What is a rockery?
“Rockery” or “rock wall” means one or more courses of large rocks stacked near vertical in front of an exposed soil face to protect the soil face from erosion and sloughing. A rockery or rock wall is not considered a retaining wall. Modular block walls are treated the same as rockeries.
Where can my rockery be located?
If the rockery is 30” high or less or stepped with no segment exceeding a height of 30” and there is at least 30” of separation between segments, it may be located nearly anywhere on your property, subject to limitations established by Land Use Code (LUC) 20.25H, Critical Areas Overlay District. If a rockery or any segment of a stepped rockery is over 30”, it is defined as a structure and must comply with the structure setback requirements in your land use district. For the purpose of applying this rule, the height is measured from the finished grade at the base of the base rock or the base of the rockery to the top of the rockery (see Table 1 and figure 1).
What other requirements should I be aware of?
Rockeries are subject to some additional requirements, summarized in Table 2. Unlike the rules establishing permitted rockery locations, for which height is measured from the finished grade to the top of the rockery, height for the requirements in Table 2 is measured from the actual bottom of the base rock (which is the bottom-most rock that is not entirely below grade) to the top of the rockery.
As Table 2 shows, rockeries up to 12’ in height may be used to protect a cut slope, but rockeries used to protect fill are limited to a maximum height of 48” unless fill slopes are otherwise stabilized. Rockery drains are required for any rockery over 4’, and a clearing & grading permit is required if the rockery exceeds 4’. Any rockery over 48” high must be designed by a licensed geotechnical engineer.