The water pump has a gear connected through a shaft to the propeller.

The shaft is sealed so the coolant stays in the engine and doesn't get on the timing belt that drives the outside gear.

Some slight wobble in the shaft will allow a bit of coolant to weep out. If the shaft doesn't make a good seal, the coolant would leak out.

Even though the seal would be bad, the timing belt still drives the propeller allowing coolant to circulate.

 

The drain bolt is BIG. 3/16 or 1/4 inch is the size of the weep hole. And it's pretty close to the plastic timing cover.

The weep hole IS an early warning for waterpump failure; here's how it works:
The waterpump shaft bearings have 2 seals. The first one begins leaking, into the space between the seals. That's where the weep hole connects, so the leaking antifreeze drips out the weep hole. The second seal prevents it from leaking all over the timing belt.

It's normal for it to begin leaking slowly, and not make any noise. If you leave it go for long enough, it'll often begin making noise, but not always.

It's unusual, but not IMPOSSIBLE, for that first seal to start leaking A LOT. Even so, the impeller of the waterpump ("propeller") is still spinning, so it still pumps water until so much drains out that the impeller is just spinning in air. I think the large amount of leakage throws us off-target because it's unusual.

There are a number of more rare possibilities, like an actual crack in the metal of the waterpump or something like that. What you want is for an honest mechanic to actually observe the fluid leaking out so he really knows the source of the leak.

We're all trying to give you possibilities, and it's tempting (for me anyway) to assume that you're going to crawl under there & check for yourself. We can't see or touch it from here, so we try to give you enough information so you can check it out for yourself. If you tell us up front that you are gonna go to a shop but you want to UNDERSTAND, then at least I can phrase the answers a little different.