# French Drains and Clay



## WilliamH4 (Jul 26, 2019)

I'm working on trying to move water from part of my yard to a drain. This past year, we had A LOT OF RAIN. So we had water standing in the yard many times this year. Sometimes the water takes a few days to go away. We already dug a trench about 70 feet long. The trench ends at a pit where I'll install a sump bin. My trench starts out at perhaps 12 inches deep to about 36 inches where the sump will be. Instead of installing French drains, why can't I just fill my trench with gravel, 1-1.5 inch gravel, all the way to ground level? I have to get a lot of rain for water to stand in the yard. Typically, we may have water stand in the yard 12 times a year. This area wont' have a lot of water running through it every time it rains. Also, the soil in my back yard is heavy with clay. The trenches pretty much channel the water to the pit already (tested it with water hose). The soil is so dense with clay, there were still a couple wet places in the trench the next day (didn't absorb quickly). I don't mind installing pipes, it just seems to be a waste given I have clay and I can fill completely with gravel.


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## twolf (Jan 25, 2019)

With french drain you are supposed to wrap gravel (and the pipe) into fabric to prevent soil from penetrating into gravel and clogging it eventually.
Can you remove the pipe? Yes, maybe. Why everybody use pipes then? I would think there is a reason for it.
Moving water tends to take soil with it, so if your water move not in the pipe but underground - eventually it will wash a bit of soil. You will have undulations in the lawn. The bigger the slope, the faster flows water, the more soil erosion it does.

On the other hand I saw a video on youtube where they used a machine to inject a layer of gravel under the sod surface. At least, I believe that is what they were doing, for exact this reason - to keep surface dry, while allowing water to move away under the surface. However, these "gravel french drains" were leading to bigger regular french drains with pipes, etc.


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## FlowRider (Apr 7, 2019)

You want the slotted or drilled corrugated plastic pipe to be covered with a filter sock so the water can drain into the pipe and exit out of the pipe where it allows the excess water to escape.

That is the whole purpose of establishing a French drain - to collect, filter, and evacuate the storm water to get it out of the area before the ground gets soft from being oversaturated.

If you just put gravel there, the sediment and siltation will fill in the voids of the gravel and it will stop draining, and all you will have is a clogged drain tile field which will become a bog every time it rains enough to fill the area up beyond surface runoff and sheet flow.

In other words, it will be a complete waste of your money & time. That is why it is called a French drain.


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## g-man (Jun 15, 2017)

@WilliamH4 I moved this to the landscape area.


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