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Natural Hazards (15730840) 120(5)pp. 4329-4348
Human activities and climate change have resulted in environmental degradation and increased environmental hazards globally. In Khuzestan province, such hazards have included droughts, heat waves, and dust storms occurring more frequently. To understand the factors contributing to the dust storms, this study evaluated changes in rainfall, air temperature maximum and minimum, and soil temperature (1985–2019), as well as land cover, land surface temperature, and water bodies in 2017 (drought) and 2019 (wet year). The findings of the principal component analysis indicate a reduction in annual water bodies, spring vegetation, and water bodies in the spring, summer, and autumn seasons. The increase in air and land surface temperature accounts for 95% of the variance in dust in the Khuzestan province. Field surveys suggest that various human activities such as hydro dam building, crude oil drilling, extracting crude oil wells in lagoons, changes in farmland use, and water transfer among water basins have intensified the phenomena in the region under study. To manage this critical issue more effectively, it is recommended to review and assess local policies regarding regional ecology and establish cooperative agreements with regional countries such as Iraq, Turkey, Syria, Jordan, and Saudi Arabia which all experience similar natural disasters. © The Author(s), under exclusive licence to Springer Nature B.V. 2024.
Acta Universitatis Carolinae, Geographica (03005402) 58(1)pp. 26-33
Social capital approaches consider the empowerment of societies against disasters, which enable rural communities to recover from the negative effects of hazards. Social capital is a mediator for collective action and can help people build common property resources. Not only can social capital improve access to natural resources, it can also improve access to physical capital. Using the descriptive and analytical survey, this article analyzes the impact of social capital on managing an earthquake in the villages of Khodabandeh in northwest of Iran. The findings indicate that according to the single sample T test as well as the opinions of local authorities and household heads. The components of attitude and cohesion have the strongest direct effect on reducing vulnerability at the level of households and rural authorities, the component of trust has the strongest indirect effect, and the network component has no indirect effect on either level. © 2023 The Authors.
Geografia Fisica e Dinamica Quaternaria (03919838) 44(2)pp. 183-196
Soil erosion is often regarded as one of the main processes of desertification. Many parts of the world have been affected by soil erosion, resulting in major environmental problems and causing land degradation, loss of agricultural land, destroyed villages and infrastructure as well as historic places. Soil erosion particularly affects arid and semi-arid regions due to long dry periods and often-intensive precipitation events. The soil particles washed off by surface and subsurface runoff are the biggest pollution factor in terms of amount and volume. Our case study is located in the Southern Isfahan province, Central Iran. The area is severely affected by water erosion such as gullies, rills and badlands. The main aim of this study is to predict the spatial distribution of the different water related erosion types and their susceptibilities using a probabilistic Maximum Entropy Model approach based on the following environmental layers: lithology, soil textures, land use, precipitation, Normalized Difference Vegetation Index and topographic indices derived from an SRTM DEM with 30 m spatial resolution. An inventory of the erosion forms and features such as gully erosion, rill erosion and badland erosion was determined based on Google Earth images (GE), aerial photos and a field campaign conducted in 2018. In order to validate the stochastic modelling approach, we divided the entire sample in a train (70%) and test (30%) dataset. We validated the model performance using the Area Under Curve (AUC) value. The model yields good (rill and gully erosion) to excellent (badland) results for both train and test data. The spatial prediction of susceptibilities for rill, gully and badland erosion show that in total more than 40% of the study area is affected by water erosion processes (4.8% rill erosion; 23.4% gully erosion and 17.9% badland erosion). The knowledge of susceptible areas is crucial for a proper land management and related soil conservation measures to guarantee a sustainable land use. © 2021 Comitato Glaciologico Italiano. All rights reserved.
Acta Universitatis Carolinae, Geographica (03005402) 56(1)pp. 120-128
Flash flooding caused by excessive rainfall in a short period of time is one of the worst environmental hazards, especially in arid and semi-Arid regions. Watershed prioritisation identifies and ranks the different watersheds in a catchment based on multiple parameters, which play a role in the land and water degradation. This article deals with the prioritization of 24 sub-catchments in the Jarahi-Zohre catchment in southwest Iran by applying the mixed multivariate linear model of TOPSIS. Morphometric parameters, such as the constant of channel maintenance, drainage density, ruggedness number, infiltration index, stream power index, stream frequency, slope, drainage texture rate, relief rate, form factor, bifurcation ratio, as well as the topographic wetness index, were used as TOPSIS input data, along with precipitation information. The results obtained from the weighting analysis show that ruggedness number, slope and rainfall information have the largest impact on flood events. The sub-catchments Seidyon, Emamzadeh Jafar, and Takht Deraza have a high flood risk and should be given the highest priority for soil and water conservation measures. To validate the results, the prioritization scheme was compared to the flood events in recent years. © 2021 Karolinum - Nakladatelstvi Univerzity Karlovy. All rights reserved.
Acta Universitatis Carolinae, Geographica (03005402) 55(2)pp. 165-182
The knowledge of actual evapotranspiration at farm level is a prerequisite for irrigation planning, farm management, to increase production and reduce water consumption. To accomplish this, comprehensive and accurate assessment methods should be applied. In order to evaluate accurately evapotranspiration processes we compared lysimeter evapotranspiration data with MODIS (Aqua and Terra satellites) and LANDSAT (SEBAL algorithm) satellite images as well as with the FAO Penman-Montith method. The findings indicate the low error rate, high correlation (1) and appropriateness of SEBAL in estimating actual evapotranspiration. The error values MAD, MSE and RMSE between lysimeter and the SEBAL algorithm were 0.59, 0.36 and 0.60 respectively. The second best performance was established for the FAO Penman-Montith method. The obtained error values MAD, MSE and RMSE between the lysimeter and FAO-Penman-Montith method are 0.91, 1.29 and 1.13, respectively. © 2020 Karolinum - Nakladatelstvi Univerzity Karlovy. All rights reserved.
Arabian Journal of Geosciences (discontinued) (18667538) 13(4)
Water level reduction of Urmia Lake Basin is the main problem in northwest of Iran during 2001–2017. Climate change and human activity have affected the water resources in this basin. In addition, continuing downward trend of water level in the Urmia Lake leads to hazard such as dust storm, lake drying, subsidence in plains, population immigration, and reduced production efficiency. Finding the causes of water level change is one of the challenges as to the unsustainability of the lake. Climate change, drought, dam construction, well drilling, land use change, land cover change, and the pattern of cultivations are inflectional here. The results of the Man-Kendall test indicate that the annual temperature (Z = 2.3, 95%) and frequency of droughts increased, and annual precipitation (Z = − 2.5, 95%) decreased. The results indicate that groundwater extraction increased from 374 to 2263.4 mcm, and the volume of dams increased from 198 to 1758 mcm (1961–2017). Surface water is reduced due to decreasing rainfall, increasing temperature, and drought frequency in the last decade. The comparison of these parameters with each other indicates high contribution of climate change and human activity in water level reduction of the subject lake. Restoration and sustainability of this lake are very important to the water management resources of Urmia Lake Basin. © 2020, Saudi Society for Geosciences.
Acta Universitatis Carolinae, Geographica (03005402) 54(2)pp. 232-239
This paper presents the Modified MEDALUS (MMEDALUS) approach, a quantitative assessment of desertification, in the case study area located in the Southern part of Iran. Six main factors of desertification including: soil, climate, plant cover, management, erosion state and ground water situation were considered for the model approach. Then several sub-factors determining the quality of each main factor were quantified according to their quality and weighted on a scale between 1.0 and 2.0. We used a Geographic Information System (GIS) software to analyze and prepare the spatial distribution of the factor layers. Subsequently, the final desertification hazard map was prepared by combining the different MEDALUS factors in Arc GIS 10.3 in order to define the final hazard classes on the basis of hazard scores based on the geometric mean of the main factors. The MEDALUS and MMEDALUS models show the “Desertification Potential” that in turn was validated with the current state of desertification observed in the field. The results show that the applied MMEDALUS approach yield significantly better results than the MEDALUS model in the study area. The results also show that the areas under severe and very severe hazard are the most extensive classes in the desertification map. Thus, we illustrate that most of the study area is sensitive to desertification. However, we highlight that management, climate and water table qualities were the most important indicators affecting the desertification processes, while soil quality seems to play a minor role in our study area. © 2019 The Authors.
Geografia Fisica e Dinamica Quaternaria (03919838) 41(2)pp. 95-104
Soil erosion in arid areas is a major environmental threat. Gullies, as one of the most intensive soil erosion processes, are very common in the southwest of Iran. Lithology, vegetation density and climate change, as well as land use and land cover change are effective drivers of soil loss in general, and gully erosion in particular. The overall objective of this research is to assess the relation between, lithology and the spatial distribution of gullies in the Mazayjan basin. Data were collected by field survey, interpreting aerial photos and analyzing ASTER multispectral images. Modeling of spatial gully susceptibility was performed with a GIS-based statistical mechanics approach (Maxent). The analysis of ASTER bands ratios yields valuable results in terms of the mineral differentiation of the Zagros Mountain substrates and hence, can be utilized as a tool for lithological mapping. Additionally, the statistical mechanics approach used to assess the relation between existing gully locations and the combinations of lithologic predictor variables show that gullies have a high probability in areas showing substrates with high amounts of salt, gypsum and marl, especially in the plain areas. The model performance shows a very high accuracy both for train and test data. The spatial prediction highlights concentrated gully erosion in areas with aeolian sediments on top of alluvial substrates. © 2018 Comitato Glaciologico Italiano. All rights reserved.
Chalov, S. ,
Golosov, V. ,
Tsyplenkov, A. ,
Theuring, P. ,
Zakerinejad, R. ,
Maerker, M. ,
Samokhin, M. Geography, Environment, Sustainability (25421565) 10(4)pp. 43-68
Sediment monitoring and assessment remain one of the most challenging tasks in fluvial geomorphology and water quality studies. As a response to various environmental and human disturbance effects, the main sources and pathways of the sediments transported within catchments, especially most pristine small one, may change. The paper discusses state-of-the-art in the sediment budget research for small catchments. We identified nine independent approaches in the sediment transport assessment and applied them in 11 catchments across Eurasia in the framework of an FP-7 Marie Curie-International Research Staff Exchange Scheme in 2012-2016. These methods were classified as: i) Field-based methods (In-situ monitoring of sediment transport;-Soil morphological methods and dating techniques; Sediment source fingerprinting; Sediment-water discharge relationships), ii) GIS and remote sensing approaches (Riverbed monitoring based on remote sensing/historical maps; parametrization of the channel sediment connectivity; Sediment transport remote sensing modeling), and iii) Numerical approaches (Soil erosion modeling and gully erosion (stochastic and empirical models); channel hydrodynamic modeling). We present the background theory and application examples of all selected methods. Linking fieldbased methods and datasets with numerical approaches, process measurements as well as monitoring can provide enhanced insights into sediment transfer and related water quality impacts. Adopting such integrated and multi-scale approaches in a sediment budget framework might contribute to improved understanding of hydrological and geomorphological responses. © 2017, Lomonosov Moscow State University. All rights reserved.
Natural Hazards (15730840) 79pp. 25-50
Soil erosion by water is a significant problem in arid and semi-arid areas of large parts of Iran. Water erosion is one of the most effective phenomena that leads to decreasing soil productivity and pollution of water resources; especially, in the Mazayjan watershed in the southwest of Fars Province gully erosion contributes to the sediment dynamics in a significant way. Consequently, the intention of this research is to identify the different types of soil erosion processes acting in the area and to assess the process dynamics in an integrative way. Therefore, we applied GIS and satellite image analysis techniques to derive input information for the numeric models. For sheet and rill erosion the Unit Stream Power-based Erosion Deposition Model (USPED) was utilized. The spatial distribution of gully erosion was assessed using a statistical approach, which used three variables (stream power index, slope, and flow accumulation) to predict the spatial distribution of gullies in the study area. The eroded gully volumes were estimated for a 7-year period by fieldwork and Google Earth high-resolution images. Finally the gully retreat rates were integrated into the USPED model. The results show that the integration of the SPI approach to quantify gully erosion with the USPED model is a suitable method to qualitatively and quantitatively assess water erosion processes. The application of GIS and stochastic model approaches to spatialize the USPED model input yields valuable results for the prediction of soil erosion in the Mazayjan catchment. The results of this research help to develop an appropriate management of soil and water resources in the southwestern parts of Iran. © 2015, Springer Science+Business Media Dordrecht.
Geografia Fisica e Dinamica Quaternaria (03919838) 37(1)pp. 67-76
Gully erosion is one of the most severe environmental problems in large areas of Iran. Land degradation and accelerated desertification are the consequence in susceptible areas. Gully erosion normally takes place when surface runoff is concentrated and thus, detach and transfer soil particles down the slopes into the drainage network. In traditional soil erosion studies these processes often have been neglected. In this study we investigate the spatial distribution of gully erosion processes with a quantitative method since in many national assessment approaches just qualitative models were applied. For this study we utilized a detailed terrain analysis and a stochastic modeling approach using mechanical statistics. Moreover we predict the potential spatial distribution of gullies in the Mazayejan plain of Fars province in southwestern Iran where gully erosion is the main environmental threat. Our methodological approach consists in the following steps: i) mapping of gully erosion phenomena in a test area based on Google Earth images; ii) development of a digital elevation model (DEM) with 10 meter resolution, iii) detailed terrain analysis deriving more than 20 terrain indices, iv) application of the Maxent model for the test area using the gully erosion forms as dependent variable and topographic indices as predictor variable and finally v) prediction of the spatial distribution of gully erosion potential for the entire study area. Model performance was evaluated by the Receiver Operating Characteristic (ROC). The results obtained show that the Maxent model perform very well and thus, it is suitable for the prediction of the gully erosion potential in the area. Among the terrain indices utilized in the prediction the most important ones are: convergence index, plan curvature, and slope. The proposed methodology allows conducting a proper gully erosion assessment in order to identify the priority areas for soil conservation and land use management.