Montgomery Point Lock and Dam, White River, Arkansas
Technical Report,01 Jan 2008,01 Jan 2012
U.S. Army Engineer Research and Development Center Vicksburg
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Montgomery Point Lock and Dam employs a unique design and is located immediately downstream of a sharp curve in the White River, AR. Bathymetric survey data were collected during May 2008, September 2008, June 2009, and June 2010. A scour hole just downstream of the navigable pass deepened and widened between May 2008 and June 2009 to dimensions 23 ft deep by 115 ft wide by 260 ft long. It was recommended that the U.S. Army Engineer District, Little Rock, fill and stabilize the scour hole with stone large enough to prevent further enlargement with potential endangerment of the navigation structures. Approximately 4 6 ft of deposition occurred during this time period in very small areas of the upstream approaches to the lock. No maintenance channel dredging was required because these small sections could be easily obliterated by propeller wash. Current direction and velocity data indicate that much of the flow passes under and around the upstream floating guide wall due to significant outdraft and moves toward the navigable pass and overflow weir. This makes downstream barge alignment with the navigation pass difficult when there are moderate to high flows on the White River and the Mississippi River is falling. It was recommended that notices to mariners re-emphasize potential hazards under these conditions to avoid future allisions with the navigation structures. Loadings on the navigation crest gates were deduced to be well within safety tolerance by placing strain gages and accelerometers on the gate struts located in the galley of the dam to monitor strain loadings during raising and lowering of the gates. This study confirmed the findings of a previous physical model study that serious flow-induced vibrations do not occur during either raising or lowering the navigation crest gates.