial distribution of springs in a watershed are required for the development of the water quality and quantity management plan. In this regard, we address the integration of GIS and decision support tools, for zoning prone areas. In this research to determine hierarchical importance of the elements on the water resources development in Karst regions, first with literature review and field studies, the effective parameters in occurrence of spring were selected. Then thematic layers of these parameters in GIS environment were prepared. Each layer separately crossed with the spatial distribution of spring's layer and priorities of each sub layer with respect to each other in terms of frequency of spring's occurrence were determined. Finally, using the analytic hierarchy process, factors affecting the occurrence of this phenomenon and the weight of each factor was calculated by Expert Choice software. Results showed that the weight of the top layer assigned to the lithology and carbonate substrate alone formed 54% of the weight of this layer. The next layers in order of importance were including the layer of the slope and elevation classes, structural elements, lineaments, limestone contact and drainage layer. Potential map prepared by this method, match 76 percent with the spatial distribution of springs.
Rahim Kazemi; Amir Safari; Amir Karam; Jahangir Porhemat
Abstract
Estimation of Base Flow Index (BFI), has always been one of the most important issues in hydrology. Base flow separation process, often is done using daily stream flow data. Lack of full coverage of daily data for the whole country, may lead to some errors for estimating the base flow and its index. ...
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Estimation of Base Flow Index (BFI), has always been one of the most important issues in hydrology. Base flow separation process, often is done using daily stream flow data. Lack of full coverage of daily data for the whole country, may lead to some errors for estimating the base flow and its index. In this research, base flow index in some catchments of Karkhe basin based on daily and monthly stream flow data and using six algorithms were extracted. Three based on recursive digital filter (One-parameter, two parameter and Lynie & Hollick algorithms), and the others on simple smoothing including, Local minimum, Fixed interval and sliding interval methods. Results were analyzed using different statistical methods such as standard deviation, mean absolute error, relative error and other descriptive methods. The results showed that minimum relative error of monthly data compared to daily data was related to two parameter algorithm with 2.45% and the maximum was related to Lynie & Hollick algorithm with 84.19 percent .In overall conclusion, two parameter algorithms because of low relative error, minimum Mean Absolute and Root Mean Square Error was recognized as a suitable method for the extraction of base flow using monthly data in the absence of appropriate data daily.
Rouhangiz Akhtari; mohammad Rostami; Bahram Saghafian; Mohammad Elmi
Abstract
Introduction
The construction of check dams in the branches is one of the common methods of watershed management to control sedimentation, watercourse stability and reduce the flood hydrograph from the time of concentration and peak flow. In Iran, despite being 50 years old, in the wide implementation ...
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Introduction
The construction of check dams in the branches is one of the common methods of watershed management to control sedimentation, watercourse stability and reduce the flood hydrograph from the time of concentration and peak flow. In Iran, despite being 50 years old, in the wide implementation of this small-scale structure by the bodies affiliated to the country's Natural Resources and Watershed Management Organization as an executive body, a suitable quantitative and qualitative evaluation method has not been provided. In expressing the effectiveness of this structure, it is inevitable to simulate natural conditions in the presence and absence of this structure in hydrological and hydraulic models. Of course, field visits and measurement of the relevant parameters in the field are also considered to be primary measures in the verification of the simulation and the approximate expression of the effectiveness. The investigations showed that in many researches, the effect of correction dams on the runoff hydrograph has been considered. Simulation of the dams has been done hydrologically with changes in the slope of the waterway and basin time concentration or by using the method of routing in the reservoir that according to simplified hypotheses, estimates more than reality. Hydraulic simulation is more precise but has its own complexity and obstacles. Therefore, in this study, we tried to apply the effectiveness of improving check dams in runoff hydrograph by using both the accuracy of hydraulic simulation and the lack of complexity of hydrological relations. The effectiveness of check dams is computed by determining and applying coefficients in the waterway output hydrograph without improving check dams to obtain the waterway output hydrograph with check dams.
Material and methods
In this research, the effectiveness of successive check dams in reducing the output hydrograph of a triangular channel with three lengths of 1000, 2000 and 3000 meters in three longitudinal slopes of five, 10 and 15%, using the MIKE 11 hydrodynamic model, is considered. In this study, it is assumed that series check dams with a height of 2.5 meters will be constructed in each triangular canal, therefore, the number of check dams will vary from 20 to 180 based on their length and slope. In this study, the output hydrograph of the triangular channel was considered as the dependent variable, and the input hydrograph, channel length, and channel slope were considered as independent variables. Variations of outflow hydrograph peak discharge were investigated under two scenarios. The first scenario for the condition where the channel is without improving check dams and the second scenario for the case where the channel was studied with full of sediment series check dams in order to simulate the effectiveness of the dams in a waterway with hydrological parameters. Two criteria were defined to express effectiveness: the percentage of the intensity of hydrograph routing and the percentage of flow discharge change. The percentage of changes in peak discharge of the hydrograph is determined in relation to the peak discharge of the inlet hydrograph. In other words, "attenuation coefficient" was named based on the difference between inlet and outlet discharge for the scenario and for changes in length of waterway, slope and different amounts of inlet hydrograph. The percentage of change in peak flow discharge from the second scenario compared to the first scenario was also considered as the percentage of flow discharge change.
Results and discussion
Evaluation of the model results for hydrograph routing along the channel in exchange for changing independent variables in the form of two scenarios resulted in decreasing peak flow, increasing the base time of output hydrograph, and delayed time due to trending. The existence of check dams has doubled the change in the mentioned parameters. As the longitudinal slope of the waterway increases, the amount of storage in the canal decreases, and the output discharge and therefore the intensity of the routing (decrease in peak outflow relative to the inlet). Increasing the volume of inflow decreases the intensity of the routing. Routing intensity has an inverse relationship with longitudinal slope and has a direct relationship with channel length. Increasing the number of check dams increases the amount of storage in the canal and as a result, slope reduction occurs and the changes in output discharge are greater than inlet flow. Therefore, the intensity of routing increases. The main purpose of this study was to determine the effectiveness of improving check dams in reducing peak discharge of ouflow hydrograph from a triangular channel based on different conditions using a mathematical model. After performing various simulations and investigating different methods, it was observed that the effects of improving check dams on a outflow hydrougraph can be modeled as the effect of a linear reservoir with a lag time at the end of the channel. In other words, two linear reservoir function and a lag time function are applied to independent variables to obtain the dependent variable. For both output hydrographs obtained in the channel without and with improving dams, K values were estimated as linear reservoir function and TL as lag time function. The average storage coefficient (K) of the linear reservoir was estimated 500, 1100 and 1400 seconds respectively for lengths of 1000, 2000, and 3000 m and for three slopes. The mean lag time for the three mentioned lengths was 540, 1750, and 3700 seconds, respectively. As the length of the channel increases, the slope of the canal, as well as the inflow to the canal, as well as the inflow to the canal decreases, and the amount of the above parameters and therefore the attenuation coefficient increases.
Conclusion
If a stream is selected for the construction of improving check dams and the output hydrograph is available using empirical, hydraulic, and hydrological models in the absence of check dams, the outflow hydrograph from the stream will be simulated and modified for the existence of small-scale structures by applying the linear reservoir storage coefficients and the lag time obtained from this research. In this way, the effectiveness of the construction of improving check dams in flood control will be achieved in the mentioned waterway.
Ali Mohammad Ghaeminia; Mohammadali Hakimzadeh Ardakani
Abstract
With regards to the wind erosion phenomenon importance, it is vital to quick identification of areas that are sensitive to dust removal and wind erosion processes. In this research, a lightweight and efficient device is designed, fabricated and evaluated in order to create conditions for applying constant ...
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With regards to the wind erosion phenomenon importance, it is vital to quick identification of areas that are sensitive to dust removal and wind erosion processes. In this research, a lightweight and efficient device is designed, fabricated and evaluated in order to create conditions for applying constant wind stress on soil particle surfaces and measuring erosive particles. The production of wind power by a blower and measuring the amount of loose and unstable particles that were harvested in the reservoir with the highest efficiency were the principles of designing the device. The prototype of the device was designed using components and parts, and the device was evaluated in the field. The device is usable by a user in the field without the need for a power generator and the weight of the particles collected in the tank indicates the relative erodibility of the test site to the wind. Using the air filter bag (tank), it was possible to achieve a minimum loss of fine particulate matter and has been reduced the measure of less than the actual amount of land erosion. The result of the comparison of the sensitivity of soil sensitivity to erosion by the device in desert lands of northern Yazd-Ardakan Plain with the height of winding of the soil with the installation of the index showed that this device has good capability (R2= 0.57) in the rapid detection of areas susceptible to wind and without measuring physical and chemical properties of the soil, there is an early identification of wind erosion-sensitive land. This device does not actually simulate the natural processes of wind erosion created by the particle saltation, but using it, a new index can be obtained for assessing soil erodibility and subsequently identified the location of dust emissions.
Houshang Jazi; Zeynab Karkehabadi; Saeid Kamyabi
Abstract
The 21st century will face the controversial debate on sustainable development with the priority of sustainable urban development. Urban planning has not paid enough attention to the sustainability of cities dependent on natural resources. The development of the city without regard to its watershed makes ...
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The 21st century will face the controversial debate on sustainable development with the priority of sustainable urban development. Urban planning has not paid enough attention to the sustainability of cities dependent on natural resources. The development of the city without regard to its watershed makes no sense. Urban strategies have focused on the implementation of static plans, followed by the modernist school, and the need for the interconnection, sustainability, and vitality of urban watersheds, which are the city's feeding vessels, has not been addressed. This research was conducted with the main purpose of explaining the sustainable development strategies of Garmsar city based on integrated management of urban watershed by understanding the factors affecting the stability of the watershed and analyzing the causal relationships of urban sustainability in the operation with Halbehrood watershed stability factors. The research method is descriptive-analytical and collecting the information required for research through library studies and field observations. In order to analyze the information, the DPSIR environmental evaluation model, the AHP model and the SWOT model have been run integrated to determine the best sustainable development strategies of the Garmsar city. The results of the studies showed that Garmsar city is not sustainable as a city dependent on urban watershed and it is not sustainable in terms of providing necessary resources of the basin, but the sustainability of the watershed and the Garmsar city is possible through the implementation of Strategies appropriate to existing resources. Based on the results of quantitative and analytical matrix analysis, eight of the main identified strategies were prioritized. Among them, the development of a joint program for water, agriculture and natural resources in order to explain the effective measures of the chain of production, distribution, and use of water in the upstream lands is the first priority.
Mirhassan Miryaghoubzadeh; Seyed-Amin Khosravi
Abstract
Nowadays remote sensing is known as practical method for studying Land Use (LU)/Land Cover (LC) changes. Due to the vast area of agricultural lands, Barandouzchay Basin is one of the important watersheds among all of watersheds in Lake Urmia River Basin. In this study, in order to evaluate LU/LC change, ...
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Nowadays remote sensing is known as practical method for studying Land Use (LU)/Land Cover (LC) changes. Due to the vast area of agricultural lands, Barandouzchay Basin is one of the important watersheds among all of watersheds in Lake Urmia River Basin. In this study, in order to evaluate LU/LC change, Landsat-5 TM and Sentinel-2A satellite images were used from 2005 to 2016. The maximum likelihood classification method was used to prepare LU/LC maps. The results of overall accuracy and Kappa coefficient showed high accuracy of maximum likelihood classification method. In order to extract the change detection maps, image difference method was used. Results showed that orchard and nonproductive trees have been increased during 2010-2016 years in Barandouzchay Basin. In the years before 2010, trees were relocated by young trees in Barandouzchay Basin. Drylands and bare lands are classified in the 2005-2010 years which has been increased. The most land use change was related to urban and lowest change was related to rainfed area from 2005 to 2010 and the most land use change is related to bare lands and lowest rate is related to nonproductive tree area from 2010 to 2016.
Alireza Dehghani; Mohammadebrahim Banihabib; Saman Javadi
Abstract
Due to lack of surface water, the most important option for water supply in arid and semi-arid areas is from groundwater resources and one of the engineering measures to use the floods for improving groundwater resources is the implementation of artificial recharge systems. The purpose of the present ...
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Due to lack of surface water, the most important option for water supply in arid and semi-arid areas is from groundwater resources and one of the engineering measures to use the floods for improving groundwater resources is the implementation of artificial recharge systems. The purpose of the present study is to provide a model-based framework based on several quantitative indicators such as recharge efficiency and flood attenuation rate for assessing the performance of artificial recharge systems. Considering the capabilities of hydrological, hydraulic and seepage models, the combination of these models was used to estimate the parameters of the indicators. Finally, by determining the indices for floods with different return periods, their average values were determined using the expected value. The studied system (Emamzade Abdollah, Sorkheh) had a good performance based on recharge efficiency and flood attenuation rate indicators in events with frequency of more than 0.2, and the average value of these two indicators was 0.54 and 0.93, respectively. Due to the model based characteristic of the proposed framework, it has the potential to be used in similar cases.
sima rahimi bondarabadi; Bahram Saghafian; Tayeb Raziei
Abstract
Introduction
Monitoring of hydrological droughts is one of the basic needs of water resources management in watersheds, especially in the field of water agriculture. Drought is divided into three major groups: meteorology, agriculture and hydrology. Hydrologic drought can be studied in different ways. ...
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Introduction
Monitoring of hydrological droughts is one of the basic needs of water resources management in watersheds, especially in the field of water agriculture. Drought is divided into three major groups: meteorology, agriculture and hydrology. Hydrologic drought can be studied in different ways. One of the common methods is the use of low flow indexes and threshold level approach.
Materials and methods
In this research, the minimum flow indices (Q75, Q90 and Q95) extracted from the flow continuity curve and minimum flow series (10 and 30 days) as well as the amount of flow deficit for hydrological drought monitoring in the Caspian Sea Basin were investigated and evaluated. For this purpose, 40 hydrometric stations with 41-year statistics (1970-2011) were selected. In the next step, the data of the studied stations were evaluated in terms of homogeneity, independence and randomness. Then, with the help of hierarchical cluster analysis and step-by-step regression, hydrological homogenous areas were determined and regional analysis of these indicators was done.
Results and discussion
In order to investigate the characteristics of the minimum current in the Caspian Sea Basin, first, the continuous flow curve was drawn for each of the stations, and then, three indices Q75, Q90 and Q95 were calculated for each of the stations. For the spatial comparison of the minimum flow, the specific minimum discharge or qs (minimum discharge value divided by the area) was used. qs75 index varies between 0.0006 and 13 m3s-1per km2. The value of qs75 is less (drier) in the eastern parts and in the western parts of the region, the amount of dryness of the stream is less than other places. Examining the spatial distribution maps of these three indicators shows that the trend of their spatial changes is almost similar and they all indicate that the western regions of the Caspian Sea Basin are more humid than the eastern and central regions. In the next step, to examine the minimum flow indicators, a series of minimum flows of 10 and 30 days was prepared. By comparing distribution parameters with the help of scoring method, Log-Pearson type 3 distribution was selected as the best distribution in most stations. After choosing the most appropriate distribution, the values of the 10-day and 30-day minimum indices with different return periods were calculated. Examining the average indicators shows that the minimum discharge value of 10 days with a value equal to 0.01 m3s-1 in Vatana Station (12-035) located in the east of the basin and the highest with a value of 19.2 m3s-1, it is at Rudbar Station (17-034) in the western region of the basin. Regarding the average minimum discharge of 30 days, the lowest value is equal to 0.20 m3s-1 and the highest value is equal to 8.52 m3s-1in these two stations. In order to investigate the temporal changes of hydrological drought intensity, the annual time series of 10-day and 30-day low flow at each station were plotted in relation to the year of their occurrence, in order to determine the trend of changes in the drought situation in different years. Examining the time trend of the minimum flow indicators on the graphs, shows a decrease in the value of the indicators in recent years and a negative trend of the indicators. In other words, the graphs in almost all stations show hydrological droughts (reduction of minimum flow indicators) during recent years. In order to determine the length of minimum flow periods, 10 and 30 day moving averages of discharge were compared with Q90 index value in different stations. The results show that the persistence of drought in the central parts of the Caspian Sea Basin (Pulor, Razan, Karsang, Tange Lavij, Pol Zoghal and Zowat sub-basins) is more than the rest of the regions, these sub-basins are located in Mazandaran Province. The lowest duration of drought (between 22 and 25 days) is related to the sub-basins of Shalman, Pol-e-Sazman, Pashaki, Astana and Tutkabon in the eastern part of the Caspian Sea Basin and in Gilan Province. The eastern parts of the basin have also experienced a drought period between 28 and 30 days.
Conclusion
Results indicate that the years 1990 to 2010 have undergone severe and long droughts in most of the stations. The review of the spatial distribution of indexes shows better conditions in the western parts of the study area compared to the eastern sections in terms of dryness. However, the duration of hydrological droughts in the central study area is longer than in other parts of the basin. Investigating the time trend of the indexes also shows the increase in the frequency and duration of hydrological droughts in recent years. A comparison of different indexes shows that all of them have similar results in the region. The results of cluster analysis divided the area into three distinct homogenous units (in 0.01 significant level). The result of the regional analysis showed that in the eastern homogeneous region, the influencing factor on low flow indexes is elevation, while in the central and western regions, the drainage area and density have a greater impact.
Reza Izadpanah; Seyed Ali Asghar Hashemi; Alireza Farrokhi
Abstract
Estimation of sediment bed load is one of the most important issues in river engineering. Accordingly, several methods and relations have been proposed to estimate the bed load in streams for the past decades. The present research aimed to select the most accurate method to estimate bed load through ...
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Estimation of sediment bed load is one of the most important issues in river engineering. Accordingly, several methods and relations have been proposed to estimate the bed load in streams for the past decades. The present research aimed to select the most accurate method to estimate bed load through the testing of various relations to estimate the bed load of the Hablehroud River. The hydraulic and geometric specifications of the Hablehroud River at Bankouh hydrometry station were measured on specific dates by the expert team. The bed load rate was calculated by four different relations in Bankouh hydrometry station from 2011 to 2017. Resultant data showed that the Toffaletti method with RMSE, MAE, and R2 of 20.07, 10.86, and 83 estimates more accurate in comparison with other methods. The sensitivity analysis of the Toffaletti equation revealed that the bed load depends greatly on the velocity of the river flow. Such a method is firmly recommended to use in the mountainous region.
Khadije Haji; Raoof Mostafazadeh; Abazar Esmali-Ouri; Shahnaz Mirzaei
Abstract
Assessment of temporal and spatial variations of runoff and sediment is needed to sustainable management of watersheds, soil erosion and sediment control, and watershed conservation projects. The amount of discharge and sediment concentration rates were assessed in 15 river gauge stations located in ...
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Assessment of temporal and spatial variations of runoff and sediment is needed to sustainable management of watersheds, soil erosion and sediment control, and watershed conservation projects. The amount of discharge and sediment concentration rates were assessed in 15 river gauge stations located in the West-Azarbaijan Province in a 20-years recorded data using double-mass curve and annual variation analysis (coefficient of variations, annual distribution of regulating coefficient, and concentration rate). The logarithmic rating curve equation was used to sediment estimation according to the nature of discharge and sediment load variations. According to the results, the maximum discharge and sediment amount were observed in the May of spring season that can be related to the high amounts of snow melt and spring precipitation and associated high river flow discharge in the study area. The cumulative double mass curve of the runoff and sediment had a constant slope in the Pole-Bahramlou, Choplojeh, Sarighamish, Peighale, Naghadeh, Dorood, and Chapasabad stations, in which the sediment load is consistent with the runoff amounts. While, the decreasing pattern of sediment load was observed in the Dizaj, Urmia, Dashband, Ghasemlou, and Bayazidabad, which can be related to rainfall decrease and conservation measures (dam construction) and lower sediment amount in the study period. The highest coefficient of variation of runoff and sediment was observed in Pole-Bahramlou (16 and 173 percent), respectively. The highest monthly runoff-sediment uniformity was identified in Chaparabad station, where the lowest concentration rate of runoff and sediment were observed by 0.25 and 0.35 percent respectively; while, the Urmia station identified as a high rate of runoff and sediment concentration rate with 0.58 and 0.84 percent in the study area. It can be concluded that the seasonal variations of runoff and sediment had a consistent manner and some different spatial variations due to climatic, hydrologic and anthropogenic conditions.
Nazila Yaghoob Nejad ASL; Fariba Esfandiary Darabad; Sayyad Asghari Saraskanroud; Amir Karam
Abstract
Alterations in river morphological quality are derived from quantification of human pressures as well as river morphological alteration. Taleghan River is an important source of water for the irrigation of Agri cultural lands in Qazvin Plain. For some economic considerations of Taleghan dam reservoir ...
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Alterations in river morphological quality are derived from quantification of human pressures as well as river morphological alteration. Taleghan River is an important source of water for the irrigation of Agri cultural lands in Qazvin Plain. For some economic considerations of Taleghan dam reservoir on the river as well as geology, some reaches of the river have undergone alterations. It seems important to morphological quality assessment in order to planning issues. Our study’s aim is to contribute to the morphological quality evaluation based on a revisited Morphological Quality Index (rMQI) protocol. The rMQI scoring system allows for the quantification of changes when compared to reference conditions. The rMQI corresponds to less than 30%, reflecting a good morphological quality; the rMQI corresponds to more than 30%, reflecting an extremely poor morphological quality. In this context, the paper presents all of the Taleghan River reaches suffer from an extremely poor morphological quality. Causes of degradation are meandering as well as numerous anthropogenic pressures in the upstream part of the basin. In order to revive Taleghan River as well as improve its water quality, preserving and remediating native vegetation, prevention and remediation of land use degradation in upstream's basin as well as river bank erosion control measures can use hard and soft strategies engineering are recommended.
Behnam Farid Giglou; Reza Ghazavi; Siamak Dokhani
Abstract
Rivers have always been considered by human societies as one of the main sources of drinking water and agriculture during human life and have been very effective in the formation of human civilizations. Aras River is a border river that is one of the most important sources of drinking water in many surrounding ...
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Rivers have always been considered by human societies as one of the main sources of drinking water and agriculture during human life and have been very effective in the formation of human civilizations. Aras River is a border river that is one of the most important sources of drinking water in many surrounding towns and villages. The aim of this study is to evaluate the water quality of Aras River at present and predict it for the future period under RCP release scenarios. In this study, monthly data of discharge, precipitation, TDS, SO4, EC, BOD, Do, COD, No3, and Po4 during the statistical period of 1995-2018 were analyzed using WQI water quality index. Also, changes in precipitation and temperature were predicted under RCP release scenarios. To investigate the impact of climate change on river water quality, regression relationships were established between rainfall, discharge and water quality parameters and according to the forecast for rainfall and discharge in the period 2017-2036, water quality conditions with WQI index for scenarios. RCP8.5, RCP4.5 and RCP2.6 were calculated. In addition, the effect of changes in climate parameters on the quality parameters of phosphate and nitrate was estimated using the SWAT model for the future. The results of statistical studies showed that the amount of nitrate, phosphate and COD parameters in all three scenarios will be increasing. Also, the simulation results of phosphate and nitrate parameters using SWAT model have predicted incremental conditions for all three scenarios. The results of the effect of climate change on water quality using the WQI index showed that water quality is in poor condition at baseline (WQI index is 15.69) and under the influence of climate change based on scenarios of RCP8.5, RCP4.5 and RCP2.6 WQI value 11.17, respectively; 12.23 and 12.45 and water quality will change to very bad, which requires attention to the quality of the Aras River and the prevention of pollutants.
Khodayar Abdollahi; Samira Bayati; Mohammadali Nasr Esfehani
Abstract
Variations in the type of storms, distribution of rainfall over the basin and other influencing factors such as soil texture, land use types and slope classes leads to significant differences in the spatial distribution of water components. In this study, using the monthly scale data, including rainfall, ...
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Variations in the type of storms, distribution of rainfall over the basin and other influencing factors such as soil texture, land use types and slope classes leads to significant differences in the spatial distribution of water components. In this study, using the monthly scale data, including rainfall, groundwater depth, temperature, evaporation and wind speed, WetSpass-M model was used to analyze the spatial distribution of water components at the basin of interest in the south-east of the Karun Basin. The modeled results were calibrated to simulate the monthly streamflow. Considering the fact that the Vanak Basin is a mountainous area, the snow cover maps were introduced to the model in order to include melting process. Evaluation of the model's performance using the Nash-Sutcliff coefficient of 0.61 and 0.54 during the calibration and validation period, respectively showed that this objective function was acceptable. This means the model has produced acceptable outputs. After this step, the spatial distribution of runoff and groundwater recharge in relation to various land use and slope classes were studied. Analysis of the monthly spatial distribution of runoff and groundwater recharge maps showed that due to change in slope and land classes, the runoff coefficient has a significant impact on both groundwater recharge and runoff. In such a way that the forest areas and mild slopes have generated an average 138 mm annual runoff and 596 mm annual recharge accordingly, it means a lower runoff coefficient and higher recharge values. The highest montly recharge value was in February (82 mm in thin forests with the slops of less than 10˚). This may be used to provide a better understanding of the factors affecting the distribution of water balance components or help in the maintenance, management and planning of surface water and groundwater resources.
