Water-rain-bottom of 12v battery "box"-best guess?

When I had to change the 12v battery(2006 prius)-I noticed water-rain in the bottom of the 12v battery"box"

I live in a suburb of New Orleans so
1)Plenty of rain
2)Plenty of tree leaves
We did have a build up of leaves pollen debris in the hatch track-where the hatch meets the body of the car-
There are seams "everywhere"
The sound deadening felt above-behind and lateral-to the battery is slightly damp-
and where the main battery duct meets the grill-it is slightly damp.

Best bet-where is the leak?? Any guesses appreciated.
It took me almost 5 years on and off to find a rain leak the 98 suburban had(I should get a sticker"my other car REALLY is a Prius)-so any guesses greatly appreciated-rain leaks are tough to find sometimes.
Thanks
Charlie

 

Patrick
Thanks
I will eyeball the hatch gaskets-leaves were "stuck" in there they might have deformed or cut the gasket

There is a gap above the tail light-meant to be there but it sure looks like water could get in-it is normal-on both sides-guess I should ignore that.

When it gets light I'll take a much better look-and when the weather improves-guess I will be spending a lot of time with a hose
Thanks
Charlie