How do you fill in a trench on a hill

[GroundsKeeperDon]

Hi I am a Grounds Keeper and I take care of 33 acres.

2-3 of these are on a big hill and on this hill there is a large 40 foot trench going down it. The trench is probably from the sewer line that runs through it
and is visable all the way down the trench.

How would I be able to fill in the trench and put in grass so I can mow over it and stop it from eroding.

Any suggestions are welcome.

thanks

[Gnome]

Don,

Where I live there are highways that were blasted through hills. For drainage purposes there are almost vertical drains visible in a similar configurations as you describe. They were carefully filled in, bottom to top, with flat stone. These were done around 40 years ago and I doubt that anyone would go to that effort today.

Perhaps you could emulate their solution and fill the trench with some stable material such as used concrete block, then gravel and finally topsoil.

Norm