This is pertaining to county codes concerning fill on a slope to create a driveway the entire code states

"Fill areas shall be contoured to two feet (2') horizontal to one foot (1') vertical slopes or flatter as directed by a qualified engineer. If the disturbed areas fail to match existing grade within ten (10) vertical feet, a retaining wall shall be used...)

The county engineer interrupts it as "the way this is measured is to begin at the proposed grade on the driveway which in your case is 6998. Using a maximum 2:1 horizontal slope, the 10-foot vertical limit described in the code would grant you a horizontal 20-foot distance within which you must meet natural grade."

I interrupt it as your slope can be no greater than 2 to1 or it needs to be engineered and if you have more than 10' of fill, measured vertically, you need a retaining wall. Anything with less than 10' of fill measure vertically no retaining wall is required.