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Showing 3 results for nohtani
The Quantitative Zoning of Ground Surface by Quantitative Coefficients for Positioning the Optimal Flood Spreading (Case Study: Fasa Garebayegan Catchment)
S. Ebrahimiyan, M. Nohtani, H. Sadeghimazidi,
Volume 21, Issue 2 (Summer 2017)
Abstract

The basis of spatial planning is the geomorphological zoning of ground surface, in which the first phase is determining the homogeneous zones of the ground surface in terms of geomorphological characteristics. The current study aimed at determining the proper zones for artificial feeding in Gahar mountainous region and Garebayegan plains in Fars province by the use of zoning the ground by Evans-Chezy quantitative coefficients. The quantitative zoning of ground surface plays a vital role in more accurate determination of the land capabilities due to precise determination and division of the types, facies, and surface terrains. For this study, the elevation numeral data with 10m resolution obtained from the National Cartographic Center was used. By the use of surface fitting tools in MATLAB software, the equation for each form was fitted to limited fragments of the surface and the program was applied. Then, each of the quantitative coefficients was illustrated as some zones. For determination of fitting degree, the total squared difference between the rate parameter was used and by the use of fitness degree, the propriety degree of the surface for optimal positioning of flood spreading with surface morphological view was determined. The results indicate that the surface downstream the alluvial fans and plains located on the southern region of the studied land is the most appropriate zone for the Flood Spreading. This area constitutes a surface of 10% of the total area of the region.


Investigation of Wind Erosion Threshold in Different Land Cover and the Effect of Soil Properties on It (Case Study: Niatak Region of Sistan)
A.r. Nourafar, A. Pahlavanravi, M. Nohtani, V. Rahdari,
Volume 26, Issue 1 (Spring 2022)
Abstract
Wind erosion is one of the most important natural processes in arid and semi-arid regions. Sistan plain has a hyper-arid climate and is one of the windy regions of the country. Due to the soil characteristics of the Sistan plain, wind erosion is very intense in this region. In this study, the relationships between some soil's physical and chemical properties and wind erosion were investigated in different land cover in a part of the central region of Sistan in 2018. A map of land cover in five classes was prepared using the results of field studies and the classification of satellite images. Fifty soil samples at a depth of 10 cm were collected to investigate the physical and chemical soil properties and the wind erosion threshold was determined at each location using a portable wind tunnel device. Also, the relationship between physical and chemical soil properties including soil texture, soil moisture, specific apparent weight, EC, SAR, ESP, Na+, k+, with the speed of wind erosion threshold was investigated. According to the results, the highest and the lowest threshold speed were 8.2 and 3.8 m s-1 and occurred in agricultural lands and hilly lands, respectively. The results of this study indicated that the velocity of wind erosion threshold in different lands adjacent to sandy areas is less than the average of that cover. Also, the soil texture, EC, and SAR have the most significant effect on soil wind erodibility at P <0.05 in the study area.

Optimal Location of Flood Dispersion Using Quantitative Fundamental Models in Fuzzy Logic (Case Study: Gorbayegan Watershed)
S. Ebrahimiyan, M. Nohtani, H. Sadeghi Mazidi, E. Soheili,
Volume 26, Issue 1 (Spring 2022)
Abstract
The basis of land management is the geomorphological zoning of the land surface, which is determined based on the same geomorphological characteristics of the zoning. Ground zoning detect land features by basic surface features such as height, slope, and slope direction. In this study, quantitative zoning of the land surface with small coefficients to the surface has been used to identify suitable areas for artificial feeding in the mountainous region of Gohar and Dasht-e Gorbayegan in Fars province. Quantitative zoning of the land surface has been performed by Evans-Shri coefficients due to the accurate determination and separation of types, faces, and surface features of the land has an important role in determining the exact land use. In this research basic models included linear, circular, and divergent models. These basic models with the dimensions of the final windows are ranked second in the MATLAB software to the level the ground is fitted to determine the fit of these models, the parameter of total squared difference has been used. In addition, the suitability of the study area for flood distribution in five different classes was determined using fuzzy logic. The most suitable areas for feeding downstream of the cones had five parameters with a maximum score of 20. The inappropriate class related to the lower plains of alluvial fans have a minimum score of five input classes in fuzzy logic, which is equal to zero.

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