Gutter Down Spout's In Ground Drain Clogged - Need Help

[Joshua Dorkin]

Hey Gang -
I've got a problem that I hoped you could help me solve without calling RotoRooter. My in-ground drain from a gutter downspout is overflowing. The drain does not run to the street, so I'm guessin git is a french drain. That said, I am able to get a hose about 20 feet or so into the drain with no interruption, but jamming it around in there isn't doing anything to get this thing drained.

I bought a declogger that attaches to the end of the hose, but it doesn't seem to help in this.

Anyone have any ideas?

Thanks!