Showing 8 results for Erosion
Seyd Fateme Hashemi, Ali Shahnazari,
Volume 0, Issue 0 (3-1921)
Abstract
Huge floods carrying enormous amounts of transported silt occur annually in the Talar River's catchment area in the province of Mazandaran. In order to investigate the sediment transport from the specified watershed, samples were collected at five different time intervals, specifically on May 22nd, 2018; May 20th, 2018; May 17th, 2018; and May 16th, 2018. The study focused on two dates, 17.11 and 5.11, and a specific stretch of land measuring 16.75 km between Darya Malakala-Najjarkala and Arab Roshan, located outside the urban area. The purpose was to analyse the patterns of sedimentation and erosion throughout a five-year period (2016-2021) using the HEC-RAS model. Inspected. The sediment transport and volume of sediment were analysed and studied based on the long-term statistics of the Kiakla hydrometric station. This analysis focused on flood conditions with return periods of 2, 10, 25, 50, and 100 years for the watershed of the station. The findings indicate that the cumulative sediment input at the start of the simulation period is 0.9 million tonnes lower than the total sediment at the end of the period. Additionally, the river is susceptible to erosion in the majority of situations. Furthermore, during the initial period (22.4-24.7), the sediment's mean height measures 11 cm, with a substantial sedimentation of 6 million tonnes. The deposition during the second period (2018-05-20) amounts to roughly 1 million tonnes. In the third quarter, there is a relatively consistent pattern. During the fourth phase, the erosion conditions, in terms of both depth and volume, are unsuitable for harvesting. During the fifth phase, which lasted from 11.5 to 16.75, the erosion amounted to approximately 8.3 million tonnes. The erosion height change in the fifth interval ranges from 10 to 20 cm. All distances are measured in km from the sea. Under such circumstances, sediment removal is unfeasible, but it is advisable to consider flood management and river engineering measures.
Aghil Madadi, Elnaz Piroozi,
Volume 16, Issue 42 (9-2016)
Abstract
The purpose of this study is erosion and sediment is estimated in whole of Lay watershed, located in the North Wast of Iran.In this study, the model of WEPP, was provided for simulation and forecast of erosion and sedimentation in the study watershed. The data required for WEPP model are entered in six files, including soil file, management, climate, slope, channel and pounds files. In this study, after determining of work units, the information for developing file were collected. In this region there are, 3 types of soil, 2 managements and 5 channel types. After making the files, WEPP model was run via Geowepp software. It is notable that in this software water erosion and sediment amount was estimated by three methodes of hillslope, watershed and fow path. In these methods sediments estimated were 0.308, 0.215, 0.491 tha-1 y-1, respectively. According to estimated results, the hillslpe with 0.308 tha-1 y-1 was in good agreement with actual amount 0.319 and is suitable for the erosion and sediment of Lay watershed.
Alireza Jafarzadeh Estalkhkouhi, Parviz Rezaei,
Volume 17, Issue 44 (3-2017)
Abstract
Among the various processes that destroy lands, soil erosion is a complex and hazardous environmental process that constitutes a serious threat to preservation of soil and water resources in Iran and has inflicted its negative effects on the vital ecosystem with the intensified utilization of nature by human beings. The present descriptive and analytic research employed the PSIAC model to study erosion and compare it with other empirical methods and models by investigating the effects of nine important and influential factors in soil erosion and sediment production in various parts of the Sefidrood Basin through giving intra-layer numerical scores to them. Erosion and landform zoning maps and also zoning maps for the nine factors were then extracted. Results indicated that 77 percent of the lands in the plain landforms faced very little erosion and 23 percent little erosion, 14 percent of the lands in the mountainside landforms were exposed to very high erosion rates, 55 percent with high erosion rates, and 31 percent with average and low erosion rates, and 17 percent of the lands in the mountain landforms experienced very high erosion rates, 58 percent high erosion rates, and 25 percent average erosion rates. In other words, the rates of erosion changed from low in the plain landforms to very high in the mountain landforms. This implies that pastures and natural resources are confronted with numerous problems. In general, considering the study carried out on the nine influential factors in the soil erosion model (the PSIAC model), we notice that the mountainside and mountainous regions are more sensitive to erosion and influential factors in erosion are more active in these regions.
Dr. Mohammad Javad Vahidi, Dr. Rasoul Mirabbasi,
Volume 19, Issue 53 (6-2019)
Abstract
In order to protect soil and water resources should be identified erodible areas of watersheds, to be able to prevent land degradation and to control erosion in the form of soil conservation planning or watershed management. Therefore, the present study aimed to classification and delineation of susceptible areas to water erosion in the Hervi watershed using Hjulstrom curve, has been conducted. Increasing of accuracy, speed and facility of spatial achievement, using GIS technology, are advantages of the present study. In this study, were separated 10 sub-watersheds based on the feeding levels of streams. Spatial variability of soil properties in sub-watersheds, such as texture and the mean diameter size of the particles using hydrometer method were measured; also the maximum potential velocity of outlet in sub-watersheds based on the characteristics of each sub-watershed were calculated. Then, status of erosion and sediment in watersheds and sub-watersheds was studied using Hjulstrom curve (based on the mean diameter size of sediment particles and the maximum potential velocity of outlet), and was comparatively classified in term of erodibility. Finally, delineation map of susceptible regions to water erosion in the study area were obtained. The results revealed that the upstream and side areas of the watershed including: Sub-watershed No.4 (8.94% of the land), has very high erodibility, and Sub-watersheds No.1 and No.9 (36.94% of the land) have high erodibility. These areas are steep and often devoid of vegetation or have poor vegetation (such as poor pastures and rain-fed farming); so, it is necessary a proper strategy to prevent further erosion.
Taher Valipour, Mohammad Mehdi Hosseinzadeh, , Saeedeh M.biranvand,
Volume 20, Issue 59 (12-2020)
Abstract
Channel retreat are an important process in the river's morphodynamics, which affects channel variation, flood plain development and habitat development. Structures and farmland the border of the Lavij River Faces the risks of river bed change every year. Therefore, there is a need for a reliable method to determine the river bank retreat and predict the river bank Stability. In this study, with the aim of investigation of the risk of erosion and identification of areas susceptible to erosion in the Lavij River, Using BEHI and NBS models, the risk of side erosion was determined in 7 sections of this river. The results of the NBS model using the tnb / tbkf index showed that the rate of erosion of the Lavij river bank in all studied cross sections, except for cross sections 2 and 6 ,erosion rate is high and very hight. According to the indicator (dnb / dbkf), the bank erosion rate of the Lavij River, except for sections 4 and 5, is approximately consistent with the erosion trend obtained from the first index (tnb / tbkf). According the BEHI model, cross sections 5, 4, 3, 1 and 6 show a high incidence of instability and have a great potential for bank erosion and sediment production. Also, cross section 2 shows the medium instability status. Cross Section 7 and 2 show a high degree of instability, which has a high potential for bank erosion and sediment production. Finally, Kruskal-Wallis statistical test was fitted to evaluate the results matching and the results showed that all three indicators were almost identical to each other in the assessment of bank erosion.
Mansor Parvin,
Volume 22, Issue 64 (3-2022)
Abstract
Semi-arid watersheds are sensitive to soil erosion process and suffer considerable losses each year. Morphometric studies are an important method for identifying susceptible erosion zones and are a prerequisite for assessing erosion patterns in watersheds.The semi-arid Kamyaran basin is at risk of soil erosion due to lithological diversity, varied geomorphology, rugged topography and the nature-based livelihoods of its inhabitants and determination of soil erosion potential of this basin is essential for scientific management and sustainable development. The purpose of this study is to prioritize soil erosion potential in the Kamyaran basin. Methodologically, this research is based on WSA and averaging methods based on the calculation and ranking of morphometric parameters. The results showed that according to WSA methods and averaging 53.63% and 75.91% of Kamyaran catchment area, respectively, are located in areas with high soil erosion potential and require protection plans. The WSA method has better performance for prioritizing soil erosion studies due to different morphometric parameters and how to calculate it accurately. Sub-basins located in the northern areas of the Kamyaran Basin have high potential for soil erosion and sub-basins in the southern areas have low soil erosion potential. In general, the amount of soil erosion potential in Kamyaran basins is affected by the lithological and geomorphological conditions of the basins and the parameters related to infiltration have the most influence on the extent of soil erosion potential in the basins.
Shamsallah Asgari, Hamidreza Peravan, Samad Shadfar, Mashallahe Mohamadpoor, Manouchehr Tahmasebi,
Volume 22, Issue 67 (12-2022)
Abstract
In some areas, it is surprisingly possible to see a dense cover of rangeland species that has sustained soils and controlled the sedimentation rate of marl lands. It seems that some of the physical and chemical properties of marl are the main reasons for such a cover in the areas covered by Marlene formations. This research was carried out with the aim of thorough and systematic examination of plant species and determining the need for habitat and their protective role in the eastern, southern and western regions of Ilam. For this purpose, 48 specimens of Marne deposit were harvested from three areas and 33 physical and chemical tests were carried out. Botanical investigations were carried out using recurrent field observations and plots at 180 points, and plant specimens were identified after transfer to the plant museum According to the results of experiments on marl samples in these three regions, according to the stratigraphy of marl formations Gurpi, Pabdeh, Gachsaran and Aghajari, the sediments of these three areas were evaluated for the salinity (EC), bulk density (BD), sodium (Na +) and Soil saturation percentage (SP) and some physical parameters such as sand, sand and silt particles have significant differences. This difference can be one of the factors affecting the diversity and diversity of vegetation grown in three areas. The most important point is that in both eastern and western regions of Ilam, the species of Quercus brantii is abundant and dominant, and it can undoubtedly be considered as the most adapted plant species in the areas covered by Marlene formations of Gurpi and Pabdeh in these zones. . The second dominant species is No mu, Ha sa and Zi nu, which is compatible with the southern marl zone of the city of Ilam.
Mr Ehsan Shahiri Tabarestani, Dr Hossein Afzalimehr,
Volume 23, Issue 71 (12-2023)
Abstract
One of the problems of controlling erosion and sedimentation in catchment areas is the lack of statistical data to accurately estimate the amount of sedimentation and erosion. In order to implement soil protection programs and determine methods to reduce sedimentation, it is necessary to estimate the total volume of annual sediment production. The purpose of this study is to estimate the erosion intensity and sedimentation of Babolroud catchment located in Mazandaran province using EPM and Fournier empirical methods and to determine the accuracy of these models. The results showed that Babolroud catchment is located on the moderate zone of sedimentation and the value of erosion rate is Z = 0.54. Also according to EPM method the sedimentation rate is . The highest amount of erosion is in the northern part of the catchment, which is due to the existence of Non-cultivable land use and erosive soil formations, including alluvial and marsh soils. In order to evaluate the accuracy of the results obtained from the empirical model, the observed information of the two sedimentation stations was used and the results indicate a relative average difference of 23.24% in the EPM model. Also, the results obtained from the Fournier method indicate the inefficiency of this method in estimating the Babolroud catchment due to the lack of consideration of the erosion potential of the area.
