I have two slit French drains. Garage side wall drain is 36'. Shed drain is 24'. Long deep trenches filled with rock. About 12" wide. I divert water to the side of my garage and send it around the corner to the long drain. It has a plastic drain trench and grate with lots of large holes in it to dump to earth that catches the bulk and takes it downhill behind garage. It works. Same thing at shed except I catch it at the side wall and dump it to a L shaped drain so it goes behind the shed and downhill behind it to dump excess if needed. It also works.

I would like to see a pic from back in the yard, stand uphill and take a pic of the whole drive/garage wall area.

from what I see so far I think your cheapest/easiest/bestust way is this.



you can find the low spot on the drive where the water exits to the gar. wall, have a slit trench cut in the drive to accommodate a grate system. have it exit to a pvc pipe 4" or larger, take it about 10-20' (or wherever the natural fall stops) and put in a small sump, this would act as an overflow regulator.


unless the natural fall of the yard drains right to the gar. you should be good this way, we did virtually all of our drives in colorado this way due to the slope.

forgot to add, those grates are a prefab mass produced item too, they are not very expensive.

https://www.metalsdepot.com/metalsdepot/steeltrenchdrainagegrate-12x36.htm