zahra abdolalizadeh; Ataollah Ebrahimi
Abstract
Sabzkouh protected area, with the variety of natural ecosystems and landscapes, is very rich from the point of diversity in climate, topography, habitats and wildlife that is located in central Zagros. Evidences show that its ecosystems such as other Iranian semiarid natural ecosystems, undergone ...
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Sabzkouh protected area, with the variety of natural ecosystems and landscapes, is very rich from the point of diversity in climate, topography, habitats and wildlife that is located in central Zagros. Evidences show that its ecosystems such as other Iranian semiarid natural ecosystems, undergone changes in their vegetation structure over the past years. Obtaining multi-spectral and multi-temporal data via Satellite Remote Sensing (RS) with Geographical Information System (GIS) would be able to identify type, quantity and location of land use/land cover changes. The aim of present study is to detect land cover changes in recent three decades by RS in Sabzkouh region. Therefore, the images of Landsat MSS (1975) and Landsat ETM+ (2003), Digital Elevation Model (DEM) and Transformed Soil Adjusted Vegetation Index (TSAVI1) were used as ancillary data to obtain land cover maps. These maps were produced by applying supervised maximum likelihood classifier and included five classes namely: agriculture, herbaceous rangeland, shrub and brush rangeland, barren land and forest. To detect changes, Post Classification Comparison approach was used. The net change calculations indicated that were added to shrub and brush rangelands and forest. On the other hand, herbaceous rangeland and barren land have been converted to the other classes.
jalil farzadmehr; payam Ebrahimi; mehdi Eslah
Abstract
Predicting the hydraulic behavior of the river and flood zone determination to reduce probable damages, are among measures which in recent years has been the attention of many researchers. Mazandaran province, especially the city of Neka, each year is affected by the floods with different return periods; ...
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Predicting the hydraulic behavior of the river and flood zone determination to reduce probable damages, are among measures which in recent years has been the attention of many researchers. Mazandaran province, especially the city of Neka, each year is affected by the floods with different return periods; therefore, land use changes and the role of these changes were evaluated in flood zones. In this study, with integration of river system analysis, GIS and Remote Sensing, images of the years 2000 and 2011 were processed and Neka river hydrological response was determined in specified return periods. The results showed Pearson type 3 distribution, roughness coefficient determined by Cowan’s method and IRS image in comparison with ETM+ image, have good accuracy. With determining land use changes in the years 2000 and 2011, the area of each land use class was specified in GIS, and then attached to the HEC-GeoRAS. By determining two flood maps with return periods of 2 to 200 years, the difference of each layer was determined. Many studies determined land use only; but according to the results of this study and impact of the 14.60-percent increase in flood area, the role of changes is noticeable. This study suggests that in the flood zone determination, addition to land use designation, we should pay special attention to its changes and hydrological response of the total area to these changes, and its role in the flood zones. The simulation of river bed and flood zone in forest areas depends on land use, and deforestation in this river is one of the most important factors.
