Mohammad Tahmoures; davud nikkami
Abstract
Erosion and sedimentation phenomena are two inevitable phenomena of watersheds that are subject to complex factors. Identifying these factors and recognizing their effect on erosion and sediment will help in better planning to reduce the damage caused by erosion and sediment in a basin. In this study, ...
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Erosion and sedimentation phenomena are two inevitable phenomena of watersheds that are subject to complex factors. Identifying these factors and recognizing their effect on erosion and sediment will help in better planning to reduce the damage caused by erosion and sediment in a basin. In this study, to determine the factors affecting sedimentation, the Urmia Lake watershed was selected as the study basin. After identifying 30 characteristics affecting the sedimentation of sub-basins of the study area, including hydrological, physiographic, geomorphological, geological and soil characteristics, climate, land use and vegetation as independent variables, the amount of sediment produced in each sub-basin. Was identified as a dependent variable. Using factor analysis, principal component analysis (PCA), cluster analysis and stepwise multivariate regression between selected independent variables and dependent variable using SPSS software Statistical relationship was obtained between sedimentation of sub-basins and watershed characteristics. According to the selected regression model, it is determined that the amount of sediment in the watershed of Lake Urmia to five factors of agricultural land area (rainfed, irrigated and orchards), the area of sub-basins, the total area of erosion and Quaternary structures, average discharge The annual and basin form factor depends on the fact that these five factors control 89% of the sediment production changes in the selected sub-basins, which is significant at the 5% confidence level. In general, the factors affecting erosion and sedimentation of the Urmia Lake watershed can be divided into three groups: human factors and land use change, geology and physiography.
Heshmatollah Agha Razi; Mehdi Mardian; Ali Akbar Davoudi Rad; Davud Nik Kami
Abstract
Land use Optimization using linear programing is a method in watershed management for access to production sustainability and decreasing of soil erosion. The sensitivity analysis of the model can with investigation of results influence form changes in input parameters, lead to decrease the uncertainty ...
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Land use Optimization using linear programing is a method in watershed management for access to production sustainability and decreasing of soil erosion. The sensitivity analysis of the model can with investigation of results influence form changes in input parameters, lead to decrease the uncertainty in decision-making of management programs. So in this research, linear programming model using Lingo software was applied to land use optimization in the Adineh Masjed watershed, Markazi province. Then was investigated a sensitivity analysis in changes of -50 to +50 percent form area of land use type on based benefit maximization and soil erosion minimization variables. According to results, objective functions are sensitive very low in conditions of changes dry farm area maximum. So that with decreasing 10% from its, benefit rate reduced equal to 3.5%, 4.2% and 2.6% for current land use, management land use and standard land sue, respectively. Also soil erosion rate reduced equal to 0.18% and 0.19% for current land use and management land use, respectively; but it increased in standard land sue equal to 0.34%. Also the results showed benefit variability is related to dry farm area and erosion variability is related to rangeland area.
