6 
Summary and Conclusions 
Simulations of harbor circulation with a 3-D hydrodynamic model indicate 
the following: 
a. 
For no-wind conditions, there is a gyre in the LA/LB outer harbor, 
which becomes stronger from bottom to top, and a net eastward flow 
through the harbors. 
. For typical summer winds from the southwest, the surface gyre in the 
outer harbor is eliminated when winds are actively blowing and reduced 
when winds are not; the gyre is present at mid-depth and increases in 
strength at the bottom when winds are actively blowing; net eastward 
flow through the harbors is not increased by typical winds from the 
southwest; phasing of winds with respect to tides (Case 1) does not 
significantly alter circulation patterns over the longer term (order of 
days). 
. For Case 2, corresponding to strong winds (31 mph) from the 
southeast, associated with an approaching front, the effects of winds 
predominate over those of tides; over a 40- to 60-hr period, there is 
only inflow through the east breakwater gap and outflow through 
Angel’s and Queen’s Gates, a dramatic change from existing conditions. 
. For Case 3, corresponding to strong winds (31 mph) from the 
northwest, winds dominate the tide, with velocities at the surface 
generally directed out of the harbors, and velocities at bottom and 
mid-depth directed in. Major changes are observed in net flow at 
Range 5 through the center of the outer harbor and the east breakwater 
gap as well as velocities at the entrances, compared with existing 
conditions. 
. In summary, effects of winds on harbor circulation can be significant, 
with circulation during storms (such as Cases 2 and 3) being 
dramatically different from that for normal summer winds. This should 
be duly taken into account in harbor design and operation. 
Chapter 6 Summary and Conclusions 
37 
