Aboalhasan Fathabadi; Vahid Anamoradi
Abstract
In hydrological models, in order to better model the runoff process, it is necessary to calibrate the model using observational data. In the process of calibration of hydrological models, in addition to the quality of observation data and the optimization algorithm, the objective function also affects ...
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In hydrological models, in order to better model the runoff process, it is necessary to calibrate the model using observational data. In the process of calibration of hydrological models, in addition to the quality of observation data and the optimization algorithm, the objective function also affects the efficiency of the model. In most studies, statistical criteria such as NSE and RMSE are used as objective functions in the calibration process of hydrological models. Given the structure of the model and the relationships used in each of the evaluation criteria, each of them has good performance in simulating a part of the hydrograph. One of the important parameters of each basin, which is a kind of basin reaction indicator for different discharge values, is the Flow Continuity Curve (FDC). In this study, the efficiency of objective functions based on flow continuity curve and statistical objective functions in optimizing the parameters of the HBV hydrological model in Ziyarat Watershed of Golestan Province was investigated and compared. After introducing input data to model using DDS algorithm, model was calibrated 100 times for each objective function. When model was calibrated, using optimized parameter sets model output for calibration and validation period was obtained. Results showed that criteria such as NSE and KGE have better performance in predicting high flows, criteria such as RMSE and AME predicted moderate flow discharge better and criteria based on FDC had better performance in predicting low flows. In prediction different parts of hydrograph FDC objective function has the best performance, RMSE and MAE were in sound order and NSE and KGE did not have suitable performance.
Seyed Hamidreza Sadeghi; Zeinab Hazbavi; Mehdi Gholamalifard
Abstract
Developing an understandable and comprehensive conceptual model for watershed health assessment is one of the main priorities of many various managerial and policy making projects in the world including the mega project on the integrated watershed management of Iran. Towards this, the present study as ...
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Developing an understandable and comprehensive conceptual model for watershed health assessment is one of the main priorities of many various managerial and policy making projects in the world including the mega project on the integrated watershed management of Iran. Towards this, the present study as the pioneering research in the country has been conducted to customize the reliability, resilience and vulnerability (RelResVul) conceptual model based on hydrological data to assess watershed health. To this end, firstly the long-term data of discharge of the Shazand Watershed that located in Markazi Province was prepared and the flow duration curve was accordingly derived. Secondly, the appropriate thresholds of low and high flow discharges as prerequisites for watershed health assessment were applied to the RelResVul conceptual model. Hence, the reliability (Rel), resilience (Res) and vulnerability (Vul) indicators were calculated for four node years of 1986, 1998, 2008 and 2014. Finally, the general health state of the Shazand Watershed and its different sub-watersheds was zoned on the basis of two low and high flow discharge criteria through the geometric integrating of the mentioned indicators. The results showed that for the four study years respectively, 59, 53, 68 and 66 % of the watershed in terms of low flow discharge as well as 19, 22, 54 and 38 % of the Shazand Watershed in terms of high flow discharge were situated beyond relatively healthy state. The watershed health index assessment indicated the moderate and relatively healthy states with improving trend for low flow discharge criterion and moderate healthy state with constant trend for high flow discharge criterion. In addition, the results were verified the spatial changeability of watershed health state in different sub-watersheds for the study years.
Davoud Nikkami
Abstract
Using erosion plots is a way to research on soil erosion and conservation that with different dimensions, which are constructed in the natural arenas or in laboratories. Mistakes and false conclusions are common task that should be avoided when sampling runoff and sediment from the tanks of these plots. ...
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Using erosion plots is a way to research on soil erosion and conservation that with different dimensions, which are constructed in the natural arenas or in laboratories. Mistakes and false conclusions are common task that should be avoided when sampling runoff and sediment from the tanks of these plots. A few researches have been done on the ways of sampling from these tanks and reducing the errors. In this study, the accuracy of sampling was investigated by placing a bucket in the tank and using bottle sampling. For this purpose, two 220 liter tanks were used. In the first tank located at the upper level, concentrations of sediment were prepared for five, 10 and 20 grL-1 and the mixture of runoff and sediment was transferred to the second tank. Coarse particles were trapped by a bucket of twenty liters placed underneath the importer tube in the second tank. The contents of the bucket were weighed in the laboratory after drying. Also, sampling of the second tank contents was carried out after mixing the solution and using one-liter bottles in three replications per each concentration. Sampling was also done without placing the bucket as a witness. The significance of the effect of concentrations on the error value was defined by analysis of variance through a random block design scheme. Results demonstrated that there was a significant difference between the concentrations obtained in the experiment with bucket and without bucket at a level of one percent. Without using bucket, the amount of errors were 63.13, 78.40 and 73.97 percent for 5, 10 and 20 gr.L-1 concentrations, respectively and with using bucket they were 15.90, 15.07 and 4.83 percent. The mean errors in all concentrations were 71.83 and 11.93 percent without and with using buckets, respectively.
Nosrat Aghazadeh; Manochehr Chitsazan; Yahya Mirzaee; Hamed Ebrahimi
Abstract
Due to various sources of contamination in the urban aquifers, the potential for pollution of groundwater resources is high. Thus, the vulnerability of groundwater resources can be very effective in identifying vulnerabilities and sensitive groundwater aquifers. The aim of this study was to present a ...
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Due to various sources of contamination in the urban aquifers, the potential for pollution of groundwater resources is high. Thus, the vulnerability of groundwater resources can be very effective in identifying vulnerabilities and sensitive groundwater aquifers. The aim of this study was to present a modified DRASTIC Model to determine groundwater vulnerability in Urmia urban aquifer. To this end, parameters with low impact such as slope and aquifer media were ignored from the DRASTIC Model. Instead, land use, urbanization index, water value and pollution sources were added to the model. Also, the impact of unsaturated zone media and recharge layers were corrected. Results of the modified DRAST-VUL Model in the study area demonstrate that in most areas, the risk of pollution is low to moderate and the vulnerability in 29% of study area is high due to agricultural and industrial activities and low groundwater depth. Considering the results, the vulnerability index is the most sensitive measure to the parameter of pollutant sources, land use and the unsaturated zone. The sensitivity of the model to recharge, transmissivity and water value parameters were low due to the increase of impermeable surface in urban area. Based on positive results obtained from model validation through nitrate, the proposed model can be considered as an effective tool for the protection, revention and optimal utilization of groundwater resources in the study area. Also, this vulnerability model can be used for other urban aquifers.
Davod Ghorbanpour; Karim Solaimani; Mir Khalaghe Mirnia; Kaka Shahedi; Abdolnabi Kolahchi
Abstract
Growth of population and changes due to earth heating, have differently affected the environment. These changes have challenged the water resources exploitation process both qualitatively and quantitatively. Reduced fresh groundwater level and higher level of seawater in coastal aquifers have resulted ...
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Growth of population and changes due to earth heating, have differently affected the environment. These changes have challenged the water resources exploitation process both qualitatively and quantitatively. Reduced fresh groundwater level and higher level of seawater in coastal aquifers have resulted in reduced water exploitation in these zones. This study simulated the aquifer quality due to seawater intrusion using a numerical model in GMS v.10. The quality of the aquifer was analyzed and predicted using two qualitative models of SEAWAT and MT3D. The 10-years prediction model has shown a direct relationship between increased Total Dissolved Solids (TDS) concentration and reduced water table. The horizontal to vertical diffusion ratio of 0.5 and vertical to horizontal diffusion ratio of 0.2 were obtained following the calibration of molecular diffusion coefficient. Analysis of qualitative results indicated the increased TDS concentration at the northwest of the aquifer which is probably due to seawater intrusion toward the coast. Results of simulation using qualitative model indicated the seawater intrusion from two dimensions of groundwater level and depth. Further, the density difference between seawater and fresh groundwater resources has resulted in seawater intrusion performance curve. The position of seawater intrusion toward the coast indicated increased concentration of more than 2000 mgL-1 during the prediction period. Three methods of reduced groundwater harvesting, increased aquifer feeding plans and construction of ground dams were examined and analyzed in this study in order to decide about the factors influencing the increase or decrease of seawater intrusion into the coast. Findings of the analysis indicated the highest effect of reduced groundwater harvesting in limiting the seawater intrusion compared to the two other methods.
Jamshid Yarahmadi; Ghobad Rostamizad; Malek Rafieai; Karim Mehrvarz
Abstract
Since the most consumed water is in the agricultural sector, available water resources, especially in arid and semi-arid regions, are the main limiting factor for agricultural production. Therefore, by rain water harvesting systems and its proper management, it is possible to compensate part of water ...
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Since the most consumed water is in the agricultural sector, available water resources, especially in arid and semi-arid regions, are the main limiting factor for agricultural production. Therefore, by rain water harvesting systems and its proper management, it is possible to compensate part of water shortage in the mentioned region. The purpose of this study was to select the most suitable rain water harvesting techniques based on multi-criteria decision-making system using Analytic Hierarchy Process (AHP) and investigation of its effectiveness in supplying the water demand of pistachio gardens. The results of the AHP analysis indicated that the environmental impact criterion with a weight of 0.342 and permanency criterion with a weight of 0.284 were the most effective criteria for selecting of the best rain water harvesting system. Finally, the rain water harvesting system with geomembrane insulator with a weight of 0.371 was selected as the most suitable insulator cover, and two other rain water harvesting systems with plastic and isogam insulator were weighted with the weight of 0.350 and 0.279, respectively in the following priorities. Also, the results showed that from the insulated surface with an area of 800 m2 and an average annual rainfall of 300 mm, it is possible to harvest at least 200 m3 rainwater per year. With this volume of harvested water and the choice of drip irrigation with gravel filter, the annual irrigation water demand of 200 fruitful pistachio trees will be supplied during a crop season. Therefore, due to rainwater harvesting techniques, some parts of irrigation water demands of gardens will be provided in arid and semi-arid regions, as well as maintaining sustainability of production and increasing gardeners' revenues, the double pressure on surface water and underground water will also be reduced.
Ramin Salmasi
Abstract
Heavy metals fixation in-situ by using inorganic amendments is a method for remediation of polluted soils. The goal of this research is to determine five kinds of amendments efficiency for heavy metals fixation of waste-water-irrigated soils of Tabriz city and to suggest the best amendment/amendments. ...
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Heavy metals fixation in-situ by using inorganic amendments is a method for remediation of polluted soils. The goal of this research is to determine five kinds of amendments efficiency for heavy metals fixation of waste-water-irrigated soils of Tabriz city and to suggest the best amendment/amendments. For this purpose, solutions containing Cd, Pb, Cu, Ni, and Zn were added to 0.5 gram of five amendments including calcite, hematite, zeolite, illite, and bentonite; and 10 soil samples from around of Tabriz city. After shaking, these five element concentrations were determined in filtered solution by using atomic absorption instrument. Retention capacity percentages of these elements were calculated and the best amendments were determined by using Dunkan method. There were sharp differences of heavy metals retention between amendments. Calcite had the highest retention of Cd, Ni, and Zn; hematite the highest one of Cu and Pb; and the least one was for illite. Calcite, zeolite, bentonite, and hematite had significant (in 5 % level) higher retention capacities of Cd, Ni, and Zn in compared to 10 the soil samples. The highest retention capacities were done by calcite and hematite (without significant differences) for Pb. Calcite hematite, and zeolite had the highest retention of Cu. However, the highest retention was done by illite with significant difference with other two amendments. The retention capacities of calcite and hematite amendments for the five elements were higher than all 10 soil samples in 5% level and can cause low uptake and accumulation of these elements in agricultural crops of polluted soils of around Tabriz city.
Seyed Ali Asghar Hashemi; Mahmood Arabkhedri
Volume 2, Issue 1 , May 2010, , Pages 25-34
Abstract
Evaluation of empirical models for sediment yield in watersheds is a necessity. One of the conventional models in Iran is MPSIAC that has been used extensively. Sediment measurement of small dam's reservoirs is one of the methods for evaluation of these models. In this research, 9 small watersheds were ...
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Evaluation of empirical models for sediment yield in watersheds is a necessity. One of the conventional models in Iran is MPSIAC that has been used extensively. Sediment measurement of small dam's reservoirs is one of the methods for evaluation of these models. In this research, 9 small watersheds were selected in Semnan Province. There is an earth small dam at the outlet of each watershed built in the past 10 years. These dams have not spilled since they were built. Therefore total sediment volume discharged from each watershed was entrapped behind the dams. The amount of deposited sediments in these reservoirs was measured by surveying and estimation of apparent Specific Weight which then compared with estimating values of MPSIAC model by paired t-test. The results showed that the difference between the means for estimated volumes of sediment yield by use of MPSIAC model at the level of 5% had no significant difference while the difference between mean weights of sediments at the level of 5% was significant. Also determination of performance and relative root mean square error showed that MPSIAC model has no appropriate efficiency for application in the region.
Najafgholi Ghiasi
Abstract
Watershed management planning and preference need variety of data like water yield and its fluctuation. Average water yield on different probabilities is needed for river discharge estimation and small and big dams utilization planning. On the other hand, annual water yield is needed for planning and ...
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Watershed management planning and preference need variety of data like water yield and its fluctuation. Average water yield on different probabilities is needed for river discharge estimation and small and big dams utilization planning. On the other hand, annual water yield is needed for planning and management of downstream agricultural lands. In this research, 40 hydrologic stations with acceptable quantitative and qualitative data within a common base period. Watersheds homogeneity was analyzed based on water yield and influence of numeral parameters and segregated into two homogenous watersheds. The accuracy of homogeneity was tested by discriminant analysis and was 100 and 94 percent in clusters one and two, respectively. In addition to regional annual water yield analysis, the discharge probability was estimated and normal distribution was chosen as the best statistical distribution for discharges of two to 100 years return periods. Regional probable water yield equations with different return periods for homogenous regions were extracted using hydrological and numeral data such as annual discharge, area, slope and forest canopy cover. The results of present research were the probable annual water yield with different return periods which could be used in watershed management and water resources projects.
Bahram Saghafian; Saman Mohammadi; Baghe Ghermezchshme
Volume 1, Issue 1 , May 2009, , Pages 32-45
Abstract
Calculating low flow characteristics is very important for planning of water diversions; providing water for hydropower, water quality threshold in streams, water supply for cities and industries and estimate of sewerage discharge threshold. The objective of this research is analyzing low flow with different ...
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Calculating low flow characteristics is very important for planning of water diversions; providing water for hydropower, water quality threshold in streams, water supply for cities and industries and estimate of sewerage discharge threshold. The objective of this research is analyzing low flow with different duration and return periods and extracting low flow regional models for locations without hydrometric station. This research was carried out in Gilan province where 35 hydrometric stations with long-term and reliable daily discharge data were selected. Low flows of durations 10, 30, 60, 90 and 180 days were estimated. Using frequency analysis, several statistical distributions were examined and log Parson Type 3 was found the best distribution for flow duration over 60 days and log normal best fitted flow durations shorter than 60 days. Then low flows of different return periods including 2, 5, 10, 25, 50, 100 and 200 year were calculated. Independent factors were identified using factor analysis that included basin area, mean annual rainfall, slope, average elevation, and drainage density. Cluster analysis divided the basins in two homogeneous regions. In each homogeneous region, multivariate regression through step-by-step method determined basin area, mean annual rainfall and slope as independent influential parameters in low flow regional models. Regional models were extracted for low flow with various durations and return periods.
Mohammad Reza Daneshvar; Mohammad Reza Danaeian
Abstract
In recent years, several flood-spreading projects are constructed in different provinces. Lack of information about planning criteria caused unsuitable ratio between flood spreading area and selected design flood discharge. To find a relation between two above-mentioned parameters this investigation ...
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In recent years, several flood-spreading projects are constructed in different provinces. Lack of information about planning criteria caused unsuitable ratio between flood spreading area and selected design flood discharge. To find a relation between two above-mentioned parameters this investigation was performed in 70-hec area of Miankooh flood spreading station. Soil infiltration tests were carried out before and after every flood spreading event. During the research period six flood events were harvested and several parameters were measured including; discharge, volume of flood, time of flood, volume of tail runoff, time of infiltration, area of flooded sections. In total, 2767288 m3 of flood volume was harvested and 2732361 m3 of water was infiltrated. Considering above-mentioned parameters, relation between maximum input discharge and flooded area, slope of the site, length of the embankment, height of weir and flood time were estimated and the final function was offered. As a result, height of weir and length of embankment have significant coordination (99%) with maximum input discharge.
Raoof Mostafazadeh; Mohsen Zabihi; Maryam Adhami
Abstract
Self-similarity characteristic of climate variables provides the spatial and temporal analysis, using fractal dimension. Therefore, the application of fractal geometry in predicting the nature of many natural processes (e.g. rainfall) in several areas is of great importance. The purpose of this study ...
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Self-similarity characteristic of climate variables provides the spatial and temporal analysis, using fractal dimension. Therefore, the application of fractal geometry in predicting the nature of many natural processes (e.g. rainfall) in several areas is of great importance. The purpose of this study is to determine and calculate the fractal dimension of wet and dry periods, interpret and evaluate the spatial characteristics of dry and wet periods over 40 rain gauge stations in Golestan Province. Toward this attempt, the box-counting method has been employed to determine the number of wet-dry months at one to nine months temporal scales and the calculation of fractal dimension. Then, the regression lines are used to estimate the corresponding fractal dimensions over rainy and non-rainy periods. As well as the severity and duration of wet-dry durations were presented over the study area. The results indicated that variations of rainy/non-rainy durations vary in a range of 11 percent. According to the results, the number of consecutive wet-dry months decreased in coarser time scales (months). The analysis of fractal dimension showed that the dry periods have a lower frequency. The fractal dimension values were considered to determine the variations of precipitation regime over studied stations. Also, the intensity of wet durations is higher in central and eastern parts of the study area, while the western part of the Golestan Province had experienced more persistent wet periods.
Ali Khodaie; Abbas Pahlavani; Zahra Ghelichipour; rahman zandi
Abstract
The protection and management of each user in different areas should be based on ecological conditions, which can be achieved by assessing the ecological potential in each area. Assessing ecological potential means examining the potential power of the land and determining its natural use by humans. The ...
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The protection and management of each user in different areas should be based on ecological conditions, which can be achieved by assessing the ecological potential in each area. Assessing ecological potential means examining the potential power of the land and determining its natural use by humans. The main purpose of this study is to identify the ecological potential in Khodaafarin City with an area of 161,607 ha, using the multi-criteria assessment method, the common land management model of Dr. Makhdoom and using GIS. In this study, after identifying ecological resources (sustainable and unstable), the resources were analyzed and summarized. Then, in the software environment (ArcGIS 10.6), the information layers were combined and then the maps were evaluated. Finally, according to the existing values, the potential strengths and bottlenecks of the region were estimated and the permitted uses were prioritized in the region. As a result, after combining the necessary maps and correcting them, the environmental capacities and ecological potential of the region were estimated as area (percentage) in Khodaafarin City. According to the objectives of the research, areas prone to segregation of aquaculture-agriculture (2.65), aquaculture-rangeland management (0.14), aquaculture-urban and rural development (0.2), aquaculture-extensive tourism (0.049), conservation-extensive tourism (0.45), conservation-forestry (0.12), centralized tourism-forestry (0.021), aquaculture (6.34), extensive tourism (12.61), centralized tourism (2.64), rangeland management (33.1), agriculture (7.51), conservation (13.57), urban, rural and industrial development (1.8), forestry (18.8) were zoned and identified. The results also showed that the highest potential is related to the rangeland management with an area of 61567.55 ha of which less than 50% (30457 ha) is consistent with the current conditions.
Seyede Maryam Bagheri; Mohammadhossein Mahdian
Abstract
Due to the complexity and wide changes in wetlands' environmental factors, pollution monitoring, protection and control of soil quality is deemed to be necessary. Therefore, understanding the spatial distribution of characteristics including the concentration of heavy metals is of great importance. In ...
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Due to the complexity and wide changes in wetlands' environmental factors, pollution monitoring, protection and control of soil quality is deemed to be necessary. Therefore, understanding the spatial distribution of characteristics including the concentration of heavy metals is of great importance. In this context, this study aimed to investigate the spatial variations of copper element as for some chemical properties of Anzali wetland's soil. In this regard, sampling was conducted at 48 sites of the wetland topsoil and copper concentration, pH and cation exchange capacity of their soil was determined. Inverse distance estimators, polynomials, five spline functions including regularized spline, tension spline, multi quadratic function spline, inverse multi quadratic function, thin plates spline and universal kriging and combination of above mentioned and fuzzy methods using cross-evaluation method have been examined in this research. Also, assessment criteria of Mean Absolute Error (MAE), Mean Bias Error (MBE) and Model Efficiency (EF) were used to compare the differences between observed and estimated values and determine the appropriate method. Based on the results, fuzzy tension spline method using the auxiliary variable of cation exchange capacity (least MAE=5.64, percent error=90/11 and EF=0.3) was chosen as the preferred method in copper's distribution mapping. This method decreased the mean absolute error of 50, 56, 56, 53, 53 and 50 percent compared with techniques such as inverse distance estimators, local polynomials, universal polynomials, spline, universal kriging and fuzzy ordinary kriging, respectively. Furthermore, comparing maximum and average values of copper's allowable concentration in this study with the same values in Poland and Australia's soil standards showed that nowadays given to the data obtained from samples, the level of copper element in Anzali wetland's soil is less than the critical level.
Aliakbar Sabziparvar; Behnaz Khataar; Majid Sadeghifar; Saba Saghaei; Farnaz Ershadfath; Reza Norooz Valashedi
Abstract
Nowadays, wise scheduling of water resources is an important task for sustainable development. In this scope, accurate knowledge about daily evaporation from surface water is important for optimum agricultural products. Shortage or lack of evaporation sites, quality of the data and gaps in pan observations ...
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Nowadays, wise scheduling of water resources is an important task for sustainable development. In this scope, accurate knowledge about daily evaporation from surface water is important for optimum agricultural products. Shortage or lack of evaporation sites, quality of the data and gaps in pan observations force the researchers to use prediction models. In this work, three different time series were applied for estimating daily pan evaporation in Hamedan province (Ekbatan dam, Kooshk-Abad and Agh-Kahriz). Evaluations of time series data indicated that pan evaporation of all stations, contains no seasonal trend. Based on the results, the ARIMA showed the highest performance in estimating the daily pan evaporation for the selected sites. With respect to the obtained errors, the best time-series structure were ARIMA(1,1,1) for Agh-Kahriz and ARIMA(2,0,1) for Ekbatan dam and Kooshk-Abad, respectively. The calculated R2 and RMSE for selected sites were 0.93 and 2.44 mm/day for Agh-Kahriz, 0.93 and 1.23 mm/day for Ekbatan dam and 0.92 and 1.03 mm/day for Kooshk-Abad. For the selected model, the Mean Percentage Errors (MPE) varied between 5.85 to 6.92 percent, which denotes models overestimation versus the measurements. The standard deviations of the best performance model are: 0.15, 0.14 and 0.13 mm for Agh-Kahriz, Ekbatan dam and Kooshk-Abad, respectively.
Salman Mirzaee; Shoja Ghorbani Dashtaki; Jahangard Mohammadi; Hossein Asadi; Farokh Asadzadeh
Abstract
Understanding the spatial distribution and variability of erodibility and soil properties is essential for planning of water conservation methods, controlling of flood and runoff and managing of soil erosion or watershed. Selecting and using appropriate interpolation techniques for soil properties and ...
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Understanding the spatial distribution and variability of erodibility and soil properties is essential for planning of water conservation methods, controlling of flood and runoff and managing of soil erosion or watershed. Selecting and using appropriate interpolation techniques for soil properties and erodibility mapping by erosion models such as WEPP is essential. The objective of this study was regionalization of interrill erodibility and effective factors like clay, organic matter and lime using kriging and cokriging and remote sensing data (Landsat 7). For this purpose, 100 soil samples were selected randomly from 0-15 cm depth of Selin watershed in Kaleibar region of East Azerbaijan. Interrill erodibility of WEPP model and some soil properties as clay, organic matter and lime were measured. Correlation analysis between soil properties and digital number (DN) ETM+ image showed that clay, organic matter, lime and interrill erodibility had the highest correlation with DN of Band 7, 1, 1 and 3 ETM+ image (−0.406, -0.431, 0.291 and 0.299), respectively. Therefore, the DN of these bands used as auxiliary data for cokriging estimator. The spherical model was fitted the best model to calculate variogram of interrill erodibility, clay, organic matter and lime. No significant difference were noted between kriging and cokriging despite using remote sensing data as auxiliary data. This can be attributed no strong correlation between interrill erodibility, clay, organic matter and lime and remote sensing data.
Mahtab Safari Shad; Mahmoud Habibnejad Roshan; Karim Solaimani; Alireza Ildoromi; Hossein Zeinivand
Abstract
Many of the environmental problems are caused by the changes in the main components of the hydrological cycle. However, water balance modeling can help to better understanding the components of the hydrological cycle in order to develop appropriate management options. The purpose of this study is to ...
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Many of the environmental problems are caused by the changes in the main components of the hydrological cycle. However, water balance modeling can help to better understanding the components of the hydrological cycle in order to develop appropriate management options. The purpose of this study is to calculate three important components of surface water balance using the WetSpass model and evaluate the model in Hamadan-Bahar Watershed located in Hamadan Province on a monthly time scale. The results of the model evaluation in the study showed that the coefficient of determination between the observed and simulated runoff in the calibration and validation period is equal to 0.79 and 0.83, respectively. Groundwater nutrition assessment was also performed according to manual calculations of the variable for 2012-2013. Then, the results of Kramer correlation coefficient between spatial distribution maps of runoff, actual evapotranspiration and groundwater recharge were investigated with input maps of the model. In general, due to the importance of evapotranspiration in water balance calculations, the evaporation and transpiration maps of the model were evaluated separately for different uses. The evaluation results confirmed the capability of the WetSpass model in simulating runoff, evapotranspiration and groundwater feeding with an acceptable accuracy. The results of spatial distribution maps of runoff, actual evapotranspiration and groundwater recharge indicate a high correlation between evapotranspiration component with land use (0.54), soil texture (0.45), evapotranspiration potential (0.42) and temperature (0.31). Also, these results indicate a high correlation between runoff components with land use (0.62) and soil texture (0.58), and average correlations between groundwater recharge component with land use (0.32) and soil texture (0.34). Therefore, land use and soil texture were the first and second factors affecting the distribution of surface balance components, respectively.
Forood Sharifi; Samane Arvandi
Abstract
This research was carried out to; evaluate the hydrological processes (rainfall, runoff, evaporation, infiltration, etc.), study the water capacity, to simulate the behavior of watersheds. After examining a number of simulation models, the SFBM, AWBM2002, SCS and ISDI were selected and adjusted. Data ...
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This research was carried out to; evaluate the hydrological processes (rainfall, runoff, evaporation, infiltration, etc.), study the water capacity, to simulate the behavior of watersheds. After examining a number of simulation models, the SFBM, AWBM2002, SCS and ISDI were selected and adjusted. Data from 15 catchments and a representative watershed were used. The results such as, simulation parameters, runoff threshold, flow duration curve, snow line, flow recession curve, and base flow index are analysed. The results showed that the models, can well simulate the runoff, and are able to estimate response of ungauged catchments, and form a good capability for design and research. In more than 61.5% of the area, after a rainfall of 5 to 10 mm, runoff generates, hence it was concluded that most of the basins are susceptible to flooding. Also, the highest threshold value in the Bandar Gaz basin is 20 mm, with a maximum specific discharge of 0.27 m3/km2. The lowest value was obtained in Azadshahr and Gonbad-Kavoos basins, respectively, equal to 2 and 4 mm, with a specific instantaneous flow rate of 0.16 in the Gonbad-Kavo basin to 0.26 m3/km2 in the basin no. 171. Also, the highest threshold value in the Bandar Gaz basin is 20 mm, with a specific maximum discharge of 0.27 m3/km2. Among the basins of the similar areas, the Delour Qotorchai Basin with an area of 45.2 km2 with a maximum specific discharge of 0.49 m3/km2, the highest and middle Shor basins, with an area of 37.22 km2and Gorgan Bay with an area of 299.26 km2 with a discharge of 0.04 m3/sec/km2.The results indicated that the runoff threshold has a good correlation with precipitation. The results of the dryness model showed that the model with a high correlation coefficient (83%) simulated the discharge.
Somayeh Emami; Javad Parsa
Abstract
Due to the flow regime and consequently the sediment regime are not constantly in the watersheds, the prediction of sediment discharge is a great help in estimating and managing the sediment input to hydraulic structures. Measurement of sediment in the usual way is not justified in nowadays and may also ...
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Due to the flow regime and consequently the sediment regime are not constantly in the watersheds, the prediction of sediment discharge is a great help in estimating and managing the sediment input to hydraulic structures. Measurement of sediment in the usual way is not justified in nowadays and may also lead to human error. Therefore, in this study, three meta-heuristic optimization algorithms, including imperialist competitive algorithm (ICA), grey wolf optimizer algorithm (GWO) and election algorithm (EA), were used to predict the suspended sediment load of the Zarrineh river. In order to calculate the sediment discharge by the models, firstly, the necessary statistics and data were collected from the studied station in the period 1993-2015. After processing the data, 210 corresponding discharge and sediment data were selected. The corresponding discharge-sediment data from the study station were randomly separated into two parts, 70% for training and 30% for testing. In order to evaluate the performance of the algorithms, four statistics consist of R2, RMSE, MAE and the NSE were used. The results showed that GWO algorithm with values of statistical criteria R2=0.96, RMSE=228.86 ton/day, NSE=0.74 and MAE=67.32 ton/day, has a very high accuracy compared to other algorithms used which this would lead to comprehensive planning for the design and construction of hydraulic structures.
Mokhtar Karami; Rasol Sarvestan; Reza Sabouri
Abstract
The purpose of this study was to investigate the effect of climate change on the monthly discharge of Karoon Catchment as the largest basin in the country. In this study, five hydrometric stations (Bamdgeh, Telezang, Gharmaleh, Gotvand and Dezful) and three synoptic stations (Ahwaz, Dezful and Masjed ...
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The purpose of this study was to investigate the effect of climate change on the monthly discharge of Karoon Catchment as the largest basin in the country. In this study, five hydrometric stations (Bamdgeh, Telezang, Gharmaleh, Gotvand and Dezful) and three synoptic stations (Ahwaz, Dezful and Masjed Soleiman) were considered. Using the SDSM software, NCEP data and large-scale data from the general circulation model (HadCM3 for temperature and CgCM3 for water discharge) were scaled parameters under two climate scenarios A1B and A2 in the Karun Basin. Then, the climate change data and the output of the microscale model were applied to the SPSS 19 and Minitab 17 to predict the significance of water discharge for future climate courses (2020-2070) be simulated. Results of climate change analysis showed that under different scenarios, monthly air temperature in the scenario A1B increases by 1.60°C and in the scenario A2 1.58°C, but the average annual rate of stations in the scenario A1B is 19.82 m S-1 in size and 16.27 m S-1 in the A2 scenario. The modified Kendall and age tests were used to identify seasonal and semi-annual seasonal time series trends. Results also showed that under climate scenarios of discharge in spring and first half of the year, there was no significant trend at 95% of confidence, but in other seasons of the second half of the year, there was a significant decrease.
Kianush Behrahi; Gholamabbas Sayyad; Ahmad Landi; Hamidreza Peyrowan
Abstract
Study of effective factors on runoff quantity to achieve optimum measures for runoff controlling is an essential subject in watershed management. This study aimed to investigate the effects of land use type and land slope degree on runoff quantity using an artificial rainfall simulator in Kakasharaf ...
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Study of effective factors on runoff quantity to achieve optimum measures for runoff controlling is an essential subject in watershed management. This study aimed to investigate the effects of land use type and land slope degree on runoff quantity using an artificial rainfall simulator in Kakasharaf watershed from branches karkhe watershed (Lorestan Province). Based on the land use map, at 6 work units (sub basins), three land use types of pasture, forest and agriculture; and three land slope degrees of 10, 20 and 30 percent was chosen. In total 93 tests were run using an artificial rainfall simulator and the runoff quantities were collected and measured. Artificial rainfall simulator was a plexiglass non-pressure rainfall simulator with a plot size of 83.5 × 119 cm2 and height 160 cm. Statistical analysis was done using SAS software. Results showed that the average, minimum and maximum runoff quantity were 1499, 0, and 9100 cm3, respectively. Analysis of variance showed a significant difference (p<0.01) between sub basins and runoff quantity. Also, the interaction of sub-basins and land use showed a significant difference (p<0.01) on runoff quantity. There was a significant difference (at 1% level) between runoff quantity and the land slope so that by increasing the slope from 10 to 30 percent, the produced runoff volume increased. Besides, there was a significant difference (1% level) among runoff quantity of pasture, forest and agriculture. The volume of runoff in the forest regions was more than pasture and agriculture land use types.
Zahra Jaberalansar; Morteza Khodagholi; Masoud Borhany; Hossein Arzani
Abstract
Rangeland ecosystems in semi-arid regions are vulnerable systems to climatic changes specially precipitation. In such conditions droughts are predictable. In this study the relationship between rangeland production and spatial and temporal changes of precipitation was investigated. Therefore, rangeland ...
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Rangeland ecosystems in semi-arid regions are vulnerable systems to climatic changes specially precipitation. In such conditions droughts are predictable. In this study the relationship between rangeland production and spatial and temporal changes of precipitation was investigated. Therefore, rangeland production through 10 years data set (1377-1387) in steppic bioclimatic of Esfahan province (Alavije, Muteh, Kalahrood and Gardaneshadian) using Standard Precipitation Index (SPI), the relationship between SPI series of 3, 5 and 8 month time scales, and rangeland production of 10 years. Thus Anova and correlation matrix between production and SPI factors were formed. Results indicated that the most severe drought has occurred in 1387 simultaneously, with the least production. A harmony between change trend of production and SPI in the sites showed that in most cases maximum and minimum production have occurred simultaneously with maximum and minimum of SPI series. Also, the production correlated with SPI series of three, five and eight months' time scales with correlation coefficients more than 63 percent which were significant in 1% and 5% level. Due to efficacy of production from spring precipitation and soil depth less than 30 cm in the sites, it is proposed to use SPI series of three months scale to evaluate drought in similar rangelands.
Vahid Chitsaz; Seyed Bagher Fatemi; Zabihollah Eskandari
Abstract
Nowadays, application of remote sensing is common in soil conservation and erosion projects and most of them are used aerial photogarphs and desipte of the numerous advantages, there are some limitations. In this study, replacemen of moderate-resolution satellite data instead of aerial photographs has ...
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Nowadays, application of remote sensing is common in soil conservation and erosion projects and most of them are used aerial photogarphs and desipte of the numerous advantages, there are some limitations. In this study, replacemen of moderate-resolution satellite data instead of aerial photographs has been investigated with emphasis on processing of satellite images and using image filters and the purpose of soil erosion figures detection. Finaly, image processing of area are prepared with maximum capability vitual interpretation of effects associated with erosion, after the study design, atmospheric and geometric corrections and perform pre-processing and initial processing on ETM+ and ASTER images. In order to evaluate the efficiency of filters for detection and identification of soil erosion were used low-pass and high-pass filters such as filters, median, mean, High Pass, Gaussian, Laplacian, Sobel and linear filters on ASTER and ETM images in the part of the Esfahan Dastkan basin. According to the results, using of low pass filters are not recommended because of the resolution reduction of soil erosion. High-Pass filters can be partialy appeard the edages of image and can be help to visual interpretation (especially in combination with the original image). Use of filters is recommended in combination with the image and as an aid to vitual interpretation, due to problems of application the fiters for separate soil erosion units. Regard to the dimension of soil erosion (rill and gully) and compared to the spatial resolution of the used sensor in this study, the erosions are not clearly appeared in the picture and application various image filters to automatically discover and exploit of these effects can not be efficiently. Resolution images of ASTER and ETM+ are not responsive for mapping erosion by using automated method and should be looked for a solution of semi-automated and visual interpretation. Also, because of the similarity between the spectral and geometrical picture was not found a major difference in the results. Therefore, it is recommended to produce a susceptibility map of erosion or erosion risk map instead the variouse types of regional soil erosion.
Tooraj Asadi; Seyed Saber Shahooei; Mohammad Asadi; Amir Mansour Shahsavar
Abstract
Due to the importance of water erosion in reducing soil fertility many studies have been done on the quantity of this destructive phenomenon. Tamura and Rogowosky found a meaningful relation between water erosion and Cs-137 loss in soil matrix. This report was the first of application of Cs-137 method ...
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Due to the importance of water erosion in reducing soil fertility many studies have been done on the quantity of this destructive phenomenon. Tamura and Rogowosky found a meaningful relation between water erosion and Cs-137 loss in soil matrix. This report was the first of application of Cs-137 method to estimate soil erosion since 1974. From 1974, the method has changed gradually and now is used in many studies. In this study,aerial photographs with scale of 1:20000 and topographic maps with scale of 1:50000 were used. 12 transects on the hilly lands (compound and uniform slopes) and 3 transects on the piedmont plain were studied. Surface samples were collected from different slope situations. The situations were collected from different slope situations.The situations were summits, shoulders, back slopes, foot slopes and toe slopes; gamma spectrometer was used to determine the Cs-137 of the samples. Soil erosion and sediment were calculated by Cochanouski (1993) Equation. Results showed that in summit, shoulder and back slope of the compound slopes, erosion is 68.42, 45.46 and51.16 Ton/ha/yr respectively. On the same situations of uniform slopes 79.6, 65.3 and 84.23 ton /ha/yr of soil losses were expected. In non-erosional situations (toe slopes), soil loss has been deposited. In foot slopes, i.e. dynamic sites, sedimentation process is more dominant than destructive ones. The correlation between USLE and Cs-137 models were statistically signification with % 95 probability.
Abbas Pourmeydani; Abolfazl Khalilpour; Hossein Tavakoli Neku; Mohammad Hassan Marefat
Volume 2, Issue 2 , July 2010, , Pages 95-101
Abstract
One of the important problems is erosion and soil degradation in watershed areas. Polymer usage is a way for both erosion control and soil and water conservation. In this research the effects of the BT53 polymer application for moisture storage in soil, reduction of runoff and erosion and prevention ...
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One of the important problems is erosion and soil degradation in watershed areas. Polymer usage is a way for both erosion control and soil and water conservation. In this research the effects of the BT53 polymer application for moisture storage in soil, reduction of runoff and erosion and prevention of loss soil are studied for 1998-2001. The research plan was CRBD and factorial method. First factor included polymer levels of 0, 2 and 4 gr/m2. Second factor included Secale montanum species planted and not-planted. After every rainfall event both runoff volume and sediment amount were measured. Analysis of variance showed there was significant difference between polymer levels and sediments amount (P<0.01). Compression of averages by Duncan's method in first factor showed all polymer levels fall in one group from runoff volume point of view, and in three groups based on sediment amounts. The most effect of polymer usage was on sediment amounts reduction rather than runoff. This means that polymer BT53 is suitable more for soil protection besides runoff reduction. Polymer level 1 had most amounts and polymer level 2 had least amounts of sediment. So application of polymer BT53 in level 2 (4 gr/m2) was suggested for sediment control. Polymer level 2 with non-planted treatment had least effects on runoff volume and sediment amounts among six treatments of polymer levels and planted or non-planted.
