Chapter 17.36
(HPD) HILLSIDE PLANNED DEVELOPMENT OVERLAY DISTRICT
Sections:
17.36.030 Hillside development project defined.
17.36.040 Materials to be submitted.
17.36.050 Additional materials which may be required on hillside development projects.
17.36.090 Setback requirements.
17.36.100 Building height on slope lots.
17.36.110 Accessory building on sloping lots.
17.36.010 Purpose.
It is the purpose of the Hillside Overlay District to provide for the reasonable use of hillside areas while achieving the following:
A. Minimizing the danger imposed on the public health, safety, and welfare by soil erosion, slippage, flooding and fire.
B. Minimizing the disturbance of the natural terrain and thereby conserving the aesthetic qualities afforded by these areas.
Accordingly, additional regulations must be applied to hillside areas to prevent unacceptable increases in hazard and environmental damage, adverse changes in community character, and to promote orderly development of hillside areas consistent with existing community character and enhance public safety and general welfare and the conservation and management of significant environmental resources. [Ord. 772 § 17.10.010, 1986. Code 1987 § 17.10.010].
17.36.020 Permitted uses.
The uses permitted in this zone shall be those allowed in the underlying zones established pursuant to this title, and the requirements of this chapter shall be in addition to and supplemental to the provisions of the underlying zone. If there is a conflict between the requirements of this chapter and any other provisions of the code, the provisions of this chapter shall prevail. [Ord. 772 § 17.10.020, 1986. Code 1987 § 17.10.020].
17.36.030 Hillside development project defined.
Applications for a hillside development permit shall be filed within the planning department if the project is within the designated Hillside Development District area adopted by resolution of the City Council.
In any base district where the district symbol is followed by, as a part of such symbol, parenthetically enclosed letters “HPD,” thus “(HPD),” the additional requirement, limitations and standards contained in this section shall apply. The district symbol shall constitute the “base district” and the “HPD” suffix shall constitute the “overlay district.” In the event of conflicting provisions of such a combined district, the requirements of the HPD district shall take precedence over the requirements of the base district. Uses permitted by the HPD district must in each instance be in compliance with those uses permitted by the applicable base district regulations and any other overlay district regulations. [Ord. 772 § 17.10.030, 1986. Code 1987 § 17.10.030].
17.36.040 Materials to be submitted.
In addition to all materials and procedures required by the City’s subdivision, zoning, building and grading regulations, and environmental review procedures applicable to hillside development projects falling within the scope of this chapter, the following application materials shall be required to be submitted for all hillside development projects:
A. Plot plan reflecting the proposed project, including representations of property lines, all recorded and proposed property lines, all recorded and proposed easements, and public rights-of-way.
B. A topographical map of the project site and all adjacent terrain located within 50 feet of the project boundaries.
C. A complete grading plan for the project.
D. A landscaping plan shall accurately show the final disposition of all existing trees on the project site and the type and extent of proposed vegetation, including provisions for ongoing maintenance and irrigation thereof. Specific consideration should be given to:
1. Vegetation on newly formed slopes.
2. Ensure slope stability.
3. Provide ongoing maintenance of vegetation associated with roadway and with private driveways of more than 150 feet in length or serving more than one building site. [Ord. 772 § 17.10.040, 1986. Code 1987 § 17.10.040].
17.36.050 Additional materials which may be required on hillside development projects.
City staff, Design Review Board, Planning Commission and City Council may require any or all of the following materials to be submitted if necessary to properly review and act upon a hillside development project:
A. All proposals for development in areas of known geological hazards shall be accompanied by a detailed geological report prepared by a recognized engineering geologist, containing conclusions and recommendations regarding the effect of geologic conditions on the proposed development.
B. A soils engineering report which shall include, but not be limited to, data regarding the nature, distribution and strengths of existing soils, conclusions and recommendations for grading procedures, design criteria for any identified corrective measures, and opinions and recommendations covering the adequacy of sites to be developed. This investigation report shall be performed by a professional soils engineer who is experienced in the practice of soil mechanics and who is registered with the State.
C. A hydrology report which shall include, but not be limited to, the hydrologic conditions on the site, possible flood inundation, downstream flood hazards, natural drainage courses, conclusions and recommendations regarding the effect of hydrologic conditions on the proposed development, opinions and recommendations covering the adequacy of the sites to be developed and design criteria to mitigate and identify hydrologic hazards consistent with these regulations. This report shall provide consideration for each lot or dwelling unit site in a proposed hillside development project. Run-off and debris amounts shall be computed using County flood control district criteria. The investigation and report shall be completed by a registered civil engineer experienced in the science of hydrology investigation. [Ord. 772 § 17.10.050, 1986. Code 1987 § 17.10.050].
17.36.060 Landscaping.
A. A landscaping plan consistent with the standards set forth herein subject to approval by the appropriate body shall be submitted for all hillside development projects. Failure to irrigate and maintain landscaping according to these approved plans shall be in violation of this code.
B. Landscaping shall emphasize the use and management of native plants. Care should be taken in plan selection and maintenance to avoid plants of high flammability either due to their intrinsic quality or the cumulative effect of dense planting especially in proximity to structures.
C. All native vegetation on property will be allowed to remain. If trees or ground cover are added they shall conform to the following requirements:
1. All ground cover within 10 feet of the structure shall not be more than three feet in height.
2. Beyond this distance landscaping will be allowed to increase two feet in height for each additional linear foot beyond the 10-foot boundary line established in this subsection.
D. Trees and nonnative evergreen shrubs shall not be within 10 feet of chimneys and should not otherwise present unusual fire hazards. [Ord. 772 § 17.10.060, 1986. Code 1987 § 17.10.060].
17.36.070 Grading.
Grading requirements shall be those referenced in most recently adopted grading ordinance and attached diagram. [Ord. 772 § 17.10.070, 1986. Code 1987 § 17.10.070].
17.36.080 Streets.
Street development standards shall be those referenced in the land division ordinance and attached diagram. The City Engineer may impose special design considerations upon streets due to health and safety, geologic, hydrologic, road maintenance, or other reasons which may adversely affect the project. Appeal of City Engineer’s requirement shall go directly to the City Council. [Ord. 772 § 17.10.080, 1986. Code 1987 § 17.10.080].
17.36.090 Setback requirements.
Setback requirements must be consistent with the requirements of the underlying zoning designation and the usable yard area requirements listed in this section. For the purposes of this section, “usable” is defined as having a gradient not exceeding that of the balance of the building pad, or five percent, whichever is the lesser.
A. Within single-family districts a usable rear yard of at least 15 feet from building to slope shall be provided.
B. Within multiple-family districts a usable rear yard of at least 10 feet from building to slope shall be provided.
C. Balconies or decks with a minimum dimension of six feet and equal to 20 percent of the dwelling area may be provided in lieu of the yard areas required above. [Ord. 772 § 17.10.090, 1986. Code 1987 § 17.10.090].
17.36.100 Building height on slope lots.
If the average slope of the land on which a building is situated is greater than one-foot rise or fall per five feet of horizontal distance, the height of the building may be 10 feet more than the limit for the zone when measured from the downhill side of the building. [Ord. 772 § 17.10.100, 1986. Code 1987 § 17.10.100].
17.36.110 Accessory building on sloping lots.
In any residential zone, detached accessory buildings shall have front, side and rear yards of the same minimum standards as is required by the underlying zoning district except as hereinafter provided.
A. If the City Engineer determines that no hazard to pedestrian or vehicular traffic will be created, a garage or carport may be built to within five feet of the street right-of-way line, if the front half of the lot or building site slopes up or down from the established street grade at a slope graded one foot for each five feet horizontal distance. [Ord. 772 § 17.10.110, 1986. Code 1987 § 17.10.110].