The plazas they are building are not on the beach, they are up the hill from the beach. I am being sarcastic. These are not plazas on the beach, they are plazas near the beach.
Bleach lasts about 6 months until the degradation becomes apparent. If the beach is 2 or three years old, it's pretty much useless.
https://www.scripps.edu/newsandviews/e_20060213/bleach.html
That has been the speculation since this thing has started. It's directly across from the plazas and being worked on at the same time. I suppose that is why?