Really long culvert ideas?

[piaffepony]

I have a 72’ x 300’ building (indoor arena and barn. My entire property slopes from the southwest down to the north east so we had to build up the whole north 72’ end quite a bit. The difference between the east and west corners is about 7’. Since there will be 2 aisle ways, we have 2 entrances. Obviously the NE entrance is much steeper which we’d like to fix, but first I have to put in some sort of culvert to allow the ditch along the west side of the building a place to drain without funneling it into storage sheds.

We’re talking probably a 90’ long culvert that has to withstand tractors and such. Culverts are so dang expensive! A 12” x 20’ HDPE corrugated pipe is like $250 and it probably needs to be a bigger diameter than that too. Any cheaper options?

 

[Oaktree]

Would a ditch or swale work? Parts that need to be driven over could either have a shorter culvert or you could fill with crushed rock.

 

[nybirdman]

That long a French drain makes more sense.

 

[Gary Fowler]

Just put in a swale, rock the bottom if concerned with wash out, then just put in culverts where you are driving in and out. Sure a culvert under the whole side would look better than a ditch, but beauty is expensive. A nice swale that can be grass covered and mown looks pretty also.

 

[Cataclysm]

Do the math and see how much water you have to deal with. That will give you a much better idea of sizing and maybe better help from everyone.

 

[rademamj]

A large french drain. Basically, a 3' deep ditch or trench made by a backhoe, then filled in with coarse gravel. Topped with 6" of normal soil and grass. Any water runoff soaks into the gravel filled trench and away from your arena.

 

[oosik]

I think the "culvert under the driving areas" and grassy swale for the remainder sound like a good idea. Either that or a french drain type arrangement. Keep it simple so annual maintenance is minimal.

I don't know about your area but the two culverts on my driveway have lead to some interesting "concerns". Both have, at one time or another, been more or less permanent homes for unwanted critters. Skunks, porcupines and badgers.

I have installed hog wire mesh on the ends of both culverts.

 

[duffer]

Agree with the other guys about a swale, with 3"-4"+diameter rock in the bottom. Rip rap would be best. Anything smaller than 3"-4" will washout during a downpour.

But you'll need a much bigger culvert than 12" for your access points. I had (4) 12" culverts, (side by side) under my driveway, and if we got more than 2" of rain, I still got flooding. Do yourself a favor and get at least 1 if not 2, 24" corrugated pipes for your access points. Not cheap, but does the job, and less expensive than multiple 12". And based on the looks of your arena, you've done everything right up to this point.

The big mistake I made was NOT putting down the straw/mesh erosion mats, like the DOT uses on sides of new bridges and berms. I lost my seed, and a ton of silt covered my rock bottom in the swale. After I reseeded and put down the straw/mesh mats, everything was good. Erosion was very minimal and the grass came up quickly.

On another property I had, the landscaper put in a french drain, covered it with rock, and topped it off with 4" of soil, sod. French drain was useless. The water just rolled over the sod, never got to the french drain. Once I made him open it up, and fill the trench to the top with coarse rock, it was perfect. And depending on the type of grass you use, it's likely the grass will eventually extend over the exposed rock. (not the dirt)

 

[newbury]

Just remember to calculate the maximum amount of water to expect and add a fudge factor.
Last year, Sep 21-22, 2018, DFW reported 8.11 inches of rainfall. That's a respectable amount of rain for one day.

 

[buckeyefarmer]

My FIL had a 24" culvert under his pole barn. Area was originally a steep ravine that was filled. Culvert was at least 200' long. Since then he has extended it at least another 200' and filled in more. Hope it doesnt clogg. There is at least 1 access hole about half way. Fortunately, very little water flow into it, and he has a grate accross top to keep large stuff from going in.