How can I stop DCs dad Letting them go in lakes

[Inim]

Dc are 7 and 4 and neither of them can swim (eldest is autistic and has adhd and hasn’t yet managed swimming lessons but we are working on it )
He takes them to a park with a huge lake, where swimming has been banned for safety reasons and he lets them “paddle” at the edge. He doesn’t ever pay enough attention to what they are doing so I doubt he’s paying them full attention, 100% of the time that they are in the water. Eldest is likely to just run off not thinking about it getting deeper etc as he can be very impulsive.
It gives me nightmares and especially so after all the tragedies this weekend.
He won’t listen to reason at all and refuses to believe me that open water isn’t safe to be paddling in, and that there can be drops in the ground level under water and they can get out of depth so easily even if you think it is “shallow”
I don’t know what I can say to him to convince him to stop?
We are separated and he thinks everything I ever say safety wise is because I’m either ‘paranoid’ or purposely trying to spite him.

Not much you can do. You've told him your concerns and he believes he can look after them safely. If they are just "paddling" up to their knees then I doubt if they'll get into serious trouble. I understand your fear but one of the big things you have to deal with as separated parents is not being able to control what he does with them, within reason.

What a selfish idiot. Is it possible he IS keeping a close eye but enjoys winding you up?

What a worry! Of course there are risks which are worse if he is unaware of them and not paying attention. 😳
I say that as someone who's takes their kids to lakes and rivers to swim, but awareness and vigilance makes all the difference and that goes for child and parent.
I'm not sure what you can do about it unless you know someone he might listen to it he won't listen to you. so just here to offer solidarity.

It’s not really a lake that lots of people paddle in it’s just a huge lake with one tiny area where the water is more shallow (it’s black park lake) it just doesn’t seem a safe lake to be letting dc in to me, swimming isn’t even allowed there.
there’s no way he’d be supervising them properly, he seems to have no idea about age appropriate supervision/parenting it really scares me

Maybe easy for me to say because I’m not in the situation but I strongly feel I just wouldn’t let him take them. Full stop.

Bombard him with links to children drowning in similar situations.

The PP saying they won’t get into trouble needs to read the other thread.

Id stop contact over this, make sure you have proof via email or text. Its an area so unsafe swimming isn't permitted, you have a sn child and neither can swim.

He won't have a leg to stand on.

If it’s this one, OP, even wading is banned: www.river-swimming.co.uk/blackpark.htm
Send him an Email confirming this and prevent contact until you have his written agreement that he will not allow them in the water...

Notjustanymum- yeah that’s the one, thanks I’ll send him the link to that but no doubt he will just say I’m being ridiculous