Centinela Creek never entered or joined with Ballona Creek.  The concrete storm drain channel that’s now commonly called “Centinela Creek” is really part of the storm drain system built in 1961 as part of the engineering required to deal with runoff from the San Diego Freeway (405) and adjacent properties appended through eminent domain.  It was further updated in stages during the 1970s as part of upgrades to the LA County storm drain system for the Marina Freeway (90).

It is also connected with the storm and street drain systems serving Ladera Heights, Inglewood, and parts of Culver City and Westchester today.

As such, it is an active component of the modern day urban Ballona Watershed (urban runoff).  But, as it never existed until 1961, it was never part of the historical Ballona Watershed and made/makes no contribution to the Ballona Wetlands per se.  

A more apropos name for that conduit would be Centinela Channel, which would be consistent with the naming conventions used for the nearby Sawtelle Channel (coming down and into Ballona Creek from WLA) and others throughout the city.
