A recent place name mystery: J G Island

J G Island outlined in red.

Does anyone know what the "J G" means in the placename "J G Island Beach?" The name refers to the "island" (really a peninsula) that was created next to the Santa Ana River's mouth in Huntington Beach around 1990 when the Talbert Channel outlet was rerouted. Most of the "island" is taken up by a Least Tern Preserve. This may be recent enough that someone out there will have a firsthand account of how it got the name "J G Island." 

For what it's worth, earlier names for the beach just north of the current river outlet (near Brookhurst) include Santiago, Celery, and my favorite: Nago. The beach there was particularly popular with local Japanese families in the early 20th Century.

Update, 4/21/2023: Drew Griffiths suggests that "JG" may stand for "Junior Guards," as in the popular Huntington State Beach Junior Lifeguards program. He was part of that program in the 1990s and says that area of the beach is "where we were based until [we] moved near the Newland station. If I remember correctly the area was called JG Island back then and to get us kids' attention the instructors would yell things like 'JG’s line up!'" So that's one distinct possibility! Still awaiting some kind of official documentation, but it's the best clue so far.