Sayyed Alireza Hosseini; Hassan Khosravi; Hamid Gholami; Yahya Esmaeilpour; Artemi Cerda
Abstract
In this study, land use change trend in coastal areas of south of Iran, including Sistan Baluchestan, Hormozgan, Bushehr were studied during 31 years (1988-2019). Landsat satellite images including TM, ETM +, OLI were used for this purpose. The maximum likelihood method was also used to classify satellite ...
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In this study, land use change trend in coastal areas of south of Iran, including Sistan Baluchestan, Hormozgan, Bushehr were studied during 31 years (1988-2019). Landsat satellite images including TM, ETM +, OLI were used for this purpose. The maximum likelihood method was also used to classify satellite images. Vegetation indices (SAVI) and salinity index (SI1) were used to influence land use classes on land degradation and desertification. The results of land use change trend showed that Changes in land use classes of man-made areas and saline lands as the most dynamic land use classes followed an increasing trend of 2.72% and 1.14%, respectively. The results of multivariate regression analysis showed that three vegetation, saline and man-made variables, and four vegetation, saline, man-made and sandy areas explain 22.3% and 37.8% of the dependent variables of vegetation and salinity indices, respectively. Therefore, in more than 60% of changes, other environmental variables are affected. Hence, with respect to the results of land use area and regression analysis and the mean trend of SAVI and SI1 changes, where vegetation and SAVI classes show decreasing trend and saline land and SI1 classes have increasing trend, it can be concluded that land use changes is phenomena that changes ecosystem services with almost irreversible impacts. This will have nothing to do with disturbing the ecosystem balance and intensifying land degradation in coastal areas.
Mohammad Nohtani; Sadat Feiznia; Hasan Ahmadi; Hamidreza Peirovan
Abstract
Loess Deposit is one of the most important Quaternary Deposits of northeastern parts of Iran which have high erosion rate. This study was performed with field- Rainfall- Simulator which has a plot area of 1 m2 in Gorganrood Drainage Basin to determine the effective factors on sediment yield. Landuse, ...
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Loess Deposit is one of the most important Quaternary Deposits of northeastern parts of Iran which have high erosion rate. This study was performed with field- Rainfall- Simulator which has a plot area of 1 m2 in Gorganrood Drainage Basin to determine the effective factors on sediment yield. Landuse, slope and erosion feature maps were overlaid in GIS to obtain land unit map. Then on work units, rainfall simulator analyses were performed. The produced runoff and sediment in 69 points on work units were collected and were measured. Adjacent to each rainfall simulator plot, samples of surface material were collected in the field to analyze for physical and chemical characteristics. In the field, descriptive tables were prepared for different work units in which locality, slope percentage, elevation, depth of A horizon of the soil and other necessary informations were recorded. In order to determine logical relationship between different variables, regression and correlation analyses were performed. In statistical analyses, it was found that slope percentage has the highest correlation coefficient and has the highest direct relationship with sediment yield and sediment production and silt amount is the second factor. The investigation of multiple regression analyses generated a model which shows %80 of sediment production variations. In this model slope percentage, cation exchange capacity and silt have possitive relationship and Calcium cation has negetive relationship with sediment yield.
Hamzeh Nour; Seyyed Khallagh Mirnia; Maliheh Sadat Zarif Moazzam
Abstract
Some contaminants associate with soil particles and, thus, their transport and fate in the environment is determined by the soil erosion processes. Eutrophication, low oxygen levels and high nutrient (nitrogen and phosphorus) concentrations in reservoirs, canals and other water courses, is a common water ...
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Some contaminants associate with soil particles and, thus, their transport and fate in the environment is determined by the soil erosion processes. Eutrophication, low oxygen levels and high nutrient (nitrogen and phosphorus) concentrations in reservoirs, canals and other water courses, is a common water pollution feature. Phosphorus (P) is one of the major plant nutrients and also the major nutrients controlling eutrophication of surface water. P load pulsed by heavy rainfall may damage the ecological quality of downstream. The present study was conducted in Kojour Watershed located in Mazandaran province.The results showed that P loss varied from 0.26 gr lit-1 to 1860.64 gr lit-1. It also proved that P concentration could not estimated by flow discharge, while sediment concentration can estimate loss of P with determination coefficient and estimation error of 94% and 23%, respectively. The results could facilitate the application of given methods obtained in the present study to other ungauged watersheds with similar conditions and leading to the suitable soil and water management and planning.
