[mdiederi]

Thanks for telling me about that book, sopas ej. On the Amazon site they show pages with the list of illustrations, which says there's a map of "Williams Ranch and the Sleepy Lagoon Reservoir". Further googleing found a Times article that said the Williams Ranch area was in Montebello, and that that part of Montebello is now part of Bell, just south of Maywood, which would put it near the river.