Large Landscaping Project Half Done - Found I Have Clay Soil

ricksample

I should have done a soil test before I started to plant anything or doing my design. We have a pretty newly built house and I noticed last year that we had standing water on the back left side (where I planted), but didn't think to much of it until this winter after all the melting snow then the 2 full days of rain. All my 60 plants were under standing water for a few days.

Since that day, I have started digging a hole for a dry river bed (25' x 3'). Right now it's only dug at about 4" deep, but will go deeper. The next rainfall, the ground still had standing water, but not as much as the first rain. Mainly because the dry river bed filled up until it couldn't hold anymore. 2 days later the dry river bed still had water to the top, so I am using hoses to suck the water out.

I'm hoping the riverbed will be the solution to my problem as I'm looking for the cheapest/quickest fix possible.

I was thinking of digging the river bed 2 feet deep, then taking sand/organic matter and mixing it with the native soil/clay in the bottom to hopefully break it up so it will drain faster before I add the rocks. I just didn't want to dig that deep, add the sand/organic material and still couldn't get it to drain. Then I would have 2 feet of standing water each hard rain. If I did this, after the rain passed through the mixed bottom layer, wouldn't it just hit more clay soil and fill back up or would the organic matter keep working it's way down?

I thought about putting a french drain from my riverbed to the back of the property, but that would be 120' and the ground is flat, if not a little up hill. I plan to do this eventually, but the cost/time right now would be a huge factor as I have already bitten off more than I can chew lol.

Daniel Holzman

You need to dig down until you determine where the clay layer ends. If the clay is four feet deep, for example, you are not going to drain anything by digging what amounts to a 2 foot deep hole. The hole will simply fill with water, as you have already experienced.

You say the ground is flat, so the "dry river" you are digging must not have much if any slope, meaning you are not going to drain water that way either. As for the French drain, you need to drain water from a higher elevation to a lower elevation, else the drain will not function.

I suggest you start by preparing an accurate topographic map of your property, accurate to an inch or so. This can be done using a builders level and a staff gage, which can be rented from any U-rent store. Until you have an accurate topographic map, it is impossible to determine what the best drainage plan is. And you need to dig some deep holes to determine how far the clay extends. Then you can develop a plan to provide yard drainage.

pls8xx

Mr. Holzman said:

“I suggest you start by preparing an accurate topographic map of your property, accurate to an inch or so. This can be done using a builders level and a staff gage, which can be rented from any U-rent store. Until you have an accurate topographic map, it is impossible to determine what the best drainage plan is. And you need to dig some deep holes to determine how far the clay extends. Then you can develop a plan to provide yard drainage.”

Every single professional with a long history of fixing drainage problems will tell you the same thing. When it comes to drainage problems, there is no such thing as one size fits all. On flat lots, lack of an accurate base map will likely lead to additional problems rather than a fix for the current situation.

Most homeowners who can communicate with photos and can follow instructions have the capacity to do an accurate topo of their property. Almost none of them do. Thus they remain an easy mark for the first small time contractor selling them some crazy French drain project.

We see a steady stream of homeowners with drainage problems through here this time of year. If just one would go through the mapping process, it would demonstrate to all what should be done.

ricksample

I'm not to sure if I would have the skills to do a map like that or not. The dry river I dug is at the lowest point of the yard. The remaining yard looks to be very flat. The river is located about 20 feet from the back of my house. The back of my house has a 2 foot slope which is causing water to roll down the hill. Meanwhile the back of the property does go up ever so slightly before sloping back down. Just standing on the back deck, you can tell the river is the lowest point of the yard. Plus after one rainfall it took a lot of the water from the yard and filled up pretty quick. It was only at 4" deep which is why it quickly filled up and spilled over. If I can get that to drain nicely, I think it would solve a lot of my problem. I know it's hard to determine without creating the map though.

The farthest I dug with a post hole digger was 3 feet on multiple locations throughout the yard and still had clay. Today I'll dig with a shovel in the river bed to see how deep of a hole I can dig to see if I can get past the clay. I was just under the impression that since I have clay, their would be no end to it no matter how deep I dug.

dinah

Have you researched rain gardens?