This phase of the model investigation of St. Louis Harbor was concerned with shoaling alone the city front and at the lower entrance to the Chain of Rocks Canal. During unusually low river stages, less-than-project depths had been ocurring at docks and terminals along the city front. Difficulties encountered during these low-flow periods led to the authorization of studies and investigations to determine the advisability of providing improved, commercial harbor facilities at and in the vicinity of St. Louis, Missouri. The purposes of the model study were to determine the causes of the shoaling in the harbor and docking areas and to develop plans that could be used to eliminate or reduce shoaling in these areas and in the lower entrance to the Chain of Rocks canal. The model used in the investigation was of the movable-bed type, constructed to scales of 1:250 horizontal and 1:100 vertical and reproducing the reach of the Mississippi River and adjacent overbank areas between miles 191.0 and 169.9. Results obtained during the investigation indicate the following: Shoaling along the city front is a natural development that can be expected along the convex side of bends in streams carrying sediment. Conditions in the city-front reach are also affected by the movement of sedimert from the Missouri River and by the differences between channel characteristics in the reach along the city front and those in the reach upstream. Improvement, in the conditions along the city front can be obtained by closing the channel along the left side of Mosenthien Island, by extending training structures into the channel on the right side of Mosenthien Island and the channel along the city front, and by constructing a lock and dam structure downstream of the harbor area. Shoaling in the lower entrance to the Chain or Rocks canal during low flows is caused by the sudden expansion in the channel width and the movement of bottom current towards the approach channel past the end of the trail dike. Flow from the channel on the left of Mosenthien Island tends to increase movement of sediment towards and along the trail dike. During high flows, surface currents carrying small amounts of sediment move over the top of the trail dike and tend to erode the material deposited in the approach channel dovmstream of the end of the trail dike. When the trail dike is overtopped, the sediment-laden bottom currents remain on the channel side of the dike and generally continue to move downstream.


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    Titel :

    Shoaling Conditions, St. Louis Harbor, Mississippi River: Hydraulic Model Investigation


    Beteiligte:

    Erschienen in:

    Erscheinungsdatum :

    1972


    Format / Umfang :

    6208179


    Medientyp :

    Report


    Format :

    Elektronische Ressource


    Sprache :

    Englisch



    Klassifikation :


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