Rain Garden Class (Amy)

last year

We have a spot in our front yard with an existing french drain that I'd like to replace with a rain garden. There are three roof sections that drain into it -- the two that are closest, as well an additional section that has been re-routed. So it gets quite a bit of water. The area seems to drain well though, we haven't had any issues with standing water or mud there.

Our kitchen window looks out at this area and directly at the road. So we'd also like to screen the road for a better view.

Here's a sketch showing the general location where I'd like to build a rain garden. The blue arrows show the water movement, and the red dashed line shows the existing french drain.

Here's the view from the kitchen window.

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Comments (9)

Susan Bryan
last year
Looks good! I love that you will be screening the view of the road. So satisfying when a rain garden does double duty. You can pick plants that will look good in all seasons, and are tall enough to block what you want to block. So many possibilities!

My only question is - does it follow rule #1: Is it at least 10 feet from your house? If not, just move it over a little. Looks like you have plenty of room.

When you get to the "Design the Overflow" part of class, pay attention. It looks like of flat, so this might be tricky. But there is a simple solution. Have the overflow go where the water flow used to go. Then you won't create any trouble.

Looks like a great spot to design something lovely! Love it.

Feel free to ask more questions as you go along!
Amy Griffis
Original Author
last year
Thanks, Susan!

I'm not sure the existing french drain is 10 feet away from the house at the closest point, but the rain garden can be. I'll be sure to include measurements when I make a more detailed drawing.
Amy Griffis
Original Author
last year
We did a percolation test a few weeks ago and the drain time was 8-10 hours. It looks like we have a few inches of topsoil over clay.
Susan Bryan
last year
Great! 8-10 hours is fast-draining. You are good to go - and at only 20% of the area of the roof. You don't have clay. :)

Back to the french drain - it is ok if the french drain is less than 10 feet from the house. A french drain is "conveyance" i.e. is moving the water away from the house. It isn't "infiltration" i.e. soaking the water into the ground. So you are good to go.
Amy Griffis
Original Author
last year
Oh, really? What kind of soil do you think it is then?
Susan Bryan
last year
With that quick of an infiltration rate, you are in the loamy range. :)
Susan Bryan
last year
Clay gardens have had infiltration rates of more than 24 hours to . . . never. Sometimes the rate is "never", because it rains before it soaks in. (insert laughing/crying emoji here.)
Amy Griffis
Original Author
last year
Oh my! That's not what we have. I've never seen any standing water in the yard.

I've measured the roof area now that flows into the current french drain. It's 1313 sq ft, so 20% would be right around 263 sq ft.

I had been considering making the rain garden larger than that. Do you see that as a potential problem with it draining so well?
Susan Bryan
last year
No problem! If you make it larger, it will capture more rain storms. So even more good! Alternatively, the garden can be larger, but the rain garden part of the garden could be just a portion of that.

Either works.