I'm trying to figure out if the size of river rocks matters when I'm trying to divert water. My friend thinks larger rocks are the way to go, but I believe that the ground conditions under the rocks are actually more crucial. I'm looking to create a swale, and I think that whether I use rocks that are 2-4 inches or 8-10 inches doesn't make a difference—the water should still flow through the swale. So, do larger rocks really create better drainage?
2 Answers
There are a few things to keep in mind here. First, if you're on a hill, smaller rocks can get moved around more easily. That's why in places like driveways on slopes, we tend to use bigger rocks to prevent gravel from washing down. Second, think about porosity—gravel allows more water to flow through it faster than a flat rock might stop it. It could be beneficial to use larger stones to line the areas where water will flow to keep things in place.
Generally speaking, bigger rocks offer more resistance against movement and erosion. If your swale has a slope that could cause a fast flow of water, opting for larger rocks is likely a better choice to maintain stability and effectiveness.
Yeah, it does have a slope. Thanks for the advice!
Gotcha, it's on a hill and next to a driveway, huh? Sounds like bigger rocks could help keep everything in check.