نتایج جستجو برای: and erosion

تعداد نتایج: 16832055  

ژورنال: علوم آب و خاک 2012
مهدی خوشخو‌, , سید محمدعلی زمردیان, ,

Internal erosion is the second major reason for earth dam's failure after overtopping. One of the effective factors in internal erosion in earth dams is the clay minerals used in dams as well as the effects of compaction efforts on soil in sample preparation. In this research, internal erosion and the effect of clay minerals and compaction effort on internal erosion were investigated. For this ...

Splash erosion is recognized as the first stage in the process of erosion that results in bombardment of the soil's surface with rain drops. Two basic processes in soil erosion are the dispersement of soil particles by rain drops and the changes caused to the soil's structure, which are then moved by runoff. In this research,the effect of various polyacrylamide (PAM)values (0, 0.2, 0.4 and 0.6 ...

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The use of new methods, remote sensing (RS) and geographical information system (GIS) in zoning the water erosion in a particular geographical area (Tang-e-Bostanak catchment area) constitute the main subjects of this study. The production, combination, and composition of effective information layers in identifying these zones have been noted, highlighting the capacity of GIS and RS. In this st...

Journal: :اکو هیدرولوژی 0
کاظم صابر چناری دانشجوی دکتری مهندسی آبخیزداری، دانشکدۀ مرتع و آبخیزداری، دانشگاه علوم کشاورزی و منابع طبیعی گرگان عبدالرضا بهره مند دانشیار گروه مهندسی آبخیزداری، دانشکدۀ مرتع و آبخیزداری، دانشگاه علوم کشاورزی و منابع طبیعی گرگان واحد بردی شیخ دانشیار گروه مهندسی آبخیزداری، دانشکدۀ مرتع و آبخیزداری، دانشگاه علوم کشاورزی و منابع طبیعی گرگان چوقی بایرام کمکی استادیار گروه مدیریت مناطق بیابانی، دانشکدۀ مرتع و آبخیزداری، دانشگاه علوم کشاورزی و منابع طبیعی گرگان

the goal of this research is gully erosion hazard zoning by using dempster-shafer theory for the garnaveh watershed (golestan province). for this purpose, at first a gully erosion inventory map with the scale of 1:200000 (dependent variable) for the gharnaveh watershed has been prepared using multiple field surveys and satellite pictures. from total gullies 70% of them have randomly selected fo...

Splash erosion is recognized as the first stage in the process of erosion that results in bombardment of the soil's surface with rain drops. Two basic processes in soil erosion are the dispersion of soil particles by rain drops and the changes caused to the soil's structure, which are then moved by runoff. In this research, the effect of various rainfall intensity (60, 90 and 120 mm/hr) on the ...

Journal: :مرتع و آبخیزداری 0
عطااله کاویان استادیار دانشکده منابع طبیعی، دانشگاه علوم کشاورزی و منابع طبیعی ساری فریال حیاوی کارشناس ارشد آبخیزداری، دانشگاه شهر کرد مهدی بروغنی دانشجوی دکتری آبخیزداری، دانشکده منابع طبیعی، دانشگاه تربیت مدرس

splash erosion recognized as first stage of erosion process that results of bombing soil surface with rain drop. falling rain drops to soil surface resulted moving soil particles and destructing soil structure. at this research effects of various pam rate (0, 2, 4 and 6 kg.ha) on splash erosion on three soil textuere clay, silty clay and sandy clay loam was tested. simulations were done with ra...

Introduction Water erosion is one of the most important factors in land degradation in large parts of Iran destroying fertile soils and agricultural land. The impact of soil erosion and related sediments decreases significantly water quality and reservoir capacity. Especially in semiarid areas like in the Menderjan watershed in the west Isfahan province sheet and rill erosion contributes to th...

ژورنال: علوم آب و خاک 2012
عطااله کاویان, , قربان وهاب‏زاده, , مریم رضایی پاشا, ,

As the first event in soil erosion, rain splash erosion causes movement of soil fragments. Splash is an important process in interrill erosion. The amount of soil particles detached from the surface is associated with soil and rain characteristics and may be affected by rainfall erosivity and soil erodibility. Therefore, in this study, splash erosion rate and its relation with some soil propert...

Extended abstract 1- Introduction The Soil surface characteristics have significant effects on the erosion process. The wide areas of watershed soil surfaces are covered with considerable amounts of rocks and pebbles. Surface rock fragments, resulting in water connectivity, change during the erosion process. Rock fragments on the soil surface may increase the infiltration and reduce soil loss...

Introduction: Cholesteatoma is traditionally diagnosed by otoscopic examination and treated by surgery. The necessity for imaging in an uncomplicated case is controversial. This study was planned to investigate the usefulness of a preoperative high-resolution computed tomography (HRCT) scan in depicting the status of middle ear structures in the presence of cholesteatoma and also to compare the...

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