I'm trying to figure out the minimum width for a berm that's going to be 20 ft tall. I heard something about a 3:1 ratio being recommended, but I'm not sure if that applies here. Plus, I've been in touch with the project engineer multiple times, and I don't want to overwhelm him with too many questions. Any advice would be helpful!
2 Answers
For a berm that's 20 feet tall, a common guideline is a slope of 3:1, which would mean the base should be about 120 feet wide. That’s 60 feet on each side from the top center. But keep in mind, the actual width might also need to factor in the width of any flat area on top where trees might be planted. Just double-check to make sure this aligns with what your town's designers think!
The 3:1 slope is generally a practical approach for mowable berms, which seems to be what you’re hearing. That said, a 20-foot height is significant, so you might want to clarify if adjustments are needed for stability or aesthetics. But to answer your question, yes, a width of 120 feet sounds about right!
Is the 3:1 ratio a standard, or could it be different for unique cases? I'd love to know!
Wow, 120 feet sounds massive! Are there other ratios they might consider for such a tall structure, like a 2:1?