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|Title:||Newport News channel deepening study, Virginia : numerical model investigation|
|Authors:||United States. Army. Corps of Engineers. Norfolk District.|
Lin, Hsin-Chi J.
Martin, William D.
Lower James River
I-664 James River Bridge-Tunnel
Newport News, Virginia
|Publisher:||Hydraulics Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
|Series/Report no.:||Technical report (U.S. Army Engineer Waterways Experiment Station) ; HL-89-12.|
Abstract: This report presents results from the numerical model investigation whose primary objective was to evaluate general changes in circulation, currents, and sedimentation associated with the overdeepening of the Newport News Channel. An additional objective of the study was to assess the effects of the overdeepening on the reported estuarine circulation cell (flow convergence) off Hampton Flats and Newport News Point. Three alternative plans of overdeepening, 57, 64, and 70 ft, were evaluated. This numerical model investigation used the TABS-2 finite element numerical models RMA-2V for hydrodynamic analysis and STUDH for sediment transport computation with a modified version of an existing numerical mesh (expansion plan B) of the Lower James River. Results from the numerical hydrodynamic modeling indicated no velocity increases in the Willoughby Bay area. The maximum velocity change identified in the Hampton Flats area was less than 0.1 fps during the maximum flood tide. The maximum velocity change in the channel was 0.2 fps. No circulation changes were identified in the base- to- plan comparison of velocity vector plots. Additionally, no change in tidal phasing or water-surface elevation was detected. The formation and location of the two-dimensional circulation cell off Newport News Point were unaffected by any of the plans. Results from the sedimentation modeling showed that a maximum decrease in shoaling in the Hampton Flats area was about 7 percent, a maximum increase in shoaling in the Newport News Channel was less than 1 percent, and a maximum increase in shoaling in the Willoughby Bay areas was about 6 percent. The various deepening plans resulted in a redistribution of sediments with a net loss over the Hampton Flats area and a net increase in the Willoughby Bay area. The channel will experience a slow rate of shoaling due to the overdeepening. However, all changes in sedimentation were small in absolute volumes. The reported frontal effect off Newport News Point is a three-dimensional density current-driven phenomenon and cannot be quantified within the two-dimensional analysis. However, no evidence was generated by this study that would indicate that the channel overdeepening will affect the front formation or propagation.
|Rights:||Approved for public release; distribution is unlimited.|
|Appears in Collections:||Technical Report|
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|TR-HL-89-12.pdf||5.07 MB||Adobe PDF|