The setbacks and other restrictions specified by Subarticle 10 of the grading manual are minimum and may be increased by the city official or by the recommendation of a civil engineer, soil engineer or engineering geologist, if necessary for safety and stability or to prevent damage to structures or adjacent properties from sediment deposition, erosion, water runoff of the slopes or to provide access for slope and drainage structure maintenance. The minimum setback may be reduced only in special circumstances where stability is proven to the satisfaction of the city official by the soil engineer or engineering geologist and other factors are of primary importance. (Ord. 48, 1990)