کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9524902 | 1635611 | 2005 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Critical specific stream power in gravel-bed rivers
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موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
فرآیندهای سطح زمین
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Critical specific stream power in gravel-bed rivers Critical specific stream power in gravel-bed rivers](/preview/png/9524902.png)
چکیده انگلیسی
Experiments with marked pebbles were carried out on different sized rivers of the Belgian Ardenne (catchment areas varying from less than 1 km2 to 2700 km2). Specific stream power required to cause bedload movement was evaluated and critical values were obtained. Three types of relationship between critical specific stream power (Ï0) and grain size (D) were established. The values for Ï0 in the largest river (the Ourthe) were the lowest and were close to the values obtained for mountainous rivers carrying large boulders. In medium sized rivers (catchment area between 40 and 500 km2), the critical unit stream power was higher. It is likely that it is due to the bedform's greater resistance. This resistance would use up some of the energy that can cause movement and transport of bedload. The amount of resistance of the bedform can be expressed as bedform shear stress (Ïâ³), determined by the relationship between grain shear stress (Ïâ²-that determines movement and transport of the bedload) and the total shear stress (Ï). This ratio varies between 0.4 and 0.5 in the medium sized rivers, compared to 0.7 in the Ourthe. In headwater streams (less than 20 km2), there is greater loss of energy due to bedform resistance (Ïâ²/Ï<0.3). Critical specific stream power is higher in this third type of river than in the other two.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Geomorphology - Volume 69, Issues 1â4, July 2005, Pages 92-101
Journal: Geomorphology - Volume 69, Issues 1â4, July 2005, Pages 92-101
نویسندگان
F. Petit, F. Gob, G. Houbrechts, A.A. Assani,