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Numerical Modeling of a Salinity

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					Numerical Modeling of a Salinity Intrusion Barrier
                  Saltwater Intrusion Prevention System

                             Developed Through a

       Cooperative Research & Development Agreement
           Patented Technology owned by Saltwater Separation, LLC

       ERDC-CHL Team                           •Saltwater Separation, LLC Team
      Jose E. Sanchez, P.E.                         •E. Robert Kendziorski
      Robert Bernard, PhD                           •robertk@saltwaterseparation.com
   Robert.S.Bernard@usace.army.mil                           •949.677.1991
         Phu Luong, PhD
     Phu.V.Luong@usace.army.mil
                                                             •Charles H. Tate, P.E.
                                                      •ctate@saltwaterseparation.com
                                                              •601.218.2173




                               www.saltwaterseparation.com
                Salinity Intrusion Barrier System

OUTLINE
 Challenges
 Cooperative Research and Development Agreement
  (CRADA)
 US Army Engineer Research and Development Center –
  Coastal and Hydraulics Laboratory (ERDC-CHL)
 PAR3D
 Miraflores Locks
 Simulation basis
 Experiments
 Results
 Recommendations and Conclusions




                         www.saltwaterseparation.com
                  Salinity Intrusion Barrier System

CHALLENGES
 Miraflores Lake brackish condition
      Current estimates of 1ppt concentration (ERDC-CHL 2000
       study)
      No salinity intrusion barrier or system in place
      Quality issues for some uses
 Increased traffic demand
      Current operations general range between 30 and 40 ships per
       day
      Future expectations of up to 53 ships per day
 Unsteady flow in the downstream lock approach conditions
  during emptying cycle
      Inconsistent navigation condition (1 out of 30 may impact the
       lock structure, as per WPSI)
 Possible Canal expansion



                             www.saltwaterseparation.com
                Salinity Intrusion Barrier System

CRADA
 What is it?
     Cooperative Research and Development Agreement
 Benefits
     Allows USACE to partner with other organizations
     Shares information, knowledge, discoveries
 Parties involved
     US Army Engineer Research and Development Center,
      Coastal and Hydraulics Laboratory
     Water Processing Systems Incorporated




                         www.saltwaterseparation.com
                Salinity Intrusion Barrier System

ERDC-CHL
 Expertise
     75 years experience in physical and numerical
      hydraulic modeling
     250 personnel
         140 Engineers and Scientists
         56 with PhDs
         60 with MS degrees
 Resources
     Many numerical models available
         PAR3D chosen
     High Performance Computing Center on site
         Among the top 10 in the world




                          www.saltwaterseparation.com
                  Salinity Intrusion Barrier System

PAR3D
 What is it?
     3-dimensional incompressible flow numerical model
     Accommodates
         Deforming grids
         Free-surface displacement
         Multiple processors
     Capabilities include
           Heat and dissolved-gas transfer and transport
           Salinity transport
           Temperature stratification and mixing
           Sediment and biomass transport (with oxygen demand)
           Turbulence modeling including buoyancy
           Flow driven by bubble plumes and mechanical mixers



                             www.saltwaterseparation.com
                  Salinity Intrusion Barrier System

PAR3D (CONTINUED)
 Governing equations
      Navier-Stokes equations for incompressible flow
      K-Epsilon turbulence model
 Pneumatic injection specialty
 Published in “Applied Mathematical Modeling”
      Independent peer review for application to independent
       experimental data, 2000
 Previous applications
      Taylorsville Lake intake structure, internal flow in the
       structure
      WES Riprap Test Facility, open-channel flow around a bend
      McCook Reservoir (in design), pneumatic bubble plume
       application




                            www.saltwaterseparation.com
             Salinity Intrusion Barrier System

MIRAFLORES LOCKS

                    INLAND SIDE




OCEAN SIDE




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                  Salinity Intrusion Barrier System

MIRAFLORES LOCKS

model grid area




                           www.saltwaterseparation.com
                  Salinity Intrusion Barrier System

INITIAL SIMULATION BASIS
 Average depth (50-ft)
      No tidal action
 No vessel
 Approximate bathymetry (el. –50ft)
      Lock exit structure modeled
      Channel width approximated (110 to 220-ft)
 Starting salinity
      10 ppt DS of miter gates (1000-ft stretch)




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              Salinity Intrusion Barrier System

  MODEL
                                                                    Pacific Ocean


                Guide wall


Miter gates


                                                     •Total length = 1000-ft
                Wing wall
                                                     •110-ft wide
                                                     •50-ft deep




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                     Salinity Intrusion Barrier System

Model Simulations
 Existing conditions without salinity barriers
      During emptying cycle
            Simplified lock release (steady state outflow)
            15 min cycle with 3kcfs flow rate
      20 min after emptying cycle ends (re-stratification)
 Effects of bubble curtains
      With/without pneumatic injection
 Bubble curtain setup
        1 bubbler 400-ft from miter gates (WPSI feasibility report)
        2 bubble curtains (100 & 200-ft from each other)
        4 bubble curtains (100-ft from each other)
        8 bubble curtains (50-ft from each other)
 Fresh water injection rates with 4 bubble curtains



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                      Salinity Intrusion Barrier System
EXISTING CONDITIONS:



                    3kcfs injection, after 15 min emptying cycle




         Water injection
                           no injection, 20 min after cycle
     (50-ft from miter gates)




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                                     Salinity Intrusion Barrier System
BUBBLE CURTAINS vs. NO CURTAINS:




    Water injection                      563 cfs fresh water injection – 3hr simulation
(50-ft from miter gates)




         water injection       bubbler        bubbler          bubbler        bubbler




water injection            bubbler           bubbler              bubbler               bubbler

                           563 cfs fresh water injection, 1100 scfm/curtain – 3hr simulation




                                                        www.saltwaterseparation.com
                             Salinity Intrusion Barrier System
FOUR BUBBLE CURTAINS:             1100 scfm/curtain, 563cfs fresh water, 3hr animation (10min intervals)




      water injection   bubbler    bubbler          bubbler        bubbler




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                             Salinity Intrusion Barrier System
FOUR BUBBLE CURTAINS:             1100 scfm/curtain, 563cfs fresh water, 9hr simulation




      water injection   bubbler    bubbler          bubbler        bubbler




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                 Salinity Intrusion Barrier System

Water injection rates (4 bubble curtain design)
               Qw inj (cfs)                           Time for < 1ppt
           fresh water (0 ppt)                       100-ft from gates
                                                              (50-ft deep)

                      563                                     180 min

                      885                                      90 min

                     1198                                      60 min

                     1709                                     60 min*

                     1812                                     60 min*

        * Time reflects salinity concentration at 100-ft from miter gates
        only. Lower concentrations were indicated further downstream
        sooner.

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                 Salinity Intrusion Barrier System

ADDITIONAL SIMULATION BASIS
 Tidal fluctuations
      Max depth – 64ft
      Min depth – 44ft
 Vessel exiting lock chamber
      With propeller action
      Without propeller action
 Stratified salinity distribution




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                  Salinity Intrusion Barrier System

Tidal fluctuation comparison

   Qw inj (cfs)                                                    Time for < 1ppt
                   Time for < 1ppt            Time for < 1ppt
 fresh water (0                                                      100-ft from
                  100-ft from gates          100-ft from gates
      ppt)           (44-ft deep)                   (50-ft deep)
                                                                       gates
                                                                     (64-ft deep)
      563             120 min                        180 min          270 min

     1812              50 min                         60 min           80 min




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                    Salinity Intrusion Barrier System

Ship and propeller mixing characteristics
 Ship Model
     Dense grid
            2000-ft channel
            Starting at US miter gates
            Divided into 100-ft cells
            Depth: 50 ft
     Panamax type ship
          965’l x 106’w x 39.5’d (centered in channel – exiting lock chamber)
          26-ft diameter propeller helix
          20,000 hp
     Simulation
          Initial conditions
               5 ppt starting 200-ft downstream of ship
               1 ppt inside of lock chamber
          563 cfs fresh water injection 100-ft from DS miter gates
          4 bubble curtain design


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                Salinity Intrusion Barrier System

Ship and propeller mixing characteristics
                                       Ship only


Stern                                            Bow                           Pacific Ocean
                Ship


                                                    < 1 ppt



                           Ship with motor in operation




                                                    < 1 ppt

         563 cfs fresh water injection, 1100 scfm/curtain – 1hr simulation
                 Initial condition: 5 ppt starting 200-ft downstream of ship




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                Salinity Intrusion Barrier System

Recommendations and Conclusions
 Conclusions
     Best design tested – 4 bubble plumes at 1100 standard
      cfm/location with minimum 563 cfs fresh water inflow
     More air flow does not improve performance
     More air injection points does not improve performance
     Higher water flow rates do improve performance, up to a certain
      limit
     Tidal fluctuations have minimal impacts on performance
     Ship and propeller have minimal impacts on performance
 Recommendations
     2D physical tests for salinity transfer at bubble plumes
     Experiments to study downstream conditions during emptying
      cycle (turbulent currents – baseline conditions)



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