Water leak by amp on th left side of trunk in 2007 335i BMW

While we were driving all of a sudden the car
speakers began to crackle and pop (making
loud noises) we turned off the car and it
continued to make noise until we
disconnected the battery in the rear right side
of the trunk, called a mobile mechanic and he
immediately notified us to look where the
amp is in the rear left side of the trunk. It was
filled with water!! Atleast an inch of clean
looking water was splashing around the amp
causing the noise! We Dried it to the best of
our ability and put open ziploc bags of rice
around the amp and in the trunk over night .
Again it has rained and is pooling up in the
amp compartment in the interior left side of
trunk. We are wondering if anyone has dealt
with this problem and if there is a simple fix
like some sort of drain that might be clogged
or what before I take Apart my trunk interior I
would appreciate any suggestions?