کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5771179 1629902 2017 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Research papersCoupling fine particle and bedload transport in gravel-bedded streams
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
پیش نمایش صفحه اول مقاله
Research papersCoupling fine particle and bedload transport in gravel-bedded streams
چکیده انگلیسی


- Daily discharge and particle loading examined for 38 minimally developed watersheds.
- Power law models are inadequate for describing particle loading rates.
- Transition to increased particle loading rate corresponds to the initiation of bedload transport.
- Bedload transport releases fine particles from the sediment bed.
- Observed clockwise hysteresis is consistent with sediment bed fluidization.

Fine particles in the silt- and clay-size range are important determinants of surface water quality. Since fine particle loading rates are not unique functions of stream discharge this limits the utility of the available models for water quality assessment. Data from 38 minimally developed watersheds within the United States Geological Survey stream gauging network in California, USA reveal three lines of evidence that fine particle release is coupled with bedload transport. First, there is a transition in fine particle loading rate as a function of discharge for gravel-bedded sediments that does not appear when the sediment bed is composed of sand, cobbles, boulders, or bedrock. Second, the discharge at the transition in the loading rate is correlated with the initiation of gravel mobilization. Third, high frequency particle concentration and discharge data are dominated by clockwise hysteresis where rising limb discharges generally have higher concentrations than falling limb discharges. These three observations across multiple watersheds lead to a conceptual model that fine particles accumulate within the sediment bed at discharges less than the transition and then the gravel bed fluidizes with fine particle release at discharges above the transition discharge. While these observations were individually recognized in the literature, this analysis provides a consistent conceptual model based on the coupling of fine particle dynamics with filtration at low discharges and gravel bed fluidization at higher discharges.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Hydrology - Volume 552, September 2017, Pages 532-543
نویسندگان
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