grass around swimming lake

I have 4 days off in a row, after a role of 10 days of working !! DAMN I needed some time off. And the sun is out and me and my partner went to some recreation zone a bit away from our town. It’s 50 minute drive. I’d like to go more often there but the problem is that there’s a playground which is not opened unless teh weather is good.. and then I can’t go inside because there are kids everywhere !! Damn. But there’s also a swimming lake. I tried detecting it before with my White Surfmaster but never found anything. The sand didn’t give anything last time, so I didn’t try today. I figured someone is scavenging it before me, and judging by the rather good finds still in the grass (such as teh 4 big bullets), I am sure that this other hunter only does the sand.

Good enough result after 1,5 hour.
-4 blank bullets (no idea why, I find them in playground and today in grass too).
-5 euro
-silver ring with missing parts.

Also found a few coins in the wooden bedding of this playstuff.
Easy to dig with a screwdriver.