Maral Khodadadi; Mohammad Sadegh Askari; Fereydoon Sarmadian; Hossein Gholi Refahi; Ali Akbar Norouzi; Ahmad Heidari; Hamid Reza Matinfar
Volume 1, Issue 2 , July 2009, , Pages 99-110
Abstract
Salinity is the major factors of soil degradation in semi arid and arid regions. The main aim of this study was to evaluate the capability of Landsat ETM+ data for soil Salinity mapping in the selected part of the Qazvin plain, an area of arid environment. In this study spectral classes carried out on ...
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Salinity is the major factors of soil degradation in semi arid and arid regions. The main aim of this study was to evaluate the capability of Landsat ETM+ data for soil Salinity mapping in the selected part of the Qazvin plain, an area of arid environment. In this study spectral classes carried out on remotely sensed data and with the help of field observation and soil analysis were regrouped to soil salinity classes to prepare soil salinity map.. Soil sampling was implemented using stratified random sampling method, depending on landscape complexity and homogeneity as well as on the representativeness of Landsat ETM+ data. Also in each soil map unit at least one profile was studied for subsoil salinity variations. Field samples taken by using augur and profiles were analyzed in laboratory for Na+ , Ca2+ , Mg2+ cations, as well as soil texture, ECe and pH. We have analyzed the effectiveness of additional data such as digital elevation model to improve the accuracy of classification. Also NDVI, SRVI, PVI, SAVI, SI, BI and NDSI indices, PCA and Tasseled cap were analyzed. Soil salinity map of each selected bands produced and with ground truth map crossed. The results indicated that combination of DEM with ETM+ bands has highest accuracy. This study addressed that thermal band of ETM+ can increase the classification accuracy which illustrated its effective role to classify the soil salinity. Tasseled cap and other indices had almost high accuracy among studied image processing techniques. The SI and BI indices had the highest correlation with EC and could distinguish the saline and non saline soils while the optimum index factor had overall low accuracy.
Akbar Hassani; Hosseinali Bahrami; Aliakbar Noroozi; Shahin Oustan
Abstract
Reflectance spectroscopy can be used to study agricultural and environmental aspect of soil that are sensitive to soil organic and inorganic compounds. Despite the extensive studies in the field of visible-near infrared reflectance spectroscopy, there are rare researches in gypseous and calcareous soils. ...
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Reflectance spectroscopy can be used to study agricultural and environmental aspect of soil that are sensitive to soil organic and inorganic compounds. Despite the extensive studies in the field of visible-near infrared reflectance spectroscopy, there are rare researches in gypseous and calcareous soils. The objective of this study was to obtain a model that can predict chemical properties of gypseous soils via reflectance spectroscopy methods. Soil samples were collected from 102 locations in five different provinces in 0-30 cm of depth. Some chemical properties of soils, such amount of gypsum, equivalent calcite, cation exchange capacity, pH, EC, exchangeable calcium, magnesium, sodium and potassium and amount of silt, clay and sand were measured by standard methods in the laboratory. Air-dried soil samples were scanned at one nm resolution from 350 to 2500 nm, and calibrations between properties and reflectance spectra were developed using cross-validation under Partial Least Squares Regression (PLSR) and Boosted Regression Trees (BRT). Raw reflectance and first derivative reflectance data were used separately and combined for all samples in the data set. Data were additionally divided into two random subsets of 70 and 30 percent of the full data, which were each used for calibration and validation. Strongest correlations were obtained with gypsum, equivalent calcium carbonate, cation exchange capacity, exchangeable Ca and Mg, organic matter, sand and clay contents. Overall, BRT provided better predictions when under cross-validation. However, PLSR and BRT results were comparable in terms of prediction accuracy when using separate data sets for calibration and validation. In conclusion, VNIR spectroscopy was variably successful in estimating soil properties and showed its potential for substituting laboratory analyses or providing inexpensive co-variable data in environmental studies.
Majid Mahmoudabadi; Samira Zamani
Abstract
Wind erosion is one of the aspects of land degradation resulting in some problems especially for arid and semi-arid regions. Recognition of Sediment size Distribution (PSD) as well as transport mechanisms is important in modelling of wind erosion. In the present study, this topic was investigated on ...
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Wind erosion is one of the aspects of land degradation resulting in some problems especially for arid and semi-arid regions. Recognition of Sediment size Distribution (PSD) as well as transport mechanisms is important in modelling of wind erosion. In the present study, this topic was investigated on two soils taken from cropland and sand dune with different PSD, using wind tunnel. Results showed that compared to the original soil, the collected sediment had finer sizes, indicating a selective mechanism in transporting detachable particles. It was found that for cropland soil, increasing wind speed from 2 to 18 m/s at the height of 20 cm, the PSD of sediment approached to the original soil. This trend was reverse for sandy soil so that, for higher wind velocities, the frequency of fine particles was more than the original soil. The result of transport mechanisms indicated that compared to saltation as well as suspension, creeping was the least important mechanism. The contributing percentage of creeping for cropland and sandy soils was determined less than 10 and 1 %, respectively. For the cropland soil at wind speed of 2 m/s, suspension was the most important mechanism of transport and depends on soil's PSD, 61.1- 68.5 % of particles were transported. Increasing wind speed up to 18 m/s, saltation with 50.4- 53.8 % was found as the main transport mechanism. Reversely, in the sandy soil at low wind speed, most of sediment (59.3 %) was transported through saltation, whereas increasing the speed, suspension with 55.3 % became the dominant mechanism. The finding of this study brings up the important of soil PSD on the PSD of sediment as well as transport mechanisms.
Siavash Taei Semiromi; Hamidreza Moradi; Morteza Khodagholi
Abstract
Now a day, long-term prediction of climate variables is necessary for climate change impact studies. Currently Global Circulation Models (GCM) are powerful tools to generate climate scenarios. These models are limited to capture the local climate due to their low spatial resolution. So, they cannot be ...
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Now a day, long-term prediction of climate variables is necessary for climate change impact studies. Currently Global Circulation Models (GCM) are powerful tools to generate climate scenarios. These models are limited to capture the local climate due to their low spatial resolution. So, they cannot be directly applied for hydrological modeling in a catchment scale. In this research, first the trend of variables such as rainfall, radiation, maximum and minimum temperature were assessed for the base period with nonparametric Man-Kendall test. Second, these variables were downscaled by using the outputs of HADCM model and under three scenarios of A1, A2 and B1 which are accepted by IPCC(1971-2010) under three scenarios and their monthly changes were investigated for three periods of 2011-2030, 2046-2065 and 2080-2099 compared to the base predicted period of (1971-2010). All these scenarios showed almost similar results on precipitation shortage and increasing of solar radiation, minimum and maximum temperature over the future periods. As an example, the results of A2 scenario showed increasing of the annual mean, minimum and maximum temperature by 1.1, 3.2, and 4.6 °C, increasing of solar radiation by 0.07, 0.30 and 0.33 mJ m-2d-1 and decreasing precipitation by 16.4, 17.6 and 31.9 percent for these periods compared to the base period.
Ali Mohammadi Torkashvand; Davood Nikkami; Mehrdad Esfandiari; Seyed Kazem Alavipanah
Volume 2, Issue 3 , October 2010, , Pages 150-160
Abstract
Rill erosion map is one of the basic maps in erosion and sediment studies and also watershed management programs. Some methodologies for preparing rill erosion map (1:250000) by using RS and GIS were compared in a research carried out in Kan-Sologhan and Jajrood sub-basins in North-west and North-east ...
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Rill erosion map is one of the basic maps in erosion and sediment studies and also watershed management programs. Some methodologies for preparing rill erosion map (1:250000) by using RS and GIS were compared in a research carried out in Kan-Sologhan and Jajrood sub-basins in North-west and North-east Tehran, Iran. At the first phase, four working units' maps were prepared by integration of a) plant cover, geology and slope b) land use, geology and slope c) land use, rocks sensitivity to erosion and slope and d) land use, rocks sensitivity to erosion and land units’ layers in Kan-Sologhan basin. For comparing the efficiency of four working units’ maps, 53 ground control points were investigated. Results showed that map "d" was better than "a", "b" and "c" in providing rill erosion regarding economic and executive considerations. At the second stage, map "d" was compared with three maps of e) land units f) rocks sensitivity to erosion and g) satellite image photomorphic units (ETM+ images) in a broader basin of Jajroud. Rill erosion intensities in 314 ground control points were controlled and ground truth rill erosion map was prepared. Rill erosion map was crossed with different working unit maps where results showed that the highest accuracy is related to the images interpretation (81.0% accuracy). Accuracy was 78.4, 66.8 and 59.9 percent for methods of "d", "e" and "f", respectively. Root Mean Squared Error was the highest for map "f" and the least for integrated layers method (map "d"). The greatest precision is related to image interpretation and the images interpretation method is better than other methods in preparation of rill erosion map.
Ahmad Fatehi marj; Farzad Hosseini Hosseinabadi
Abstract
Drought is a phenomenon which is not preventable, but its outcomes could be mitigated by a holistic and scientific managerial vision. In order to approach to this goal, some practical frameworks is needed for different parts of the country, in respect to their climates. This paper is introducing development ...
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Drought is a phenomenon which is not preventable, but its outcomes could be mitigated by a holistic and scientific managerial vision. In order to approach to this goal, some practical frameworks is needed for different parts of the country, in respect to their climates. This paper is introducing development of the first agricultural drought risk management plan by experts of Agricultural Drought Management (ADM) for a pilot area. This project lasted for three years from 2009 to 2011. In this project some educational workshops and specialized meetings were held and have helped the plan to be more succeeded. At first, all needed climatic and agricultural information were collected and then a program for agricultural risk assessment in the region were selected. The drought plan was developed with a nine steps proposed method, in respect to advice of experts. Considering the average income of 41 billion Riyals from agricultural and animal husbandry activities, damages costs of poor to very severe drought varied from 3.450 to 10.350 billion Rials. Agricultural drought risk management plan can reduce drought damages from 30 to 47 percent, depended on drought intensity.
Morteza Dehghani; Ali Karami Khaniki; Seyed Hamid Reza Sadeghi
Abstract
One of the main objectives of hydrology is rainfall–runoff forecasting process for determination of flood hydrograph at the outlet of a watershed. The aim of this study was to investigate the consistency, accuracy and reliability of time–area and Clark instantaneous unit hydrograph models ...
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One of the main objectives of hydrology is rainfall–runoff forecasting process for determination of flood hydrograph at the outlet of a watershed. The aim of this study was to investigate the consistency, accuracy and reliability of time–area and Clark instantaneous unit hydrograph models for estimating the shape, peak discharge, time to peak, base time and volume of flood resulting from a rainfall with certain intensity and duration. For this purpose, the topographic map of Bazoft watershed was digitized by using R2V package, the digital elevation model (DEM) and isochronal prepared with the ILWIS software. Finally, the flood hydrographs were estimated by Clark and time-area models for six selected storm events. The computed hydrographs then compared with those obtained by measured data an outlet of the basin. The results showed that while both methods have some errors, the Clark model gives a better estimation of outlet hydrograph in comparison with time-area model. The amount of relative error for peak discharge for Clark and Time- Area methods were 23.3% and 32.8%, respectively.
Mahnaz Babaei; Seyed Zeynalabedin Hosseini; Aliakbar Nazari Samani; Seyed Ali Almodaresi
Abstract
Recently soil erosion and sediment yield has become one of the most important problems of the environment. Soil erosion risk assessment and sediment yield are first steps to confront with this problem. In this regard, various models and methods proposed. What is certain, first of all must be verified ...
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Recently soil erosion and sediment yield has become one of the most important problems of the environment. Soil erosion risk assessment and sediment yield are first steps to confront with this problem. In this regard, various models and methods proposed. What is certain, first of all must be verified the functionality of these models. The present study is carried out to KanSoleghan watershed in order to estimate the soil erosion risk and sediment yield. RUSLE 3D was used in geographical information system platform. Rainfall Erosivity (R), were obtained from monthly and annual data and IDW techniques, Soil Erodibility (K) were obtained from soil data and regin map, Land cover Management (C) using remote sensing techniques (with use of NDVI), LS using digital elevation model, Soil Conservation Practice with using slope percent map. Eventually based on RUSLE 3D model combining these factors together, annual average risk of soil erosion was obtained 22.20 t.ha-1.y to estimate the sediment delivery ratio was used several models, accordingly, the estimated annual sediment yield was overestimated in all models. Sedimentation basin was calculated using statistics gauging stations sooleghan (1.82 tons per hectare per year). Our study indicated that LS factors of the RUSLE 3D model (r2=0.68) were the most effective factors controlling soil erosion in the region. In general, it can be said that the reliability of the used data and used methods is too low and too many uncertainses exist for areliable calculation of soil loss amounts in kan soleghan watershed using the RUSLE 3D Model.
Mohammad Reza Yazdani; Sattar Chavoshi; Morteza Khodagholi; Bahram Saghafian
Volume 1, Issue 3 , October 2009, , Pages 167-178
Abstract
Most parts of the Isfahan province are located in central arid land of Iran and are sensitive to drought occurrences. So it is required to study drought for prediction. There are many ways to define drought using different indicators. Climatology drought was evaluated using annual precipitation time ...
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Most parts of the Isfahan province are located in central arid land of Iran and are sensitive to drought occurrences. So it is required to study drought for prediction. There are many ways to define drought using different indicators. Climatology drought was evaluated using annual precipitation time series and different truncation levels including 30% 40, 50, 60, 70, 80, 90 and 95%. In this study 85 precipitation stations were selected in Isfahan province and around of it, in period of 1966-1998.Interpolation methods such as, kriging, Co-kriging, inverse distance weighted and TPSS were evaluated for interpolation of truncation levels and the error of each method was calculated. In the selected methods, Co-kriging method had minimum error and TPSS method had maximum error. Drought extension maps were drawn for each truncation levels using ILWIS software. Also water volume of probable precipitation is calculated for each truncation levels. Results showed about half of rainfall events occurred in 30 percent truncation level, whereas about 80 percent of the events are in 30 percent truncation level. Thus intense droughts occurred in the study area. Maximum frequency of drought occurrences in basis of truncation levels in study area are 30, 80, 60, 50, 40, 90, 70, 95%, respectively. Results indicated that truncation levels are suitable method for climatological drought evaluation in the studied area.
Afrouz Bagheri; Bahram Malekmohammdi; Banafsheh Zahraei; Amirhesam Hassani; Farzam Babaei
Abstract
The formulation of strategies for sustainable groundwater resources needs an integrated view of land-use, climate changes, social system, and the response of the hydrological system. Negligence in creating a balance between these variables in charging and discharging groundwater resources has led to ...
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The formulation of strategies for sustainable groundwater resources needs an integrated view of land-use, climate changes, social system, and the response of the hydrological system. Negligence in creating a balance between these variables in charging and discharging groundwater resources has led to problems such as land subsidence, saline water advancement, reduced water quality, increased pumping costs, etc. in most of the country aquifers. In this study, the Lenjanat region was selected as a case study and one of the important regions of the Zayandehrud Watershed due to its interaction with the river, the existence of land-use changes, and increasing harvest from the regional aquifer. The results of temperature and precipitation prediction in an optimistic and pessimistic scenario until 2035 by the LARS Model and the results of examining past and future land-use changes and calculating the impact factor (adjustment coefficient) using IDRISI SELVA, ENVI, and CA-Markov were included in the study model (a combination of WEAP and ANFIS) to investigate future runoff and its contribution to aquifer recharge. The results showed that both climate and land-use changes have some impacts on water resources. In the case study, the amount of runoff decreases due to the decrease in rainfall and increase in temperature, and runoff infiltration, and subsequent feeding and groundwater level decrease due to land-use changes and increase in groundwater abstraction. The average rainfall volume was estimated at 194.17 million cubic meters in the observed years, of which 99 million cubic meters rechrged the aquifer. The average volume of groundwater supply after the effect of an adjustment coefficient of 1.051 was predicted in the optimistic scenario of 10.09 and the pessimistic scenario of 93.72 million cubic meters, respectively.
Mohammad Rostami; Nima Rohani; Hamdi Reza Sheybani
Abstract
Login driftwoods into the river flow and their accumulation in the upstream of the bridge will decrease the flow carrying capacity of the bridge. Blockage may cause a strong reduction in the flow rate through the bridge and therefore a strong increase in upstream water level which may lead to flooding ...
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Login driftwoods into the river flow and their accumulation in the upstream of the bridge will decrease the flow carrying capacity of the bridge. Blockage may cause a strong reduction in the flow rate through the bridge and therefore a strong increase in upstream water level which may lead to flooding or nearby urbanized areas. Drift woods either accumulates at a single pier, or it spans between two or more piers or it gets blocked at the bridge deck. Since the evaluation of such a mechanism in nature and in flood time is very difficult and limited knowledge is currently available on the likelihood of bridge blocking by the driftwoods, therefore, it is necessary to evaluate experimentally the movement of the driftwoods through the river flow and the effect of bridge characteristics on driftwood accumulation and blockage. The main purpose of this experimental study is to analyze the driftwood blocking probability at bridge depending on drift dimensions, driftwood shape (single log and log with branches), flow characteristics, method of driftwood entry into the flow and bridge characteristics. Tests were carried out in an inclinable rectangular flume and a bridge with guard rails was installed into the flume. The tests were performed by different length of driftwood, smooth and with branches, the number of entering driftwood to the channel flow (individual or aggregate), in the presence and absence of bridge pier and with three levels of water flow in the upstream face of the bridge. Entering each case of driftwoods has been repeated 10 times and then bridge clogging probability has been determined. The results showed that in case of water level come to low cord of the bride's deck , the clogging probability a bridge with and without pier changed from 13% to 93% and 33% to 100 respectively. The results showed that lengthening and increasing the number of driftwood and trunk with branches, the presence of the pier, and finally the rising water flow will increases the clogging possibility.
Azade Jabary; Majid Hosseini; Amir Khosrojerdi
Abstract
The present research is looking for determining and evaluation of water balance in Sanjabi Watershed located in Kermanshah Province due to a variety of problems raised by the population increase. For this purpose, the SWAT model parameters have been calibrated by applying required information layers ...
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The present research is looking for determining and evaluation of water balance in Sanjabi Watershed located in Kermanshah Province due to a variety of problems raised by the population increase. For this purpose, the SWAT model parameters have been calibrated by applying required information layers in a period extending from 1995 to 2004 and their sensitivity were analyzed by SUFI2 program. The flow parameters’ sensitivity was computed by P-Value and t-State in SUFI2. The most sensitive parameters were calibrated and thereafter model was validated for a period extending from 2005 to 2007. The model evaluation results showed that the value of NS (Nash Sutcliff), R2 (Coefficient of determination), Mean Absolute Relative Error (MARE) and Percent Difference (D) for calibration period were 0.78, 0.78, 0.2 and -0.2, respectively and for validation period were 0.74, 0.86, 0.3 and 0.01, respectively. Results showed the desired accuracy of SWAT for runoff simulation. Discharges for calibration and validation periods were generally under and overestimated, respectively. The water balance values are calculated as the amount of water available in the soil. So that the water balance resulted as negative in years 2005 (normal year), 2006 (wet year) and 2007 (dry year). Nevertheless, in these three years, autumn and winter monthly water balances were positive while in spring and summer were negative. The results also showed that most water losses were due to evapotranspiration in this watershed.
Hamid Reza Peyrowan; Amir Samadi Tabrizi; Samad Shadfar; Ahmad Motamed
Abstract
Marl formations are widespread in Iran. High potential to erodibility of marl formations in watershed basins of Iran cause many problems including loss of soil quality in agricultural and pasture lands and forests, increasing the risk of landslides and mass movements, reducing the quality of ground and ...
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Marl formations are widespread in Iran. High potential to erodibility of marl formations in watershed basins of Iran cause many problems including loss of soil quality in agricultural and pasture lands and forests, increasing the risk of landslides and mass movements, reducing the quality of ground and surface water, sediment load increases entered into the reservoirs, desertification areas due to intensive erosion and watershed management plan failure due to inadequate knowledge of the susceptibility to erosion the formations. The study area, Gatchab and Siahkooh Mountains situated in the northwest of central playa of Iran (Kavir plain). It is located in southwest of the Semnan city with 74 km distance. The widespread of the geological unit in the area is upper red formation with three members M1, M2 and M3. With respect to sedimentology finding on textures of Neogene sediments, they are sandy silt, silt, sandy mud and mud particles. The examination of distribution of various particle size of the sediments have shown that these sediments deposited in shallow water and lagoonal environments with changing of the depth, that changed to high dynamic environments condition of channel rivers. The results of analyses have shown that the percent abundance of lime in these sediments change from 24.28% to 34.98%. Because of the low contents of lime compound and clay particles, it is better to called them salty and gypsiferous siltstone and mudstone instead the marl term for these sediments.
Saeed Choopani; payman rezaee; Mohammad reza Gharibreza
Abstract
Extended abstractIntroductionRivers are highly variable systems and one of the most important water ecosystems that play an important role in the life of humans and other living beings and are easily affected by pollution. (Maanan et al., 2015). The concentration of heavy metals in sediments is generally ...
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Extended abstractIntroductionRivers are highly variable systems and one of the most important water ecosystems that play an important role in the life of humans and other living beings and are easily affected by pollution. (Maanan et al., 2015). The concentration of heavy metals in sediments is generally several times that of water bodies, and heavy metals are not destroyed and decomposed during natural processes, therefore, heavy metals can be stored in sediments and remain there for a long time. For this reason, surface sediments are one of the main reservoirs of heavy metals and other pollutants (Islam et al., 2016). The Karoun River is not immune from these pollutions and many wastes from metal, petrochemical and oil, cellulose and food industries, domestic and hospital sewage and agriculture are discharged into this water environment. On the other hand, this river supplies water for these industries and is a source of drinking water for cities such as Ahvaz, Khorramshahr and Abadan. The fishes of this great river are one of the main sources of nutrition for the people of the region, as a result of the presence of pollutants, especially potentially fertilizing elements in Karoun, it can cause pollution of sediment, water and food and affect the life cycle of this great river. damage (Rastmanesh et al. 2015). Considering the quantitative extent and diversity of human activities in the Khuzestan plain and the entry of all kinds of effluents and sewage into the Karoun River, investigating the pollution, pollutants and risk levels is an inevitable necessity. Therefore, this research aims to determine the level of enrichment of elements, to determine the ecological risk and dangerousness of pollution in comparison with the quality standards of sediments in the Karoun river in the Weis basin to the beginning of Ahvaz city using geochemical data and statistical analysis. It was done by XLSTAT2018 software. Materials and methodsIn order to evaluate the pollution of the sediments of the Karoun River bed, 22 samples were taken with a boat from a depth of 0-10 cm and based on common methods in sedimentary geology Tucker (1988) and Arzani (1997) of sediments was harvested. Then, the samples were prepared in the water and soil laboratory of the Soil Conservation and Watershed Research Institute for the granulation test and determination of the concentration of toxic metal elements. In order to investigate the state of sediment pollution, the obtained concentrations have been compared with the standard values of ISQGs, severe effect level (SEL), probable effect level (PEL) and global base values. Results and discussion According to the results obtained from the grading, the sediments of the river bed in most of the stations have a granular texture and are of the type of mud, silty sand and sandy mud. These sediments have an average of 0.62% organic matter in terms of organic matter. The results of the pollution level also showed that the concentration of toxic elements As, Cr and Ni have values beyond the standard values of ISQGs and PEL. Based on the comparison between sediment quality criteria and standards, Karun River in the studied area has clean sediments from the point of view of Cd and Pb elements. The results of calculation of enrichment factor showed that Zn element has moderate to significant enrichment. The enrichment of Cu, Ni and Cr was in the range of moderate pollution. The semi-metal As is in the range of low to medium enrichment and the two elements Cd and Pb have low enrichment. The average enrichment of elements is Zn>Ni>Cu>Cr>As>Pb>Cd. Finally, the results obtained from the risk index showed that the values of the risk index for all samples are in the low risk range (RI<150). The statistical analysis of the samples showed that there is a significant positive relationship between Cr, Ni, Cu and AS with clay. So clay particles are the main carriers of Cr, Ni, Cu and AS elements. A high correlation coefficient between elements indicates a common source, mutual dependence, and the same behavior during transportation. ConclusionThe current research leads to sufficient understanding of the geochemical situation and any change from natural conditions and revealing the local and thematic enrichment of pollution levels for aquatic animals and users, especially in the field of agriculture and food cycle in the Karun River in the Vays basin to the city of Ahvaz. has been The results of the enrichment factor showed low to high pollution for selected elements. The potential ecological risk values of all selected elements except As in sample 21 are in the low risk range, and AS in sample number 21 is in the medium risk range . The risk index values for all samples are in the low risk range . Based on the comparison of sediment quality criteria with the standards, Karoun River has clean sediments from the point of view of Cd and Pb elements in the studied period. So that 100 percent of the samples have a concentration lower than ISQG. Cr with 27% and Ni with 100% has a concentration beyond the PEL pollution level and all the values obtained for Cr and Ni elements have a concentration beyond the minimum concentration of the ISQG pollution level. In this way, there is a possibility of poisoning for aquatic animals and water exploitation by the toxic elements Ni and Cr. Comparing the concentration of elements with the standards showed that in stations number seven (subordinate to Mahi Shiban), 21 (east coast of KianPars) and 10 (Kouresh sewage), Cr and Ni elements have concentrations beyond the PEL pollution level and more As. It is from the minimum level of ISQG and the most polluted stations are in the study period. So, the maximum enrichment of Cr and As has also happened in station number seven. Element clustering analysis showed that organic materials are the main carriers of Cu and Zn elements and clay particles are the main carriers of Ni and Cr elements. Also, in the case of Cu and As elements, clay particles play the main role. But the toxic metal Pb has not shown any significant relationship with other elements as well as organic materials and clay particles. So Pb element has a different origin than Cu, Zn, Cr, Ni and As elements. The results of principal component analysis, while confirming the correlation coefficient and cluster analysis, showed that Cu, Zn, Cr, Ni, and As are of anthropogenic origin, and Pb and Cd are of terrestrial origin. This study has an important contribution in determining the origin, pollution and ecological risk of potential fertilizing elements and can help in identifying pollutant sources and pollutant control.
Hamid Reza Matinfar; Fereydoun Sarmadian; Seyed Kazem Alavipanah
Volume 2, Issue 4 , January 2011, , Pages 211-220
Abstract
Soil salinity is one of the main increasing problems of the world. In the recent years application of remote sensing and GIS techniques in order to assess saline soils is used because they bring about vast uniform coverage of ground phenomena in a short time. The images of LISS III sensor of the Indian ...
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Soil salinity is one of the main increasing problems of the world. In the recent years application of remote sensing and GIS techniques in order to assess saline soils is used because they bring about vast uniform coverage of ground phenomena in a short time. The images of LISS III sensor of the Indian satellite (IRS) were used in this research. The Brightness index (BI) could discriminate highly saline soils from non –saline and the salinity index (SI) show high potential to separate very high, high and non- saline soils. Results of supervised classification without combination DEM and remote sensing data have overall accuracy of 76%, producer accuracy of 78% and user's accuracy of 82%. While in supervised classification combination of remotely sensed data and DEM have overall accuracy of 98.1% , producer accuracy of 98.28% and user's accuracy of 98.4% .The reason for low accuracy of the classification , before combination of remote sensing and topographic data , can be explained by highly moist saline soils spectral interference with non-saline soils (soil with 25 to 65% gravels) , but these two soils had different topographic condition with 200 meters elevation difference , thus , with combination of the DEM , this kind of area and other areas with similar conditions have been separated from each other.
Amin Hassani; Masoud Tajrishy; Ahmad Abrishamchi
Abstract
Knowing the rate of evaporation from surface water resources such as channels, reservoirs and lakes is essential for precise management of water balance. In this study, monthly evaporation was determined by Bowen Ratio Energy Budget (BREB) method for Alghadir Lake (Saveh, Iran) from 1995-2007. Some variations ...
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Knowing the rate of evaporation from surface water resources such as channels, reservoirs and lakes is essential for precise management of water balance. In this study, monthly evaporation was determined by Bowen Ratio Energy Budget (BREB) method for Alghadir Lake (Saveh, Iran) from 1995-2007. Some variations have been observed on the estimated evaporation of the energy budget at different years, ranging from 151 cm for 1997 to 174 cm for 2005. Also, there is no specific monthly evaporation pattern for all the years, but evaporation rates were low in Jan and Feb and highest during the Jul and Aug. Surveying of lake thermal structure showed that inflow and outflow energy fluxes to this water volume have large variations and incoming solar shortwave radiation, incoming atmospheric longwave radiation and longwave atmospheric radiation emitted from the water surface are largest energy fluxes for this small and deep lake.
Hossein Eteraf; Mohammadali Dorri; Davood Nikkami
Abstract
Abstract Soil erosion is one of the most obvious factors of soil degradation. Vegetation can affect on maintaining soil fertility and the amount of soil loss by reducing runoff and sediment. This study was conducted in Maraveh-Tapeh in the north-eastern part of Kalaleh watershed, located in 55◦ 56' ...
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Abstract Soil erosion is one of the most obvious factors of soil degradation. Vegetation can affect on maintaining soil fertility and the amount of soil loss by reducing runoff and sediment. This study was conducted in Maraveh-Tapeh in the north-eastern part of Kalaleh watershed, located in 55◦ 56' 35" and 37◦ 49' 01" to investigate the role of plant species on soil stability with in a randomized complete block design with five treatments and three replications. Crop and pasture plants as herbal treatments were included Medicago sativa, Agropyron elongatum, Cyminum cuminum, Hordeum vulgare and a mixture of alfalfa and Agropyron. Plots were considered to have a 22 m long on slope direction (10%) by a wide of 5 meters. Runoff and sediment collecting tanks were installed at the bottom end of each plot to measure runoff and sediment. In this study the effect of cultivated plant species on the amount of soil erosion and fertility was investigated. The average volume of runoff during four years of executing the project was 6.93 and 22.9 m³ha-1in treatments of Hordeum vulgare and Cuminum cyminum, respectively. The average amount of sediment yield was 48.42 and 124.72 kgha-1 in treatments of mixed Medicago sativa and Agropyron elongatum and Cyminum cuminum, respectively. Results also demonstrated that Cyminum cuminum is not an appropriate species for cultivation on steep terrains with the aim of soil conservation due to its reverse effects on increasing runoff and reducing soil fertility in Maraveh-Tapeh.
Majid Mohammdi; Hamid Reza Moradi; Sadat Feiznia; Hamid Reza Pourghasemi
Volume 1, Issue 4 , February 2010, , Pages 248-258
Abstract
Landside is a natural disaster with great human and economic losses in Iran. In recent year, landslide occurrence due to change of land use and construction of roads, has been on the increasing trend in northern regions of Iran. This phenomenon is more occurring in developing countries due to high rate ...
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Landside is a natural disaster with great human and economic losses in Iran. In recent year, landslide occurrence due to change of land use and construction of roads, has been on the increasing trend in northern regions of Iran. This phenomenon is more occurring in developing countries due to high rate of population growth and natural resources deterioration. There are several methods for landslide hazard zoning and in this research density area and analytical hierarchy process models were utilized. For landslide susceptibility mapping, field study landslides distribution map and effective factors are required. Prioritization of effective factor was carried out using AHP. Our investigation indicates that lithology, distance from road, slope, distance from drainage network, land use, elevation and aspect are the main land slide controlling factor in the area respectively. Evaluation of these models using QS index showed that density area is a better approach for landslide hazard zonation in the region.
Ebrahim Borooshke; Mahmood Arabkhedri
Abstract
Soil erosion and sediment transport is an important issue in many Iranian watersheds. Watershed planning without accurate estimates of erosion and sediment yield with appropriate models is not possible. The objective of this study was evaluating of two common empirical models of MPSIAC and EPM. First, ...
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Soil erosion and sediment transport is an important issue in many Iranian watersheds. Watershed planning without accurate estimates of erosion and sediment yield with appropriate models is not possible. The objective of this study was evaluating of two common empirical models of MPSIAC and EPM. First, 10 small watersheds were selected in Western Azerbaijan Province, with several consecutive check dams on their streams implemented under watershed management projects. No flow over the last downstream check dam was considered as the main criterion in each selected basin. In addition to the direct measurement of sediment deposited behind the dams, sediment yield of watersheds were estimated using the models. Comparison of means using (Mann-Whithney) did not show any significant difference at 0.05 percent level between measured and estimated data. At final step, both models were tested by MAE and MBE statistics. The MPSIAC showed better performance than EPM with MAE=1.34 and MBE =-0.12.
Davood Nikkami; Reza Sokouti Oskuee; Ebrahim Brooshkeh; Faniz Heshmati
Abstract
Eroded soil particles within watershed areas are transported in three shape of dissolved, suspended and bed loads by river water discharge. Knowing the amount of suspended and bed loads are necessary in estimating sediment yield of watersheds. Usually, suspended load is measured daily in hydrometric ...
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Eroded soil particles within watershed areas are transported in three shape of dissolved, suspended and bed loads by river water discharge. Knowing the amount of suspended and bed loads are necessary in estimating sediment yield of watersheds. Usually, suspended load is measured daily in hydrometric stations, while this does not happen for bed load. Although, there are many differences between geology formations, rainfall intensities and water discharges of watersheds, the amount of bed loads are considered as a constant unique coefficient of suspended load. So, there would be highly errors in watersheds’ sediment load estimates. In this research, after collecting bed and suspended load data of three hydrometric stations of Badlan on Alandchay, Pol Yazdakan on Ghotourchay and Mazraeh on Baroonchay Rivers in Western Azerbaijan, the data were analyzed and best relations were fitted between bed load and suspended loads. According to statistical analysis all data had high coefficient of correlation at the level of 99 percent and the best equations were chosen accordingly. The ratio of bed to suspended load in Yazdakan, Badlan and Mazraeh stations were 79, 49 and 13 percent, respectively. This ratio was 47 percent for all three stations.
Alireza Habibi; Amir Safari; Amir Karam
Abstract
Process erosion is one of the most important degradation process, particularly in semi-arid climate. Identify the sediment of the issues is important for watershed managers and planners. The main purpose of evaluating and comparing the potential contribution of this research has been deposition of marl ...
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Process erosion is one of the most important degradation process, particularly in semi-arid climate. Identify the sediment of the issues is important for watershed managers and planners. The main purpose of evaluating and comparing the potential contribution of this research has been deposition of marl formations. This study was conducted in hablerood basin and in the northern city of garmsar. for this reason, constructive map lithological was prepared as a unit in geographic information systems.then, the potential value erosion on sediment collected simulators rain comforts' with intensity4mm and continuing 10 minutes in the category marl and none marl has been determined. the results showed that in hablerood basins contribution marl and none marl land respectively59.4 and 40.6 percent. While in terms of lands area. marl and none marl land respectively 21.4 and78.6 percent.particularly sedimentation marl lands was 2.38 ton in hectares, that twice none marl land.this study showed that the use of simulators rain in order to determine the contribution of sediment formations suitable method for watershed planners, to estimate the erosion rate is correct.
Milad Moradi; Sabereh Darbandi
Abstract
Urban inundation is a serious challenge that increasingly face the residents of many cities, as well as policymakers. Accordingly, inundation assessment is becoming increasingly momentous around the world. This comprehensive evaluation involves numerous indices in urban catchments, but the high-dimensional ...
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Urban inundation is a serious challenge that increasingly face the residents of many cities, as well as policymakers. Accordingly, inundation assessment is becoming increasingly momentous around the world. This comprehensive evaluation involves numerous indices in urban catchments, but the high-dimensional and non-linear relationship between the indices and the risk presents a tremendous challenge for accurate evaluation. In this study a project based on Stormwater Management Model (SWMM), Kriging and k-means clustering was used for quantitative and qualitative flooding risk assessment in urban drainage system over the western part of Kerman city. Flooding risk in the drainage system over the study area was evaluated by various precipitation scenarios and required parameters were calculated by land use map, DEM and field study. For calibration and assessment of model, calculated runoff in 3 point was measured and was compared with simulated runoff.Results show that,the proposed approach can identify the main driving factors, i.e., inundation duration, largest water flow and total flood amount in this study area. The inundation risk of each node can be qualitatively analyzed and quantitatively calculated. There are 3, 10, 13, 23, 30, and 33 node at risk under the return periods of 1-year, 5-years, 10-years, 20-years, 50-years and 100-years, respectively. This study proposes a novel and successful approach to assessing risk in urban drainage systems and provides guidance for improving urban drainage systems and inundation preparedness.
Amirhossein Halabian; Ali Ghasemi Siani
Abstract
In this research, for analysis the spatial- temporal trend of precipitation in Caspian basin, the monthly data of GPCC data base in the spatial resolution of 0.5°×0.5° during 63 years period(1951- 2013) have been used. In order to analyze of the spatial- temporal trend of precipitation, ...
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In this research, for analysis the spatial- temporal trend of precipitation in Caspian basin, the monthly data of GPCC data base in the spatial resolution of 0.5°×0.5° during 63 years period(1951- 2013) have been used. In order to analyze of the spatial- temporal trend of precipitation, the mean of annual, seasonal and monthly amounts of precipitation were prepared and then by applying Mann-Kendall nonparametric test at 0.95 level of significance, 17 maps precipitation spatial trend were produced in GIS. To examine the temporal trend of precipitation, first 17 graphs were prepared using the weighted amount of precipitation and then the trend was evaluated using Mann-Kendall nonparametric test at 0.95 level of significance. The evaluation of monthly precipitation spatial trend maps indicated a significant downward trend at 0.95 level of significance in March and April on the western, eastern and southwest regions of Caspian basin. Only in spring and autumn there have been a significant downward trend and in none of the other seasons no meaningful trend was detected. Also, the analysis of yearly precipitation spatial trend illustrated a significant downward trend on western region. The analysis of precipitation revealed significant downward trend on monthly time series at the 0.95 level of significance in March on Caspian basin.
Narges Ghasemiamin; Nasim Arman; Hossein Zeinivand
Abstract
Land use involves exploitation type of land for resolving human different needs. Land use changes is the result of interaction between human and affective factors on environment which is considered in spatial and temporal scale. Awareness of land use rates and its change in time is one of the most important ...
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Land use involves exploitation type of land for resolving human different needs. Land use changes is the result of interaction between human and affective factors on environment which is considered in spatial and temporal scale. Awareness of land use rates and its change in time is one of the most important factors in planning and management. By knowing rate of land use changes time scale, forecasting feature changes will be possible and do appropriate act. In this research, 2014 land use map was prepared by RS with Kappa coefficient of 0.88 and overall accuracy of 0.86 which has high accuracy. For investigating each effective factor on land use in CLUE-S model logistic regression was used and for assessment of logistic regression, ROC curve was used. After determination of demand ratio according to past changes, land use map of 2025 was prepared. Assessment of CLUE-S model showed its high accuracy (Kappa coefficient is 0.88). Also, the results demonstrated that the most land use change are related to forests and ranges to farmlands, as range and forest lands decreases 28.12 and 82.20 present respectively and farmlands increases 10.33 percent until 2025.
Mahbobeh Akramian; Mohammadtaghi Dastorani; Mohammad Farzam; Ehsan Abdi
Abstract
Vegetation has a fundamental role in controlling surface landslides by its mechanical and hydrological effects. However, due to the complexity of vegetation-soil interactions, quantification of the effects of roots on soil remains as a challenge. This study tries to evaluate and quantify the effects ...
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Vegetation has a fundamental role in controlling surface landslides by its mechanical and hydrological effects. However, due to the complexity of vegetation-soil interactions, quantification of the effects of roots on soil remains as a challenge. This study tries to evaluate and quantify the effects of Tamarix roots in increasing the soil shear strength of Kashafroud banks in Khorasane_Razavi Province, Iran. After field observations, a number of 18 samples of soil containing Tamarix hispida roots and also three samples of soil without any root with the sizes of 10×10 cm were collected from the research area and transported to the laboratory. Direct shear test was carried out for the samples and by drawing Mohr-Coulomb failure envelope, the shear strength of soil reinforced by the roots was obtained and compared to those of the soil samples without any roots. Results showed that roots increase the soil cohesion and shear strength by 216.6 and 41.64 percent, respectively. Results also indicated that by increasing the vegetation indices of RAR and RDR, soil cohesion and as a result, shear strength is increased. Of course, this shear strength increase will support natural stability of river banks against erosion and destruction.
