It's interesting to see all the variations on this Hispanic ghost story. I'm from Albuquerque and there the legend of La Llorona is associated with the many irrigation ditches that run through the valley along the Rio Grande. The most common variant is of a woman who dies of grief after her child falls into a ditch and drowns. She returns as a ghost who weeps and moans by the banks of the ditches, calling out for her dead child.
The Rio Grande as it runs through Albuquerque (and most of New Mexico) has a half mile or so of cottonwood forest (bosque) on both its banks. When you're down there at night with the wind blowing through the trees it's easy to imagine that the quiet moaning sound is more than just the wind.
So, what is it about waterways, drowning, and ghosts in fokelore? Seems like this story has counterparts all over the world. Thoughts?