Forest floor cleared by downpour &caused driveway washout. Preventable?

[lhfarm]

Our gravel drive is 1400' long and climbs 250' through the woods. For several hundred feet, the drive goes across the face of the hill. There are two culverts that carry water under the drive from the ditch on the upside of the drive. The ditches are cleaned in the fall. A couple of nights ago, we had a torrential downpour and a large amount of debris (leaves and small branches) washed down the hill and filled the ditches and blocked one culvert. Luckily, the major washouts were restricted to a couple of spots.

The one picture was taken, looking up hill from the drive and you can see the washed area. The second is of the tractor parked at the clogged culvert and one of many loader loads of leaves. (Figured if I put that picture in, I could post in the projects forum.) We have lived her for almost 30 years and I don't remember this ever happening. We often have the "dry creeks" and other wash areas "cleaned" of leaves after heavy rains, but not so much of the forest floor.

Short of building a several hundred long catch fence, is there any other means of preventing a repeat? Or should I assume this was a 100-year event and just fix the road? I am considering just placing some downed branches and logs in hopes of catching some of the low up hill. I have spent 8 hours cleaning up and don't want to have to do that again, if possible.

Any thoughts/suggestions appreciated.

 

[tcreeley]

Our gravel drive is 1400' long and climbs 250' through the woods. For several hundred feet, the drive goes across the face of the hill. There are two culverts that carry water under the drive from the ditch on the upside of the drive. The ditches are cleaned in the fall. A couple of nights ago, we had a torrential downpour and a large amount of debris (leaves and small branches) washed down the hill and filled the ditches and blocked one culvert. Luckily, the major washouts were restricted to a couple of spots.

The one picture was taken, looking up hill from the drive and you can see the washed area. The second is of the tractor parked at the clogged culvert and one of many loader loads of leaves. (Figured if I put that picture in, I could post in the projects forum.) We have lived her for almost 30 years and I don't remember this ever happening. We often have the "dry creeks" and other wash areas "cleaned" of leaves after heavy rains, but not so much of the forest floor.

Short of building a several hundred long catch fence, is there any other means of preventing a repeat? Or should I assume this was a 100-year event and just fix the road? I am considering just placing some downed branches and logs in hopes of catching some of the low up hill. I have spent 8 hours cleaning up and don't want to have to do that again, if possible.

Any thoughts/suggestions appreciated.

Larger culverts that don't clog as easily? More of them?

Good luck. I think we are going to see more of these storms as time goes on - new pattern.

 

[stub]

I would rent a trencher and dig a trench along the top side of the road, in the ditch, about 2 feet deep. I would put perforated drain pipe in the trench and fill it up with pea gravel making a french drain. Now when your runoff hits the ditch, your french drain will carry it down the hill instead of over the road. The wider the french drain the better but I think any size would work. You would still need to keep the ditch reasonably clear of leaves but I don't think leaves in the runoff will prevent the french drain from working. My house is on a slab on a slope I've done this around the uphill side of my house. Haven't had a drop of water get in since.

 

[Diamondpilot]

I agree. You need a backhoe to come in and dig larger culverts.

Chris

 

[dave1949]

I agree the ditches look on the minimal side. If you aren't cleaning them with a backhoe, they have probably shrunk over the years.

In terms of mitigation, over the past 30 years your woods may have matured with a more closed crown than earlier which shades new growth. The woods "floor" looks barren of new growth, grasses, shrubs, etc. Those plants are all natural erosion preventers and act like a fence for leaves washing down the hill.

Only you can compare now to 30 years ago, but if that is what has happened, you could harvest/thin a belt of trees across the slope to get some sunlight in and promote new growth.

I think laying some logs and brush in rows along the slope is an excellent idea.

 

[Doloe]

The floor of your woods looks really empty. Not much vegetation or downed trees.
Is that normal for your area?
It seems to me that those things would go long ways to minimizing this damage.

 

[radioman]

I'd cut the hill back by 4-8 ft away from road. Dig a large swale in that area and on the downside put in a large culvert 20" in diameter or bigger under the road to let the water wash with debris. If you put in a smaller culvert - it wil just clog up from debris. The culvert only needs to be long enough to go on the other side of road at a steep angle so water can rush out. Its the only way to let debris settle in the swale area in light rains, but in torrential raids, it can wash out without going over the road.

Just my 2 cents.

 

[gilbertmsg]

Looks like a normal gully washer that we have with severe thunderstorms. We clean out culverts and ditches and drive on.

Eddie

 

[forgeblast]

http://www.dnr.wa.gov/BusinessPermits/Topics/ForestPracticesRules/Pages/fp_board_manual.aspx
lot of different manuals the one you want to look at is Section 3 Guidelines for Forest Roads updated 8/11 (1,625KB PDF)
starts about page 11

 

[lhfarm]

Thanks for the suggestions. I'm going to call the guy who put in the culverts and see about adding a couple more. While we have plenty of gully washers around here, it was more than just the gullies that are clean. We got lucky and missed the rain that was to the west and north of us here in central Indiana.

I'll do a follow-up when I get something worked out.

 

[Gary Fowler]

Thanks for the suggestions. I'm going to call the guy who put in the culverts and see about adding a couple more. While we have plenty of gully washers around here, it was more than just the gullies that are clean. We got lucky and missed the rain that was to the west and north of us here in central Indiana.

I'll do a follow-up when I get something worked out.

I don't think more culverts is the answer, just some larger ones that can take the leave debris and pass it thru to the other side. You will still have to keep limbs cleared that might wash down and into the culvert but an 18" or larger culvert should allow leave debris to pass thru without clogging. I like the suggestion of opening up the timber a bit to allow some sunlight to the bottom for grass to grow also. Use the downed trees to make some flow restrictors, like little terraces, for water coming down the hill.
Larger culverts, thin the timber, plant some grass.

As a last resort if that doesn't work, widen the ditches on the uphill side. I think I would only do this if all else doesn't work as that will be some major dirt work to cut back that slope and get enough area to put in a wide ditch without compromising the road bed.

 

[Kapnfriday]

Just for comparison - the gravel road up to my property in north west NC is about 2100 feet and rises about the same as the original poster's from top to bottom - 250'. Going just from my memory we have at least 7 culverts along the course of the road that divert water under the road and out the downhill side. Most are 15" a couple are 12". The idea of more culverts is simply to reduce the volume of water the ditches are carrying as it all makes its way downhill.

We clean all the ditches out in the fall - usually at Thanksgiving when all the leaves have fallen and we have a little more time. Even with this things don't always work perfectly. This year we had a nasty ice storm in February that brought down a lot of debris - sticks, twigs, branches, etc. A torrential rain last week caused all this debris to clog a couple culverts and left the resulting washout.

Clogged culvert

Washout

Dug out culvert

The original poster's property does seem to be unusually devoid of understory vegetation in the first picture. You might try planting some creeping red fescue: http://plants.usda.gov/factsheet/pdf/fs_ferua3.pdf It's good for erosion control and apparently is shade tolerant.

 

[dave1949]

One technique to consider with multiple culverts in a sloping ditch that continues on to the next culvert, is to open up the continuing ditch at the top of culvert height. Then, if a culvert clogs, the overflowing water is still running in a ditch on its way to the next culvert and not across the driveway.

A clogged culvert in a dead end ditch is always going to be a problem.

 

[paulharvey]

You could simply.put some staked silt fence across the ditch about 5 ft up stream of your culverts. Costs about $0.50 per linear foot, can order at ASC, or pick up at Lowes, Home Depot. It will allow water through, but catch silt, sediment, leaves ect, keeping them from clogging your culverts.