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Study of density and discharge currents of the third sets of locks

 

The assignment
The Third Set of Panama Locks Project, comprises of the construction of a new shipping lane with locks on both sides of the Gatún Lake, at the isthmus of Panama. Ships approaching the locks navigate at a very low speed and are therefore susceptible to currents that affect the heading of the vessel. These currents can be caused by the spill released during the equalization the water level of the locks with the ocean (spill currents) or by density currents caused by salinity differences of the ocean water and the water in the locks (exchange currents).

IMDC, as part of CPP, was assigned to carry out 3D mathematical model studies and the necessary in-situ measurements for the calibration and validation of the models.

The goal is to study the discharge and density currents that affect the maneuvering vessels during present (Miraflores) and future (Third Set) lock operations at the Pacific side of the Panama Canal and to recommend alternatives that mitigate or eliminate the adverse effect of density currents on navigation and throughput.
Current maps (vectors) with weighted averaged velocities and transverse weighted averaged velocities (15.2 m in future approach, 12 m in present channel) have been produced and will be implemented in ACP's Navigation Simulator.

Approach
A measurement campaign has been executed in the chambers of the Miraflores locks and in the Pacific Ocean approach from May 5th until May 31st 2007. During this period stationary measurements have been performed in the lower and middle chambers, tail bay and at in far field area at the Bridge of the Americas and at the Diablo Pilot station. With mobile measurements in the lock chambers and the tail bay about 490 vertical profiles, 215 longitudinal transects and 90 cross-sections have been measured during 11 days.

Various 3-dimensional numerical models have been set-up that represent the density currents at the present locks. The 3‑dimensional hydrodynamical software Delft3D-Flow was applied to compute the longitudinal and lateral (cross) currents. The models of the present locks (Miraflores) were calibrated and validated for the Miraflores locks in the present conditions using the results of the in-situ measurement campaign. Sensitivity tests with the calibrated near-field model of the present condition have been performed, to study how a variation of the driving forces would affect the density currents.

After the numerical models for the present locks were successfully calibrated and validated, the future situation models were set-up to study various design and functional parameters.

The model has proven to be an effective design tool to evaluate the (density-driven) currents after changes to the design (tail bay, culvert location, navigation channel, center wall) or the forcing (lock operation, tidal conditions, salinity, river discharge, etc.) of the future Third Lane Locks. Results of the model can be used to assess forces on the vessel while in the tail bay and the current fields can be imported in the ACP's Navigation Simulator.

Enveloping the following design and functional aspects, ten alternative scenarios for the configuration of the Third Lane have been tested and reported:

  • Base-line scenario
  • Three center wall alternatives:
  1. Closed center wall;
  2. without center wall; and 
  3. permeable center wall (base-line).
  • Four different shapes of the bifurcation point:
  1. With shoal south of bifurcation point;
  2. dredged bifurcation point;
  3. extended tail bay;
  4. submerged bifurcation point.
  • Alternative locations of the culverts
  1. Culverts at the gates;
  2. culverts at end of tail bay;
  3. culverts in present channel.
  • With and without Water Saving Basins
  • With and without design vessel

Contact us

For more information about this project, contact:

monitoring@imdc.be

coast@imdc.be

waterways@imdc.be