My uncle's farm grass strip its going to be fixed this week.
It is 60 mts wide and 990 mts long.
Problem I think it is soo wide it doesnt drain.
Just one night of rains converts it into a muddy pit.

He has some gravel from a river nearby and wants to put a 25cm high and 10 meters long base .
Initially he wanted to cut down the ground and refill it with the gravel , so its even with the actual terrain, I think that wouldnt help drainage.

I told him was better just a 10cm gravel base on top of the grass with a small curve to each side so the is no gap between the new gravel and grass , then will be compacted and the grass should grow thru.

Any other ideas of how to spread this gravel?

In my personal experience with grass strips as quick as you add gravel to soft and wet soil the gravel sinks in as you taxi and you end up with rocky mud. Proper drainage is the best solution I think. Judging by your pictures it looks recently seeded and the grass will need to thicken up to absorb any kind of moisture.
Now from experience operating in South America during rain season (particularly Colombia and Bolivia) some off strips are just not useable no matter what you do and we stayed off them.
I am sure some heavy equipment operators on this site will come forward with good advice on drainage.

The cheapest drainage fix would be to doze a gradual swale/ditch on each side of the runway and push the dirt into a good crown on the runway before adding gravel. A good dump truck driver can spread the gravel adequately either on top the crown or just on the field without dirtwork. The dirtwork is expensive but will save regravelling almost yearly. You need to run grade and insure that you have a place for the runoff water in the swale, the low point, drain to. It is nice to have two decimeter of fall per 30 meters, but it looks very flat there. If you had to drain all the way to the sea, that would be expensive. However, before starting any drainage project, you have to run grade and find a place to take the water. Otherwise, all is for naught.

Just a thought, looking at the pictures again, the ridge behind the tail would provide adequate length. It is much easier to run grade with good drainage either on top a long straight ridge or on the side of a long straight ridge. Neither drainage nor adequate dirt, building material, is a problem. On the flat, both drainage and adequate building material are problems. How big are those loach eaters?

There are one drainage ditche alongside the runway on each side two meters deep.
Problem is that this strip its too wide.

This drainage ditches are 60 meters apart.

Geotextile fabric. Laid on the grass. Then gravel on top. River gravels....alluvial or fluvial gravels do not compact well and will cause damage to the leading edges of the horizontal stabilizer, nicks and chips on the back side of the prop... Less so with the spec rock gravel runways in Alaska. 3/4 minus fractured....has flat sides, compacts well.

I'm wondering if spreading minus 12 mesh sand on the grass with a box drag. Road grader works best. Then use a drum roller (home made out of four to six foot diameter pipe... Sort of thing) to compact the sands into the grass. That'll stiffen up the soils a bit.
Mark M.

I would cut the topsoil aside, lay in your gravel, be sure to crown it higher in the center and tapered to the sides, then lay a thin layer of topsoil back on top so the grass will grow. Gravel on a runway is not a highly desired surface. You'll forever be sucking it up and into your prop, struts, and horizontal. By laying it under the grass on hard ground and using it to create sloping drainage, you can add topsoil back on and pack it so the grass has good growing material. You want to keep the topsoil fairly thin so it cannot get soft and muddy.

The width of my farm strip used to be about 1/4 the size of yours and it was plenty wide. It is hard to tell from a picture if there is any change in elevation down the length of your strip, if there is (and depending on your soil types) I would suggest installing a perforated drainage tile about 60 cm under the surface, the entire length of the strip (just off to the side of where you would normally land), providing there is a place to outlet the water. If if you have anyone that installs drainage tile in your area this would be much more desirable than using gravel, as it would dry the ground quickly and no prop concerns as with using the gravel. I you are handy, have access to a backhoe and laser, or transit, you could do it yourself. I used to have a drainage business, feel free to ask if you have any questions.

Steve

steve wrote:The width of my farm strip used to be about 1/4 the size of yours and it was plenty wide. It is hard to tell from a picture if there is any change in elevation down the length of your strip, if there is (and depending on your soil types) I would suggest installing a perforated drainage tile about 60 cm under the surface, the entire length of the strip (just off to the side of where you would normally land), providing there is a place to outlet the water. If if you have anyone that installs drainage tile in your area this would be much more desirable than using gravel, as it would dry the ground quickly and no prop concerns as with using the gravel. I you are handy, have access to a backhoe and laser, or transit, you could do it yourself. I used to have a drainage business, feel free to ask if you have any questions.

Steve

This exactly, drain tile (big-O) under the strip taking the water from the soil to the ditches and shoot lots of levels before and while laying tile. I'd also ask though, what kind of soil are you on? Just looking at the photos it seems like your strip is in a low area relative to the surrounding ground, is there anywhere for the water to go once it gets to the ditches?
It also looks to me like this might be a new seeding and those are always quick to get mucky and if you go out on it while it's mucky the situation will never improve. My fields are exposed to a level of traffic your strip is unlikely to see but after two cuttings of a new seeding things are compact from the tractor tires and the muddiness stops being a problem so another fairly easy thing you might try is waiting for it to get as dry as it can and then running over the thing a few times to press the soil a bit more compact. This only really applies though if it's a new seeding.
If your area sees significant rainfall I'd avoid using swales to the ditches as you'll likely run into erosion problems.
I'd also avoid laying down any gravel until you've solved the mud or you'll just have gravelly mud.

steve wrote:It is hard to tell from a picture if there is any change in elevation down the length of your strip, if there is (and depending on your soil types) I would suggest installing a perforated drainage tile about 60 cm under the surface, the entire length of the strip (just off to the side of where you would normally land), providing there is a place to outlet the water.

+2 on this one. The photo makes it look like there is a slight grade to the runway and it's obviously in a hilly area, so hopefully the photo doesn't deceive.

As an added bonus, proper drainage will result in much healthier grass, so in the long run you'll have fewer disease, reseed, fertilizer issues than with other approaches.