9.4.3 Fills and Embankments

Unless otherwise recommended in an approved geotechnical report, all fills and embankments shall comply with the following minimum requirements.

1. Preparation of Ground – Fill slopes shall not be constructed on natural slopes steeper than 2H:1V. The ground surface shall be prepared to receive fill by removing vegetation, noncomplying fill, topsoil and other unsuitable materials, scarifying the surface to provide a bond with the new fill and, where natural slopes are steeper than 3H:1V and the height is greater than 5 feet, by benching into sound bedrock, glacial till or other competent material as determined by a geotechnical engineer. The bench under the toe of fill on a slope steeper than 3H:1V shall be at least 10 feet wide. The area beyond the toe of fill shall be sloped for sheet overflow or a paved drain shall be provided. When fill steeper than 3H:1V and higher than 5 feet is to be placed over an excavation, the geotechnical engineer shall certify that the foundation is suitable for the fill.

2. Fill Material – Detrimental amounts of organic material shall not be permitted in fills. Except as permitted by the director, no rock or similar irreducible material with a maximum dimension greater than 12 inches shall be buried or placed in fills.

   Exception: The director may permit placement of larger rock or similar irreducible material (i.e., concrete, etc.) when a geotechnical engineer properly devises a method of placement and continuously inspects its placement and approves the fill stability. The following conditions shall also apply:

   1. Prior to issuance of a SDAP for grading, potential rock disposal areas shall be delineated on the grading plan.

   2. Rock sizes greater than 12 inches in maximum dimension shall be 10 feet or more below grade, measured vertically.

   3. Rocks shall be placed so as to ensure filling of all voids with well-graded soil.

3. Compaction – All fills and embankments shall be compacted to a minimum of 90% ofmaximum dry density, as determined by the tests described in the WSDOT/APWA Standard Specifications for Road, Bridge, and Municipal Construction. Embankments constructed as berms for the holding back of water shall be compacted to a minimum of 95% of maximum dry density. Soil density shall be determined utilizing the Modified Proctor method. Fills on sites of proposed structures shall be compacted as directed by the Kitsap County Building Official in accordance with the International Building Code (I.B.C). Where the director requires testing of the compaction of soils outside public right of way, compaction shall be tested by an independent soils testing lab at the owner's expense.

4. Slope – The slope of fill surfaces shall be no steeper than is safe for the intended use and shall be no steeper than 2H:1V.

5. Structures – Fills that are intended to support structures shall be constructed in conformance with the requirements of the latest edition of the I.B.C., and an assignment of allowable soil-bearing pressures will be under the jurisdiction of the Kitsap County Building Official in accordance with the I.B.C. When fill is proposed over an area that the County deems to be a potential building site, and the applicant does not state an intent to construct buildings on the fill area, Kitsap County may at its own discretion require that a notice be recorded as a public record containing provisions that will include the nature and extent of the grading that has occurred on the parcel.