That is very sad. I can't even imagine what that child is going to go through for the rest of her life.
It makes you think, though. First and foremost.... Where was the child's parent when this happened? Didn't anyone notice that the child was stuck. I'm sure that the child was feeling pain, and no one heard her cry out?
We have a pool (only an above ground one, nothing special) and I make sure my son is in my sight at all times. Even if I have to only run in the house for a second to go pee... I make him get out of the pool while I'm inside.
Also... if this was a public pool... where were the lifeguards? Didn't they see that this child was in distress? And, being a public pool... What about the maintenance people, and/or public inspections for safety issues.
I think there's a "law" or "regulation" around here that those types of covers must be secured in place somehow, not just "pop" off-able (if pop off-able is a word...) What I mean is, my skimmer and cover hang off the outside of the pool, & it doesn't pose a threat. So, I don't have to "secure" it in place, I can just lift it off and place it back on. But a skimmer opening located directly inside the pool has to have a secured lid.
It's so sad that a child has to suffer at the hands of other people's neglect.