A subdivision, land use permit, or Building Permit application for a site or development that meets or exceeds the thresholds in § 83.08.020 (Applicability) shall require a Hillside Grading Review.
(a) Procedure. The review shall be conducted concurrently with any required discretionary review or in conjunction with an application for a Grading Permit for any project that meets or exceeds the thresholds listed in § 83.08.020 (Applicability).
(b) Submittal Requirements. An application for a Hillside Grading Review shall require the following documents, reports, maps and such others as determined appropriate by the Director. Exceptions to the filing requirements shall require a written justification supported by factual information submitted to the Director for consideration. Some of the required submittals listed below may be displayed on a single map or plan.
(1) Natural Features Map. A natural features map shall identify all existing slope banks, ridgelines, canyons, natural drainage courses, Federally recognized blue line streams, rock outcroppings, and existing vegetation. When a geology report is required, landslides and other existing geologic hazards shall also be depicted.
(2) Grading Plan. A conceptual grading plan shall include the following items:
(A) A legend with appropriate symbols shall include the following items: change in direction of drainage, elevation of regulated trees subject to the provisions of § 88.01.070(b) (Regulated Trees), estimated volumes proposed to be cut and/or filled, finished floor elevations, high point, low point, pad elevations, spot elevations, top of curb, and top of wall;
(B) A separate map, with proposed fill areas colored in green and cut areas colored in red, with areas where cut and/or fill exceed depths established in compliance with this Chapter. If custom foundations are proposed, this shall be noted on the map. Additionally, the area of cut and/or fill, calculated as a percentage of the total surface area of the site, shall be included on the plan; and
(C) Contours for existing and natural land conditions and proposed work. Existing contours shall be depicted with a dashed line with every fifth contour line darker; and proposed contours shall be depicted similarly with solid lines. Contours shall be shown at maximum five-foot intervals above 20 percent slope.
(D) For the efficient use of water, grading of the project site shall be designed so that soil erosion, runoff, and water waste are minimized. As part of the landscape document package, if a project’s grading exceeds 100 cubic yards, then the project developer shall submit the most recent rough and/or precise grading plan(s) that have been prepared and signed by a licensed professional.
(3) Drainage Map. A conceptual drainage and flood control facilities map describing planned drainage improvements.
(4) Slope Analysis Map. A slope analysis map for the purpose of determining the amount and location of land as it exists in its natural state falling into each slope category as specified in this Subdivision. This map shall be prepared and signed by a registered civil engineer or licensed land surveyor, and shall have a scale of not less than one inch to 100 feet and a contour interval of not more than two feet, provided that the contour interval may be five feet when the slope is more than 20 percent. A scale of not less than one inch to 200 feet may be used for developments greater than 100 acres in size. This map shall show the closest structures on all contiguous properties. It shall delineate slope bands in the range of zero to less than 15 percent, 15 to less than 30 percent, 30 percent to less than 40 percent, and 40 percent or greater. Also included shall be a tabulation of the land/area in each slope category specified in acres.
(5) Slope Profiles. A sufficient number of slope profiles shall be provided as required by the Director to clearly illustrate the extent of the proposed grading. The slope profiles shall:
(A) Be drawn at the same scale and indexed, or keyed, to the grading plan, and project site map.
(B) Show existing and proposed topography, structures, and infrastructure. Proposed topography, structures, and infrastructure shall be drawn with a solid, heavy line. Existing topography and features shall be drawn with a thin or dashed line.
(C) The slope profile shall extend far enough from the project site boundary to clearly show impact on adjacent property, within at least 150 feet.
(D) The profiles shall be drawn along those locations of the project site where:
(I) The greatest alteration of existing topography is proposed;
(II) The most intense or dense development is proposed;
(III) The site that is most visible from surrounding land uses; and
(IV) At all site boundaries illustrating maximum and minimum conditions.
(E) At least two of the slope profiles shall be roughly parallel to each other and roughly perpendicular to existing contour lines. At least one other slope profile shall be roughly at a 45-degree angle to the other slope profiles and existing contour lines.
(6) Slope Design. Slopes with a 5:1 ratio or greater; cut slopes with a five-foot vertical height or greater; and fill slopes with a three-foot vertical height or greater shall be protected against damage from erosion. In addition to the stabilizing mulch, drought-tolerant plant material and hardscape features shall be utilized on slopes to promote water retention and erosion control. Decorative boulders and other suitable hardscape materials may be utilized on slopes, but the dominant visual character of the slope shall be made up of drought-tolerant plant materials. Shrubs shall be used in combination with lateral spreading groundcovers; trees shall be used where slope exceeds 15 feet vertical height. Trees and shrubs shall be planted in visually attractive groupings that provide a more natural appearance.
(7) Dust Control. If grading takes place, a dust control plan shall be submitted for review. All grading and dust control measures shall be conducted in compliance with the provisions of Chapter 88.02 (Soil and Water Conservation).
(Ord. 4011, passed - -2007; Am. Ord. 4400, passed - -2021)