There is an area 5 feet or sixty inches wide where I have removed an old, dying hedge and want to replace it with a berm. I can make the base of the berm nearly 5 feet or sixty inches deep, but how high can I make it, and how can I calculate how much soil I will need?

My first two "designs" were 12 inches/1 foot high, and then 16 inches or 1-1/3 feet high, but both seems too flat and blah on paper? Is there a formula or algorithm which would tell me:

1. For a berm with a 5 foot wide footprint, it can be ___ feet high at the center;

2. You need so many truckloads of soil, or fractions of a truckload, or cubic yards of soil for a berm five feet/60 inches deep and running 30-31 feet long and _____ recommended height?

For the one foot high and the 16 inch high berm, I calculated I would only need 2. 8 cubic yards for the 12 inch high berm, and only 3. 75-3. 87 cubic yards of soil for a berm 16 inches high.

These estimates seemed low, even given the short height 12-16 inches of the berm I want to build, and the berm seemed flat, as I wrote above, but how high can I build a berm -- is there a table or a chart for good seived and steamed/weed free black topsoil required for such a berm? Thanks very much.