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首页> 外文期刊>Environmental Science & Technology >Large Shift in Source of Fine Sediment in the Upper Mississippi River
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Large Shift in Source of Fine Sediment in the Upper Mississippi River

机译:密西西比河上游细沙来源发生较大变化

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摘要

Although sediment is a natural constituent of rivers, excess loading to rivers and streams is a leading cause of impairment and biodiversity loss. Remedial actions require identification of the sources and mechanisms of sediment supply. This task is complicated by the scale and complexity of large watersheds as well as changes in climate and land use that alter the drivers of sediment supply. Previous studies in Lake Pepin, a natural lake on the Mississippi River, indicate that sediment supply to the lake has increased 10-fold over the past 150 years. Herein we combine geochemical fingerprinting and a suite of geomorphic change detection techniques with a sediment mass balance for a tributary watershed to demonstrate that, although the sediment loading remains very large, the dominant source of sediment has shifted from agricultural soil erosion to accelerated erosion of stream banks and blu0s, driven by increased river discharge. Such hydrologic amplification of natural erosion processes calls for a new approach to watershed sediment modeling that explicitly accounts for channel and floodplain dynamics that amplify or dampen landscape processes. Further, this finding illustrates a new challenge in remediating nonpoint sediment pollution and indicates that management efforts must expand from soil erosion to factors contributing to increased water runoff.
机译:尽管沉积物是河流的自然组成部分,但河流和溪流的超载是造成损害和生物多样性丧失的主要原因。补救措施需要确定沉积物供应的来源和机理。大流域的规模和复杂性以及气候和土地利用的变化改变了沉积物供应的驱动因素,使这项任务变得复杂。先前在密西西比河上的天然湖泊佩平湖上进行的研究表明,在过去150年中,该湖的沉积物供应量增加了10倍。在这里,我们结合了地球化学指纹图谱和一套地貌变化检测技术以及支流域的沉积物质量平衡,以证明尽管沉积物负荷仍然很大,但主要的沉积物来源已从农业土壤侵蚀转移到水流的加速侵蚀在河水流量增加的驱动下,河岸和河床。这种自然侵蚀过程的水文放大要求对流域沉积物建模采用一种新方法,该方法应明确考虑扩大或减弱景观过程的河道和洪泛区动力学。此外,这一发现说明了纠正面源沉积物污染的新挑战,并表明管理工作必须从土壤侵蚀扩大到导致径流增加的因素。

著录项

  • 来源
    《Environmental Science & Technology》 |2011年第20期|p.8804-8810|共7页
  • 作者单位

    Department of Watershed Sdence, Utah State University, Logan, Utah 84332, United States National Center for Earth-surface Dynamics, University of Minnesota, Minneapolis, Minnesota 55414, United States;

    National Center for Earth-surface Dynamics, University of Minnesota, Minneapolis, Minnesota 55414, United States Department of Geological Sciences, University of Minnesota Duluth, Duluth, Minnesota 55812, United States;

    St. Croix Watershed Research Station, Science Museum of Minnesota, Marine on St. Croix, Minnesota 55047, United States;

    National Center for Earth-surface Dynamics, University of Minnesota, Minneapolis, Minnesota 55414, United States Department of Geography and Environmental Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States;

    National Center for Earth-surface Dynamics, University of Minnesota, Minneapolis, Minnesota 55414, United States Geology and Geophysics, University of Minnesota-Twin Cities, Minneapolis, Minnesota 55455, United States;

    Geology and Geophysics, University of Minnesota-Twin Cities, Minneapolis, Minnesota 55455, United States Minnesota Geological Survey, St Paul, Minnesota SSI 14, United States;

    Department of Civil and Environmental Engineering, Seattle University, Seattle, Washington 98122, United States;

    National Center for Earth-surface Dynamics, University of Minnesota, Minneapolis, Minnesota 55414, United States Department of Civil & Environmental Engineering and Department of Geology, University of Illinois, Urbana, Illinois 61801,United States;

    National Center for Earth-surface Dynamics, University of Minnesota, Minneapolis, Minnesota 55414, United States Department of Earth and Environmental Science, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Section 3.4, Earth Surface Geochemistry,D-14473 Potsdam, Germany;

    St. Croix Watershed Research Station, Science Museum of Minnesota, Marine on St. Croix, Minnesota 55047, United States;

    National Center for Earth-surface Dynamics, University of Minnesota, Minneapolis, Minnesota 55414, United States Department of Civil & Environmental Engineering and Department of Geology, University of Illinois, Urbana, Illinois 61801,United States;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
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  • 正文语种 eng
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