(a) General. Unless otherwise recommended in the approved soils engineering report, fills shall conform to the provisions of this section. In the absence of an approved soils engineering report, these provisions may be waived for minor fills not intended to support structures.
(b) Fill Location. Fill slopes shall not be constructed on natural slopes steeper than two to one.
(c) Preparation of Ground. The ground surface shall be prepared to receive fill by removing vegetation, noncomplying fill, topsoil, and other unsuitable materials, scarifying to provide a bond with the new fill, and, where slopes are steeper than five to one and the height is greater than five feet, by benching into sound bedrock or other competent material as determined by the soils engineer. The bench under the toe of a fill on a slope steeper than five to one shall be at least ten feet wide. The area beyond the toe of fill shall be sloped for sheet overflow or a paved drain shall be provided. Where fill is to be placed over a cut, the bench under the toe of fill shall be at least ten feet wide but the cut must be made before placing fill and approved by the soils engineer and engineering geologist as suitable foundation for fill. Unsuitable soil is soil which, in the opinion of the building official or the civil engineer or the soils engineer or the geologist, is not competent to support other soil or fill, to support structures or to satisfactorily perform the other functions for which the soil is intended.
(d) Fill Material. Detrimental amounts of organic material shall not be permitted in fills. Except as permitted by the building official or city engineer, no rock or similar irreducible material with a maximum dimension greater than 12 inches shall be buried or placed in fills.
EXCEPTION: The building official or city engineer may permit placement of larger rock when all the following conditions are met:
(1) The soils engineer properly devises a method of rock placement;
(2) The soils engineer continuously inspects placement of the rock and approves the fill stability;
(3) Potential rock disposal areas are delineated on the grading plan prior to issuance of the grading permit;
(4) Rock sizes greater than twelve inches in maximum dimension will be placed ten feet or more below grade, measured vertically; and
(5) Rocks will be placed so as to assure filling of all voids with fines.
(e) Compaction. All fills shall be compacted to a minimum of ninety percent of maximum density.
(f) Slope. The slope of fill surfaces shall be no steeper than is safe for the intended use. Fill slopes shall be no steeper than two horizontal to one vertical.
(g) Drainage and Terracing. Drainage and terracing shall be provided and the area above fill slopes and the surfaces of terraces shall be graded and paved as required by Section 16.28.320.
(Ord. 4564 § 1 (part), 1999)