This is the drawing of where we want to create a rain garden. There is a driveway at the bottem . Just above is the future RG. Three ft by 22 ft. Run off would drain into the aborvitaes. Down spout is at the top of drawing left of gate. There is 12 ft between garage and RG. Arrows point to the lowest areas. The drive is built 6-8inches higher than grass area. So, I would have an existing berm.