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Sedimentation dynamics within a large shallow lake and its role in sediment transport in a continental-scale watershed
Journal of Great Lakes Research ( IF 2.2 ) Pub Date : 2021-04-27 , DOI: 10.1016/j.jglr.2021.03.022
Masoud Goharrokhi , Gregory K. McCullough , Philip N. Owens , David A. Lobb

A comprehensive understanding of the sedimentation dynamics within Lake Winnipeg (surface area: 23,750 km2) and its role in sediment transport in the downstream river system was achieved by determining the properties of lake bottom sediment and patterns of sediment accumulation rates and by constructing a conceptual total (i.e., organic and inorganic) sediment budget. Net deposition was the governing process in the South and North Basins, whereas transportation dominated in the Narrows. The largest fluvial source of sediments to the lake, the Red River, supplies 35% of the total sediment load. Although accumulation rates in profundal zones progressively decreased northward from this source at the south end of the lake, high accumulation rates with low inventories of fallout radionuclides in the northern margin of the North Basin indicate a second sediment source, which was determined to be erosion of north shore banks, which accounts for up to 50% of the total sediment load to the lake. The nearshore-offshore gradient in bottom sediment properties in the North Basin confirmed that the signature of this source can reach at least 20 km southward into the lake. However, the properties of bottom sediments, sedimentation dynamics, and sediment budget suggested that some of the materials eroded from the north shore are exported without interaction with the lake bottom and this local sediment source is the dominant source for the downstream river system. It was concluded that Lake Winnipeg effectively disconnects the downstream Nelson River from sediment transport processes in its upstream watershed (953,250 km2).



中文翻译:

大型浅湖内的沉积动力学及其在大陆尺度流域沉积物输送中的作用

全面了解温尼伯湖内的沉积动态(表面积:23,750 km 2) 及其在下游河流系统中的泥沙输运中的作用是通过确定湖底泥沙的特性和泥沙堆积率的模式以及通过构建概念性总(即有机和无机)泥沙收支来实现的。净沉积是南部和北部盆地的主导过程,而运输在狭窄地区占主导地位。湖泊最大的河流沉积物来源红河提供了总沉积物负荷的 35%。虽然在湖的南端从这个源头向北,深部区域的积累率逐渐降低,但北盆地北缘的高积累率和低放射性核素库存表明存在第二个沉积物来源,被确定为侵蚀北岸银行,占湖泊总泥沙量的50%。北部盆地底部沉积物性质的近岸-近岸梯度证实,该源的特征可以向南至少延伸到湖中 20 公里处。然而,底部沉积物的性质、沉积动力学和沉积物收支表明,从北岸侵蚀的一些物质在没有与湖底相互作用的情况下输出,这种局部沉积物来源是下游河流系统的主要来源。得出的结论是,温尼伯湖有效地将下游纳尔逊河与其上游流域(953,250 公里 北部盆地底部沉积物性质的近岸-近岸梯度证实,该源的特征可以向南至少延伸到湖中 20 公里处。然而,底部沉积物的性质、沉积动力学和沉积物收支表明,从北岸侵蚀的一些物质在没有与湖底相互作用的情况下输出,这种局部沉积物来源是下游河流系统的主要来源。得出的结论是,温尼伯湖有效地将下游纳尔逊河与其上游流域(953,250 公里 北部盆地底部沉积物性质的近岸-近岸梯度证实,该源的特征可以向南至少延伸到湖中 20 公里处。然而,底部沉积物的性质、沉积动力学和沉积物收支表明,从北岸侵蚀的一些物质在没有与湖底相互作用的情况下输出,这种局部沉积物来源是下游河流系统的主要来源。得出的结论是,温尼伯湖有效地将下游纳尔逊河与其上游流域(953,250 公里 和沉积物收支表明,从北岸侵蚀的一些物质在没有与湖底相互作用的情况下被输出,这种局部沉积物来源是下游河流系统的主要来源。得出的结论是,温尼伯湖有效地将下游纳尔逊河与其上游流域(953,250 公里 和沉积物收支表明,从北岸侵蚀的一些物质在没有与湖底相互作用的情况下被输出,这种局部沉积物来源是下游河流系统的主要来源。得出的结论是,温尼伯湖有效地将下游纳尔逊河与其上游流域(953,250 公里2)。

更新日期:2021-06-02
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