The purpose of this chapter is to provide regulations for the development of areas in the city that, because of their topography, require special consideration to ensure that they are developed in a way that substantially maintains their natural character and environmental and aesthetic values to implement the general plan, and to provide for the safety, health, and welfare of the public by:
A. Providing guidelines and standards for development in visually sensitive hillside areas to minimize the ad-verse impacts of grading and to promote the goals and objectives of the general plan;
B. Maintaining an environmental equilibrium consistent with existing vegetation, wildlife, soils, geology, slopes, and drainage patterns, and to preserve natural topography and scenic character, including canyons, creeks, knolls, rock outcrops, and ridgelines whenever feasible;
C. Encouraging development proposals that feature water conservation and aquifer recharge techniques;
D. Encouraging development proposals that are sensitive to fire, flood, slide, erosion, pollution, or other safety hazards;
E. Encouraging sensitive development through flexible design and innovative arrangement of building sites by utilizing variable lot sizes, clustering, and setback variations;
F. Utilizing nontraditional design standards for streets and hillside grading where development quality and public safety are not affected;
G. Encouraging developments that incorporate desirable existing features of land (e.g., natural vegetation, viewsheds, topographic features);
H. Protecting significant natural areas for ecologic purposes, educational, and other scientific study purposes; 1. Encouraging the use of drought-tolerant plant material to protect slopes from soil erosion and slippage, preserve natural watershed, minimize fire hazard, and minimize the scarring and deformation of the natural landscape;
J. Limiting the impact of cut slopes on adjacent developed and undeveloped properties; and
K. Providing for appropriate intensity of development (e.g., density, massing, etc.) in hillside areas through a variety of design techniques to ensure that development intensity decreases as slopes become steeper (e.g., lot sizes appropriate for steeper topography and separation of structures sufficient to preserve the viewshed).
(Ord. 182 § 2 (part), 1997)
A. Hillside Area. The standards contained in this chapter apply to uses and structures within areas that have a slope of twenty (20) percent or greater and/or are designated on the significant features map on file with the department.
B. Basis for Slope Determinations. For the purpose of this chapter, slope shall be computed on the natural slope of the land before grading is commenced, as determined from a topographic map having a scale of not less than one inch equals one hundred (100) feet and a contour interval of not more than five feet.
C. Development Plan Permit Required. Hillside developments shall be subject to the approval of a development plan permit in compliance with Chapter 16.56.
D. The development standards, guidelines and provisions of this chapter shall be applied to those portions of land with a predominance of significant natural slopes exceeding twenty-five (25) percent and areas that are integrally contiguous or slopes determined as significant by the director. The provisions of this chapter shall apply to projects relating to subdivisions, permits, uses, structures, specific plans, master development plans, and associated site plans for development review except as specifically exempted by Section 16.02.020.
(Ord. 293 § I (part), 2004; Ord. 182 § 2 (part), 1997)
For the purposes of this chapter the following definitions shall apply:
Clearing. The removal of vegetation (grass, brush, trees, and similar plant types) by mechanical means (also known as brushing and/or grubbing).
Cluster Development. A concept where structures are grouped on certain portions of a site, frequently of different shapes and sizes, surrounded by large expanses of open space.
Contour. A line drawn on a plan that connects points of equal elevation.
Cut. The mechanical removal of earth material.
Daylight Line. The line between the finished grade and natural terrain drawn by connecting points where pro-posed contours meet existing contours.
Elevation. Height or distance above mean sea level.
Erosion. The process by which the soil and rock components of the earth's crust are worn away and removed from one place to another by natural forces (e.g., as wind and water).
Fill. A deposit of earth material placed by artificial means.
Finished Grade. The final elevation of the ground surface after development, that is in conformance with the approved plan.
Grading. To bring an existing surface to a designed form by excavating, filling, or landforming operations in excess of fifty (50) cubic yards.
Contour Grading. A grading concept designed to result in earth forms that resemble natural terrain characteristics. Horizontal and vertical curve variations are often used for slope banks.
Conventional Grading. A grading concept that results in simple, straight forward, cut and fill lines and even planed slopes. This is the most basic type of grading often resulting in an "engineered or man-made" appearance attributable to a lack of curvilinear or natural-appearing shapes.
Landform Grading. A grading method that replicates the irregular shapes of natural slopes. Landform graded slopes are characterized by continuous series of concave and convex forms interspersed with mounds that blend into profiles, nonlinearity in plan view, varying slope gradients, and significant transition zones, between man-made and natural slopes.
Hillside. Land with an average rise or fall of twenty-five (25) percent or greater or a vertical rise of thirty (30) feet or more.
Mass Grading. The movement of large quantities of earth over large areas. Disruption of the majority of the on-site surface terrain resulting in a successive pad/terrace configuration. Modification or elimination of natural landforms may result.
Minimal Grading. A grading concept designed to minimize excavation and filling. Allows the movement of earth for projects (e.g., as individual building foundations, driveways, local roads, and utility excavation). The concept is associated with roads conforming closely to natural contours and with structures being built on natural terrain.
Pad. A level area created by grading to accommodate development.
Prominent Ridge. A ridge or hill location that is visible from Interstate 15, Interstate 215, or from an arterial or secondary street, that forms part of the skyline or is seen as a distinct edge against a backdrop of land. Ridge. An extended, narrow, conspicuous elevation of land generally between valleys.
Slope. An inclined ground surface, the inclination of which is expressed as a ratio of the vertical distance (rise), or change in elevation, to the horizontal distance (run). The percent of a given slope is determined by dividing the rise by the run, multiplied by one hundred (100).
Slope, Average. The method of determining average natural slope of land using the following equation:
I x L x .0023 where
A
A
I = Contour interval in feet.
L = Combined length in feet of contour lines measured on the project site.
.0023 = A constant that converts square feet into acres and expresses slope in percent.
A = Project site area in acres.
Slope, Man-made. A manufactured slope consisting wholly or partially of either cut or filled material. Slope, Natural. A slope that is not man-made.
Slope, Significant Natural. A slope that is not man-made that exceeds twenty-five (25) percent and a vertical rise of thirty (30) feet or more.
Slope Ratio. The relationship of a slope's horizontal length to vertical height, with the height specified as one (e.g. 2:1).
Slope Transition. The area where a slope plane changes to meet the natural terrain or a level graded area either vertically or horizontally.
(Ord. 182 § 2 (part), 1997)
Applications for development within the hillside overlay zoning district shall comply with the submittal requirements of this chapter. When a development project is a specific plan or master development plan, the submittal requirements shall be incorporated in the appropriate sections of the corresponding documents. If adequate detailed studies are provided with the specific plan and/or master development plan, subsequent implementing development applications shall be reviewed for substantial conformance with these plans.
Application filing requirements are as follows:
A. A Natural Features Map. This map shall identify slope banks, ridgelines, canyons, natural drainage courses, U.S.G.S. blueline streams, rock outcroppings, sensitive biotic habitat, cultural resources, and other natural features determined to be worthy of consideration for preservation.
B. A Conceptual Grading Plan. A conceptual grading plan shall be submitted at a minimum scale of one inch to two hundred (200) feet (this scale may be adjusted with the approval of the department). The plan shall include the following items:
1. A legend with appropriate symbols indicating high point, low point, spot elevations, pad and finished floor elevations, top of wall, top of curb, change in direction of drainage, and planned drainage improvements;
2. A separate map with proposed fill areas and cut areas, depths of these areas clearly shown in five-foot topographic lines. Quantities of each cut and fill area shall be clearly marked and calculated as a percentage of the total site area. The fill and cut areas shall be either colored green and red, respectively, cross-hatched, or screened to delineate the separate areas;
3. Contours for existing and proposed land conditions. Existing contours shall be depicted with a dashed line with every fifth contour darker, and proposed contours shall be depicted as above except with a solid line. Contours shall be shown at minimum intervals of five feet of change in elevation, with two-foot contours in the flatter areas (if using Riverside County flood control district topographic maps, a four-foot interval may be used); and
4. Additional information as required to assist department review of the project.
C. Drainage Map. A conceptual drainage and flood control facilities map describing planned drainage improvements. The map shall utilize city standards or an acceptable alternate as determined by the city engineer.
D. 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 and for calculating average slope categories. A base topographical map of the site shall be prepared and shall have a scale of not less than one inch to two hundred (200) feet. The base topographical map shall include adjoining properties within one hundred (100) feet of the site boundaries to portray the site's context. Slope bands in contrasting colors shall be delineated in the range of zero to twenty-five (0—25) percent, twenty-six to fifty (26—50) percent, and fifty (50) percent or greater. A tabulation of the land area by slope percentage shall also be provided.
The exact method for computing the percent slope and area of each slope category shall be sufficiently de-scribed and presented so that a review can be readily made. A heavy solid line indicating the twenty-five (25) percent grade differential shall be clearly marked on the plan. An eight and one-half by eleven (8 1/2 x 11) inch legible acetate reduction of the slope analysis with appropriate legend shall also be provided.
E. Slope Profile Drawings. A sufficient number of slope profiles shall be provided to clearly illustrate the ex-tent of the proposed grading. A minimum of four cross-section slope profiles shall be included with the slope analysis. Additional profiles may be required by the city engineer. The slope profiles shall:
1. Be drawn at the same scale and indexed, or keyed, to the slope analysis map, grading plan, and project site map. Both vertical and horizontal scales shall be indicated;
2. Show existing and proposed topography, structures, and infrastructure. Proposed topography, structures, and infrastructures shall be drawn with a thin, solid line. Existing topography and features shall be drawn with a dashed line;
3. Extend at least one hundred (100) feet outside the project site boundary to clearly show the impact on adjacent property.
4. Be drawn along those portions of the site where:
a. The greatest alteration of existing topography is proposed;
b. The most intensive or massive development is proposed;
c. The site is most visible from surrounding land uses; and
d. Where grading will impact natural drainage conditions.
5. 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 ninety (90) degree angle to the other slope profiles and existing contour lines.
F. Indicate Source of Data. Both the slope analysis and slope profiles shall indicate the datum, source, and scale of topographic data used in the slope analysis and slope profiles.
G. Geotechnical Report. A geotechnical and soils report, prepared by a registered geotechnical engineer to city standards and in sufficient detail to substantiate and support the design concepts presented in the application as submitted. Additional environmental studies and investigations, including, but not limited to, hydrologic, seismic, access/circulation, and biota research may also be required to help in the determination of the buildable area of a site.
H. Design Guidelines. Design guidelines shall be provided for projects that are to be reviewed by the commission. Otherwise, illustrative building elevations showing all sides shall be provided.
I. No Grading Proposed. In the event that no grading is proposed, (e.g., custom lot subdivision) a statement to that effect shall be filed with a plan that shows possible future house plotting, pad grading, driveway de-sign, and septic system location for each parcel proposed. The plan shall be prepared on a topographic map drawn at a scale of one inch to two hundred (200) feet.
J. Additional Information. The following items may be required if determined necessary by the director to aid in the analysis of the proposed project:
1. A line of sight or view analysis;
2. Photographic and/or computer generated graphic renderings;
3. A topographic model and/or large scale detailed partial model; or
4. Other illustrative techniques determined necessary to aid in review of the project.
K. Exceptions to the filing requirements shall be determined by the director.
(Ord. 293 § 1 (part), 2004; Ord. 182 § 2 (part), 1997)
Loading...