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.
Narges Javidan; Ataollah Kavian; Sajad Rajabi; Hamidreza Pourghasemi; Christian Conoscenti; Zeinab Jafarian
Abstract
Slope instability and landslides are important hazards to human activities that often result in the loss of economic resources, property damage and facilities. These hazards occur in the natural or man-made slopes. In the current study, the maximum entropy model was used which is one of the progressive ...
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Slope instability and landslides are important hazards to human activities that often result in the loss of economic resources, property damage and facilities. These hazards occur in the natural or man-made slopes. In the current study, the maximum entropy model was used which is one of the progressive data mining models, in order to modelling landslide susceptibility map for Gorganrood watershed. In the first step, the landslide inventory map was prepared consiste of 351 landslides. 18 geo-environmental factors were selected as predictors, such as: Digital elevation model, slope percent, aspect, distance from fault, distance from river, distance from road, rainfall, landuse, drainage density, lithology, soil texture, plan curvature, profil curvature, lithological formation, Topographic wetness index, LS factor, stream power index, Relative Slope Position and Surface roughness index. Three different sample data sets (S1, S2, and S3) including 70% for training and 30% for validation were randomly prepared to evaluate the robustness of the model. The accuracy of the predictive model was evaluated by drawing receiver operating characteristic (ROC) curves and by calculating the area under the ROC curve (AUC). The ME model performed excellently both in the degree of fitting and in predictive performance (AUC values well above 0.8), which resulted in accurate predictions. Furthermore, In this study the importance of variables was evaluated by the model. Dem (digital elevation model) (32.4% importance), lithology (22.9% importance) and distance from fault (14.8% importance) were identified respectively the main controlling factor among all other variables.
Abolghasem Dadrasi Sabzevar; Nader Jalali; Ebrahim Gohari
Abstract
Productivity of the floods in the country which suffering from a severe shortage of water resources, is inevitable and flood spreading in areas prone water is one of the simplest methods for efficiency of flood. Identification of suitable areas for flood spreading by traditional methods usually is very ...
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Productivity of the floods in the country which suffering from a severe shortage of water resources, is inevitable and flood spreading in areas prone water is one of the simplest methods for efficiency of flood. Identification of suitable areas for flood spreading by traditional methods usually is very expensive and takes up time. Using GIS and RS can reduce such costs and increase the speed and accuracy. The study area is part of the provinces of Khorasan Razavi and north Khorasan which included the cities of Sabzevar, Esferayen, Jagarm, Kashmar, Bardeskan and Khalilabad. In this study, seven layers, including units of the quaternary deposits, limitation of land use, slope, infiltration rate, runoff, storage coefficient and bed rock depth were selected and analyzed. Map of quaternary deposits was prepared from geological map at scale of 1:250000 and controlled by photo-interpretation. 43 sites were selected by field survey. A Land use restriction was prepared by field Investigation and visual interpretation of satellite images. The slope map was obtained by GIS method, using digital topographic map of the area with 100m interval and 30m Pixel size. Infiltration rate in each area was calculated by double ring test and geoelectric study was used for bed rock depth estimation. Also storage coefficient for each site was calculated by typical table related on soil texture using soil sampling to a depth of one meter. And finally volumes of overland flow were calculated for all sites by Jasten method. Booleain logic, index overlay and fuzzy logic were selected and tested in those areas to mapping suitable areas for flood spreading, using the weighting method. The results show that the fuzzy sum is the best and visual interpretation of RGB742 Integrating GIS, is more suitable to identify and prioritize areas prone to spreading.
Malihe Mohamadnia; Abolghasem Amirahmadi; Liela Goli Mokhtari
Abstract
Introduction
Humanity is facing many environmental challenges. Natural disasters are among these problems, causing the death and injury of hundreds of thousands of people and rendering millions homeless worldwide every year. Geomorphological hazards, particularly mass movements and landslides, are considered ...
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Introduction
Humanity is facing many environmental challenges. Natural disasters are among these problems, causing the death and injury of hundreds of thousands of people and rendering millions homeless worldwide every year. Geomorphological hazards, particularly mass movements and landslides, are considered some of the most potentially harmful phenomena. Mass movement refers to the outward or downward movement of domain-forming materials under the influence of gravity. These movements are primarily triggered by gravity, natural factors such as heavy rainfall, earthquakes, and soil saturation with water, as well as human activities like deforestation and improper engineering operations. According to the 2012 World Natural Hazards Report, landslides were ranked among the seven most dangerous natural disasters globally. The occurrence of natural hazards, including landslides, exerts considerable pressure on the economic development of countries, especially in developing regions, with financial damages hindering economic growth and prosperity. Iran, with its mountainous terrain, high tectonic and seismic activity, and diverse geological and climatic conditions, has created natural conditions conducive to a wide range of landslides.
Materials and Methods
The aim of this study is to spatially model landslide susceptibility using machine learning techniques, including random forest, support vector machine, and enhanced regression tree, in Razavi Khorasan province. Initially, the distribution map of landslides in the region was prepared through field visits and data from the national landslides database. In the next step, 70% of the identified landslides were used for model development, while 30% were reserved for model evaluation. The information layers for altitude, slope, slope direction, distance from waterway, waterway density, distance from roads, distance from faults, land use, vegetation index, surface curvature, profile curvature, precipitation, and selected lithological units were prepared and mapped using ArcGIS.
Results and Discussion
Prioritization of the factors affecting landslide occurrence using the random forest model showed that precipitation and altitude had the greatest impact on landslides in the study area. Additionally, the evaluation of the machine learning models using the relative operating characteristic (ROC) curve indicated that the landslide potential map generated by the random forest method had the highest accuracy (0.97). Based on this map, more than 25% of the area was classified into high and very high-risk zones.
Conclusion
This map can assist environmental planners in construction projects and help prevent land-use changes and construction in high-risk areas. Additionally, public awareness campaigns can reduce harmful human activities in these zones. While controlling landslides may not always be feasible or is often very expensive, proper management can help mitigate or reduce risks. By identifying the key factors in mass movement occurrences and zoning the areas accordingly, it is hoped that this research will contribute to the development of effective risk management plans and reduce the damage caused by landslides.
Reza Sokouti; Hamidreza Peyrowan; Davood Nikkami; Mohammadhossein Mahdian
Abstract
Considering to high distribution of the marly lands in west Azarbaijan province and high sediment yield of such lands, in this research, the relation among the form and the rate of erosion on marls with their erodibility properties were studied. So marly regions of province with the special properties ...
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Considering to high distribution of the marly lands in west Azarbaijan province and high sediment yield of such lands, in this research, the relation among the form and the rate of erosion on marls with their erodibility properties were studied. So marly regions of province with the special properties were recognized and soils were sampled. Soil erodibility indices were determined and analyzed by statistical methods considering the form and the rate of erosion. Also portable rain simulator were used to study of the runoff and sediment yield potential of such soils. Finally the factors affected the soil erodibility were determined by variance analysis. Results showed erosion rate could be classified as moderate. Gully erosion had highest number in Gara-agaj and Gara-tape areas whereas rill erosion had high number in all area of marlly lands. Surface runoff volume ranged between 255 to 577 cm3 in Shabanlu and surface runoff coefficient 0.23 to 0.53 in Gara-tapeh. Maximum yielded turbidity was 180 gr/lit in Gara-Agaj area. Clay ratio was the effective factor to gully form and Surface runoff volume also was the factor to form surface and rill erosion.
Reza NoroozValashedi; hadigheh bahrami pichaghchi
Abstract
Introduction
In the mountainous regions of Iran, a significant part of the precipitation is in the form of snow, which is considered an important source of river flow. Accurate knowledge of the quantity of these resource is necessary in terms of the ever-increasing value of fresh water and also in terms ...
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Introduction
In the mountainous regions of Iran, a significant part of the precipitation is in the form of snow, which is considered an important source of river flow. Accurate knowledge of the quantity of these resource is necessary in terms of the ever-increasing value of fresh water and also in terms of the optimal use of water resources. From a global point of view, snow monitoring and accurate information on the spatial distribution of snow cover, are necessary for weather forecasting and hydrological and meteorological modeling. An important feature of mountainous regions is the snow cover, which has a high reflectivity, has a great influence on the local weather, reduces the net radiation at the surface and as a result, transfers energy. In addition to being an important factor for ecosystem development, snow cover is very important for human activities. Accurate estimation of the coverage level is considered as one of the central and fundamental operations in the field of water resources management, especially in areas where snowfall is a major part of precipitation. Revealing and determining different characteristics of snow and ice using remote sensing data, which is widely used in hydrology, has created a new method to obtain the required parameters of hydrology.
Materials and methods
The Alborz Mountain range which is under study of the current research, separates the coastal plains of Mazandaran Province from the interior of Iran. The eastern half of Western Alborz and all of Central Alborz and a part of Eastern Alborz are within Mazandaran Province. In this way, along with other natural factors, certain geographical conditions have emerged. In this region, snow plays a key role in the hydrological cycle and hydroclimate, and a significant part of the total annual runoff in this region is the result of snowmelt. So that global warming affects the management of watersheds and the downstream water requirements of its sub-basins. First, MODIS sensor data was obtained daily with a spatial resolution of 500×500 meters from NASA's National Snow and Ice Database (NSIDC). The received images are related to the period of 2000-2018. To process the images, first pre-processing wacovered ars applied in the ENVI 5.3 software environment. The NDSI index was used to monitor the snowed area. Mann-Kendall test, Sen’s slope estimator, and Pettitt's homogeneity test were used to investigate the snow cover variation trend. Also, the seasonal and annual anomalies of snow cover, temperature and precipitation in the study area were investigated based on standard Z score.
Results and discussion
The results of the Mann-Kendall test and the Sen’s slope estimator method in the northern slope of Central Alborz, show that the largest reduction of the snow covered area occurred in January and winter season, respectively, equal to 220.39 and 50.41 km2 each year. The results of Petit's homogeneity test, using the Change Point Analysis (CPA) method, in January 2010 for the snow-covered area and May 2014 and June 2010 for the monthly mean temperature, showed a climatic jump at 0.05 significant level. Also, the change point in the snow-covered area time series of January has been descending, but the change point in the mean temperature time series of May and June has been ascending. Comparing the snow cover conditions with the mean temperature and total precipitation conditions, shows that in most cases the negative anomalies of snow cover are consistent with the positive anomaly of temperature and the negative of precipitation. The obtained results are a warning about the climate change in this region, which is known as the phenomenon of global warming and meteorological drought. Surely, these changes have a direct effect on the reduction of water resources for the agricultural and drinking sectors.
Conclusion
In general, the analysis of the snow-covered area variations in January during the studied 19 years, shows that for an increase in the average temperature of 0.13°c, the snow-covered area in this month decreased by 220.39 km2 every year. Also, according to the results of Pettitt's homogeneity test in 2010 and 2014, it can be concluded that global warming and meteorological drought caused a sudden change in the snow-covered area and temperature in these years and months. The comparison of precipitation and temperature conditions with the snow cover condition showed that in most years, the negative anomaly of snow cover was simultaneous with the positive anomaly of temperature and the negative anomaly of precipitation. The greatest effect of temperature increase has been observed in spring. Therefore, with the increase in temperature and the change in climatic conditions, the winter precipitation that will turn into snow accumulation has decreased and can affect the runoff caused by these precipitations in the spring season. Since this region has the ability to receive snow from mid-autumn to early spring, information about the snow covered area in this region is essential for many hydrological, meteorological, and climatological applications, as well as hydroelectric power generation and flood forecasting.
Ahmad Nohegar; Arash Malekian; Majid Hosseini; Arashk Holisaz; Edris Taghvaye Salimi
Abstract
Two factors of cost and time are related directly to the accurate estimate of runoff in the watersheds. More detailed information on the status of rainfall runoff also facilitate decisions on future programs for watershed managers, a step towards the preservation of natural resources for sustainable ...
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Two factors of cost and time are related directly to the accurate estimate of runoff in the watersheds. More detailed information on the status of rainfall runoff also facilitate decisions on future programs for watershed managers, a step towards the preservation of natural resources for sustainable development. In this study, in order to achieve optimal amount of runoff in the Shafaroud watershed, first significant rainfall data of four stations during 1998 to 2011 were collected and combined with other maps of the study area, such as DEM, land use and soil as input data in the form of SWAT model was software. After running the model, the SUFI-2 and GLUE algorithms in SWAT-CUP program used to evaluate the data uncertainty and the most accurate simulation. The first three years (1998-2000) of rainfall data for warm-up and the next 7 years (2001-2007) for the calibration and final 4 years (2008-2011) were used for the validation. Finally, with multiple simulations, the uncertainty of the parameters assessed with P-factor, R-factor, and NS coefficients. The results indicated in runoff simulation, the SUFI2 algorithm ( =0.85, NS=0.74) is more accurate than GLUE algorithm ( =0.82, NS=0.71).
Samane Arvandi; Forood Sharifi; Ali Shahnazari
Abstract
Water is a major factor in food production and sustainability of ecosystems. The need for water resources is increasing. Due to the scarcity of water and also aridity in many regions, development of new technologies to meet the plant water needs is important at plant establishment and specifically at ...
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Water is a major factor in food production and sustainability of ecosystems. The need for water resources is increasing. Due to the scarcity of water and also aridity in many regions, development of new technologies to meet the plant water needs is important at plant establishment and specifically at the development stage. Development of new technologies is a key for solving the problem of water shortage. Steam condensation in soil (using renewable energies) is a new and developing method that has the potential of increasing water efficiency. In this method, the steam transfers directly to the root zone and increases the moisture content of the soil. The purpose of this study was to investigate the efficiency of evaporation-condensation irrigation system in increasing water use productivity and evaluating performance of this technology in moisture absorption of various soils improved using organic matter. In order to increase water condensation, the produced steam, conveyed into steam chambers and after distillation, it increases the moisture content of the soil. In this study, a number of experiments were conducted on small flumes. Results showed that the moisture condensation of the soil with organic matter 11% higher than that of soil without organic matter. Then, with the possibility of increasing the moisture with this method, the experiments were carried out in larger pots. The result of analysis of variance of soil texture, steam temperature and organic matter interactions showed that these three parameters had no significant effect on soil moisture increase. Based on the results, the soil with medium texture, 35% organic matter and steam at 45 °C in coated conducting tube showed better results than other treatments. The steam blown into vapor tubes in flume and pots was at two temperatures of 45 and 55 °C that 30°C was selected for planting. After determining the proper temperature and selecting soil texture, plant cultivation was carried out by evaporation-condensation irrigation method. Then the water consumption was compared with greenhouse and field planting. Selected soil for cultivating lettuce under controlled conditions and with evaporation-condensation irrigation, was designated to be medium and in combination with 35% organic matter and coated conducting tube at steam temperature of 30°C. The results of this study showed that after harvesting and full growth of lettuce in all three conditions, production per 1 m3 of water for lettuce in evaporation-condensation irrigation, greenhouse and field was 1250, 333 and 75.5 kilograms, respectively. Water use efficiency was investigated in all treatments and the results showed that there is a significant difference between different irrigation methods (P≼0.01), and the highest water use efficiency resulted from evaporation-condensation irrigation method. The consumed water during the growing period in the greenhouse was approximately 4 times that of evaporation-condensation irrigation method and in the field was about 21 times that of condensation irrigation, which indicates a significant reduction in water use. By examining dry matter the weight of lettuce in all three methods, the results showed that in all samples taken from condensation irrigation, greenhouse and field, the average dry matter was 12.5% and average water was 87.5%, which indicated the same quality of the product in all three methods.
Davoud Davoudmaghami; Hossein Banejad; Mojtaba Saneie; Seyyed Asadollah Mohseni Movahhed
Abstract
Sharp-crested weirs are widely used for the purposes of flow measurement, flow diversion and water level control in hydraulics, irrigation, and environmental projects. Discharge coefficient at these weirs is a function of head to weir height ratio (H/P). In a constant head, flow increases by increasing ...
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Sharp-crested weirs are widely used for the purposes of flow measurement, flow diversion and water level control in hydraulics, irrigation, and environmental projects. Discharge coefficient at these weirs is a function of head to weir height ratio (H/P). In a constant head, flow increases by increasing the length of weir in the plan. One of these weirs is the duckbill weir. Sometimes, it is changed upstream and downstream bed level by deposition of sediments in the upstream of weir, erosion in the downstream of the weir, etc. These changes cause changes in the flow characteristics such as discharge coefficient. In this study, the effect of these changes on the discharge coefficient of duckbill weir is studied. The results showed that the change in the height of duckbill weir has no effect on the discharge coefficient. But, increasing L/W ratio (L and W are respectively length of weir and width of flume) decreases discharge coefficient. Also, with increasing, maximum of discharge coefficient gives in the amount of H/P less. So that maximum of discharge coefficient in L/W ratio 2, 3 and 4 is respectively 0.73, 0.68 and 0.63 which respectively occurred in the amount of H/P of 0.5, 0.3 and 0.25. Discharge coefficient is reduced with increasing upstream bed level. In submerged flow, Reducing the downstream bed level increase discharge coefficient but changes in downstream bed level have no effect on discharge coefficient until flow is not submerged, also, conditions of aeration are the same. By increasing the L/W ratio in duckbill weir from 3 to 4, amount of H/P in threshold of flow Interference and local Submergence decreased from 0.5 to 0.3.
Babak Homayunpur; Massoud Goodarzi; Qolamreza Zehtabian; Baharak Motamedvaziri; Hassan Ahmadi
Abstract
Nowadays, global climate change has been observed which had an impact on both surface and groundwater resources management. The main objective of this research is change detection of groundwater fluctuation caused by climate change in Borkhar Plain, Isfahan Province. In this way, both Mann-Kendal and ...
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Nowadays, global climate change has been observed which had an impact on both surface and groundwater resources management. The main objective of this research is change detection of groundwater fluctuation caused by climate change in Borkhar Plain, Isfahan Province. In this way, both Mann-Kendal and Sen’s slope non-parametric analysis were used using 19 piezometric wells data for the period of 1991-2019. Pearson correlation matrix along with correlation between climatic elements including temperature, precipitation and evapotranspiration (Thornwhite) with water table levels were determined. Based on this, a multivariate regression model was developed to model the annual time series at a confidence level of 0.95. Climatic factors of 2080-2099 period were simulated using the output of HadCM3 model through Lars-WG downscaling model for Maymeh Station under two scenarios A2 and A1B and based on the developed regression model, the water level of Borkhar Plain was simulated. The results showed that in the base period, the water table in the study area has been decreased with an annual slope of 47 cm per year. Correlation analysis showed that the three climatic elements of precipitation, temperature and evapotranspiration in a linear composition modeled 0.75 of the annual groundwater changes in the plain. The results of the exponential microscale model implemented on HadCM3 data showed that in the period 2080-2099 under both scenarios, the groundwater level of the region will decrease between 15 to 17 meters compared to the base period.
Banafshe Yasrebi; Mehri Dinarvand
Abstract
Introduction
One of the key challenges in rehabilitating degraded lands in arid areas is ensuring adequate moisture to enhance biomass production. This water supply must be achieved without further straining the already limited water resources or causing social conflicts in the region. Utilizing runoff ...
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Introduction
One of the key challenges in rehabilitating degraded lands in arid areas is ensuring adequate moisture to enhance biomass production. This water supply must be achieved without further straining the already limited water resources or causing social conflicts in the region. Utilizing runoff from rainfall and creating water storage systems is an effective method for restoring and improving pastures, particularly in desert and dry regions. This study aims to evaluate the impact of pitting on the restoration of native vegetation in degraded lands and dust emission hotspots in southern Khuzestan province, specifically in Bandar Mahshahr city.
Materials and methods
The transect-quadrat method was employed to investigate changes in vegetation cover. Two transects were randomly established in opposite directions and perpendicular to the rows of pitting within the study area. Each transect included 15 plots, resulting in a total of 30 plots in pitting areas and 30 plots in the control area (between the pitting rows). Canopy cover and plant species were measured in all plots. Additionally, vegetation richness and diversity indices were calculated using PAST software. To examine the impact of pitting on soil properties, 60 soil samples were collected from pitting and control areas at three depths: 0–30 cm, 30–60 cm, and 60–90 cm. Laboratory analyses were conducted to measure organic carbon, salinity, and moisture. An unpaired t-test, following a normality test, was used to assess significant differences in vegetation cover and soil characteristics between pitting and control areas.
Results and discussion
The results revealed that species density in pitting areas increased by 81%, canopy cover by 14 times, the Shannon diversity index by 82%, and the Simpson diversity index by 67%, compared to control areas. Conversely, the dominance index decreased by approximately 60%. In terms of soil conditions, salinity decreased across all three depths, while moisture significantly increased at a depth of 60–90 cm. Furthermore, organic carbon content increased by 40% at a depth of 0–30 cm.
Conclusions
The implementation of pitting has successfully restored native vegetation and improved soil conditions by enhancing moisture storage. Field observations indicate that pitting not only facilitates desert restoration by reintroducing and establishing valuable native species but also enhances soil quality. This approach demonstrates the potential of pitting to act as a critical link between various ecosystem components, promoting ecological balance and sustainability.
Heshmatola Agharazi
Abstract
Banketing and artificial afforestation are effective processes for soil carbon storage and removal of carbon from the atmosphere. In this research, land use change and its effects on carbon storage has been studied in Pakal Basin in Markazi Province. Rangeland was selected as a witness for ...
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Banketing and artificial afforestation are effective processes for soil carbon storage and removal of carbon from the atmosphere. In this research, land use change and its effects on carbon storage has been studied in Pakal Basin in Markazi Province. Rangeland was selected as a witness for comparing soil carbon storage with areas with banketing operations and planted with almonds (biomechanical activity) . Soil was sampled on transect and plot in systematic random samplingFor this purpose, three plots were used randomly, along each transect. Soil samples of one kilogram were taken from 0-15 and 15-30 cm depth of each plot. . Soil physico-chemical properties such as bulk density, organic carbon and soil texture were analyzed. Resalts showed that total carbon stored in the soils of bio-mechanical operation is 33.65 t.ha-1 from which 30% belongs to above and underground biomass, 2% litter,38.9% in the depth of 0-30 and 29.1% in the depth of 15-30 cm. Also, the the results showed theamount of soil organic carbon of 30.16 t.ha-1 in witness area from which 4% belongs to above and underground biomass, 3% litter, 62% in the depth of 0-15 and 31% in the depth of 15-30 cm.. As a result, biomechanical operations are more effective in carbon sequestration compared to rangelands as witness areas.
Ali Bakhtiarizadeh; Mohammad Najafzadeh; Sedigheh Mohamadi
Abstract
Introduction
The groundwater aquifer is one of the most vital resources, being considered more important in the countries (e.g., Iran) located in hot and dry areas. One of the ways to prevent contamination of groundwater resources is to focus on their vulnerability. So, a trustworthy assessment of groundwater ...
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Introduction
The groundwater aquifer is one of the most vital resources, being considered more important in the countries (e.g., Iran) located in hot and dry areas. One of the ways to prevent contamination of groundwater resources is to focus on their vulnerability. So, a trustworthy assessment of groundwater vulnerability is useful to determine the contamination points of the aquifer for effective protection and management of groundwater resources.
Materials and methods
In this research, DRASTIC index was applied to evaluate groundwater susceptibility while considering effects of land use and nitrate pollution for Kerman-Baghein Plain located in Kerman Province. In this regard, seven parameters including the depth of the water table, net feeding of aquifer, aquifer texture, surface soil texture, topography, impact of the vadose zone, and hydraulic conductivity were employed to calculate the DRASTIC index. It should be noted that this index has previously been applied by researchers for assessment of the vulnerability of the aquifer against groundwater pollution in different regions. However, despite the complexities in the underground water system and the opinions of experts in assigning the rank and weight of the parameters in this index and the difference in the conditions prevailing in the studied areas, it has always prompted researchers to take practical steps to improve this index. This improvement has been carried out in a number of studies by adding other parameters (e.g., land use and the effect of nitrate) to the parameters of the DRASTIC index. Therefore, in the present research, the parameters of land use and potential risk associated with land use have been used to compute the Composite DRASTIC index (CD) and Nitrate Vulnerability Index (NVI) in the Arc/GIS software environment, respectively. In this way, the CD index was obtained by adding the land use parameter to the DRASTIC index and the NVI index by multiplying the raster map of the potential risk rating related to the land use in the DRASTIC index. It should be noted that according to the land use map evaluation, this plain includes 54% of low-density pastures, 24% of irrigated agriculture, 10% of hand-planted forests, 6% of bare and desert lands, 5% of residential areas, and 1% of claypans. After the evaluation of three vulnerability criteria using all three indices DRASTIC, CD and NVI, their correlation with Ggroundwater Contamination Risk (GCR) was also investigated.
Results and discussion
The results revealed that the correlation of the DRASTIC index with the risk of underground water pollution is 8%, the CD index is 30% and the NVI index is 54%, with a probability of 99%, they show a significant correlation. The results indicated that the addition of the land use parameter caused to increase the correlation of vulnerability with the risk of groundwater pollution, and multiplying the potential risk associated with land use led to further increase of the correlation. As a result, the NVI index was selected as the superior index compared to the other two indices.
Conclusion
The results of the NVI index of Kerman-Baghin Plain indicated that this plain is divided into two categories including very low vulnerability with an area of 1528.07 km2 (75.52 %) having an NVI value of less than 70 and low vulnerability with an area of 495.33 km2 (24.48 %) having NVI value from 70 to 110. Taken together, in order to properly manage the groundwater resources and prevent the pollution of these resources, it is recommended to prohibit the establishment of industries and the cultivation of agricultural sector causing the pollution in areas with low vulnerability.
Sima Rahimi Bondarabadi; Saeed Jahanbakhsh; Behrooz Sari Saraf
Abstract
Any change in the concentration of greenhouse gases will upset the balance between the components of the climate system. But, the change in the concentration of these gases and how they will affect in the future is unknown. To study the effects of climate change on different systems in the future, climate ...
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Any change in the concentration of greenhouse gases will upset the balance between the components of the climate system. But, the change in the concentration of these gases and how they will affect in the future is unknown. To study the effects of climate change on different systems in the future, climate variables must first be simulated under changes in greenhouse gases (climate scenarios). There are several ways to do this, the most reliable of which is the use of climatic models. AOGCMs can simulate climate parameters globally in large scale, while these may not be suitable for small scales. One of the most important downscaling methods is dynamic methods that are based on increasing the resolution and analysis of planetary climate models. Here, in this research, climate change status in Karkheh River Basin where a major basin for water and agricultural yields is studied. For this purpose, the PRECIS model was used. PRECIS is an exponential dynamics downscaling model used to estimate the temperature and precipitation rates for the period of 2070 to 2100 under A2 and B2 scenarios. According to the results of climate change assessment under scenario A2, precipitation would increase up to 11% and up to five degree centigrade would rise in average maximum and minimum temperature while concerning B2 scenario, an increase in precipitation up to 7% and a rise in temperature rise up to three degree centigrade are estimated. However, under both the scenarios, despite, the fall’s precipitation is higher than the winter’s precipitation.
Mohammad Reza Dahmardeh Ghaleno; Mohammad Nohtani; Saeedeh Khaledi
Abstract
Human interventions on natural trend and overexploitation of natural resources, altogether have interrupted nature reclamation and accelerated its degradation. The present research aims to determine anthropogenic factors on wind erosion intensification in Hamun area, Sistan. The study populations included ...
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Human interventions on natural trend and overexploitation of natural resources, altogether have interrupted nature reclamation and accelerated its degradation. The present research aims to determine anthropogenic factors on wind erosion intensification in Hamun area, Sistan. The study populations included two groups, first all experts in the natural resources sector in city of Zabol (36 experts) which were surveyed and second group included all households in Hamoon area of Sistan which their number was 4121 households and according to Cochran formula, the sample size was obtained 221 households. The results of the questionnaires responded by experts showed that off-season cultivation of melon Hamoon lake bed, Excavation of water storing pits and manipulation of stabilized Lake bed and overgrazing vegetation in Hamoon bed are found to be the most important factors in exacerbation of wind erosion in this area. Pearson correlation coefficient was used to determine anthropogenic factors affecting the above three factors. Data analysis showed that experience of stakeholders and number of stockholders family members both have positive significant role in increasing our off-season cultivation of melons on the lake bed, Excavation of water storing pits and grazing on lake bed in 99% confidence level. On the other hand those stakeholders owning greater farmlands, high education level and income have fewer tendencies to overexploitation and degrade area.
Majid Kazemzadeh; Ali Salajegheh; Arash Malekian; Abdolmajid Liaghat
Abstract
On average, 70 percent of the precipitation that reach Earth's surface, returns to the atmosphere through evapotranspiration, and this rate reaches 90 percent in arid areas. Meanwhile, watershed measures directly related to water, soil and plant, and ultimately to evapotranspiration on the natural resources ...
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On average, 70 percent of the precipitation that reach Earth's surface, returns to the atmosphere through evapotranspiration, and this rate reaches 90 percent in arid areas. Meanwhile, watershed measures directly related to water, soil and plant, and ultimately to evapotranspiration on the natural resources region (ecochydrology). In this study, in order to study the effect of biological activities of watersheds (enhancement and increase of vegetation) on the process of soil moisture and evapotranspiration changes, paired watersheds of Taleghan, Alborz Province were selected. In order to calculate evapotranspiration by soil moisture balance method, soil moisture monitoring points were selected using field and laboratory studies in three main areas (northwest, eastern and southeast) and three replications and at three depths of 0-20, 40-20 and 40 -60 cm during plant growth period in 2017. Data were analyzed by ANOVA method, and Duncan test. The results showed that the actual evapotranspiration in the treated watershed and control watersheds were not statistically significant and, respectively, they showed 181 mm and 159 mm in a period of growth. In other words, the actual evapotranspiration value in the treated watershed was 14% higher than the control one during the growth period. Also, the results showed that evapotranspiration under different aspect slopes had a significant difference. The total actual evapotranspiration in the northwestern slopes were 229 and 226 mm, in east slopes were 207 and 171 and in the southeastern slopes were 109 and 80 mm in the treated and control watersheds, respectively.
