Division 2 — HILLSIDE DEVELOPMENT OVERLAY ZONE

Sec. 90-935. - Purposes.

The purpose of the hillside development overlay zone is to:

(1)

Establish regulations and standards for the identification and protection of hillsides, ridgelines, canyons, and other natural land forms such as rock outcroppings in recognition that such features are community assets that help define the city as a desirable place to live, work, and recreate; and

(2)

Ensure that roadways, driveways, and other access points in the hillside overlay zone provide adequate emergency access;

(3)

Comply with the goals and policies of the general plan regarding the protection and preservation of hillside areas as an important aesthetic and community resource; and

(4)

Implement the HR (hillside residential) land use designation of the general plan.

(Ord. No. 1949, § 10(Exh. A, 10), 9-25-18)

The hillside development overlay (H) zone is established in accordance with the standards of this article and as shown on the official zoning map pursuant to section 90-6.

(Ord. No. 1949, § 10(Exh. A, 10), 9-25-18)

All uses permitted in the underlying zone over which the hillside development overlay zone is placed shall be permitted in the overlay zone. The regulations of the hillside development overlay zone shall apply in addition to the regulations of the underlying zone. In the event of a discrepancy between the regulations of the underlying zone and the overlay zone, the overlay zone shall take precedence.

(Ord. No. 1949, § 10(Exh. A, 10), 9-25-18)

The maximum density on any parcel to which this section applies shall not exceed the units per acre for each of the average percent slope ranges indicated below:

(Ord. No. 1949, § 10(Exh. A, 10), 9-25-18)

Within a project having the hillside development overlay zone, a density transfer may be granted when permitted development is transferred from one slope category to a lower slope category. In consideration for such a transfer of development, the allowable density of the lower slope category may be increased by 50 percent. For example, if density/development is transferred from the 25 percent and above slope category (from the above table) to the next lower category (15 percent to 25 percent), the allowable density of the lower category, 1.0 dwelling units per acre, may be increased to 1.5 units per acre. In no situation shall the total number of units permitted for any project exceed the number of units that would have been permitted without any transfer of density. Areas from which density is transferred shall be restricted from future development in an appropriate manner.

(Ord. No. 1949, § 10(Exh. A, 10), 9-25-18)

The following minimum performance standards are required for any development in the hillside development overlay zone.

(1)

Soils/grading.

a.

Grading of any site shall conform to the following grading standards, based upon the percent of natural slope. The city engineer shall review the proposed grading with respect to the following:

1.

Zero—ten percent. Redistribution of earth over large areas may be permitted. Significant environmental features may be required to be preserved.

2.

Ten—15 percent. Some grading may occur, but landforms must retain their natural character. Padded building sites may be allowed, but custom foundations, split level designs, stacking and clustering is expected to mitigate the need for large padded building areas.

3.

Fifteen—25 percent. Limited grading may occur, however, major topographical features shall retain their natural landforms. Special hillside architectural and design techniques are expected in order to conform to the natural land form, by using techniques such as split level foundations of greater than 18 inches, stem walls, stacking and clustering.

4.

Greater than 25 percent. Development and limited grading can only occur in this category if it can be clearly demonstrated that safety, environmental, and aesthetic impacts will be avoided. Use of larger lots, variable setbacks and variable building structural techniques such as stepped or pole foundations are expected. Structures shall blend with the natural environment through their shapes, materials and colors. Impact of traffic and roadways is to be minimized by following natural contours or using grade separations.

b.

Grading shall be designed to:

1.

Conserve natural topographic features and appearances by means of land sculpturing to blend graded slopes and benches with natural topography.

2.

Retain major natural topographic features such as canyons and prominent landmarks.

3.

Graded slopes over 25 feet in height and over 100 feet in length shall be contour graded. A variety of slope ratios (i.e., 2:1, 3:1, 3.5:1, 5:1, etc.) shall be used to blend graded slopes into the adjoining natural terrain.

4.

Terracing shall be designed with small incremental steps, avoiding wide step terracing and large areas of flat pads.

c.

All graded areas shall be protected from wind and water erosion through acceptable slope stabilization methods such as planting, walls, or netting. Interim erosion control plans shall be required, certified by the project engineer, and reviewed and approved by the city engineer.

d.

Slopes created by grading of the site shall not exceed 50 percent or 2:1, without a soils report and stabilization study indicating a greater permissible slope; or shall not exceed 30 feet in height between terraces or benches.

(2)

Water/drainage.

a.

On-site catch basins or siltation basins, as well as energy absorbing devices, may be required as a means to prevent erosion as well as to provide for ground water recharge.

b.

Natural drainage courses should be protected from grading activity.

c.

Where brow ditches are required, naturalize with plant materials and native rocks.

d.

All benchdrains (interceptors) and downdrains shall be constructed to match the natural contours of the lands.

e.

Downdrains on manufactured slopes shall be staggered between terrace drains to be less obtrusive.

f.

Maximum coverage of a parcel by impervious surfaces shall not exceed 40 percent of the gross land area, and such maximum may be reduced by the planning director in areas where the slope exceeds 15 percent.

(3)

Animal and plant life.

a.

Areas of a site which are identified in the environmental study as having biological significance shall be preserved.

b.

Natural vegetation shall be maintained wherever possible. If removal is required, re-establishment of a compatible plant material will be required at a ratio of at least 2:1.

c.

All exposed slopes and graded areas shall be landscaped with groundcover, shrubs, and trees.

d.

Existing mature trees shall be incorporated into the project where feasible.

e.

Water and energy conservation techniques shall be utilized, such as special irrigation techniques (e.g., drip irrigation), drought tolerant plant species, alluvial rockscape, etc.

f.

Wherever possible, fire resistant native vegetation shall be preserved and planted.

g.

Introduction of landscaping within the hillside areas should make maximum use of texture, color, and be capable of blending in with the natural landscape, and help to soften the effects of buildings, walls, pavement, and grading. Irregular tree and shrub spacing shall be used to achieve a natural appearance on graded slopes.

h.

With the exception of landscaping for street parkways, trees and shrubs shall be placed in swale areas to more closely reflect natural conditions.

i.

Screening along roadways should make maximum use of berming and landscaping but shall not interfere with sight distance.

j.

Landscaping and berming shall be used to screen views of all benchdrains and downdrains.

k.

Planting in riparian areas shall be kept as close as possible to their natural state. Ornamental plants and the introduction of non-native species should be avoided.

l.

The keeping of pigs, goats, sheep, horses, and other similar animals shall be limited to two per acre in areas that are determined to be of biological sensitivity, in addition to the requirements of section 90-77.

(Ord. No. 1949, § 10(Exh. A, 10), 9-25-18)

Structural design and construction for wildland interface areas is found under section 14-420.

(1)

Dwelling units and structures shall be compatible with the natural surroundings of the area and shall not dominate the natural environment.

(2)

Exterior finishes of dwelling units and structures should blend in with natural surroundings by using earth tone colors and avoiding reflective materials or finishes and be of fire resistive materials.

(3)

Site design should utilize varying setbacks, building heights, innovative building techniques, and building and wall forms which serve to blend buildings into the terrain.

(4)

Dwelling units and structures shall be sited in a manner that will:

a.

Retain outward views from each unit;

b.

Preserve or enhance vistas, particularly those seen from public places;

c.

Preserve visually significant rock outcroppings, natural hydrology, native plant materials, and areas of visual or historical significance.

(5)

The highest point of any structure shall not be located above the ridgeline.

a.

Use the natural ridgeline as a backdrop for structures;

b.

Use landscape plant materials as a backdrop; and

c.

Use the structure to maximize concealment of cut slopes.

(6)

Accessory buildings. Detached accessory buildings which do not have solid exterior walls (carports, patio covers, etc.) shall have supporting members of heavy timber or be constructed with materials approved for one-hour construction.

(7)

Decks and patios. Decks, balconies, roof overhangs, attached patio covers, and similar architectural features shall be protected on the underside with materials approved for one-hour resistive construction

per the requirements found in section 14-420.

(8)

Retaining wall/fences.

a.

Retaining walls shall be used in the following manner:

1.

Upslope not exceeding six feet in height.

2.

Downslope not exceeding 42 inches in height may be used.

3.

Lots sloping with the street of access or other conditions. One retaining wall on each side of the lot may be used not exceeding 42 inches in height.

4.

Retaining walls adjacent to driveway walls being an integral part of the structure may exceed six feet in height if necessary.

5.

All retaining walls, visible from the public right-of-way shall be constructed of decorative block materials and be of earth-tone colors to minimize visibility.

b.

Exposed retaining walls facing roadways shall be not greater than five feet in height.

c.

Where retaining walls face roadways, they shall be faced with aesthetically pleasing materials (e.g., split face block, etc.).

d.

Precision block walls, wood and chainlink fencing are specifically prohibited for use in hillside developments in relation to perimeter fencing or retaining walls.

e.

Interior fencing along property lines shall be constructed of decorative masonry block, wrought iron with pilasters that are of similar architecture to the buildings, or other non-combustible materials approved by

the planning director.

f.

Coated chain link fencing may be allowed to enclose tennis courts but must of a material and color that is approved by the planning director.

(9)

Circulation. The intent of this section is to reduce the visual impacts created by hillside roadways, yet provide safe circulation. Roadways shall conform to the standards specified for development for wildland interface areas in section 14-418. Roadways should conform to the natural hillside landform and not greatly alter the physical and visual character of a hillside by creating large notches in ridgelines or by defining wide straight alignments. The following circulation standards and policies shall be implemented for all new hillside projects:

a.

Single-loaded streets are recommended on steep terrain where it can be demonstrated that the overall grading for the project can be reduced.

b.

All hillside development shall have two points of access to provide a safe ingress and egress for hillside developments. This is not applicable to cul-de-sacs that are less than 350 feet in length.

c.

Street grades shall not have slopes greater than those allowed in subsection 14-418(6). Generally eight percent maximum is allowed in areas of extreme fire hazard.

d.

Street rights-of-way widths can, for hillside development, be reduced from the city's general standards when the city engineer and fire chief determine that their implementation will not be hazardous to the public safety.

e.

Roadway design, wherever practical, shall be parallel or diagonal to the existing hillside contours. Roads shall be curvilinear fashion and blend in with the existing topographical slopes. Circulation plans for hillside development shall be designed to minimize both their visual and grading impacts.

f.

Private driveways may provide access to a public street of up to two units per driveway. Such driveways shall have a minimum paved width of 25 feet and a maximum slope of 14 percent. Any drives exceeding 12 percent slope may not exceed 600 feet in length.

(10)

Fuel modification. A permanent fuel modification area shall be required for the perimeter of development projects that are located in the hillside zones. Specific requirements are contained in section 14-421 (landscaping and perimeter). The recommended width of the fuel modification areas shall be determined by the fire chief, but in no case shall it be less than 100 feet in width as measured from the development perimeter. The width of the fuel modification area shall be determined by the following:

a.

The natural ungraded slope of the lands with the project and in areas adjacent to the project.

b.

Fuel loading.

c.

Access to the project and access directly to the fuel modification area, and

d.

The on-site availability of water that can be used for firefighting purposes. The fuel modification areas shall also incorporate soil erosion and sediment control measures to alleviate permanent scarring and accelerated erosion.

(11)

Water supply. All development shall be provided with adequate water supply according to the requirements set forth in section 14-419 (water supplies).

(Ord. No. 1949, § 10(Exh. A, 10), 9-25-18)

Applications for development of property within the hillside development overlay zone shall be submitted for site development plan review pursuant to section 90-48 of the Code. In addition to the items specified in

section 90-48, the applicant shall submit the following:

(1)

A topographic map of the project site and land and structures within 100 feet of the project boundaries. The map shall be drawn to a scale of not less than one inch equals to 100 feet with a maximum contour interval of ten feet. The maximum contour interval shall be five feet where terrain has a slope of less than 25 percent.

(2)

A site plan of the proposed project showing property lines, recorded or proposed easements and public rights-of-way. Existing structures within 100 feet of the site shall also be shown on the site plan.

(3)

A preliminary grading plan for the project, drawn to the same scale as required above. Existing and final slope shall be shown in the following categories by average slope (percent): 0 to 10, 10+ to 15, 15+ to 25, 25+ and above.

(4)

A soils engineering report including data regarding the nature, distribution and strengths of existing soils, conclusions, and recommendations for grading procedures, design criteria for and identified corrective measures, and opinions and recommendations regarding existing conditions and proposed grading. The investigation and report shall be performed by a professional soils engineer experienced in the practice of soil mechanics and registered with the state.

(5)

A hydrology report shall be provided including areas of possible inundation, downstream effects, natural drainage courses, conclusions, and recommendations regarding the effect of hydraulic conditions on the proposed development, opinions and recommendations regarding the adequacy of facilities proposed for the site, and design criteria to mitigate identified hydraulic hazards. This report shall account for runoff and debris from tributary areas and shall provide consideration for each lot or dwelling unit site in the development. Runoff and debris volumes shall be computed using county flood control district criteria. This investigation and report shall be prepared by a registered civil engineer experienced in hydrology and hydraulic investigation.

(6)

A preliminary landscaping plan showing disposition of existing trees, and the type and extent of proposed vegetation. The method of open space maintenance shall also be identified.

(7)

A geotechnical study shall be provided including the surface and subsurface geology of the site, degree of seismic hazard, conclusions and recommendations regarding the effect of geologic conditions on the proposed development, opinions and recommended design criteria to mitigate any identified geologic

hazards. This investigation and report shall be performed by a professional geologist experienced in the practice of engineering geology and registered with the state.

(8)

A landform study shall be provided with a site inventory and map identifying existing landforms shall be submitted for the project including the following:

a.

All U.S.G.S. blue-line streams, springs, perennial and intermittent streams with drainage areas that are 50 acres or greater at or above the project site.

b.

Rock outcroppings that are greater than 300 square feet in surface area.

c.

Classification of "grading zones" that are identified in this article.

d.

Identification of primary and secondary ridgelines.

e.

Identification of the most prominent topographical features of the project site. This identification is relative to each project site and should include any ridges, peaks, knolls and any other similar types of features.

(9)

A biological survey shall be submitted. This survey shall inventory both flora and fauna found at the site. All endangered, threatened or rare species shall be identified. Survey shall be conducted by a qualified biologist selected from then approved listing maintained by the planning department.

(10)

Other information or applications materials as may be deemed necessary or desirable by the planning director such as archaeology, paleontology, and visual analysis studies.

(Ord. No. 1949, § 10(Exh. A, 10), 9-25-18)

Secs. 90-945—90-950. - Reserved.