Changes in the Sediment Regime and Channel Morphology of the Lower Mississippi River

在上个世纪，许多河流的河道都被大幅度地改造了。大坝、防洪堤、护岸、曲流截流和水库已经建成，以控制洪水和改善航运。这些变化严重地改变了河道的形态，改变了侵蚀和沉积的模式。然而，这些变化的确切特征并没有得到很好的记录。密西西比河下游是变化最剧烈的河流之一。该项目将使用历史水文调查地图来测量上个世纪密西西比河下游河道形态和沉积物制度的变化。该项目收集的数据还将用于分析人类与自然力量在多大程度上改变了水流和沉积模式，它们将为更详细地研究大型河流的蜿蜒过程提供基础。这个项目将在许多层面产生有用的结果。它将提供一个特定于密西西比河下游的数据集。这些数据将对研究这一水流的学者和必须直接处理洪水控制和导航系统的从业者提供宝贵的帮助。该项目得出的结论也将具有更广泛的意义，为河流流量和沉积物运输对人类活动和自然条件变化的响应过程提供了新的见解。

Many stream channels have been modified significantly in the last century. Dams, levees, revetments, meander cut-offs, and reservoirs have been constructed to control floods and to improve navigation. These modifications have severely altered the morphology of the channels and have changed the patterns of erosion and sedimentation. The exact character of these changes is not well documented, however. Among the most drastically modified streams is the lower Mississippi River. This project will use historic hydrographic survey maps to measure changes in channel morphology and sediment regimes on the lower Mississippi over the last century. The data gathered in this project will also be used to analyze the degree to which human versus natural forces have altered flows and depositional patterns, and they will provide a basis for more detailed examination of the processes of meandering in large streams. This project will yield useful results at a number of levels. It will provide a data set specific to the lower Mississippi River. These data will be valuable aids to scholars studying this stream and to practitioners who must deal directly with flood control and navigation systems. The conclusions drawn in this project will also have broader significance, offering new insights into the processes by which stream flow and sediment transport respond to modification by humans and to changes in natural conditions.