Backyard Drainage Issues

draindrainagefrench-drain

I recently had a sink hole in my backyard that I consulted with here on DIY and got some helpful responses. This was as a result of an old well. It was fixed by a landscape architect.

However, after some more heavy rain I can now see other issues that my back yard is having with drainage. Can anyone recommend additional drainage fixes?

Along the side of the first picture I have three french drains. Those drains hook to a larger drain that goes to the main neighborhood reservoir. They do not seem effective though, and neither does the mulch as it just flows downward. Water flows onto the deck posts and soaks them, as well as along the back line of the yard and down to the lower side as you can see in the pictures. I am thinking this is where the issues lie – need a better solution here.

In the second picture (yes I know, its blurry but it was raining heavily) you can see some standing water in the grass which I have highlighted. Some water flows along the back fence/grass line which is fine. I obviously can't force a drain line to flow into my neighbors yard as this is illegal.

That water all comes down along the fence line next to the neighbors house which sits lower than mine. It piles up along the side of my house as you can see in the third picture. Maybe that needs some french drains as well?

enter image description here
enter image description here

Best Answer

I had nearly the same problem and a single french drain made the problem go away. It is important (and probably worth reinstalling if not done) to have:

  • a 10% grade (1 inch down for every 10 inches of pipe length)
  • cloth covered french drain pipe
  • plug off the yard-end or open it to a ground level drain (cloth and grate covered!) and make sure you can access it to clean it out
  • make sure your trench is at least 8 inches wide (2 inches clearance on either side of a standard 4 inch french drain pipe)
  • place the french drain pipe in a channel that has 1-2 inches of pea gravel for a bed
  • cover the pipe with at least 2 inches of pea gravel before putting in the dirt

The french drain also should start prior to the onset of the wet area. (Please note the image does not accurately reflect the opening of the yard end - i.e. you can't clean this one out!) french drain diagram