A. Prohibited Excavations: Notwithstanding any other provision of this code, it shall be unlawful to grade, fill or excavate any land in any manner which presents an unreasonable risk of erosion, flooding, landslide or any other unsafe condition. It also shall be unlawful to erect any structure which will not be reasonably safe for use as human habitation because of risk of erosion, flooding, landslide, earthquake related hazard or any other unsafe condition.
B. Cross Slopes Permitted; Conditions: Any area within a subdivision, or other parcel of real property, which has a slope greater than thirty percent (30%) shall remain ungraded, except for streets, roads, private access roads, and other vehicular routes. These routes shall be allowed to cross slopes between thirty percent (30%) and fifty percent (50%) if specifically authorized by the planning commission, upon the favorable recommendation of the community development director, after finding that all of the following conditions and constraints are applicable:
1. No alternate location for access is feasible or available;
2. No individual segment or increment of the street, road, private access road, or other vehicular route that will cross slopes between thirty percent (30%) and fifty percent (50%) exceeds one hundred feet (100') in length; and
3. The cumulative length of individual segments or increments that will cross slopes between thirty percent (30%) and fifty percent (50%) does not exceed ten percent (10%) of the total length of the street, road, private access road, or other vehicular route.
C. Subdivisions: Any area within a subdivision, or other parcel of real property, which has a slope greater than thirty percent (30%) shall not be graded, except for roadway purposes as provided in subsection B of this section. Areas with slopes between twenty percent (20%) and thirty percent (30%) may be graded; provided, that the area to be disturbed shall be less than one-half (1/2) of the area of such slopes.
D. Grading Plan: No grading, filling or excavation of land shall take place on a hillside or an area with an average slope of twenty percent (20%) or greater until a grading plan has been submitted and approved by the city engineer and a grading permit issued by the community development department.
E. Preparation And Compaction Of Fill Material: Any fill material shall be prepared and compacted as specified in the city's then effective building code.
F. Steepness Of Slopes: Cut and fill slopes shall be no steeper than two feet (2') horizontal to one foot (1') vertical.
G. Tops Or Toes Of Slopes: Tops or toes of slopes shall be set back from property boundaries as required by the city's then effective building code.
H. Lot Size And Usable Area For Single-Family Dwelling Units: The minimum lot size and minimum usable area with respect to parcels of real property upon which single-family dwelling units may be located shall be determined by reference to the following table:
Average Slope Of Development Site | Minimum Lot Size | Minimum Lot Width | Minimum Usable Area |
0 - 15% | As indicated by zoning | 70 ft. at front setback line | 3,200 sq. ft. not less than 50 ft. in width or length |
Over 15% - 20% | The greater of 10,000 sq. ft. or as indicated by zoning | 80 ft. at front setback line | 4,000 sq. ft. not less than 50 ft. in width or length |
Over 20% - 30% | The greater of 15,000 sq. ft. or as indicated by zoning | 100 ft. at front setback line | 5,000 sq. ft. not less than 50 ft. in width or length |
Over 30% | Not permitted |
I. Location Of Single-Family Dwelling Structures: Single- family dwelling structures shall not be located farther than one hundred fifty feet (150') from the nearest public street; provided, however, that the planning commission may grant all exception to this requirement if its review of utility services, fire access, surrounding land conditions, coordination of development or similar circumstances warrants the exception.
J. Maintenance And Erosion Control: Areas which have been graded shall be prepared and perpetually maintained to control erosion. After approval of the city engineer and its building inspector, and prior to calling for final inspection, the area shall be planted with appropriate vegetation. Where necessary, check dams, cribbing, riprap and other devices or methods approved by the city engineer shall be employed to control erosion. If the final grading is completed between October 15 and March 15 of the next year, then organic cover material shall be placed on the graded area to eliminate erosion until the soil can be permanently planted.
K. Natural Vegetation: Natural vegetation shall remain in areas where grading is not permitted, and additional mitigation measures may be required by the city engineer in ungraded and graded areas to prevent erosion and slope failures.
L. Drainage Systems For Surface Water: Surface water runoff drainage systems shall be designed and installed to carry water to the nearest practicable drainageway. Drainage systems shall be approved by the city engineer.
M. Ridgeline Protection Areas: No development shall intrude into any ridgeline protection area that has been identified and designated by the city during the development review and approval process for any development or redevelopment within the city. For the purposes of this chapter, "designated ridgeline protection areas" shall consist of prominent ridgelines that are highly visible from public rights of way or trails, and shall include the crest of any designated hill or slope, plus the land located within one hundred feet (100') horizontally (map distance) on either side of the crest. (Ord. 2012-15, 9-20-2012)