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					Modeling Navigation Channel Infilling
   and Migration at Tidal Inlets:
  Sensitivity To Waves And Tidal Prism

            Kenneth J. Connell
                Morphologic Features of
                 Navigable Tidal Inlets



Assateague    Ocean City
Island        Beaches                       WA


                                                 Moriches Inlet, NY
  Bypassing Path
 Ocean City Inlet, MD

                            Mouth of the    OR
                           Columbia River
             Presentation Overview



• Discussion of Scope and Methods

• Presentation of some of the results obtained

• Concluding remarks and significance of findings
                 Scope and Methods



•   Idealized simulations to examine 1st-order effects
•   Varied channel-bar systems
•   Sensitivity to wave forcing
•   Sensitivity to tidal prism forcing
            Coastal Modeling System (CMS)


2-D and 3-D Numerical modeling
at local- to regional-scale
coastal projects including:       Existing        Alt 1
    • Inlets
    • Navigation channels
    • Coastal structures
                                  Alt 2           Alt 3
                               Matagorda Ship Channel, TX
        Mouth of the Columbia River      Flood Current analysis
                                          of design alternatives
                             CMS Capabilities

• CMS model interconnectivity - all
  supported within the SMS interface:
   –   CMS-M2D (w/explicit and implicit modes)
   –   CMS-WABED
   –   CMS-M3D
   –   STWAVE
   –   ADCIRC                                                        Initial Forcing:
                                                                Measured WSE, ADCIRC Tidal
• Efficient, high-resolution calculation of:                     Constituent generated WSE,
                                                                      Wind, River input

   – Hydrodynamic circulation & water level
        •   Tide (including flooding & drying)                  Hydrodynamic Module

        •   Waves                                    Hydro ∆t          CMS-M2D

        •   Wind forcing                                               CMS-M3D                Circulation-Wave


        •
                                                                                              Steering interval
            Flow from river input
        •   Advection                                                 CMS-WABED
                                                                                                        Sediment
                                                                       or STWAVE
        •   Storm surge and wave setup                                                                transport ∆t

   – Sediment Transport                          Morphology                                   Sediment
                                                                                              Transport
   – Geomorphic evolution                         Change
                                                                  Morphology ∆t
   – Salinity
Model Domain
Initial Channels
                               Waves


  Designation         Height (m)   Period (s)     Direction (deg)

     Typical              1            8                30

      Storm               3            14               30

  Shore normal            1            8                0

    No waves
                         N/A           N/A             N/A
(Tide forcing only)




                         Wave Angle:         30
        Results

                    Bay


Barrier Island
                              Barrier Island




                 navigation
                                30º
                  channel
   Ocean          infilling
2 m Channel, Typical Waves
4 m Channel, Typical Waves
6 m Channel, Typical Waves
2 m Channel with Equilibrium Bar,
        Typical Waves
2 m Channel with Equilibrium Bar,
         Storm Waves
2 m Channel with Reduced Bay Area,
         Typical Waves
6 m Channel, No Waves
      (Tide Only)
                   Concluding Remarks



• Morphologic features systematically linked to channel
  morphology

• Storm condition bypassing occurs at greater depths due to
  increased depth of closure under the large wave regime

• Numerical modeling of channel infilling, migration, and
  sediment bypassing is becoming more reliable
                  Acknowledgements




• PIANC USA
   –   John Paul Woodley, Jr. – Chairman
   –   Major General Don T. Riley – President
   –   Bruce Lambert – Secretary
   –   Edmond J. Russo, Jr. – Publications Chairman


• Coastal Inlets Research Program (CIRP)
   – Nicholas C. Kraus – Program Manager
   – Jack Davis, Jim Clausner – Technical Directors
                   Bay


Barrier Island
                              Barrier Island




                 Thank You!
                 navigation
                                 30º
                  channel
   Ocean          infilling
    Ac  CP n          Ac  3.76 x 10-4 P 0.86


(Cd ) (Cqx ) (Cqy )      C        C 
                      Kxd       Kyd     P D
  t     x      y    x    x  y     y 
                                 cr 
            cR  AcR cw, m exp  b  
                                 cw 

        h   1  qbx qby         
                          P  D
        t 1  p  x   y         
                           Cohesive Transport
                         in Navigation Channels


                                                Hindered settling
                                                   ‘fluff layer’
             Turbidity maximum                       Fluff impedes
                                                     navigation
                water surface

freshwater
discharge        flocculation
                                 salt water
                                 intrusion
                   bed
                                                 Channel Bed
        Important considerations in bays and
        sheltered areas were fine material is   Matagorda Ship
        source of channel infilling              Channel, TX
2 m Channel with Equilibrium Bar,
      Shore Normal Waves
2 m Channel with Equilibrium Bar,
      Shore Normal Waves
6 m Channel with Equilibrium Bar,
        Typical Waves
6 m Channel, Storm Waves
6 m Channel with Equilibrium Bar,
         Storm Waves
2 m Channel, Storm Waves

				
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posted:11/27/2011
language:English
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