On Jul 8, 8:55*am, Ed wrote:
Here is a possible solution. Instead of a gutter, consider a
dispersion system to distribute the water over a wider area so it is
less likely to splash under your doors. One such product is
Rainhandler (www.rainhandler.com). I have never used this product but
it would seem to help in your situation.

But the water will still all end up outside his garage doors, the OP
wants to keep the water away from the garage doors.