Dry (wet!!) creek bed / french drain
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.