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This report embodies a review describing the potential impacts on aquatic vegetation from waves generated by commercial and recreational vessel traffic, and contrasts these impacts with effects of natural forces. The review was undertaken as part of a Corps of Engineers study on navigation impacts on the Upper Mississippi River. Interactions between waves and aquatic vegetation are summarized in the report. Waves act directly by uprooting or fragmenting plants. Wave action can resuspend and transport sediments, resulting in altered sediment texture and sediment resuspension. Changes in sediment texture potentially affect plant nutrition. Resuspended sediments can limit plant photosynthesis, due to reduced availability...
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Large beds of Vallisneria americana declined in the backwaters of the Upper Mississippi River after a drought that occurred between 1987 and 1989. One hypothesis for this decline is that low light availability may have decreased net photosynthesis to the extent that overwintering tubers were not formed. Following the decline, light availability remained low. To determine what light levels would be necessary for the re-establishment of Vallisneria in the Upper Mississippi River, the long-term growth of plants in a backwater lake and in an experimental pond was measured while the surface and subsurface light were monitored continuously. Plants grown from tubers transplanted to 0�5, 1�0, and 1�5 m depth in the lake...
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