OMG SWAMP WATER FLOORBOARD!! anyone know how to fix this? (pic inside)

[SLiguykyle]

Hello zilvia. so last night here in socal, we got some rain for the first time in a while haha, first time since i picked up my coupe. It's an '89 KAE coupe so i expected it's fair share of problems and messiness anyways, but wtf i've never had this much water on the inside of a car (even my track car with left over holes from the old bolt-in-cage setup doesn't get this bad in the rain) i soaked up as much of it as i can, and i noticed it was all a pretty rusty color. almost like transmission fluid, but its water. i thought it might have been a cracked hose in the heater core but it's not coolant that i can tell, it seems to be just water. (brown might be color from the 23 year old brown carpet? no idea...)

I also noticed that when i make a LEFT turn, water "waterfalls" out from behind my glovebox all over the floorboard... please help me figure out where this is coming from and how to stop it!!! any advice on where to check or where to start checking will be greatly utilized and even more so appreciated. thanks!