§ 19.46

A.

General. These Hillside Development Standards are established in recognition of the unique and sensitive environment and environmental hazards that exist in Duarte's hillside areas. This Chapter establishes regulations focused on protecting and maintaining landforms, sensitive and unique vegetative and wildlife communities, scenic qualities, and open spaces, and also minimizing risk to properties associated with wildfires, unstable slopes, rapid water movement, and other natural hazards inherent in hillside environments.

B.

Consistency with general plan. This Chapter contains regulations intended to implement General Plan policies aimed at:

Ensuring that infill residential development in hillside areas is compatible in design, bulk, and height with existing residential development on surrounding properties;

2.

Providing hillside development that is sensitive to local views of the hills and the natural environment;

3.

Preserving the characteristics of the mountains, river beds, and canyons;

4.

Protecting valuable watershed;

5.

Maximizing the use of native and other drought-resistant plants to reduce the amount of water used for landscaping;

6.

Protecting public health, safety, and welfare from the dangers of flood, fire, seismic, and unstable geologic conditions; and

7.

Utilizing design approaches that require single-family homes to fit the landform rather than adjusting the landform to fit the house.

A.

These regulations shall apply to the development of all new structures, additions to existing structures, and other property improvements within the City's hillside areas, defined as all properties within the R-1B, R- 1D, and R-1F zones, as well as properties within the R-1 and R-1A zones that are located north of Sunnydale Drive and Brookridge Road. (as shown in Figure 3-24).

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Figure 3-24. Hillside Designation Boundary

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B.

In addition to the standards contained in this Chapter, all properties within the R-1D zone shall comply with the development regulations set forth in 19.10.050 (R-1D Zone: Additional Standards).

All new construction within the hillside areas defined in 19.46.020 (Applicability), above, shall comply with the California Building Code, Chapter 7A regarding construction requirements for structures within a Wildland-Urban Interface Fire Area, as defined in Chapter 7A, and the California Fire Code, Chapter 47.

In addition to any application requirements for a proposed improvement and/or subdivision of land otherwise set forth in this Code, all development applications for properties subject to the requirements of this Chapter shall require the following, unless waived by the Director:

A.

A topographical map, at a scale specified in development applications, which shall identify all existing slope banks, natural drainage courses, rock outcroppings, and existing vegetation. The vegetation map shall indicate whether the plant communities or habitat are native (e.g. southern mixed chaparral) or exotic (e.g. palm trees). Also depicted shall be known landslides and other existing geologic conditions.

B.

A conceptual grading plan for all proposed grading involving earth movement in excess of 50 cubic yards, which shall include the following items in addition to those required by the Municipal Code:

1.

Top of walls.

2.

Top of curbs.

3.

High point and low point elevations.

4.

Elevation of significant trees, which are defined to be trees with a greater than six-inch trunk diameter measured at four feet above grade.

5.

Spot elevations, where appropriate.

6.

Pad and/or finished floor elevations.

7.

Change in direction of drainage.

8.

Contours for existing and proposed topography.

9.

Lot and pad dimensions, along with a statistical summary.

10.

Design of driveways, including average grades indicated, as well as areas of the steepest grade.

11.

Lot drainage, including the gradient of the drainage and flow velocities.

C.

Map identifying proposed fill areas colored green and cut areas colored red, with depths of such areas clearly shown in five-foot topographic lines. Quantities of each cut and fill area shall also be clearly marked. Areas of cut and fill, calculated as a percentage of the total site area, shall be marked.

D.

In the event that no grading is proposed, a statement to that effect.

E.

The following technical reports, unless waived or conditionally waived by the Director:

1.

A geologic and soils report prepared by a registered geotechnical engineer and in sufficient detail to substantiate and support the design concepts presented in the application as submitted. A map shall be included that details geotechnical and soils conditions, including known faults and landslides.

2.

A biological resource survey report identifying all existing plant communities, with sensitive or protected species or communities clearly delineated, as well as known habitat area for protected animal species, including the location of sensitive biological resources. All sensitive species surveys shall be conducted in accordance with any applicable protocols established by the U.S. Fish and Wildlife Agency and the California Department of Fish and Game. The report shall be signed by the person preparing such report, with the signature intended to verify that the mandatory protocols were conformed to in the analysis. A map shall be included that shows all of the existing plant communities, with sensitive or protected species or communities clearly delineated, as well as known habitat area for protected animal species including the location of sensitive biological resources. The map should including identifying significant trees, which, for the purposes of this map, are defined to be trees with a caliper greater than six inches when measured four feet above grade.

F.

Visual simulation of the post-development condition, including use of photographic and/or computergenerated graphic renderings. The purpose of requiring a visual simulation is to provide decision makers with a pictorial representation of the future condition of a development project as close to reality as possible.

G.

The following property slope information:

1.

A detailed slope analysis map for the purposes of determining the amount and location of land as it exists in its natural state and for calculating the average slope. For the slope analysis map, the applicant shall use a base topographical map of the subject site, prepared and signed by a registered civil engineer or licensed land surveyor. The map which shall have a scale of not less than one inch to 100 feet and a contour interval of not more than 10 feet with two-foot intermediates. This interval may be adjusted with the approval of the Director and City Engineer on the basis of good engineering principles. This base topographical map shall include all adjoining properties within 150 linear feet of the site boundaries to portray the site's context. The slope map shall delineate slope bands, with contrasting colors, for the following slope ranges:

a.

Up to 10%

b.

10.1% to 20%

c.

20.1% to 25%

d.

25.1% to 30%

e.

Greater than 30%

2.

A calculation of the average slope of the entire parcel. Such calculation shall be performed by using the average percent slope formula, pursuant to Section 19.46.050 (Determination and Use of Average Property Slope).

3.

Calculations of average slope percent shall be based upon accurate topographic surveys using a contour interval no greater than 10 feet and a horizontal map scale of 1 inch: 200 feet or larger.

4.

The slope analysis shall be stamped and signed by a registered or licensed professional competent to provide such analysis and indicating the datum, source, and scale of topographic data used in the slope analysis, and attesting to the fact that the slope analysis has been accurately calculated.

H.

Sufficient number of slope sections to clearly illustrate the extent of the proposed grading. The slope profiles shall:

1.

All be drawn at the same scale and indexed, or keyed, to the existing topography, grading plan, and project site map. Both vertical and horizontal scales shall be indicated and not exaggerated. The slope section shall extend at least 150 feet outside the project site boundary to clearly show impact on adjacent property.

2.

At a minimum, be drawn along those locations of the project site where:

a.

The greatest alteration of existing topography is proposed;

b.

The most intense or massive development is proposed;

c.

The site is most visible from surrounding land uses;

d.

At all site boundaries illustrating maximum and minimum conditions; and

e.

Where grading will impact natural drainage conditions.

3.

Include at least two of the slope profiles roughly parallel to each other and roughly perpendicular to existing contour lines. At least one other slope profile shall be roughly at a 45° angle to the other slope profiles and existing contour lines.

4.

Be stamped and signed by a registered civil engineer or landscape architect registered in the State of California, indicate the datum, source, and scale of topographic data used in the slope profiles, and attest to the fact that the slope profiles have been accurately calculated and identified.

5.

Show existing and proposed topography, structures, and infrastructure facilities. Proposed topography, structures, and infrastructures shall be drawn with a dashed line. Existing topography and features shall be drawn with a thin, solid line.

The average slope of any parcel shall be determined by the following formula:

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Where: S is the average slope expressed as a percent;

I is the contour interval in feet;

L is the combined length of contour lines in scale feet; and

A is the gross area in acres of the parcel lot.

The contour map submitted for use in determining average slope shall have a maximum interval of 10 feet for slopes greater than 20 percent and a contour interval of five feet for slopes less than 20 percent.

19.46.060 - Development standards—New development projects and additions to existing development.

A.

General. The standards for the underlying zone shall apply, unless modified by this Section.

B.

Minimum distance between structures and slopes. In addition to the setback requirements that apply to the underlying zone, no building or structure shall be permitted to be erected closer to the toe or top of cut or fill slopes than the following distances. For the purposes of this Section, swimming pools, spas, and fish ponds constructed on the lot shall be considered as structures.

1.

Between a structure and the toe of slope where the slope is between the structure and front or side property line: five feet.

2.

Between a structure and the toe of slope where the slope is between the structure and rear property line: 15 feet

3.

Between a structure and the top of slope where the slope is between the structure and front, side or rear property line: 15 feet, unless a civil engineer, registered in the state of California, submits proof in writing that foundation conditions and slope stability are such that the distance may be safely reduced. Under no condition shall the distance be less than five feet.

19.46.070 - Grading standards—New development projects and additions to existing development.

A.

Supplemental to chapter 16.04. The requirements in this Section shall be supplemental to the requirements of Chapter 16.04 (Building Laws) of the Municipal Code. Where conflict between these provisions and those of Chapter 16.04 exist, the provisions of this Section shall govern.

B.

General grading standards.

1.

Landform grading techniques such as varying slope height, rounding tops and toes of slopes, and incorporating variable gradients shall be used to ensure that manufactured slopes mimic natural hill forms. Landform grading shall be used for all post-disturbance conditions unless determined by the Director and

the City Engineer that landform grading is not feasible due to soil conditions, encroachment into sensitive biological resource areas, protection of watersheds or watercourses, or other similar considerations.

2.

Berming shall be used to screen utilitarian features such as, but not limited to, water tanks and detention basins.

3.

All slopes which are visible from any public right-of-way shall be landform graded.

4.

No excavation or other earth disturbance shall be permitted on any hillside area prior to the issuance of a grading permit, with the exception of drill holes and exploratory trenches for the collection of geologic and soil data. Such trenches shall be properly backfilled and erosion treatment shall be provided where such slopes exceed 20 percent.

5.

Graded or cut embankment adjacent to a publicly maintained right-of-way shall not exceed a slope ratio greater than two feet horizontal to one foot vertical.

6.

Graded slopes that are characterized by linear (in plan), planar slope surfaces with unvarying gradients and angular slope intersections are prohibited.

7.

No fill slope shall exceed two-feet horizontal to one-foot vertical, and no cut slope shall exceed a slope of one-and-one-half feet horizontal to one-foot vertical. Slopes steeper than specified may be approved if verified by a full soil investigation and report, including a deep soil test made by a geologist or soil engineer, and the report and recommendations are acceptable to the City Engineer.

8.

Whenever the depth of a cut and/or a fill exceeds 30 feet, eight-foot-wide benches paved in concrete shall be installed at not more than 30-foot vertical intervals. Approved drainage facilities shall be installed to drain benches. Concrete shall be three inches thick. Wire mesh shall be used when deemed advisable by a soil engineer's report. Modification shall be subject to proof by a geologist or a soil engineer's report acceptable to the City Engineer.

9.

No areas which are presently usable for firefighting shall be graded in relation to hillside development unless an access way is provided around the cut to the top of the ridge for firefighting equipment.

Within six months, or such other period established by the Director, after the commencement of grading activities, all graded areas not covered by impervious surface shall be stabilized in such manner as shall be approved by the Director. In no case shall slope planting lag grading completion by more than six months.

11.

Landscaping coverage and stabilization of graded slopes shall be selected and designed to be compatible with surrounding natural vegetation or to replace removed natural vegetation and should recognize climatic, soil and ecologic characteristics of the region. Plant materials that require excessive water after becoming established should be avoided. Native grasses and other plants native to arid climates, consistent with guidelines adopted by the City, shall be selected wherever feasible.

12.

Trees which have a six-inch or greater trunk diameter at a point four and one-half feet above grade shall not be removed without specific approval. The location of all such trees shall be shown on all plans submitted for approval, including tentative tract maps, and tree removal shall be subject to approval of the map.

13.

The overall shape, height, grade of any cut or fill slopes shall be developed in concert with existing natural contours and scale of the natural terrain of a particular site.

14.

Where two cut or fill slopes intersect, the intersection shall be horizontally rounded and blended.

15.

Where any cut or fill slopes intersect the natural grade, the intersection of each slope shall be vertically and/or horizontally rounded and blended with the natural contours so as to present a natural slope appearance.

16.

Where any cut or fill slope exceeds 150 feet in horizontal length, the horizontal contours of the slope shall be developed in concert with existing natural contours.

C.

Grading for house sites—New construction.

1.

All graded slopes are to be contoured and blended to complement natural slopes.

2.

Housing is to be designed to fit the natural landform in a manner that does not require extensive grading through split-level house designs and other similar techniques.

3.

Significant landmark features, as determined by the responsible Review Authority, such as natural rock outcroppings, prominent trees, vegetation and wildlife communities, and other natural characteristics of significant geologic landform of special natural beauty, shall be preserved.

4.

Maximum vertical height of cuts, exposed or retained by walls, from toe to top, shall not exceed 12 feet, unless approved by the responsible Review Authority.

5.

Maximum vertical height of fills, exposed or retained by walls, from toe to top, shall not exceed 12 feet, unless approved by the responsible Review Authority.

6.

Building sites shall not be pre-graded until specific house site plans and elevations have been approved for the individual site.

D.

Retaining walls.

1.

Properly designed retaining walls, approved by the City Engineer, may be permitted to retain portions of front, side, and rear slopes, subject to the following:

a.

The height of any such wall shall not exceed ten feet.

b.

Such retaining walls may be permitted to be located on side and rear property lines when the vertical distance between adjacent properties does not exceed six feet. Such vertical distance shall be measured at the property line where such wall is to be located.

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Figure 3-25. Retaining Walls

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2.

No building or structure shall be located closer than five feet from any retaining wall, with the exception of retaining walls that are an integral part of an approved dwelling, accessory structure, or any other approved structure.

3.

When a retaining wall is used to increase the usable area around structures, the minimum distance between such retaining wall and a structure shall be as set forth subsection 19.46.060(B).

E.

Erosion control planting.

1.

All cut and fill slopes shall be planted and irrigated with an approved automatic sprinkler system to promote growth of deep-rooted plants and groundcover that easily and quickly acclimate to their environment and prevent erosion.

2.

In developing a site, the developer shall plant and maintain all slopes where required by this Chapter until the property is occupied by reason of lease of purchase or until such time where the City accepts the landscaped area for maintenance per established city procedures. The developer shall provide suitable guarantees, planting, and maintenance required in this Chapter. The minimum requirements are as follows:

a.

All cut or fill slopes except slopes less than three feet in vertical height and all cut or fill slopes included within a slope maintenance district, shall be planted with adequate plant materials to protect the slope

against erosion. Plant material shall be selected from a list of plant materials adopted by the City. The planting shall be in the ratio of at least one tree per 300 square feet of actual slope, at least one shrub per 150 square feet of actual slope area, and ground cover to completely cover the bank within two years from time of planting. An automatic sprinkler system shall be installed to irrigate the slopes, trees, and shrubs.

b.

Landscape plans and plans of the permanent automatic sprinkler system shall be prepared pursuant to the requirements of Chapter 19.40 (Landscaping). In no event shall the rate of precipitation or duration of sprinkling be permitted to create an oversaturated condition or cause an erosion problem.

3.

Grading bonds shall not be released until all conditions of the landscaping plans and specifications are met and acceptance by the Director and City Engineer is given.

19.46.080 - Required street improvements—New construction.

A.

Access. All lots or parcels shall have direct access from a public dedicated street.

B.

Curbs and gutters. Vertical curbs and gutters consistent with adopted City specifications for public streets shall be constructed on both sides of all streets.

C.

Parking lanes. Parking lanes, eight feet in width, shall be provided on at least one side of all public streets, except where existing topography renders development adjacent to the street impractical, or where offstreet parking spaces are provided on each lot adjacent to the street or in parking bays. Roads without parking lanes shall be provided with emergency parking stalls adequate to contain two vehicles and spaces at an average distance of 500 feet. Such stalls are to be posted for Emergency Parking Only.

D.

Cut and fill slopes. All manufactured slopes adjacent to the roadway shall be a maximum of two horizontal to one vertical, unless limited by existing topography or constructed in rock. Manufactured slopes steeper than two to one may be permitted where adequate slope control measures are utilized. The slope shall in no case exceed the natural angle of repose of the material. Cut and fill slopes shall be constructed to eliminate sharp angles of intersection with the existing terrain and shall be rounded and contoured as necessary to blend with the natural topography to the maximum possible extent. Maximum vertical height of cut or fill slopes is to be 25 feet unless approved by the responsible Review Authority.

E.

Storm drainage. The design of storm drainage facilities shall ensure the acceptance and disposal of storm runoff without damage to the street or to adjacent properties impacted by storm water runoff. The use of

special structures to accept design storm runoff shall be incorporated into the street design where appropriate.

F.

Sidewalks. Sidewalks of five feet minimum width shall be provided along or in the proximity of all public streets and along private streets, as determined by the Director to be necessary. Walkways shall be constructed consistent with standard City specifications.

G.

Street lighting. All hillside public streets shall be provided with a level of street lighting designed to protect the health, safety, and welfare of those living within the hillside areas, but to avoid excessive light and glare. Street lights shall be mounted on ornamental light standards as approved by the Director.

H.

Driveways and drives. Driveways and drives shall be designed to a grade and alignment that will provide the maximum of safety and convenience for vehicular, emergency, and pedestrian use and in a manner which will not interfere with drainage or public use of the sidewalk and/or street area.

I.

Grade. A street shall have a grade of not more than 12 degrees. Where topography makes it impractical to keep within such grades, the responsible Review Authority may approve a grade in excess of 12 degrees, provided in such cases the developer submits evidence satisfactory to the City Engineer that a lower grade is not feasible.

J.

Design. Streets shall be designed to City standards and subject to the approval of the City Engineer. No cul-de-sac street shall have a length exceeding 700 feet, unless approved by the responsible Review Authority.

K.

Secondary access. A second access shall be required when deemed necessary by the Fire Department or the Director.

L.

Drainage provisions required. No building permits shall be issued for construction on any site which does not have provisions for conducting water drainage from the site and from adjacent properties impacted by runoff to a natural drainage course, a drainage channel or a public street in a manner approved by the City Engineer. Perpetual maintenance by a public agency shall be required for storm drain facilities including debris basins.

The use of private streets or lanes within hillside area developments shall not be allowed except where the Council determines that such streets will result in a more environmentally sensitive utilization of the hillside topography. Provisions shall be made for maintenance of private streets to the satisfaction of the Council. Private streets shall be built to City standards, and provisions for perpetual maintenance shall be established by the developer.

19.46.100 - Slope maintenance—New development projects and additions to existing development.

All slopes shall be maintained as follows:

A.

A declaration of covenants, conditions, and restrictions (CC&Rs) relating to the maintenance of slopes less than 30 feet in vertical height or located below a bench drain shall be required. A declaration of CC&Rs relating to the maintenance of slope areas, signed and acknowledged by those parties having any record title to the land to be developed, enforceable by the City, shall be recorded.

B.

All improvements located within the slope areas, such as landscaping and sprinklers, shall be maintained in a safe condition and a state of good repair. Any failure to maintain such improvements located on slope areas shall be deemed a public nuisance endangering the health, safety, and general welfare of the public and a detriment to the surrounding community. In addition to any remedy provided for by law for the abatement, removal and enjoinment of such public nuisance, the City, after giving proper notice, may cause the necessary work of maintenance or repair to be done, and the cost thereof shall be assessed against the owner.

C.

A landscape maintenance district must be established to maintain all manmade and natural slopes in excess of thirty feet or located above a bench drain.

19.46.110 - Fire prevention standards—New development projects and additions to existing development.

A.

In areas where, in the opinion of the Fire Chief, there will be a fire hazard to the watershed or any other properties, unobstructed fire protection equipment access easements, not less than 15 feet wide, shall be dedicated from the public highway to the subdivision boundary. The Fire Chief shall recommend to the responsible Review Authority where such easements are needed.

B.

Water mains and water systems shall be sized to provide sufficient water to meet the firefighting requirements of the area involved. The Fire Chief shall review proposed systems in relation to the National Board of Fire Underwriters' Standards for water systems, and shall make recommendations for the systems.

C.

The maximum distance between any residential structure and a fire hydrant shall be 250 feet, and hydrants shall be connected directly to water mains by not smaller than a six-inch pipe.

D.

All landscape planting and brush clearance shall comply with adopted fire regulations.

19.46.120 - Landscaping and irrigation standards—All development.

A.

All landscaping provided within 500 feet of the primary residential structure shall comply with the landscape materials and maintenance requirements for fuel modification zones.

B.

All portions of a site where existing vegetative cover is damaged or removed, or consists primarily of weeds (typically unwanted plants that grow aggressively and are damaging to native plants), and are not otherwise covered with new improvements, must be successfully re-vegetated with a substantial mix of native and/or drought tolerant grasses and ground covers. The density of the re-established vegetation must be adequate to prevent soil erosion and invasion of weeds after one growing season.

C.

Prior to planting, consideration of soil compaction shall be used to determine planting pit depths and drainage.

D.

The Director shall have the authority to require other improvements such as the removal of dead or diseased trees and the thinning of trees or other vegetation to encourage desirable growth.

E.

Landscaping and irrigation shall be maintained by the developer until the property is occupied. The developer shall provide guarantees, satisfactory to the reviewing body, for maintenance.

F.

The interface between new development and natural open space shall be designed to provide a gradual transition from manufactured areas into natural areas. Landscaping compatible with natural vegetation shall be designed so that it extends out from developed areas and forms a cohesive pattern with existing natural vegetation. The purpose is to blend the new landscape with the natural vegetation.

G.

Trees and shrubs shall be arranged in informal, randomly spaced masses, and shall be placed selectively to reduce the scale of and help to blend manufactured slopes into natural terrain.

H.

Landscape palettes shall be derived from the Los Angeles County Fire Department's fuel modification plan desirable plant list and landscaping guidelines adopted by the City.

I.

For fire prevention purposes, a fuel modification plan consistent with Los Angeles County Fire Department fuel modification plan requirements shall be submitted to the Director for review and approval prior to issuance of building permits.

J.

For each existing native tree or shrub removed or damaged with a combined caliper equal to or greater than four inches at four feet above finish grade, a 24-inch box minimum replacement tree or shrub of the same genus and species shall be planted on the site. For trees equal to or in excess of an eight-inch combined caliper, the replacement tree shall be a 48-inch box or larger of the same genus and species. Should a tree of the same genus and species not be available, the applicant shall submit reasonable proof of general unavailability in the region, and a list of no less than five substitutes, one of which shall be of the same genus, for approval by the Director. The Director may approve a substitute or may require provisions, including but not limited to bonds or similar security, to assure the installation and maintenance of the specific genus desired.

Chapter 19.48 - PROPERTY MAINTENANCE

Sections: