I’ve got a fairly steep section of gravel driveway, which of course wants to wash out in any heavy rain. To prevent that, I’ve placed shallow trenches across it in 3 places that divert runoff to a ditch alongside. While these diverters work pretty well, they need regular reshaping and cleaning out. I’d thought to replace them with concrete or composite trench drains, but the $1200 price tag these carry has me reconsidering my options. I’d even thought to cast my own concrete trench drains, but the net savings is only a couple of hundred bucks. I’ve considered paving, but $1.50/sq. ft. x 10,000 sq. ft. = out of the question. Anybody have a clever alternative?
Thanks,
Andy Engel, The Accidental Moderator
Replies
What about burying some cement blocks even with the ground (hollows showing) and fill with gravel. Would hold the gravel from washing out and still look like a gravel driveway.
Is re-grading the driveway an option? Like knocking things down a bit so it isn't so steep?
If not, how about having it oiled? The road commissioner around here will oil driveways in his township while he's oiling the roads. And there are a couple of companies around who will do it. Don't know how the cost compares to paving.
I doubt, therefore I might be.
How about swales, but a lot more of them.
The idea is to divert and/or spread the water back out before it get concentrated enough to do any damage.
Bill, swales are exactly what I've got, just couldn't come up with the word. They do work, but they're a bump in the road, the UPS guy hates 'em and they fill in. I'd like to add one more, but that section of driveway is in a cut, so there's no convenenient place to drain the water. Perhaps that's where to put one trench drain which could run to daylight through a pipe, and leave the others as swales.
There's no chance of changing the grade. There's 20 ft. of drop over 200 ft. in that spot, nothing to cut, no width for turns.
Never thought about oiling it. That's just not done here for driveways, and I wouldn't know who to ask. Worth thinking about.
I'm interested in the concrete block idea. I had considered doing some concrete swales, but a swale of buried block would probably hold its shape pretty well and be easier to install.
Thanks for the ideas. Andy Engel, The Accidental Moderator
You didn't say how wide the driveway is, but if you crown it, you'll get chevrons rather than a stream down the wheel tracks. The steeper the pitch, the more you need to crown it, and the less likely you'll get rutting, but the more likely you'll slip off the side when iced.
Be seeing you...
Andy, there's your next idea for a feature article. Who do you know in your area that does competent site work and wouldn't mind demonstrating his techniques for a few of Taunton's bucks?
Your driveway is what - a quarter mile long at 10,000sf? The problem area is where? At the top? The middle? The bottom? You have the means - POST a picture.
Can you pitch the area above the washout prone area to divert most of the water coming from above into a drainage swale on either side before it reaches that critical area? And NOT have it run to the swales along the driveway section that drops thru the cut.
Thru the cut, do you have enough room beside the driveway to form a swale all the way (200ft)? Calculating material costs for a 40" wide swale, either in concrete block or poured cement 3" thick show a saving of roughly $200 when using concrete. (My local prices). You'll still need a gravel base either way. A concrete spillway should also be easier to clean out. You could have some fun free forming with a super stiff mixture.
You might consider contacting a cement culvert casting company or contractors who use such animals and see if you can obtain their cracked or broken pipes. They aren't usable for their intended purpose and could be had for a song or for the carting away. Rent, beg, borrow or steal a gas concrete saw, cut them in half length wise and you have instant preformed swale material. Then you need some grunt labor and machinery to finish the job.
Andy,
I'm kinda in the same boat...though my boat is a little more steady in the water.<g>
I've got a 900' long gravel drive, though not with a slope as severe as yours.
I had the same problems with runoff. I took a concrete-filled lally column and laid it it a shallow diagonal groove in the driveway, with the diagonal running across the drive the way I wanted the runoff to run.
I then dry-mixed some portland cement with some stonedust and essentially layed a layer over the lally column, tapering it over a few feet on each side to die into the surface of the driveway.
When I had a plate compactor handy, I compacted it, then misted it.
It's been a couple of years and it's held just fine.
This fall I'm (hopefully<g>) putting a garage/mudroom/half bath/sunroom on the house...and maybe a swimming pool. After the heavy construction vehicles are gone for good I'll consider "upgrading" from gravel to something else. I'm not a fan of asphalt, so I'm searching for something that will blend with the aesthetic with my current long, gravel driveway...and that won't bankrupt me!<g>
Andy:
Sounds like you have both a fairly steep road and have constructed "water bars" across it; a common method that loggers and trailmakers use. Realize alternatives are what you're seeking, but below site has correct sizing and spacing for what you have. http://www.siu.edu/~ilbmp/water_bars.html
Regarding crowning/grading of driveway profile, this would certainly help if not already done. You're slope is over 5% so vegetated stabilization of swales will require more than grass. Stabilizing these may reduce some of the water bars failure--if from sedimentation. If it's crushing/slumping from traffic than compaction is key. This is really too general to be of much use -for site specific assistance may I suggest you try contacting your state's equivalent of a department of environmental protection, section dealing with wetlands and waterways should be able to offer assistance. Basically you have an erosion/sedimentation control issue and they commonly deal with them. If they cannot assist, then the department/division that deals with forestry issues (again the logging road) may be the key. One note on hardening the channel, there is a trade off. The exit velocity is going to increase, so increased erosion at the outlet must be accounted for.
Regards,
Rework, a third generation italian ditch digger
Edited 8/24/2002 10:04:31 PM ET by Rework
Thanks for all the advice. The cut section is only about 10 ft. wide, maybe 2 ft. deep at the most. It's not very long. The drainage area, btw, is not huge. No other area drains onto the driveway and so far, grass has done a fine job of preventing erosion in the side swale. I might try a trench drain across the cut section, and Mongo's lally columns elswhere. Well, not Mongo's lally columns, 'cause I think they'd be hard to swipe, but ones like his. I think they'd be a more stable version of the swales that already cross the driveway.
Mongo, did you stake the lallys, or is it just concrete that holds them in place?
Andy Engel, The Accidental Moderator
Mongo, did you stake the lallys, or is it just concrete that holds them in place?
Originally I was going to pin them with lengths of #4 rebar, but that portion of the driveway was built on boulders and some blast rock...not to mention Connecticut's greatest natural resource...more buried rocks.
Needless to say, I couldn't drive the pins in so I just laid the lallys in a bed, tamped them, laid the stonedust/portland mix over the lallys, tamped then compacted it, then wet it down. With your slope being steeper you may need to pin it. Not sure, though.
Again, I didn't expect this temporary fix to last as long as it has.
"It's a good thing."
Hmmm...that reminds me...I need to go sell some shares of stock.
I've just been reading a book on roads, and there's a drawing in there of wooden trench drains, made from a pair of 3 x 6 sides spiked to a 3 x 10 bottom. The sides are only 3 1/2 in. apart, so you can drive right over them. I know of a sawmill up in Gaylordsville that specializes in locust. I'm going to give them a call, price the lumber and maybe try one out.
Andy Engel, The Accidental Moderator
Thanks for the link. That's just what I've done, and now I can do it right.Andy Engel, The Accidental Moderator