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Gold Member
I spent 40 years building and repairing roads from dirt roads to superhighways and rip rapping sometimes by the mile and hundreds of tons. The bigger the rock, the better it will stay. On some jobs we individually placed huge rocks where you might get only 2 or 3 on a truck and weighing many tons. It all depends on the force of the water in flood conditions and how steep the slope is. The small stuff 4 inches and under are for dressing up that gently flowing brook in your backyard. Most of our jobs used man size that are up to 8 -12 inches. The step up from that are the large, up to 2-3 ft that must be placed with at least a backhoe. Most of the time we placed them on geo-textile to prevent erosion behind the rocks but if the slope is to steep the rocks can slide on the geo-textile. If you have vertical slopes you can use it against the bank and 2 or 3 feet into the stream to prevent washout and collapse behind the rocks. What we called shot rock, blasted from quarries is best because of the sharp edges and varying sizes locking together. Cobbles can be used and look nicer but can be moved easier under extreme conditions. Gabions are another option where space is limited and near vertical faces are necessary. They are large wire baskets in many sizes Seach gabions. Generally we used about 3 x 3 x 8 ft for road use, that are set in place and filled with smaller, generally 4" stone. I also saw but never built a used tire retaining wall that seemed to work well. You can search it online and find a lot of info.See attached photo, which unfortunately doesn't show the 10-12 vertical inch drop from driveway surface to water very well.
I have this drainage ditch along my gravel driveway feeding multiple culverts all in the hope it will keep my driveway from washing away.
Mostly it works. Most of the length of the driveway the bedrock is right at the base of the ditch. It probably is here too, the pebbles you see are the gravel it's constantly washing out of my driveway. So it's not something I can deepen with a tractor. I might be able to push it back a, but that probably wouldn't work unless I move the ditch back the whole length of the driveway, which isn't pragmatically feasible (trees, rocks, difficult spaces).
So need some way to line the driveway gravel so that the next rain won't just wash it out. I have no idea what to use. Cement / cinderblocks of some kind seems easiest, would that work? I'm looking for suggestions from people who have overcome this particular erosion problem.
I hate having to regularly throw more gravel (purchased by the truckload) at this problem.
Hope this helps with any size job you have.
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