Drainage Experts Needed

coastalguy · Jan 1, 2006

I have a large parcel land (5 acres) and it used to be old fields and have recently built a home on it. The problem is that is doesnt have much elevation change and there is a impervious layer of clay 24 inches down. The water will just sit after it rains. I was thinking about putting some swales in and running them to the property edge where there is a ditch. Should I use surface drainage assumming I cant get an adequate slope (1.5%) or should I use subsurafce drainage (trench drain - perforated pipe with sock)? If I do swales would a dozer do the job or would I need to get a motor grader and hire someone. I think I could handle the dozer myself. Any advice is appreciated and thanks in advance,

Wet Yard in SC

uhmgawa · Jan 1, 2006

( I have a large parcel land (5 acres) and it used to be old fields and have recently built a home on it. The problem is that is doesnt have much elevation change and there is a impervious layer of clay 24 inches down. The water will just sit after it rains.)

It wasn't clear if the house has a basement. If so you'll
need to lower the ground water level at least to the bottom
of the foundation footers. This can be fairly straightforward
assuming you have a suitable low spot to where you can
direct the drain pipe..

If the foundation is a slab without basement either
grading the surface to direct water away from the
foundation or creating a depression in the ground
water table will likely do. Personally I'd do both in
this case.

For a point of reference I have a high seasonal
water table and a basement. I used a double loop
of 4" perforated pipe around the foundation footer
perimeter as well as two loops inside the footer
sitting in ~12" of drainage stone. On top of this
lies the floor slab. The whole shebang is tied together
into a double run of solid 4" drain pipe and heads
down hill to the stump dump. The drains emit
water year around but the basement remains bone dry.

nobull1 · Jan 1, 2006

Without the pic's my guess would be to get a trench down as far as possible(more than 24") graded towards the ditch you talk about. This could be dug and graded around the house in the direction of the ditch(if water around the house is a problem /forums/images/graemlins/confused.gif). I assume that the clay can be moved with a big enough machine? As I said pic's would be nice and maybe I would think different if I see them. In my business I don't estimate anything without seeing it, in person. Other than that it is only a guesstimate. Pic's are the next best thing.

Egon · Jan 1, 2006

Where would the trenched or purposly diverted water go to? If it's not on your property there may be complications! /forums/images/graemlins/confused.gif

Egon

nobull1 · Jan 1, 2006

(
Where would the trenched or purposly diverted water go to? If it's not on your property there may be complications! /forums/images/graemlins/confused.gif

Egon )

You are absolutely right Egon that could be a real problem. That is why I need pic's and don't do estimates without seeing the property /forums/images/graemlins/smile.gif Now if you were the next door to this property we could go out and dig a dry well next to the property line. If we went out after dark we could dig and cover over and no one would be the smarter until it rained /forums/images/graemlins/blush.gif /forums/images/graemlins/grin.gif.J/K buddy

Glenn9643 · Jan 1, 2006

I think the first thing I would do is try and determine how much elevation change there is. You might rent a transit to do this, and identify your low areas, and see how deep your swales would need to be to drain the water to the ditch. I wouldn't be too concerned about adequate slope, but just remember that water won't run uphill. The required depth for your swales will depend on the elevation changes of your property. If your low places are lower than the ditch you can't drain to the ditch...
You don't mention owning a tractor, so I'll assume you don't. You might be better off renting a tractor and box blade. A dozer or grader seems like overkill to me, but I haven't seen your problem either.

gates · Jan 1, 2006

Find the low areas, either with a transit or when it rains, set drain vaults, culverts or catch boxs in the low areas and pipe them underground to the drainage area. This will save you from regrading the whole lot. This work can be done by hand or if the trenchs are long rent a ditch witch with a hoe on the back for the vaults.

Ron

coastalguy · Jan 1, 2006

Thanks for all the replies. I will try to post some pictures. The drainage immediatley around the house is not a problem (50 ft radius), it's the other areas. I am trying to get the water to a ditch that surrounds 3 sides of the property. I took some elevations with a level and the max ele. change is 1.1 ft. I am hoping I won't have to put in subsurface drainage. I don't own any heavy equipment. Would I be better off renting a tractor with a box blade or a dozer to cut the swales? The yard is flat and I am trying to come up with a permanent solution for a mushy yard. It just seems that other yards' soil accepts water better than mine. I heard of something called "plough pan" that happens in old fields and leads to poor drainage.

Highbeam · Jan 2, 2006

Does the ditch remain free flowing year round? Does it back up? Does it actually lie on your land? Do you feel you have the right to dump to it? Is that 1.1 feet of fall measured from the bottom of the ditch to the high point of the land? If so, how much distance is there between these points. We run open ditches at 0.5% in these parts.

What is likely happening is the water runs through the topsoil and then sitting on top of the clay.

Start from the ditch and run the smoothest trench you can with as much slope as you can given the site. You can have several different trenches to drain the each section of the site to the ideal ditch. Backhoe, trackhoe, or something similar. You will want a 2 foot or so wide trench. Given the flatness you're talking about I would be leaning towards underdrains and not open ditches.

rambler · Jan 2, 2006

Where I live, we tile the whole farm, several 100 acres at a time. Don't like any surface swales at all. Funny you say a large parcel..... /forums/images/graemlins/wink.gif

However, we have no net loss of wetlands, so would need permits to do this. as well, the surrounding ditches require a permit to access them.

So....... did you get permission to do this work - swales or tile?

--->Paul