Division 10. Environmental Management
Chapter 17.100
HILLSIDE MANAGEMENT
Sections:
17.100.010 Intent and purpose.
17.100.030 Definition of hillside area and slope steepness.
17.100.040 Exemptions from hillside area definition.
17.100.070 Required approval for projects in hillside areas.
17.100.080 Processing procedures and submittal requirements for projects in hillside areas.
17.100.090 Development standards.
17.100.100 Slope density standards.
17.100.110 Construction on slopes greater than 50 percent.
17.100.160 Hillside street standards.
17.100.170 Landscape and erosion control standards.
17.100.190 Hillside development findings.
17.100.010 Intent and purpose.
The intent and purpose of this Chapter is to implement the goals and policies of the General Plan and the various elements contained therein as they relate to development and resource management in hillside areas within the City. The provisions contained herein will allow for orderly and sensitive development in hillside areas in conjunction with the preservation of natural open space on steeper terrain. The following specific goals and policies reflect those contained in the General Plan and provide the purpose and intent for this Chapter:
(A) To allow for development patterns in hillside areas that minimize erosion and geologic hazards and that provide for the protection of the public health, safety, and welfare.
(B) To provide for density of development that respects and is reflective of the natural terrain.
(C) To encourage grading techniques that blend with the natural terrain, minimize earth moving activity, minimize visual impacts of large cut and fill slopes and provide for the preservation of unique and significant natural landforms.
(D) To promote development in hillside areas be concentrated in areas with the least environmental impact and be designed to fit existing landforms and features.
(E) To encourage retention of natural drainage patterns and the preservation of significant riparian areas, both of which are commonly located in hillside areas.
(F) To reduce water use in slope replanting and retention by encouraging grading design that minimizes manufactured slopes.
(G) To allow density transfers where appropriate to facilitate development in more developable locations while retaining significant natural slopes and areas of environmental sensitivity.
(H) To substantially retain the integrity and natural grade elevations of the significant natural ridgelines and prominent landforms that, in aggregate, form the City’s skyline backdrop. Natural landforms and features forming this backdrop include Ritter Ridge, Portal Ridge, Verde Ridge, the Ana Verde Hills, the Sierra Pelona mountains, and secondary ridges associated with the San Andreas Rift Zone and the lower foothills of the San Gabriel mountains.
(I) To encourage the design of development of hillside areas, provide safety with respect to fire hazards, geological and geotechnical hazards, drainage, erosion, and materials of construction; to provide the best use of natural terrain; and to prohibit development that will create or increase fire, flood, or other safety hazards to public welfare, and safety. (Ord. 1603 § 4 (Exh. I), 2023)
17.100.020 Applicability.
This Chapter establishes specific submittal requirements, review standards, and processing procedures for projects within hillside areas as defined herein. Development applications proposed on a parcel or parcels containing slope areas that fall within the definition of a hillside area shall comply with all procedures, standards, and findings contained in this Chapter. Because this Chapter contains provisions that address a variety of site and project characteristics, the extent that a specific section will impact a project will vary.
Although directed primarily toward minimizing the impacts of residential development, specific provisions of this Chapter, which address grading and slope revegetation, will apply to all types of development in hillside areas, including, but not limited to, commercial, industrial, and civic uses. (Ord. 1603 § 4 (Exh. I), 2023)
17.100.030 Definition of hillside area and slope steepness.
(A) A “hillside area” is defined as any property in the City that contains slope areas of 10 percent or greater.
(B) The “steepness of a slope” is defined as the ratio of the change in elevation (rise) to the horizontal distance (run) over which that change in elevation occurs. The percentage of steepness of any given slope is determined by dividing the rise by the run on the natural slope of land, multiplied by 100. (Ord. 1603 § 4 (Exh. I), 2023)
17.100.040 Exemptions from hillside area definition.
Parcels containing only individual minor topographic features or drainage courses that contain slopes greater than 10 percent may not be considered a hillside area and will not be required to follow procedures set forth in this Chapter if said feature, or features, fall under one of the following categories:
(A) The feature or features contain a vertical height no greater than 50 feet and a horizontal dimension no greater than 200 feet in any direction as measured from the 10 percent slope line. In the case of multiple isolated landforms on the same property, said isolated landforms shall be physically separate topographic features that are clearly not a component of a significant ridgeline or any other prominent landform that contains slopes greater than 10 percent;
(B) Properties only containing slopes of 10 percent or greater associated with minor drainage courses not indicated on the United States Geological Survey (U.S.G.S.) maps as intermittent or perennial (blue-line) streams; and
(C) Previously created manufactured slopes. (Ord. 1603 § 4 (Exh. I), 2023)
17.100.050 Definitions.
Refer to PMC Chapter 17.16 (Definitions). (Ord. 1603 § 4 (Exh. I), 2023)
17.100.060 Exclusions.
This Chapter shall not be applicable to the following activities and types of projects:
(A) Construction of a single dwelling unit on a parcel of land legally established prior to the adoption of this Chapter regardless of the slope steepness on the property.
(B) Any application for a tentative tract or parcel map, planned development, minor site plan review, site plan review, or conditional use permit which was submitted and deemed complete prior to adoption of this Chapter, or any time extension to a previously approved project, shall be exempt from the provisions of this Chapter unless the Review Authority finds that changes to the project constitute a major modification to the original project approval. Modifications considered major would include, but not be limited to, the following:
(1) An increase in the number of developable lots;
(2) A reduction of lot sizes below the minimum lot size established for the zone or below a size previously approved by the Review Authority;
(3) An increase to the vertical height or horizontal width of manufactured slopes that, in the opinion of the Director, alters the plan to a level that may be inconsistent with the original Review Authority approval;
(4) An increase to building bulk or site/lot coverage that, in the opinion of the Director, alters the approved plan to a level that may be inconsistent with the original approval; and
(5) A combination of minor alterations that represent substantive, cumulative changes to the project, or other similar modifications to the previously approved project that significantly change the design or character of the project as determined by the Director.
(C) Modification of or addition to an existing single-family dwelling and accessory buildings on an existing parcel created prior to the date of adoption of this Chapter. This exemption shall not include an increase in the number of units/lots or change in use.
(D) Any parcel involving a sanitary landfill operation, landfill related gas recovery, and collection systems and ancillary electrical power generating and transfer station facilities as well as equipment storage, administrative facilities, and ancillary improvements related to a landfill.
(E) Fire breaks and fire roads required by the Los Angeles County Fire Department.
(F) Recreation trails for pedestrian, equestrian, or multi-use purposes.
(G) The construction of public improvements initiated by a public or quasipublic agency including, but not limited to, drainage channels, retention basins, water tanks and pumping stations; provided, that such facilities are landscaped and bermed to minimize visual impacts.
(H) Lot line adjustments or lot mergers.
(I) Specific Plans conditionally approved prior to the effective date of adoption of this Chapter. (Ord. 1603 § 4 (Exh. I), 2023)
17.100.070 Required approval for projects in hillside areas.
No tentative map, conditional use permit, site plan review, or other discretionary approval shall be granted for a project in a hillside area unless the person or entity authorized to grant approval therefor affirmatively finds, in addition to the required findings for the underlying discretionary approval, that the project satisfies the findings set forth in PMC § 17.100.190 (Hillside development findings) and otherwise complies with the provisions of this Chapter. (Ord. 1603 § 4 (Exh. I), 2023)
17.100.080 Processing procedures and submittal requirements for projects in hillside areas.
(A) At the time an applicant applies for a tentative map, conditional use permit, site plan review, or other discretionary approval of a project in a hillside area, the applicant shall submit the items and information listed in Subsection (C) of this Section to the Planning Division. This list is not exclusive and additional information or studies may be required for review of the project pursuant to the California Environmental Quality Act (CEQA) Guidelines and other laws. The Director, at their discretion, may modify or eliminate one or several of the submittal requirements listed in Subsection (C) of this Section upon review of specific projects.
(B) In the event it is uncertain whether or not a parcel or parcels of land falls within a hillside area, as defined in this Chapter, the applicant shall submit a slope map and related topographic information to determine the applicability of this Chapter to the project area. The decision as to the applicability of this Chapter to a parcel or parcels of land shall be made by the Director.
(C) Application submittals for development projects in hillside areas may include, but are not limited to, the items listed below. Additional information or studies may be required if deemed necessary under CEQA review procedures.
(1) Slope map and analysis which shall be prepared as set forth below.
(a) Slope Map. The slope map shall be prepared by a registered civil engineer or land surveyor. Said map shall provide the following information:
(i) The map shall be based on contour intervals no greater than 10 feet except where steep terrain warrants contour intervals greater than 10 feet;
(ii) Slope bands in the ranges of 0 to 10 percent, 10 to 25 percent, 25 to 50 percent, and over 50 percent shall be identified in clearly distinguishable graphic representations (i.e., shading, pattern, numerical highlighting within clearly defined slope category boundaries, etc.) on the slope map; and
(iii) Individual contours shall be clearly indicated on the slope map. The slope and topographic overlay maps shall extend off-site a sufficient distance to incorporate the topography of all abutting properties as it relates to the proposed site.
(b) Slope Analysis.
(i) The slope analysis shall specifically identify and calculate the slope percentages for each individual topographic feature. Horizontal runs used to calculate slopes shall be limited to each individual feature.
(ii) Total land area within each category shall be indicated on a table provided on the map.
(2) Preliminary Grading Plan.
(a) A preliminary grading plan prepared by a registered civil engineer indicating the height and width of all manufactured slopes, proposed drainage patterns, methods of stormwater detention/retention, and identification of areas to remain in a natural state shall be clearly shown. Off-site contours for adjacent, unimproved areas within 50 feet of the site boundaries shall be provided. When an adjacent property is improved, pad elevations, street grades, wall sections, and any approved or existing improvements immediately adjacent to the subject property shall also be shown.
(b) One colored copy of said preliminary grading plan showing all proposed cut and fill areas.
(3) Cross Sections/Preliminary Cut and Fill. No less than two cross sections which completely traverse the property at appropriately spaced intervals in locations where topographic variation is greatest shall be provided. Said exhibits shall be prepared by a registered civil engineer. The cross sections shall clearly depict the vertical variation between natural and finished grade.
(4) Visual Impact Analysis. The purpose of these exhibits is to replicate how the project would appear if it were to be constructed as conceptually proposed. The study shall include, but not be limited to, panoramic photographs of the project site with an overlay of scaled rendering(s) of the conceptual project designed to depict project appearance when viewed from the valley floor within the sphere of influence of the City or adjacent valleys as determined by the Director. In addition to guidelines for the preparation of visual studies required by the Planning Division, specific requirements for the visual study shall be established by the City during preliminary or formal application review.
(5) Building Envelopes. Horizontal and vertical building envelopes or plot plans/building elevations may be required for subdivisions where visual impacts are being evaluated.
(6) Pedestrian Circulation/Trails Plan. For projects in which hillside street sections as specified in PMC § 17.100.160 (Hillside street standards) are proposed, the necessity for sidewalks or alternative pedestrian circulation systems shall be considered during project review. A pedestrian circulation and trail plan may be required if alternatives to standard sidewalks are proposed.
(7) Required Technical Reports. In any area proposed for development subject to the standards and procedures of this Chapter, certain technical reports are required. Such reports will be used to determine the suitability of the subject site for development and suggest special construction and design measures necessary to mitigate identified problems which may endanger the public health, safety, or welfare. These reports shall be submitted at the time that the application is submitted.
(a) Geotechnical Report. A geotechnical report shall be submitted with each application for development under the requirements of this Chapter. The geotechnical report shall comply with City’s Engineering Design Standards and City manual, titled “Guidelines For Preparation of Geotechnical Reports.”
(b) Geologic Report. A geology report shall be prepared by a registered geologist with the State of California. Such a report shall include, but not be limited to, the surface and subsurface geology of the site, conclusions, and recommendations regarding the effect of geological conditions on the proposed development, opinions and recommendations covering the adequacy of sites to be developed and design criteria to mitigate any identified geologic hazards consistent with this Chapter.
(c) Hydrology Report. A hydrology report shall be prepared by a registered civil engineer. Such a report shall include, but not be limited to, the hydrologic conditions on the site, the location of any above or below ground springs, the location of all wells, possible on-site flood inundation, downstream flood hazards, identification of 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 any identified hydrologic hazards consistent with these regulations. This report shall also account for runoff and debris from tributary areas and shall provide consideration for each lot or dwelling unit site in a development. Runoff and debris volumes shall be computed pursuant to the City’s Engineering Standards.
(D) Standards for Exhibits. The completeness and accuracy of the above-specified plans, studies, and other submittal requirements will be determined by the Director, City Engineer, or their designees pursuant to Section 65943 of the California Government Code. All studies shall be in conformance with the current City guidelines for each individual study or report. (Ord. 1603 § 4 (Exh. I), 2023)
17.100.090 Development standards.
(A) Single-Family Residential.
(1) Side Setback.
(a) Maintenance and revegetation of downslopes to property lines shall be ensured through use of slopes no greater than a 3:1 ratio, which may be used in combination with retaining walls. Where necessary, additional lot width may be required to meet this requirement.
(b) A minimum five-foot-wide flat surface shall be provided between any slope break and the primary structure.
(2) Rear Setback.
(a) Maintenance and revegetation of downslopes to property lines shall be ensured through use of slopes no greater than a 3:1 ratio, which may be used in combination with retaining walls.
(b) Where manufactured slopes exceed 20 feet in height, lot depth shall be increased to create additional flat lot area and minimize the visual effect of these slopes. For every foot of slope height over 20 feet, the flat portion of the rear setback area shall be increased by five percent.
(c) Manufactured slopes may be used to calculate no more than 25 percent of the required rear setback.
(d) Manufactured slopes shall not exceed 30 feet in height.
(e) A minimum 15-foot setback from rear dwelling wall to any slope break in excess of a 3:1 ratio shall be provided. (Ord. 1603 § 4 (Exh. I), 2023)
17.100.100 Slope density standards.
(A) Slope Density Table. Except as otherwise provided in other portions of this Chapter, no project shall be approved unless the density of the proposed project complies with the following slope density standards, as interpreted and applied by succeeding Subsections of this Section:
|
Slope Category |
Allowable Density |
Equivalent Number of Units per Acre |
|---|---|---|
|
0 – 10% |
Upper Limit of the Applicable General Plan Density Range |
Same |
|
10 – 25% |
0.57 du/ac |
1 unit/1-3/4 acres |
|
25 – 50% |
0.40 du/ac |
1 unit/2-1/2 acres |
|
Greater than 50% |
0.025 du/ac |
1 unit/40 acres |
(B) The overall number of units allowed on a property shall be based on the summation of the total number of units allowed within each slope category. All areas within the project boundary shall be included in one of the established categories.
(C) Should slope density calculations allow more units than the underlying General Plan designation, the General Plan designation shall take precedence and is the basis for determining the allowed number of units on a property. In all other cases, the slope density table shall be utilized for calculating allowable density and represents implementation of General Plan policies pertaining to hillside development.
(D) The slope density standards are intended to establish the maximum number of units allowed on a specific property. How and where those units will be placed on the property shall be based on standards and criteria contained in this Chapter. It is not required that units be allocated within a property based on the location of individual slope categories, although the underlying premise of this Chapter is to encourage development on flatter, more developable areas.
(E) Fractional remainders resulting from area calculations multiplied by slope density ratios for individual slope categories shall be included when determining the total number of units possible in a particular category. Any fractional remainders resulting from the summation of allowable density from all categories shall be rounded down when determining the total number of units allowed on a property.
(F) No industrial development shall be allowed on natural slopes of 15 percent or greater. (Ord. 1603 § 4 (Exh. I), 2023)
17.100.110 Construction on slopes greater than 50 percent.
No construction or grading shall be allowed in areas containing slopes of 50 percent or greater except under the following circumstances:
(A) Development is proposed on isolated peninsula shaped fingers of 50 percent slope within an otherwise developable area of lesser slopes;
(B) The grading involves the filling of small ravines or drainage courses not shown on the U.S.G.S. maps as intermittent or perennial (blue-line) streams which contain ancillary slopes of 50 percent or greater if said ravine or drainage course is not deemed a significant biological area (as determined by the biological study for the project) and if measures to convey surface water are proposed to the satisfaction of the City Engineer; or
(C) The grading involves the construction of roads if the 50 percent slope area is an isolated landform as defined in PMC § 17.100.040 (Exemptions from hillside area definition), or if no other reasonable alternatives are available and all hillside street design criteria are met as specified in PMC § 17.100.160 (Hillside street standards). (Ord. 1603 § 4 (Exh. I), 2023)
17.100.120 Density transfers.
Density transfers, wherein permissible densities on steeper portions of a property are transferred to portions of the property that require less grading and are less steeply sloped, less ecologically sensitive, and less Visually zprominent, may be allowed if the proposed transfer complies with the provisions of this Section and Chapter. The purpose of this Section is to establish criteria that address the positive benefits and potential negative impacts created by density transfers. Primary consideration shall be given to established neighborhoods that may be negatively impacted if a project proposing density transfer creates an incompatible interface caused by land uses of significantly different densities and physical characteristics typically associated with those densities. Buffering techniques and physical location are critical factors in minimizing potential impacts.
(A) Density Transfer Procedures. Any proposal to transfer density shall be in full compliance with this Chapter and any other provisions contained in this Title.
(B) Density Transfer Review Criteria. A transfer of density shall be found suitable for a particular site only if the proposed density transfer complies with the following standards:
(1) Design of the density transfer minimizes impacts on adjacent areas;
(2) The physical location is suitable for a project proposing density transfer. If available, natural physical features shall be utilized to visually and physically separate higher density housing from nearby areas that are developed at lower densities;
(3) On sites where physical separation utilizing natural features is not feasible, buffering techniques shall be utilized to ensure that density transfer does not result in negative impacts upon existing neighborhoods of a lower density or rural development pattern. Appropriate buffering techniques may include, but are not limited to:
(a) Incorporation of larger lot sizes/patterns which are consistent with the immediately adjacent neighborhoods;
(b) Utilization of architectural styling, fence details, landscape and lot patterns, or similar features that are compatible with those found in adjacent areas; and
(c) Establishment of buffer areas of appropriate size to ensure that transition of densities is gradual to minimize incompatible mixing of development types associated with various intensities of development. (Ord. 1603 § 4 (Exh. I), 2023)
17.100.130 Development proposed on significant ridgelines and prominent landforms forming the City’s skyline backdrop.
(A) Purpose and Intent. This Section is intended to assure that the physical characteristics of the significant natural ridgelines and prominent landforms on the perimeter of the City, as defined in PMC § 17.100.050 (Definitions), are retained as a skyline backdrop to the City, and that any development on physical features encompassing these landforms will integrate with, rather than significantly modify, existing topography. The goal of this Section is to encourage site planning techniques that ensure integration of development with physical features including but not limited to natural bowls, broad plateaus, valleys, and similar natural landforms. Implementation of this Section will ensure that the natural form and elevations of the City’s skyline backdrop will be retained.
(B) Requirements. All applications for development proposed in these areas shall be subject to the standards and procedures set forth below.
(1) Visual Impact Study.
(a) A visual impact study shall be required for projects located on the crest or slope face of prominent landforms and ridgelines that are physical components of the topographic features generally described in PMC § 17.100.050 (Definitions) and which form an integral part of the City’s natural skyline backdrop. Applicability of this Section may be determined by the Director during preliminary conceptual review or during application review. In cases of dispute, the decision-making body for the appropriate application type shall have final decision-making authority on applicability of this Section.
(b) The above criteria for requiring a visual impact study are not all inclusive and do not preclude the requirement of alternative visual studies for unique circumstances as determined necessary by the Director.
(2) Review Standards. The criteria listed below shall be utilized in evaluating projects located on the crest or slope face of significant ridgelines or prominent landforms forming the City’s skyline backdrop.
(a) All development proposed on prominent landforms or significant ridgelines as defined in PMC § 17.100.050 (Definitions) shall be designed to substantially retain the natural contour elevations of these features as viewed from vantage points on the valley floor within the sphere of influence of the City or from smaller adjacent valleys.
(b) Grading to substantially reshape prominent landforms and ridgelines that form a component of the City’s skyline backdrop shall be prohibited.
(c) Dwellings constructed near the crest of a ridgeline or prominent landform shall utilize architectural, grading, and landscaping elements that serve to integrate the structure with the landform upon which it is constructed. In determining whether a project complies with this requirement, a project shall be found consistent with the following criteria:
(i) On steep natural grades, foundation and floor plans shall be designed with multiple levels to change elevations with natural contours;
(ii) Roof planes shall be angled in the direction of the natural slope. The main building mass, including gabled sections of roof structures, shall face away from lower lying areas;
(iii) Roof lines shall undulate to replicate the natural contours of the land;
(iv) Building colors shall emphasize blending with the surrounding natural terrain;
(v) Daylight grading techniques shall be utilized where appropriate to reduce disruption of natural topography and vegetation;
(vi) Structural setbacks from the edge of natural slopes shall be utilized to reduce visual prominence of structures; and
(vii) Berming and tree massing near the landform crest shall be utilized to blend in with the natural landforms and to screen view of the structure from lower lying areas. (Ord. 1603 § 4 (Exh. I), 2023)
17.100.140 Grading standards.
(A) Purpose and Intent. The standards contained in this Section are established to ensure that grading techniques are utilized which reduce potential erosion, minimize visual impacts, promote the use of development patterns and street designs that follow natural contours, and minimize the length and width of manufactured slopes. These regulations shall be pursuant to Appendix J (Grading and Excavation), PMC § 8.04.240.
(B) Grading Standards. Except as otherwise allowed pursuant to PMC § 17.100.150 (Landform grading), no project in a hillside area shall be allowed unless the project, or the project as modified with conditions, complies with the following standards:
(1) The maximum height for manufactured slopes shall be 30 feet except as specified in PMC § 17.100.150 (Landform grading).
(2) Manufactured fill slopes adjacent to regional, crosstown, or connector streets shall be no steeper than a 3:1 ratio within landscape easement areas and public rights-of-way, and shall not exceed 10 feet in height unless the slope is lower in elevation than the roadway.
(3) Where a proposed subdivision contains average net lot sizes exceeding 20,000 square feet, lot grading shall be limited to building pad and related functional setback area. Flat pad grading of the entire lot shall be prohibited. The grading plan submitted for the project shall clearly delineate the graded and natural portions of proposed lots.
(4) Grading on the perimeter of the site shall not be designed with perimeter downslopes to property lines unless a homeowner’s association, slope maintenance district, or similar entity is established for maintenance of said downslopes. Exemptions to this requirement may be made for downslopes to property lines that are a ratio of 4:1 or less. For interior slopes between lots, manufactured building pads shall be designed with up-slopes to property lines.
(5) Subdivision development plans shall indicate a minimum 20-foot setback from the rear dwelling wall to the top or toe of a manufactured slope or retaining wall. The only exception to this standard would be in the case of a terraced rear setback where multiple levels of functional setback space are provided.
(6) Manufactured slopes greater than eight feet in height shall be rounded at the top and at the toe of slope to simulate natural topography. The radius of the rounded slope shall be calculated by dividing the overall height of the slope by three (i.e., Height/3).
(7) Manufactured slopes in excess of 200 feet in length and greater than eight feet in height shall be designed with horizontal curvature that simulates the horizontal surface variations of natural contours.
(8) Dwellings proposed on ungraded lots with natural grades of 10 percent and greater shall follow natural contours, utilizing such techniques as stepped foundations and split-level floor plans.
(9) For projects on property defined in PMC § 17.100.030 (Definition of hillside area and slope steepness) as a hillside area, and where it can be clearly established that reduced setbacks will enhance preservation of natural terrain and reduced grading, front setbacks may be reduced to a minimum of 10 feet as applied to the main portion of the dwelling. The garage setbacks shall remain at 20 feet except for a side loaded garage where a minimum driveway depth of 20 feet from right-of-way edge is provided.
(10) Cross lot drainage may be utilized to reduce grading if an overall design and method of maintenance is established to the satisfaction of the City Engineer and Director. Terrace drains shall be subject to maintenance by private homeowner’s associations or individual property owners.
(11) Any continuous manufactured slope within a subdivision with a slope steepness of a 3:1 ratio or steeper, a vertical height of 30 feet or greater where so allowed under PMC § 17.100.150 (Landform grading), and which abuts five or more lots, shall require the creation of a homeowner’s association or other maintenance entity with provision for the collection of fees or assessments designated specifically to pay costs associated with the maintenance of these slopes, as well as to create easements or homeowner’s association lots for maintenance of all slopes falling under this category. The slope maintenance entity, rather than individual property owners, will be responsible for the maintenance of said slopes. The tentative tract map shall be designed in a manner that provides access to said slopes by accessible easements and which avoids the necessity of gaining access to the slopes through individual lots. No fences shall be allowed between lots within the slope easement areas. Slope easement areas may be included as lot area for the purposes of calculating lot size. Habitable structures shall not be allowed within common slope easement areas. (Ord. 1603 § 4 (Exh. I), 2023)
17.100.150 Landform grading.
(A) Purpose and Intent. Landform grading, as defined in PMC § 17.100.050 (Definitions), provides an alternative grading technique that may be utilized where unique topographic conditions exist that warrant a nontraditional and creative approach to grading a site.
(B) Authorization for Landform Grading. The height and slope steepness limitations and other applicable standards for manufactured slopes established under PMC § 17.100.140 (Grading standards) may be modified under an approved landform grading plan, if the proposed project is found to incorporate the following design elements:
(1) Variation to slope gradients utilizing compound slopes and state of the art grading techniques with maximum slope steepness to be determined by the City Engineer as specified in the Uniform Building Code. An example of this technique would be slope transitions varying from 4:1 to 1:1 punctuated by slopes of varying steepness.
(2) Variation to pad sizes and shapes that correspond to variable topography.
(3) The artful utilization of contour and daylight grading to achieve a subtle transition between natural landforms and manmade slopes.
(4) Use of drainage and landscape elements including but not limited to clustering of trees and shrubs typical of concentrations found in nature, incorporation of rock elements into manmade culverts and down-drains, and angling and naturalized coloration of concrete drainage elements to reduce visibility.
(5) The preservation of natural open spaces as part of the overall grading concept.
(C) Determination of Compliance with Landform Grading. Conformance with landform grading provisions shall be determined during project review. It shall be the responsibility of the applicant to provide the City with exhibits necessary to establish compliance with mandated design characteristics of landform grading. No modification to the grading standards may be granted unless this determination has been made. (Ord. 1603 § 4 (Exh. I), 2023)
17.100.160 Hillside street standards.
(A) Except as otherwise provided in Subsection (B) of this Section, streets within any project proposed in a hillside area as defined in PMC § 17.100.050 (Definitions) shall be designed and constructed pursuant to the standards listed below:
(1) Proposed streets in hillside areas shall be aligned parallel to the natural contours of the land where feasible.
(2) Bridges and oversized culverts, if recommended as a biological mitigation measure, shall be required when streets cross drainage ways and ravines that serve as important wildlife corridors.
(3) Streets oriented along the top of a significant ridgeline shall be avoided.
(4) Standard street sections may be modified in hillside areas where streets are proposed on natural grades of 14 percent or greater, if approved by the City Engineer. Said modifications may include the following:
(a) Connectors in hillside areas: Right-of-way width may be reduced to 44 feet and curb to curb width reduced to 36 feet;
(b) Neighborhood streets in hillside areas: Right-of-way width may be reduced to 40 feet and curb to curb width reduced to 32 feet. A six-foot-wide public utilities easement shall be provided outside of the right-of-way;
(c) Neighborhood cul-de-sacs in hillside areas: Right-of-way width may be reduced to 34 feet and curb to curb width to 28 feet. The cul-de-sac radius for hillside streets may be reduced to 32 feet; and
(d) Any street with a curb to curb width of less than 36 feet may have parking prohibited on one side. Any cul-de-sac with a radius of less than 40 feet may result in restricted on-street parking as determined by the City Engineer.
(5) Split level, one-way streets may be permissible in areas of steep terrain when deemed acceptable by the City during project review.
(6) Street lighting shall be designed to minimize visual impacts and retain rural character while conforming to acceptable safety standards.
(7) Street grades shall not exceed the following except as may be modified by the appropriate decision-making body:
(a) Crosstown. Eight percent;
(b) Connectors. Eight percent; and
(c) Neighborhood Streets. Fourteen percent, except for limited distance that may exceed 14 percent if approved by the City Engineer and the Los Angeles County Fire Department.
(B) Modifications to these standards may be made by the appropriate decision-making body if it can be found that such modifications further the purpose and intent of this Title by reducing grading and overall visual impacts while retaining acceptable traffic safety and street design characteristics as determined by the City Engineer. (Ord. 1603 § 4 (Exh. I), 2023)
17.100.170 Landscape and erosion control standards.
(A) The grading plan shall preserve natural terrain and vegetation to the maximum extent feasible by utilizing creative design concepts as allowed by standards established in this Chapter. However, it is recognized that grading in some areas may involve considerable surface disruption and removal of natural vegetation. Where this occurs, and manufactured slopes are created, the following standards and submittal requirements shall apply:
(1) With formal application: conceptual landscape plans indicating both temporary and permanent slope plantings shall be submitted to the Engineering Division. Plans shall include a conceptual plant palette and description of the irrigation system to be utilized. Conceptual landscaping design and planting palette shall comply with the City’s Landscaping Standards, City’s Approved Planting List, and County of Los Angeles Fire Department Fuel Modification Standards (if the project site is located in a Fire Hazard Severity Zone); and
(2) Prior to grading permit issuance: a manufactured slope revegetation report analyzing existing soil conditions, proposed soil amendments, and plant suitability for review and approval by the City Engineer. (Ord. 1603 § 4 (Exh. I), 2023)
17.100.180 Slope maintenance.
(A) Developer Maintained Slope Areas. The developer shall be responsible for slope revegetation including compliance with all provisions of Appendix J (Grading and Excavation), PMC § 8.04.240, prior to the transfer of perpetual maintenance responsibilities of said slopes to individual property owners, a homeowner’s association, or other slope maintenance entity. A performance bond for an amount to be established by the Public Works Department shall be posted with the City in order to ensure that the ultimate establishment of all revegetation is completed.
(B) Commonly Maintained Slopes. Projects containing slopes requiring homeowner’s association maintenance shall be subject to comprehensive conditions, covenants, and restrictions (CC&Rs) which shall include slope maintenance provisions. Said CC&Rs shall be subject to review and approval by the Director, City Engineer and City Attorney prior to recordation of a final map for the project.
(C) Erosion Control Standards. Erosion control measures meeting the current specifications of the City Engineering Design Standards and the Palmdale Building Code that are in effect on the date when the formal application for the project is submitted shall be provided. (Ord. 1603 § 4 (Exh. I), 2023)
17.100.190 Hillside development findings.
No project in a hillside development area shall be approved by the appropriate decision-making body unless it is found to conform to all of the following findings based on criteria and standards set forth in this Chapter:
(A) The density, grading, and design standards contained in this Chapter have been complied with in the overall design of the project;
(B) The project design and site layout retains and utilizes natural contours of the site to the maximum extent feasible;
(C) The project design incorporates drought tolerant landscape materials, water conserving irrigation techniques and erosion control measures in a manner that eliminates both short- and long-term erosion hazards while providing for aesthetic and effective revegetation of these slope areas;
(D) Development is designed in a manner that substantially retains the visual qualities and natural elevations of the significant ridgelines and prominent landforms forming the City’s skyline backdrop and preserves those portions of the ridgelines visible from the valley floor, or adjacent valleys, as a scenic skyline backdrop to the City; and
(E) The impacts on adjacent neighborhoods of an established character are minimized when density transfer is proposed by employing design elements and locational characteristics consistent with criteria contained in PMC § 17.100.120 (Density transfers). (Ord. 1603 § 4 (Exh. I), 2023)
17.100.200 Variances.
No variance from the provisions of this Chapter shall be allowed unless it is approved pursuant to the provisions of PMC Chapter 17.23 (Variances and Minor Exceptions). (Ord. 1603 § 4 (Exh. I), 2023)