Saeed Farzin; Hamid Mirhashemi; Hamed Abbasi; Zohreh Maryanaji; Payam Khosravinia
Abstract
In this study, long-term memory and dynamic behavior of daily flow time-series of Khorramabad River, which its basin is mountainous and has urban land use, is investigated by Hurst exponent. The Hurst exponent of runoff signal of Khorramabad River during 1991-2014 period was obtained as 0.8. This value ...
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In this study, long-term memory and dynamic behavior of daily flow time-series of Khorramabad River, which its basin is mountainous and has urban land use, is investigated by Hurst exponent. The Hurst exponent of runoff signal of Khorramabad River during 1991-2014 period was obtained as 0.8. This value shows long-term memory and nonlinear, dynamic signal of this river’s runoff. By applying neural network and wavelet transforms, the rainfall-runoff time-series of this river was simulated. In this respect, by taking the time-series of rainfall and rainfall-runoff as input to the artificial neural network and wavelet-neural network hybrid, four models including: 1) rainfall, neural network, 2) rainfall-runoff, neural network, 3) rainfall, wavelet-neural network and 4) rainfall-runoff, wavelet-neural network were developed. In the hybrid models of wavelet-neural network, time-series of rainfall and runoff were decomposed to high-frequency and low-frequency sub-signals. Results of evaluating the accuracy and efficiency of the four models showed that the wavelet–neural network model correctly simulated the runoff behavior with the best efficiency at 99% confidence level. Comparison of the results of wavelet–neural network model to the neural network model, using Morgan-Granger-Newbold, showed significant superiority of the first model. Also, results of evaluating signal error of the four implemented models, using two tests of Von-Neumann and Buishand test, showed that there is a significant substitution point in the signal error of the neural network model and signal of rainfall-runoff model. Therefore, existence of very different monthly and periodical fluctuations in 1991-1998 and 1999-2014 in the behavior of rainfall-runoff leads to reduction of efficiency and precision coefficient of neural network model. While, in the hybrid model of wavelet-neural network, allocation of relative weight to each sub-signal, has effectively reduced the short-term, average and long-term fluctuations in modeling error.
Saeideh Ansariyan; Mahnoosh Moghaddasi; Mojaba Moradi
Abstract
The success of the artificial recharge projects of aquifers need to recognition the appropriate points. The aim of this investigation is finding appropriate points for artificial recharge in “Kavir Meighan” basin in Markazi province. Because of that the Geographical Information System (GIS) ...
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The success of the artificial recharge projects of aquifers need to recognition the appropriate points. The aim of this investigation is finding appropriate points for artificial recharge in “Kavir Meighan” basin in Markazi province. Because of that the Geographical Information System (GIS) is used. In this investigation. the method“Analytic Hierarchy Process (AHP)” is used to find suitable points. By using the opinion of the experts, the necessary criterion to choose suitable points are: Water Quality, Water Depth, Slope, Land use, Geology, Soil texture and the position of wells, springs and Qanats. In AHP methods the raster layer of used criterion was prepared. Then by using double comparison and Expert choice software, the weight of the any layers was made. In this method the maps were put together by overlap methods. After that, inappropriate points those are too close to wells, springs and qanats, were showed. Finally, the potential map of artificial recharge zone was prepared. In AHP method the potential map contents 29 zones, the total area of them is 14,770,183 square meters.
Mansour Jahantigh; Seyed Ahmad Hosseini
Abstract
Aim of this research was Studying and Recognition of lithology and Erosion Rivers in Sistan region. To done this research distinct situation of rivers according of basin and collected inform about basin of Sistan and review different parts of them such as type of erosion in river banks by using available ...
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Aim of this research was Studying and Recognition of lithology and Erosion Rivers in Sistan region. To done this research distinct situation of rivers according of basin and collected inform about basin of Sistan and review different parts of them such as type of erosion in river banks by using available reports and filed works. We have used available scale of 1:50,000, 1:250,000, Geologic maps, field observation and global positioning system (GPS). We found erodible area of river banks according to scale of 1:250,000 erodible Geologic maps. The data show that’s the main factor of cause to erosion is effect geologic conditions. The main parts of the basin covered with sediment of quaternary which is very sensitive to water erosion.The sistan rivers classification shows that stone, alluvium and other are 20.7, 38.1 and 41.2 percentage of rivers length, respectively. 7.2 percentages of area rivers occur erosion that bed and banks erosion are 85.1 and 14.9%, respectively.
Samira Rezapourian Qahfarokhi; Mohammad Mehdi Ahmadi; Kourosh Qaderi
Abstract
The geomorphological changes of the bed and bank of rivers can affect the migration and expansion rate of the meandering rivers. A knickpoint in the bed slope is one of the most common geomorphologic changes in the river. Measuring the migration and expansion rate of meandering rivers, in addition to ...
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The geomorphological changes of the bed and bank of rivers can affect the migration and expansion rate of the meandering rivers. A knickpoint in the bed slope is one of the most common geomorphologic changes in the river. Measuring the migration and expansion rate of meandering rivers, in addition to taking the necessary actions in order to protect the structures located along and over the river are considered as engineering measures in the field of river engineering. In this regard, to study and measure the rate of migration and expansion of meandering rivers with knickpoint in the flow at downstream, experiments were carried out in a laboratory flume with an erodible bed. The channel was carved on the sedimentary bed, and was studied and evaluated the migration and the expansion rate in to two experimental groups in the presence and absence of the knickpoint (control tests) for three different widths of the channel (different wavelengths of the initial bend), three discharges, and three different bed slopes. Results showed that the flow began to create meandering bends at a very high rate in order to modify the knickpoint at downstream, and as a result, the migration rate of meander has increased compared to the control experiments and decreased the expansion rate. An increase in the rate of migration up to 32% and the decrease in the rate of expansion up to 36% are achieved by comparing the results of experiments with presence of the knickpoint at downstream and its absence.
Fahimeh Mirzaei-Nodoushan; Omid Bozorg Haddad; Majid Khayat Kholghi
Abstract
In groundwater resources management, continuous monitoring of wells discharge and charge and groundwater quantitative and qualitative variations are very important. Groundwater monitoring network could provide information on quantitative and qualitative variations in groundwater situations. Hence it ...
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In groundwater resources management, continuous monitoring of wells discharge and charge and groundwater quantitative and qualitative variations are very important. Groundwater monitoring network could provide information on quantitative and qualitative variations in groundwater situations. Hence it would be used to predict the behavior of the aquifer in the future. This study describes an optimizing method to design the optimum groundwater-level monitoring network in aquifer of Eshtehard. Two scenarios were considered to optimize the locations of the observation wells: (1) exploring optimal locations of existing observation wells and (2) adding optimal observation wells to existing well network. Kriging method was utilized to estimate groundwater-level for preparing the database. Optimization of groundwater monitoring network with two objectives: (1) minimizing root mean square error and (2) minimizing number of wells, was implemented by non-dominated sorting genetic algorithm (NSGA-II). The results show that by using this method it is possible to remove redundant wells in a monitoring network or to add new wells in case of shortage of observation wells in a network having acceptable accuracy.
Maryam Hosseinpour; Ahmad Fatehi Marj
Abstract
Drought is one of the natural disasters impacting on socio-economic of the society during short, mid and long terms. Continuously monitoring and evaluating of droughts, which are accounted for the main object of the present study, can affectively alleviate drought impacts helping to come up with a drought ...
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Drought is one of the natural disasters impacting on socio-economic of the society during short, mid and long terms. Continuously monitoring and evaluating of droughts, which are accounted for the main object of the present study, can affectively alleviate drought impacts helping to come up with a drought risk management plan. In this research, the spatial variation of meteorological drought was analyzed for the first half of the hydrological year 1392-1393. Drought indicators used in this study were SPI and PN and their results were compared through the prepared maps. Results indicated that spatial variations of the rainfall have been considerable in some provinces which has led to severe droughts whereas, other provinces have received more precipitation compared to normal situation. In addition to variation of drought intensity, its spatial extension has been changing significantly. In this regard, the drought intensities have been decreasing in North Khorasan, Razavi Khorasan, Alborz, and Tehran province with regard to the SPI classification namely -2.5
Amin Salehpour Jam; Hamid Reza Peyrowan; Mahmoud Reza Tabatabaei; Amir Sarreshtehdari; Jamal Mosaffaie
Abstract
The desertification process, by reducing the biological production potential, leads to the destruction of ecosystems. In this research, to assess the role of edaphic factors on desertification in rangelands surrounding Eshtehard, Halgh-e-Darreh highlands, first, the map of units was created by crossing ...
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The desertification process, by reducing the biological production potential, leads to the destruction of ecosystems. In this research, to assess the role of edaphic factors on desertification in rangelands surrounding Eshtehard, Halgh-e-Darreh highlands, first, the map of units was created by crossing maps of slope classes, land uses, and geology using ArcGIS 10.3 software. Three indices of erodibility, salinity and permeability for each land unit were considered and classified. 185 and 179 samples were taken during 2018 and 2019 for indices of salinity and permeability for zoning of the study area, respectively. Then, weights of indices and consistency ratio were calculated by the AHP method. Method of multicriteria optimization and compromise solution, VIKOR method was used to prioritize the alternatives. After calculating the weighted normalized values, priority was given to desertification potential of the units. Also, the results of AHP showed that from the experts' point of view, salinity is the most important factor in desertification. Other factors such as susceptibility to erosion and permeability coefficient are in the next rank order, respectively. The AHP-VIKOR model has very high degree of adaptation to the corresponding classes in the control map. The percentage of compliance and non-compliance of the classes of the potential of desertification risk were 92.91% and 7.09%, respectively. The range of changes of Vikor index based on AHP-VIKOR method varies from 0.443 to 0.967. Accordingly, the study area has three classes of potential or severity of desertification areally 0.5% moderate, 7.06% high and 92.43% very high class respectively.
Abbasali Mohammadian; Ali Talebi; - -; - -
Abstract
Weather generator models are used to predict climate parameters variations caused by climate change phenomenon. It can be used as a downscaling method for hydrological modeling, risk assessments in agriculture etc. Herein this research, HadCm3 model were used. Three different scenarios were considered. ...
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Weather generator models are used to predict climate parameters variations caused by climate change phenomenon. It can be used as a downscaling method for hydrological modeling, risk assessments in agriculture etc. Herein this research, HadCm3 model were used. Three different scenarios were considered. Downscaling were done using LARS-WG model. LARS-WG is a statistical downscaling model. Different climatic parameters such as minimum and maximum monthly temperature, minimum and maximum precipitation were predicted based on A1B, B1 and A2 scenarios. This research was done for Balqur Watershed in Kardeh Dam in Mashhad. Base line period is 1961-2010. Prediction was done for 2046-2065. Results showed that changes in minimum temperature would be higher than maximum in 2046-2065. Generally precipitation would be decreased except for a light increase in A2 scenario. But even if it is considered, it would not be as important as an increase in temperature would increase evaporation too. So, with regard to this fact and be aware of directly and indirectly negative effects of climate change on the environment and other sectors, strategic long-term plans to manage the new situation seems inevitable and necessary.
Saeed Rashvand; Negin Shirzad; Hassan Yeganeh
Abstract
The goal of rangeland management is preservation, restoration, development and sustainable utilization of rangeland resources. In this study, species Bromus tomentellus is one important, species of site is the mountains of Qazvin’s Alamut has been studied. In order to do the research, first area ...
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The goal of rangeland management is preservation, restoration, development and sustainable utilization of rangeland resources. In this study, species Bromus tomentellus is one important, species of site is the mountains of Qazvin’s Alamut has been studied. In order to do the research, first area equivalent to 0.5 acres was selected and through operations grazed has been enclosed in the first year of study. In above species, 40 stocks has been selected, that monthly in the season has been cut in up to; 25, 50, 75, by hush’s scissors. Also, for every 10 base has been applied to a control treatment. the end he effect of changes in the operating characteristics of phonological, Forage production, vitality, mortality and other characteristics has been studied of selected species. The results showed that increase of 75% in utilization and deterioration caused negative effects on the critical capabilities and Harvest limit of 50% with the lowest incidence of adverse effects on plant characteristics and capabilities were proper.
moslem dehdari far; Mohammad Faraji; Mohammad salehi veisi; Jahangir Ehsani
Abstract
Rock behavior varies with different erosions, which depends on the inherent and environmental characteristics of the rock. In other words, some petrological units are susceptible to erosion and have sediment production potential. This study is conducted to investigate the sensitivity to erosion and resistance ...
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Rock behavior varies with different erosions, which depends on the inherent and environmental characteristics of the rock. In other words, some petrological units are susceptible to erosion and have sediment production potential. This study is conducted to investigate the sensitivity to erosion and resistance of rock formations of Fars group (Mishan limestone, Aghajari sandstone and Gachsaran Anhydrite) and Asmari formation using Selby method in Behbahan, Gachsaran, Deylam and Dehdasht areas. Results of analysis of ANOVA variance based on the comparison of 81 samples from 4 types of rocks showed that there was a significant difference between the rocks (p= 0.05).In general, the Asmari limestone with scoring mean of 66.72-70.99 is the most rock resistant based on theSelby method. Mishan, Aghajari limestone, Gachsaran Anhydrite will be in the next ranks, respectively.
Marziye Sadat Mirahsani; Abdolrasol Salman Mahini; Reza Moddares; Alireza Soffianian; Reza Jafari; Jahangir Mohhamadi
Abstract
Zayandeh Rood Basin has a vital role in Iran's poetry, biomass, agriculture, industry and tourism, faced with drought problems. Clustering approach can be a management approach to reduce drought risk impacts which groups the members with regard to the division based on the Euclidean distance of stations. ...
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Zayandeh Rood Basin has a vital role in Iran's poetry, biomass, agriculture, industry and tourism, faced with drought problems. Clustering approach can be a management approach to reduce drought risk impacts which groups the members with regard to the division based on the Euclidean distance of stations. In this research, the approach of determining the spatial-temporal distribution of drought clusters in watersheds is used to express variations based on precipitation precipitation index (SPI) parameters of stations, which depends on the probability of precipitation for any time scale. Since the maximum spatial distribution of the meteorological stations in the region and the maximum time period of the long-term and possible long-term statistical period were considered the same, the data of 26 stations from 12 years (2003 to 2014) was used as reference data. In this regard, the12 months SPI index was first calculated. Then, the 12-month SPI index, which ended in December, was used for cluster analysis of the SPI, and then 144 data were clustered into four groups. Further, zoning analysis was performed on data clusters. Then, the relationship between elevations as an effective landform factor in drought with SPI drought index cluster was investigated using correlation of variables. SPI correlation with mean height of each cluster stations was studied and the results were compared and analyzed. The results of the SPI drought fluctuation chart showed a very severe drought in 2008 and 2009 and 2010, and severe drought in 2010 and mild drought in 2003, 2005 and 2013. Also, 12-month SPI drought data showed a high and negative correlation with height data. Consequently, spatial-temporal monitoring of drought indicators clusters is recommended as a way to manage the impacts of drought risk.
Ali Akbar Nazari Samani; Shahram Khalighi Sigaroodi; MAHSA abdolshahnejad; Sina Syadi Lotf Abadi; Majid Habibi Nokhandan
Abstract
Greenhouse gases have continued to increase in the atmosphere. This is largely due to industrial activities. The warming effect of greenhouse gas, increased over the last 200 years, due to carbon dioxide; hence the temperature of the lower levels of atmosphere will be increased. The climate change across ...
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Greenhouse gases have continued to increase in the atmosphere. This is largely due to industrial activities. The warming effect of greenhouse gas, increased over the last 200 years, due to carbon dioxide; hence the temperature of the lower levels of atmosphere will be increased. The climate change across the world resulted in an increased drought; disturbance in rainfall as well as desertification. Desertification has been caused by a variety of factors such as climate change. It is a significant natural resources problem. The aim of this study was to evaluate the desertification during five periods (1978-1987, 1978-2007, 2012-2041, 2042-2071, and 2072-2101) during the last, present, and future, using IMDPA model as well as climate and geology-geomorphology criteria. For each criterion, some indexes were selected, using area condition. First, air temperature and precipitation during the previous time was evaluated. Then, the climate change was estimated using two climatic models of HADCM3 and GFDL2.1 and three scenarios of A2, B1 and A1B of GCM as well as small scale exponentially. The land use map for four classes in two periods (1986 and 2010) was prepared and used for input data to the Markov chain for estimating future land changes through the three periods (1419, 1449, and 1479). Results were used as the land use index for working unit in geology-geomorphology criterion. It was assumed that the tolerance of stone to the erosion and slope of maps were constants. Hence, this criterion was studied during five periods. Results showed that the intensity of desertification was increased during the time.
Abstract
Physicochemical properties and the forms of erosion of marl formations as well studied in this experiment within Zanjanrud watershed basin. At first, the distribution and erosion landscape maps for different marl formation were prepared and then by overlying different maps the final map of working units ...
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Physicochemical properties and the forms of erosion of marl formations as well studied in this experiment within Zanjanrud watershed basin. At first, the distribution and erosion landscape maps for different marl formation were prepared and then by overlying different maps the final map of working units were produced. Soil samples from selected points within each working unit were collected and after laboratory measurements statistical analyses were applied. The results suggested that surface and sheet erosion were more dominated than other forms of erosion. While gypsum content was concentrated at surface, some elements such as Ca, Mg, and dissolved Na subsided in lower layers. Marl units account for 20% of the total area of the basin, which consists of two types of Marl Pliocene (Plm) (99.75%) and the upper Red marl (Mur) (0.25%). In this basin, there are four superficial erosional facies, surface,rill, badland and gully erosin, with the rill erosion facies having the highest and most expanse of 61%. Toward the deeper layers in marl soils level of salinity, pH and clay percentage increases as the result of leaching of salts and fine material by runoff and transferring them from surface to depth. There is statistical significant difference in the amount of EC, clay, limestone, and gypsum among various forms of erosion, so that the highest and lowest level of EC were found respectively in deep gully and upper layers of surface erosions. Highest content of gypsum was found in badland erosion while the lowest of that was found in surface erosion. Therefore, changes of chemical properties are mostly found in surface and badland erosions. Finally, prevention of these two types of erosion must be prioritized because they can be precursors to other forms of erosion in this type of marl soil.
Behrooz Mohseni; Benyamin Matinnia; Hadi Razzaghian
Abstract
Determining the precise location of sub-watersheds in flood production is very important. In some cases, it is time consuming and costly to do this by conducting field studies and mapping topographic maps. Today, the new and growing technology of LIDAR active sensor data is used to collect data from ...
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Determining the precise location of sub-watersheds in flood production is very important. In some cases, it is time consuming and costly to do this by conducting field studies and mapping topographic maps. Today, the new and growing technology of LIDAR active sensor data is used to collect data from the ground surface, which operate based on measuring the distance of the laser. In this research, Gorgan Shast-Kalateh forest basin was selected due to various data. In order to prepare sub-watersheds and their characteristics, it is necessary to have a digital elevation model. In the above model, LIDAR and radar data and other sensors were used with spatial resolutions of 1, 12.5 and 30 m, respectively to control the ground data. The streams were extracted using the appropriate model in each method and all types of watershed characteristics were obtained through Arc-Hydro and IDRISI software. The distance index of each stream from others and ground reality were investigated. Comparison of analyses was done in SPSS software. The sig-value for comparing altitudes along the streams for LIDAR with a pairwise t test was 0.13, which shows no significant difference. Comparison of the streams of different digital models between the land 12.5th m and 30th m and LIDAR, the sig-value of 0.002 in Wilcoxon test, shows significant difference. Also, based on the overall conclusion, it was observed that there is a significant difference at 95% probability level, between the methods used. Eventually, LIDAR data had the highest accuracy with ground reality.
Gholamreza Ghahari; Samad Shadfar; Hamid Hosseini Marandi
Abstract
Erosion and sediment resulting from it, is one of the most important factors in watershed management. The estimation of sediment yield and prioritization of watersheds in terms of water erosion is the main objectives of watershed management. One of the ways to estimate soil erosion and sediment yield ...
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Erosion and sediment resulting from it, is one of the most important factors in watershed management. The estimation of sediment yield and prioritization of watersheds in terms of water erosion is the main objectives of watershed management. One of the ways to estimate soil erosion and sediment yield is to use empirical models. The aim of this research is to evaluate the efficiency of the EPM Model in Fars Province. To examine this, five small watersheds were selected in Fars Province. Five basins in which the earth dams and check dams were built were selected. There is no overflow from these dams in rainfall events and the most of them was made near to 10 years. The amount of sediment deposited in upstream of the reservoirs was calculated by means of precision mapping. Deposit bulk density was determined in the field to convert the volume into the weight. In parallel, the sediment yield of the basins was determined by EPM Model. Results showed that the minimum and maximum sediment yield measurements varied from 0.89 to 2.62 tonh-1y-1, but the estimated sediment was between 3.3 to 6 tonh-1y-1. The results of the relative error of estimation of EPM Model in each of the studied basins showed an over estimation in all basins (minimum 121.5 and maximum 447.2 percent). The Relative Root Mean Square Error (RRMSE) of the model was calculated as 2.39, which indicates a too much error of the model. Statistical analysis results comparison of actual sediment yields of watersheds with estimated values by model, using paired t-test, shows that there is a significant difference between these values (t=8.728 and sig.=0.001). According to the presented findings, the results of this model estimation for the investigated areas are not accepted.
Ramin Papi; Saeid Hamzeh; Masoud Soleimani
Abstract
The climate change over the past few decades, and consequently decrease in the precipitation, along with the population growth in different regions in Iran have led to an increase in demand for water for domestic agricultural, industrial, etc. consumption. This has led to uncontrolled exploitation of ...
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The climate change over the past few decades, and consequently decrease in the precipitation, along with the population growth in different regions in Iran have led to an increase in demand for water for domestic agricultural, industrial, etc. consumption. This has led to uncontrolled exploitation of groundwater resources, causing severe decrease in the groundwater level. Artificial recharge technique is one of the methods to compensate for the groundwater deficit, especially in arid and semi-arid regions. Selection of suitable sites before artificial recharge can help improve the efficiency of the project and ensure its success. Having in mind the problems related to decrease in groundwater resources in Tehran due to the increasing population and the expansion of industry and agriculture. This study aims to identify and zoning of regions that are suitable for artificial recharge of groundwater in Tehran Province. The GIS can help determine such regions more precisely, faster, and with better results. For this purpose, the present study integrated GIS and Fuzzy AHP to weigh and combine factors that play a positive role in artificial recharge, such as the depth and changes in the groundwater level, precipitation, drainage density, elevation and land slope, distance from fault, distance from river, geological properties, and land use. After investigating the views of experts about the binary comparison of the criteria, and prioritizing them using AHP, it was found that the hydrological properties were the most effective criteria for the subject under study. Results indicated that 6.2% and 15.75% of the entire area of the region under study are very suitable and suitable for artificial recharge of groundwater, respectively. Very suitable regions are mostly located in the east of the province, with suitable geologic formations, short distance from river, and predominant rangeland and agricultural land use. They also, have a very low and decreasing groundwater level.
Hassan Vagharfard; Hassan Moghim
Abstract
Flood spreading is an effective way to increase the groundwater level, rectify the critical conditions of groundwater, and prevent flooding at Naeim-Abad, Fars Province. The most important step in the successful implementation of artificial recharge is the selection of recharge areas in the studied region. ...
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Flood spreading is an effective way to increase the groundwater level, rectify the critical conditions of groundwater, and prevent flooding at Naeim-Abad, Fars Province. The most important step in the successful implementation of artificial recharge is the selection of recharge areas in the studied region. In this research, the GIS technique and Analytical Hierarchical Process (AHP) method have been used. We considered nine factors–land, slope, and distance from the road, altitude, thickness of the alluvium, distance from the stream, surface permeability, land use, and fault for analysis in this research. Each layer was prioritized using the AHP method and the different layers were integrated. Expert Choice software was used to prioritize nine considered factors. The results showed that 3.6% of the Naeim-Abad area was suitable for flood spreading based on the AHP method and GIS technique. In this research, hydrologic factors with a weight of 0.687 had the most impact among the main criteria for locating areas prone to flood spreading. Among the sub-criteria of this criterion, surface permeability with a weight of 0.558 had the greatest influence. In addition, the sub criterion of land use was weighted equal to 0.701, which had the highest weight among the sub criteria. The lowest weight among the sub criteria was attributed to the distance from the road with a weight of 0.106, which indicated the least influence on locating suitable areas for flood spreading.
Salahudin Zahedi; Kaka Shahedi; Mahmod Habibnejad Rawshan; Karim Solimani; Kourosh Dadkhah
Abstract
This study was conducted to evaluate the capability of the DHSVM model to simulate hydrological processes in a mountainous watershed with a minimum agricultural land use. The required climatic parameters were set for the daily time step. The inverse distance method was used to interpolate the climatic ...
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This study was conducted to evaluate the capability of the DHSVM model to simulate hydrological processes in a mountainous watershed with a minimum agricultural land use. The required climatic parameters were set for the daily time step. The inverse distance method was used to interpolate the climatic variables from the stations to the network cells. Time inputs to the model were prepared for the years 2008 to 2013. The land cover map was prepared using the supervised classification method of Landsat TM data. The stream network map was generated using the DEM map in ArcGIS software. The soil texture map was prepared using field sampling and in the laboratory. Primary tests to the determine sensitivity of input parameters showed that this model is sensitive to lateral hydraulic conductivity, exponential coefficient of hydraulic conductivity, porosity, field capacity, and minimum stomatal resistance. In this study, except for the lateral hydraulic conductivity and exponential decrease coefficient, all other parameters (soil and vegetation) were determined based on previous studies and field measurements in a similar way for both categories of data. The time series of the data were divided into three, warm- up or preparation periods (2008-2009), calibration (2009-2011) and validation (2011-2013). The model was calibrated using streamflow data from 2008 to 2010. Different efficiency criteria were calculated between simulated and observed flows. NSE value for calibrating was 0.59 and for validation was 0.606. In general, the results of this model implementation in the studied basin with the quality and quantity of input data to the model are satisfactory.
Sima Rahimi Bondarabadi
Abstract
Increasing the greenhouse gases not only has impacts on the weather parameters, but also, has impact on water resources, agriculture, environment, health and economy. Climate change has significant effects on water resources by changing the hydrological cycle. There are several simulation methods for ...
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Increasing the greenhouse gases not only has impacts on the weather parameters, but also, has impact on water resources, agriculture, environment, health and economy. Climate change has significant effects on water resources by changing the hydrological cycle. There are several simulation methods for investigating the effects of climate change on different systems in the future, like climate models. The AOGCM model is able to simulate global climate in an area of some ten dousant km2, but, while they are not suitable for regional scale. For this reason, downscaling methods such as dynamic methods are used. These methods are based on high resolution and analysis of climate models. In this research, the impact of climate change was investigated on the low flow of Karkheh Basin as one the most important basins due to its water product and agricultural point of view. For this purpose, the PRECIS which is exponential dynamics and downscaling model, was used to estimate the temperature and precipitation in the period of 2070 to 2100 under A2 and B2 scenarios. The SWAT model, a comprehensive and continuous hydrological model was also used to estimate the flow discharge for the watershed. After calibration and validation of the SWAT model, the amount of rainfall and temperature used as input for PRECIS model under different climate scenarios and finally the daily flow rate was estimated for sub-basins. Then the indices of low flow rates (Q75, Q90 and Q95) and low flow series frequency analysis of 10 and 30 days were assessed. Results showed that rainfall and flow rate have negative and temperature have positive trend. In general, the results of PRECIS model indicated that this model has a good estimate of temperature and precipitation in the region, but, it is not strong for rainfall in autumn and spring, due to the local nature of the precipitation. The climate change assessment under scenario A2, indicated the rise of low flow rate by 70 percent, and this increase of low flow was more in the northern parts of basin, while under the scenario B2 the low flow rate droped by 50 percent for the period of 2080. But, low flow distribution had no change compared to base period.Thus, sever droughts would happen in the central and some northern parts of basin. It can be concluded that under different scenarios, climate change has different impact on the low flow rate. Therefore, due to the different impacts of climate change on low flow rate under different scenarios, uncertainties of scenarios as well as regional economic and social status should be considered in the management plans.
Alireza Habibi; Hamidreza Peyrowan
Abstract
The erosion rate ranking of geological formations can be a useful way for identifying and prioritizing the watershed sub-basins and it is important in view of decision making and management of the watersheds. Therefore, the present research was conducted with the aim of prioritizing the implementation ...
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The erosion rate ranking of geological formations can be a useful way for identifying and prioritizing the watershed sub-basins and it is important in view of decision making and management of the watersheds. Therefore, the present research was conducted with the aim of prioritizing the implementation of soil conservation operations in the Hablehrood sub-basins in northern Garmsar based on the degree of sensitivity of rock units to erosion. The method is based on the expert opinions and rainfall simulator experiment and comparison of the obtained results with erosion and sediment estimations of empirical models such as PSIAC, EPM and SWAT. Results showed that erosion rate ranking of the sub-basins based on the results of rainfall simulator conformed to the output of the three mentioned models in 12 sub-basins of 21 sub-basins and in other six sub-basins with two models, and in the remaining three sub-basins, it only conformed to one model output. Rainfall simulation results showed the highest correlation with the PSIAC model with a specific sediment yield of 9.2 t km-2 and based on the results of the observation data of the Bonkouh sediment-debit station, a special sediment of 8.02 t km-2 without considering the bedload, it became clear that the PSIAC model provided the most reliable estimate of sediment yield. Thus, matching the results of rainfall simulator in the erosion rate ranking of sub-basins with the PSIAC model shows that the rainfall simulator study on lithology units quite reliable with a 90% confidence level for erosion ranking classification of sub-basins and it can be used in similar basins.
Seyed Masoud Soleimanpour; Majid Soufi; Mohammad Javad Rousta; Samad Shadfar; Ladan Jowkar; Hojatollah Keshavarzi
Abstract
Gully erosion is one of the main types of water erosion and is known as one of the destroying forms of land degradation and soil loss in the world. Therefore, knowing the most effective factors on extending this type of erosion is utmost important. Beside, management and control of gully erosion require ...
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Gully erosion is one of the main types of water erosion and is known as one of the destroying forms of land degradation and soil loss in the world. Therefore, knowing the most effective factors on extending this type of erosion is utmost important. Beside, management and control of gully erosion require knowing the most effective factors on gullies extension. So, the present study was performed to determine the most effective factors on gullies in Khorrambid Watershed, North of Fars Province through measuring the permanent gullies during 13 years (2004-2016). Results showed that the average of gully length extension was 21.67 m throughout this period. This data indicated that the length of gully extension was 1.67 m per year. Further, it is determined that the length expansion of permanent gullies in this region was a function of bare soil and saturated electrical conductivity, using SPSS and backward multivariable regression. In conclusion, it is suggested different management solutions to increase the soil resistance against the erosion be prioritized in management and implementation plans such as increasing adoptable cover vegetation for the natural condition of the region and exclude the area to restore vegetation cover and pay more attention to control erosion in gully head cuts.
Ehsan Hajibabaei; Seyed Abbas Hosseini; Mojtaba Saneie
Abstract
Bedload movement plays an essential role in the process of bedload transport and morphological characteristics of rivers. Slope, flow rate and particle size are important parameters in the amount of bedload transport in the erodible beds. Many studies have been investigated the effects of these parameters ...
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Bedload movement plays an essential role in the process of bedload transport and morphological characteristics of rivers. Slope, flow rate and particle size are important parameters in the amount of bedload transport in the erodible beds. Many studies have been investigated the effects of these parameters on the non-erodible beds. In this research, performing a laboratory model in the erodible substrates, the effects of slope, flow rates, particle size and suspended particle concentration on the amount of bedload transport was investigated. The experiments were carried out in the discharge rate of 0.90 to 4.75 ls-1 with the concentrations of the suspended particles 0, 10gl-1 and the slopes of 2, 3 and 5 percent, on the uniform non cohesive particles with the grain diameter of 1.7 and 3.29 mm. The Froude numbers of these currents were obtained in the range of 0.93 to 1.51 and the non-dimensional bed load discharge was calculated in the range of 0.004-0.131. In the experimental results, the variation of the bedload transport capacity in relation to the discharge was shown in the different slopes and grain sizes. Furthermore, increasing the concentration of suspended particles to 10 gl-1, did not has a significant effect on the bed transport capacity. Applying dimensional analysis, the effective parameters on the non-dimensional bed load discharge (ϕ)were investigated. Moreover, to determine ϕ relation to the shear stress (ϴ), particle size (D*) and slope (S). In the scope of the experiment, an experimental relationship was proposed. Results indicated that for determining the non-dimensional bedload discharge in the steep slopes of erodible beds, considering the slope and dimensionless particle diameters as independent parameters had a better result than shear stress correction. Sensitivity analysis of effective parameters on the experimental relationship showed that the slope parameter had the most effect on the experimental relationship.
mehri raoofi; Mahmoud Habibnejad Roshan; Kaka Shahedi; Fatemeh Kardel
Abstract
Rivers are the main arteries of watersheds that play an important role in providing water for agriculture, drinking and industry. On the other hand, the reduction of river water quality has been one of the biggest human concerns in the last century. In order to evaluate the quality of running water, ...
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Rivers are the main arteries of watersheds that play an important role in providing water for agriculture, drinking and industry. On the other hand, the reduction of river water quality has been one of the biggest human concerns in the last century. In order to evaluate the quality of running water, biological indicators and the study of benthic invertebrates can be used. The aim of this study was to investigate the water quality of the main rivers of Babolrood watershed using the Hilsenhof Biological Index (HFBI). For this purpose, sampling of benthic invertebrates in 5 main river stations was performed using a net frame (sorber) with a cover area of 40 cm2 and transferred to the laboratory for identification. Then, using Pennak (1953) and Mellenby (1963) identification keys, the samples were identified by family and sex and counted and weighed. Also, at the same time as sampling of benthic organisms to study the physicochemical properties of water, samples were taken from river water. Pearson correlation coefficient was used to investigate the relationship between biological samples and physicochemical properties of water. The results showed that Babolk station with the lowest FBI and Babolrood-Babol station with the highest FBI were in the category of non-organic pollution and some organic pollution, respectively. The results of correlation of biological samples with physicochemical parameters in most cases were not significant at 95% confidence level. The highest correlation coefficient between Oligochaeta species was with Diversity biodiversity.Keywords: Benthic invertebrates, water quality, HFBI, Babolrood watershed, Mazandaran province
Amin Salehpour Jam; Fahimeh Rasooli; Amir Sarreshtehdari; Jamal Mosaffaie; Mohammad Kia Kianian
Abstract
People participation in the implementation of natural resources practices is one of the approeches that ensure the fulfillment of the goals and success of the projects. In this study, based on expert experience and different projects of natural resources implemented in watershed area surrounding city ...
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People participation in the implementation of natural resources practices is one of the approeches that ensure the fulfillment of the goals and success of the projects. In this study, based on expert experience and different projects of natural resources implemented in watershed area surrounding city of Tehran, the preventing social indices and sub-indices affecting on people participation were recognized and determined into three indices and 10 sub-indices. Obtained results from prioritizing effective social indices on preventing people participation in natural resources plans based on obtained weights from AHP method and expert questionary indicate that “unfavorable behaviorial indices” with weight of 0.623 and “unfavorable demographic indices” with weight of 0.130 have respectively maximum and minimum priorities, in the manner that prioritization of indices based on weights from maximum to minimum importance are “unfavorable behaviorial indices”, “cultural problems” and “unfavorable demographic indices”.Obtained results from prioritizing effective sub-indices based on expert questionary and the Kendalls' W rank test indicate that sub-indices have different roles on preventing people participation in natural resources plans, in the manner that the indices of “shortage of people trust in considering their ideas” with rank mean of 6.80 and “being low literacy and knowledge” with rank mean of 3.16 have respectively maximum and minimum priorities. The results also show that the index of “shortage of people trust” has the most priority as a preventing factor affecting on people participation, in the manner that two sub-indices of “shortage of people trust in considering their ideas” and “shortage of trust to continue projects”are two first priorities, respectively. Sub-indices of “shortage of young people in villages” from index of “unfavorable demographic indices” and also “being low or lack of culture of participation” from index of “cultural problems” were ranked as the most important social sub-indices.
Mohseen Kazemi; Sadat Feiznia; Hassan Khosravi; Sadegh Naji; Hamid Mesbah
Abstract
Monitoring the area and their marginal land uses changes in lakes are one of the strategies to achieve proper management of lakes and wetlands. In the present study to monitor Maharlu Lake area and its marginal land uses changes in Fars Province, the Landsat images of 1987, 2001 and 2013 were selected ...
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Monitoring the area and their marginal land uses changes in lakes are one of the strategies to achieve proper management of lakes and wetlands. In the present study to monitor Maharlu Lake area and its marginal land uses changes in Fars Province, the Landsat images of 1987, 2001 and 2013 were selected in wet and dry periods (March and September). By applying geometric and atmospheric corrections, the maximum probability algorithm was used for providing land use map. The Kappa coefficients for the September of 1987, 2001 and 2013 were 0.85, 0.88 and 0.89, and for April of 1987 and 2013 were 0.86 and 0.88, respectively. After providing land use map and validation, the method of comparing satellite images was used to monitor the changes. The changes were monitored by comparing Landsat images after classification. Results showed that the Maharlu Lake area has decreased by 82% in September 2013 compared to 1987. This reduction was 20% in March, 2013 compared to 1979. By reducing the water level of lake in September, bare soil and saline lands were increased by 39 and 37.5%, respectively. Agricultural and range lands have been decreased by 28 and 3.5% from 1987 to 2013, respectively. In general, the area under cultivation around the Maharlu Lake and the water level has been decreased significantly due to the lack of significant changes in rainfall during the long-term period and significant increase in evapotranspiration of Maharlu area during the last three decades. Due to recent droughts, bare soils and saline lands have been increased during this period. This has different consequences which require the proper management and planning of lakes and wetlands, especially during the drought periods.
