They're more compatible with human activity and can be adapted to many uses. They can be used as a bench wall, as a base for a fence, or an accent element in the landscape. The higher the retained slope, the more structural stability is required. Many times, critical structural requirements necessitate engineering a design that considers the length of slope, site-soil characteristics, the wall material used, construction space available and height of the wall. Complex structural walls require the design expertise of an experienced engineer.
Many municipalities require that walls greater than four feet in height be designed by engineers.
You'll need to verify this requirement with your municipality prior to planning construction of any major wall. Permission is hereby given to duplicate this Plant talk Colorado TM script as is if credit is given to the sources.