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Dry (wet!!) creek bed / french drain

Posted by lauren02 7 (My Page) on
Sat, May 10, 14 at 21:26

We are having a drainage issue and are desperately looking for help on how to fix it. When we bought the house, it had a dry creek bed in the back. It never really seemed to work quite right, though, and after a time, there was standing water and algae in it and around it. We had someone out to "fix" it, but that fix only lasted a few months.

Now, this is in an very wet spot - we are in the middle of a hill so get some water from uphill. There is water constantly trickling into (and out of) the dry creek bed - the flow just wasn't anything near reasonable enough to prevent standing water and algae.

So, we had another company come out and put in a "proper" french drain. It worked OK until a couple weeks ago where we had some torrential rain. Now it is back to having standing water everywhere. We are in the process of taking the rocks out and it is just all gunked up (both the rocks and the lining fabric of the slotted pipe) with algae, mulch, muck, etc., and so the water just isn't flowing.

Here are some issues that I see complicating the issue:
--The french drain slotted pipe doesn't connect straight to the drain, but instead empties into the creek bed about 6" away from the drain. We asked the french drain guy why he didn't connect directly, he said that it cut down on sediment getting into the pipe leading to the street (which is corrugated, so hard to clean).
--The drain intakes water via holes drilled in an extension placed on top of a round spee-d basin. So, the water level is always above the top holes and it drains depending on the current water pressure. These holes also easily get clogged by the muck and so only flow really nicely when there is a lot of water backed up. (pic of this attached after removing a bunch of rocks)
--The last 6-12" if the "system", leading up to the drain, is flat (if not slightly uphill).
--These three above points result in a very slow-draining outtake of the french drain pipe. There's algae in that as well (we've also seen larvae in there, species unknown).
--The french drain isn't buried deep enough - the top of it is level with the ground. This is due, in part, to there being a ton of trees surrounding the path of the drain/creek that we didn't want to kill by sawing off all of their roots. This means that there is not a lot of room for gravel to the sides/above to keep things from getting clogged. They put the gravel up to 1/3-1/2 of the height of the pipe and an assortment of variously-sized round rocks on top.
--The grading/slope of the drain/creek overall is not exceptionally steep.

The guy who installed our french drain is not being exceptionally response and I think just wants to avoid doing more work. We don't mind fixing this ourselves but at this point have no idea about what would work. Taking most of the rocks, and the pipe, out of the creek bed so it's more like a gully/stream that can just flow down the hill? Connecting the french drain slotted pipe directly to the drain even though it "may clog it up"? Regrading that last foot? Turn the whole thing into a pond (only sort of kidding)? Or do we just need to clean it out several times a year? Ahhhhhh.


Follow-Up Postings:

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RE: Dry (wet!!) creek bed / french drain

Bigger view of area around drain.


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RE: Dry (wet!!) creek bed / french drain

Wider angle showing standing water and algae.


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RE: Dry (wet!!) creek bed / french drain

Back up and show the whole thing insofar as how it relates to the back yard and house. Try to show the overall lay of the land. Then show how the grading of your yard fits within all the properties that surround it.


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RE: Dry (wet!!) creek bed / french drain

Here's a pic during winter that shows the area. Left end is where the drain is.

For our yard vs. others, we are in the middle of a hill. Back yard slopes towards house, front yard towards street. Left neighbor (same side as french drain) slightly higher, right neighbor slightly lower.


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RE: Dry (wet!!) creek bed / french drain

Can we clearly identify the original source of water and show where it enters your property? Is it coming from a natural or man made source?


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RE: Dry (wet!!) creek bed / french drain

Natural. It comes from the woods on the other side of the fence. Where the beginning of the creek bed is (on the right, black arrow) is a slight low point and so it congregates there, and get collected by the dry creek bed. There is also a ton of ground water that is almost constantly trickling in at a couple places along the way (via the much on the far side of the creek bed - red arrow is one point, green arrow shows path of the other). The mulch on that side is permanently wet, which I am fine with and will plant appropriately.


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RE: Dry (wet!!) creek bed / french drain

Seems like the main objective would be to bring the drain pipe to a single low point where the water is collected, so I don't understand why the separate pipe in a sock and the gap between it and the drain. Also, seems like you would be better off if the collection point were a larger catch basin and larger grate. I think that all the rock is an impediment to creating a clean, simple solution and that you would be better off if working only with regular soil.


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RE: Dry (wet!!) creek bed / french drain

First, thanks for taking the time to help us out on this!

I agree with the pipe/drain gap, which is why we thought originally that the pipe should/would connect directly to the drain (but, as I said, the landscaping guy said that then more sediment could get in the drain?).

I don't think a larger grate would readily do the trick - the water level rarely reaches the level of the grate (which is elevated off of the "bottom" of the trench. It enters the drain primarily through those holes drilled in the side, as I mentioned.

So you think the water would move well enough through soil? I thought in general that rocks were better at moving water quickly - hence the commonality of dry creek beds, surrounding french drains in gravel, etc.?


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RE: Dry (wet!!) creek bed / french drain

No. The objective is not to get water to move THROUGH soil. Let the water flow at grade to the logical collection point. That's where the water should enter the grate. Below the grate should be a collection "box" (could be plastic; could be concrete). Inside the box is the pipe inlet set just a little higher than the bottom (so there is room for sediment to collect, which is periodically cleaned out.) I said larger grate so that it isn't constantly being clogged by debris. What you have now seems messy and troublesome to me. The basic premise:

This post was edited by Yardvaark on Mon, May 12, 14 at 14:17


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