10 Hours later . . . an update

[Digger 258]

Ponytug, I'm planning on undertaking the same type of drain - with gravel in the bottom. How did you end up compacting the gravel and the soil? My plan, which is unencumbered by experience, is to cut a trench, fill with gravel, install 4" drain pipe and then put the topsoil back over the top. I also have to ensure that all of the trenches get deeper as I go so the water flows down hill. Essentially, I have to put 5-6 drains in, each about 300' to drain a field.

 

[ponytug]

Dear Digger258,
I would recommend that you think about what will clog your system before you start. Something will eventually, you just want it to be later, rather than sooner, e.g. silt, sand, roots. Plan to minimize the clogging and your system will last longer. If you backfill soil on top of the drain pipe, you run the risk of the drain pipe getting clogged from the soil. You might want to think about sand/gravel for some of the backfill. I was told that french drains with corrugated pipes and no geotextile have a short life. If you can have a design that enables you to run a hose into the drain to flush it, the system will last longer.

I surveyed the site first, then laid out the french drains and cross drains on the appropriate slopes. I went with 6" trenches because some of the cross drains were pretty deep, and the estimated flow necessitated 6" drains. The hardest part (after the design/planning stage) was probably clearing the trenched soil without dribbling it back into the trenches.

I used about 4" of 1/4" gravel, then laid geotextile wrapped drain pipe (I used Multi-Flow, but no particular endorsement- talk to me in ten years.), with a surrounding layer of ~10" of gravel, then filled the trench to the surface with 1/4" gravel. The soil surface was covered with geotextile at a 24" overlap. If I were doing it again, I would have used 100% overlap. By filling in layers, I was able to ensure that it was all bedded in in sequence. I compacted by leaving the gravel about 1-2" high, and running the tractor wheels along the gravel ridge. Not much happened.

If you are doing this in a lawn, I would look at some of the designs at Multi-Flow for ideas on sand vs gravel and designs.

All the best,

Peter

 

[Digger 258]

Thanks for the detail - I am doing this across a large lawn that is currently very swampy, but has a creek running along the low end. I'll be digging trenches running from the house to the creek, intersecting the creek at 90 degrees. Not sure if I need to run any drainage parallel with the creek . . . Using the geotextile (landscaping cloth) makes sense. Based on my rudimentary google images search, and your description, it seems I'll line the 6" wide trench with landscape cloth, insert about 4" of gravel (making sure to keep a downhill slope to the creek), put in perforated pipe, fill the rest of the trench with gravel, wrap the landscape cloth liner over the top of the gravel, put on a layer of top soil, compact, and plant seed. I'm sure the hard part is the planning, measuring and figuring slope under grade. Now I just have to order those 6" trencher teeth . . .

 

[dmac128]

the cursing will start once you begin cutting the horse mat.....haha.......I have tried everything......circular saw blades gum up to quickly......sawzall very difficult to control and also bind up.......jig saw works ok but takes freaking forever.......I've used the clamping method but once the rubber strip is started it takes on a mind of it's own...

Try a bandsaw - the constant downforce really helps. I use a 5-6 TPI bimetal blade at 1100 SFM and it cuts great. I run it dry. You do need a large table for support, but it makes all the difference. I'd tried all of the above, before it dawned on me to fire up the Grob.

 

[ponytug]

If it were me, I would just run them straight down toward the creek on some constant slope, with a perforated cap on the end. You could always run a pressure washer hose and nozzle up every so often to clean things out. Recess the ends so you can mow over it, and mark it so you can find them later...

Around here, most rental places rent laser levels, or leveling telescopes. You can lay out the level lines and add slope, or just lay out the slope. Lots of how to dos out there. I bought mine for the project because I didn't have the time do it in one go. Yours sounds simpler.

All the best,

Peter

Thanks for the detail - I am doing this across a large lawn that is currently very swampy, but has a creek running along the low end. I'll be digging trenches running from the house to the creek, intersecting the creek at 90 degrees. Not sure if I need to run any drainage parallel with the creek . . . Using the geotextile (landscaping cloth) makes sense. Based on my rudimentary google images search, and your description, it seems I'll line the 6" wide trench with landscape cloth, insert about 4" of gravel (making sure to keep a downhill slope to the creek), put in perforated pipe, fill the rest of the trench with gravel, wrap the landscape cloth liner over the top of the gravel, put on a layer of top soil, compact, and plant seed. I'm sure the hard part is the planning, measuring and figuring slope under grade. Now I just have to order those 6" trencher teeth . . .