The trench vs the rain

[Old Guy in Tenn]

4 weeks ago in Tennessee we used a ditch-witch to dig a 2-foot deep by 4 inches wide trench about 450 feet long, from the house down to the spring. 150 feet is on our rolling hilltop, the remaining 300 feet are down a steep hillside though the forest. We placed the pipes and wires in the trench and started filling it back up.

On the first try we started from the bottom, packing it down with a hand thumper as we went. We were 3/4 of the way up the hill when the thunderstorm hit. In 20 minutes the trench was totally open again from the runoff, and the dirt was scattered evenly over half an acre of forest floor. The downpour's runoff got into the trench, slowly scoured it deeper, and then became a rushing torrent of destruction.

The next day we hired a college kid to help and started over, this time filling the trench from the top down, again packing it down hard as we progressed. We were well over half way down the hill when the rain hit us again. We stayed out in the rain and tried to divert the water where we saw it starting to erode. We failed. Maybe if we had 50 helpers we could have held our own.

My son has been trying to fill the trench for the last few weeks. He has built water bars and ditches to keep water out of the trench, but the water overwhelmed and destroyed them. He buried boards on edge trying to divert it, but the water dug under and flowed over the boards. He laid strips of plastic dropcloths over the trench, but the water found a way under and washed the dirt away.

The trench goes mostly straight down the hill, although for much of it there is a slope that brings water in from the side. This water from the side was one of my son's biggest problems. He is leaving tomorrow morning for Texas, and I will arrive in a week to pick up where he left off. It will almost certainly rain again while no one is there. I am at a loss for what to try next. I think I can salvage the hilltop, but am not even certain about that.

Anyone have any suggestions?

 

[KiotiKowboy]

Perhaps creating a series of gravel dams inside the trench would stop the runaway erosion?

Sounds like what you need most is a few DRY weeks.

 

[CalG]

Don't you have a tractor for back filling?

 

[Industrial Toys]

Man do I know about stuff like that. I have buried a lot of services on this property and quickly learned that you close it up fast. One time, I partially backfilled thinking that was good enough. Then the rains came and the pipes floated right out of the fill to the top!

 

[Old Guy in Tenn]

The Cub is currently out of commission, but does not have a loader in any case. The big problem is the steep stretch through the woods. Much too steep for any tractor. We used a come-along and lowered me and the ditch-witch one click at a time while cutting the ditch.

Yes, what I really need is a couple of dry weeks to let everything firm up. In the meantime, though, I need to keep it from washing away.

 

[KiotiKowboy]

Just throwing ideas at the wall ...

I've not worked on anything that steep but ...
Seems like filling it half way with gravel would allow water flow below the top fill until it all settled. Then you could put another layer of dirt on top later in better weather.

 

[LouNY]

If you can get it filled and throw a hay bale across it a lot of time the hay bale will soak up the water and silt to make a small dam. It may take a bale every 20feet where it's steep.

 

[3Ts]

Man do I know about stuff like that. I have buried a lot of services on this property and quickly learned that you close it up fast. One time, I partially backfilled thinking that was good enough. Then the rains came and the pipes floated right out of the fill to the top!

and broke some of the fittings. This was a sewer pipe that "T'ed into my septic tank, but fortunately the contractor used a fernco fitting so the pipe rotated up and didn't flood the tank.

No real suggestion for you other than what you already know. Fill the trench and pack it down as quickly as possible, and try to keep the water off the surface of the trench.

 

[RNeumann]

Homepage | Weather Underground

And a Wacker packer (slang) or Wacker Rammer (real name).

 

[Tough Luck]

Welcome to East Tennessee...worst weather I have ever seen in the ten years I have lived here. No one can predict the weather here. The local so called meteorologists only repeat what their 'weather model' tells them. I've had 3"/hr rain events with a forecast of 'slight chance' of rain. Couple that with the red clay they call soil here, and you have a runoff disaster. You may try to install some water bars. Good luck with your trench.