Sec. 21-44. - Special definitions.

Average slope of a parcel of land or any portion thereof shall be computed by applying the formula S = (.00229 IL)/A to the natural slope of the land, before grading is commenced, as determined from a topographic map conforming to National Mapping Standards and having a scale of not less than one inch equals two hundred feet and a contour interval of not less than five feet. The letters in this formula shall have the following significance:

S = The average cross slope of the land in percent.

I = The contour interval.

L = The combined length of all contours in feet, excluding the length of contours in drainage channels below the twenty-five year flood level.

A = The net area of parcel or portion thereof, in acres, after deducting all areas in drainage channels below the twenty-five year flood level, for which the slope is to be determined.

Unstable geological or soil formations includes but is not limited to formations having stability problems, susceptibility to slippage or subsidence, vulnerability to erosion and other special geological and soil conditions potentially hazardous to persons or property, or both.

Special treatment area means and includes land having physical characteristics which require application of one or more special conditions in order to protect and preserve the public health, safety and welfare. It shall include many areas of land containing extensive hillsides or rugged terrain. The Board of Supervisors, upon recommendation of the Planning Commission, may by resolution or minute order designate by map or metes and bounds description, or otherwise, areas in the County which shall be deemed to be "Special Treatment Areas" by reason of conditions affecting such areas generally.

(Ord. No. 1751, § 2)

Sec. 21-45. - Procedure.

(a)

It shall be the responsibility of all persons desiring to subdivide land in the unincorporated territory of the county, and of their agents and representatives, to inform the department of public works of the county in writing of the exact boundaries of the land proposed to be so subdivided. Topographical maps may be

required to be submitted wherever deemed appropriate by the department of public works, the planning department or subdivision committee of the county. Further, the planning department shall notify the department of public works in writing of all formal written applications for the subdivision of land and the boundaries thereof forthwith upon receipt of such applications.

Where a proposed subdivision contains land designated by metes and bounds description or map as a special treatment area by the board of supervisors, then the subdivider shall not be required to follow the procedure set out in subsections (a) and (b) of this section relating to determination of whether or not a subdivision is, or contains, a special treatment area. The subdivider, however, shall follow all of the other procedures and meet all of the requirements imposed pursuant to this division.

ial treatment area by the board of supervisors, then the subdivider shall not be required to follow the procedure set out in subsections (a) and (b) of this section relating to determination of whether or not a subdivision is, or contains, a special treatment area. The subdivider, however, shall follow all of the other procedures and meet all of the requirements imposed pursuant to this division.

Within ten days after receipt of such information by the department of public works, that department shall notify the subdivision committee and the applicant, or his agents and representatives, in writing of its recommendation as to whether or not the land proposed to be subdivided contains special treatment areas.

(b)

At the next meeting after the meeting where the recommendation of the department of public works is received and before any other consideration of such proposed division of land, the subdivision committee will consider the recommendation and thereafter determine whether or not the land to be subdivided, or any portion thereof, is a special treatment area. The subdivision committee shall not be bound by the recommendation of the department of public works and shall make its determination on the basis of a consideration of all of the purposes set out in this division. The applicant, his agents and representatives shall be entitled to be present when such determination is to be made and may present evidence on the matter.

In the event the applicant or his agents or representatives are dissatisfied with the determination of the subdivision committee, they may appeal in writing from such determination within ten days from the date thereof to the planning commission which may sustain, modify or reverse the determination of the subdivision committee.

In the event the applicant or his agents or representatives are dissatisfied with the decision of the planning commission, they may appeal in writing from such decision within ten days from the date thereof to the board of supervisors, which may sustain, modify or reverse the determination of the planning commission.

(c)

Where land is being subdivided and is shown on a map or designated by metes and bounds or other description as being or containing within it a special treatment area, the applicant or his agents or representatives may request the planning commission to recommend to the board of supervisors that such land, or portions thereof, not be deemed to be a special treatment area, and the applicant, his agents and representatives shall be entitled to present evidence in support of their position. The planning commission shall consider such application and make its recommendation to the board of supervisors. If such recommendation approves in whole or in part the request of the applicant or his agents or representatives, the board of supervisors shall hear the matter, and, without being bound by the recommendation of the planning commission, may take such action as it deems appropriate. If the recommendation of the planning

der such application and make its recommendation to the board of supervisors. If such recommendation approves in whole or in part the request of the applicant or his agents or representatives, the board of supervisors shall hear the matter, and, without being bound by the recommendation of the planning commission, may take such action as it deems appropriate. If the recommendation of the planning

commission is contrary to the request of the applicant and recommends denial of the applicant's entire request, the board of supervisors may, but need not, hold a hearing on the matter and, without being bound by the recommendation of the planning commission, may, if it holds a hearing, take such action as it deems appropriate.

(d)

After final determination that a proposed subdivision, or any portion thereof, is a special treatment area, the applicant or his agents and representatives shall hold design conferences with appropriate members of the subdivision committee before submitting a tentative map. The applicant, his agents or representatives may be required by the subdivision committee to present any one or more of the following: A preliminary subdivision map; a contour map of the land affected with five foot contours to a scale of at least one inch equals one foot; plans, cross sections and profiles of the proposed grading of the land; preliminary geological report by an engineering geologist; a soil report by a registered civil engineer experienced in the field of soil mechanics; representative percolation tests where community sewer systems are not to be used; and other relevant data. The date of filing which commences the period for action on a proposed subdivision shall not be prior to the date of determination as to whether the subdivision or any portion thereof is a special treatment area.

(e)

After tentative criteria for the subdivision are established at the design conferences, the subdivision committee may, at its option, require submission by the applicant of a preliminary map. The subdivision committee may also require a proposed grading plan and any other maps or data which are reasonable or appropriate in order to assist the subdivision committee in determining what conditions it should recommend from those set out in this division. It is understood that the subdivision committee may apply any one or more of the special provisions of this division or of any other sections of this Code or any county ordinance or any special regulations set up by the board of supervisors which are reasonable and appropriate in order to carry out the express purposes of this division and are not in conflict with general law relating to these matters. Special treatment subdivisions shall always be treated as other subdivisions except as expressly provided by this division or by resolution of the board of supervisors adopted pursuant hereto.

(f)

On all lot splits, the subdivision committee may determine that the land concerned includes areas which are special treatment areas as defined herein and may impose these special treatment conditions as conditions of approval of such lot splits as provided in subsection (e) of this section. In the event the applicant or his agents or representatives are dissatisfied with the determination of the subdivision committee as to a special treatment area, they may appeal in writing from such determination within ten days from the date thereof to the planning commission which may sustain, modify, or reverse the determination of the subdivision committee. If a proposed lot split is already shown on a map or otherwise designated as a special treatment area, then appeal may be made as set out in subsection (c) of this section, to have the land declared not to be a special treatment area. Otherwise, if so designated as a special treatment area, these special treatment conditions may be imposed as conditions of approval of the lot split as provided in subsection (e) of this section.

(Ord. No. 1751, § 2; Ord. No. 2380, §§ 1 to 3)

Sec. 21-46. - Special grading and landscaping provisions.

The following provisions are intended to prevent flooding, creation of unsightly raw earth areas, erosion and stability problems, and to promote proper drainage and attractive appearance.

(a)

In order to keep all graded areas and cuts and fills to a minimum, to eliminate unsightly grading, and to preserve the natural appearance and beauty of the property as far as possible as well as to serve the other specified purposes of these special provisions, limitations may be placed on the size of areas to be graded or to be used for building pads, and on the size, height and angles of cut slopes and fill slopes and the shape thereof. In appropriate cases, retaining walls may be specified.

(b)

Submission for approval of planting plans or elements thereof on special treatment areas within a subdivision may be required, particularly in connection with proposed reshaping of sloping land. Reshaping of sloping land rather than mass "pad" grading of steep terrain may be permitted provided the resulting appearance is as natural as possible, adequate drainage is provided and the slopes are properly stabilized and foundation conditions will be sound. In all cases numerous and extensive steep cut and fill slopes shall be avoided and conditions imposed to eliminate such dangerous and unattractive grading.

(c)

Either drainage to the street on which the lots front, or acceptable artificial drainage facilities may be required wherever such drainage is necessary.

(d)

Sheet drainage between building sites may be permitted on lots twenty thousand square feet or more in net area where no appreciable damage is likely to be caused thereby.

(e)

Drainage facilities including but not limited to terraces, storm drains, roof gutters and downspouts, ground gutters and berms may be required.

(f)

The date when grading is to be commenced and the date when it is to be completed may be prescribed and grading operations may be prohibited during certain months because of anticipated seasonal weather conditions. In subdivisions being developed in successive units, grading and drainage requirements may be applied to any proposed units whether development is current or pending where necessary in order to protect units already graded or to protect the land in the ungraded units or adjoining land.

(g)

Lot line locations in relation to cut or fill slopes may be prescribed.

(h)

Minimum spaces between structures and the tops or toes of slopes may be prescribed.

(i)

In order to avoid detrimental effects to neighboring property, contour maps of appropriate portions of property adjacent to the subdivision may be required and conditions may be prescribed so that the grading will not detrimentally affect such adjacent property. This requirement shall not be imposed unless the right of entry is available to the subdivider or the county takes necessary steps to acquire and provide such right of entry for the subdivider.

(Ord. No. 1751, § 2)

Sec. 21-47. - Special fire prevention and suppression provisions.

(a)

Public interest in protecting Southern California's mountains from fire stems from the need to protect improvements below from the threat of aggravated flood damage due to burning of the vegetation, and to preserve the natural functions of these mountains as watersheds in absorbing rainfall needed to replenish underground water storage basins. Because of dry climate, combustible vegetation, and rugged terrain, fire hazard in these mountains is great and fire control is difficult.

(b)

Increasing population has complicated the mountain fire problem and has intensified the public health and safety aspects of watershed resource fire protection. Homes and other structures have been built in the mountain watersheds without regard to the hazards involved. Such development and use not only increases the chances of disastrous brush fires, but the dwellings and people themselves are exposed to serious fire threats.

(c)

Uncontrolled development of the hazardous mountain areas sets the scene for disaster. Structural fire losses from brush fires have been great, and losses have been increasing in recent years. Fire fighting forces alone cannot always furnish protection; measures to compensate for hazardous conditions must be planned and built into subdivisions.

(d)

The dominant vegetation in the county's mountainous areas is brush or chaparral—the dense growth of many shrub species, mainly chamise, scrub oak, manzanita and ceanothus. It makes pleasant surroundings for homesites, but it is deceptively flammable. The natural dryness of the brush, its structure, and dense growth present a fire hazard which becomes critical during the summer and fall months, especially when the hot, dry winds blow in from the deserts. This native brush is a good protective watershed cover, but in developed areas it is extremely hazardous around homes and communities.

(e)

The drying effects of several days of wind can evaporate the beneficial moisture of rain, creating fire weather conditions during the winter months. Disastrous fires can occur any month of the year.

(f)

The mountains in the county rise abruptly from densely populated valleys and coastal areas. These rugged mountains make fire control difficult because of the physical obstacles involved and the influence of the terrain on fire behavior. The same characteristics which intensify the fire problem—the rugged terrain, steep slopes, and loose soils—also intensify interlocking problems of flooding prevention and control, water supply and distribution, roads, and building construction.

(g)

Dense, dry, explosive brush growing on rugged slopes, ridges, and in canyons is a condition of environment which is hostile to uncontrolled development. Ever-increasing numbers of people have compounded the wildland fire problem and have made the protection of life and property of utmost importance.

(h)

In Southern California, subdivisions have been located within high fire hazard areas. In the county, encroachment of urban areas into the watershed lands—moving up the mountain slopes and into the canyons—into areas of increasing hazard and more difficult fire control has commenced and will increase.

(i)

The fire problem is no longer solely one of protecting a valuable natural resource—it is also one of people, lives, and property.

(j)

Direct fire losses and losses due to ensuing flood damage are costly to the individual and to the public. Public benefits must be protected, and the exposure charges of fire insurance in hazardous areas brought down to a level comparable to similar developments in other areas.

(k)

Mountain land considered for subdivision, or mountainous land within or adjacent to cities, is not "wildland"—it is undeveloped "urban" land. It must be regarded in this light and be developed properly. The development of private lands in Southern California is inevitable. Comprehensive land-use planning is necessary for orderly growth and realization of the full economic and social benefits of this resource.

(l)

Fire protection is a fundamental need—a common denominator—to man's safe habitation and use of these mountainous lands.

(m)

Elements of integrated fire protection planning include:

(1)

Topography. A study of the slopes and the relation of the proposed developments to the configuration of the land.

(2)

Land Use. A determination of centers of development, and zoning to include the various residential, business, agricultural, and manufacturing districts, the location of schools, and the location of open areas such as parks, green belts, and golf courses.

(3)

Traffic Flow. The road network, consisting of arterial and collector streets, should circulate to provide for fire access and public evacuation.

(4)

Water System. The distribution and source facilities should be of a design sufficient to support necessary fire flow.

(n)

Areas of extreme fire hazard shall be deemed to be special treatment areas. In general, areas of extreme fire hazard shall be deemed to be any area which is covered with a continuous or nearly continuous highly flammable vegetative growth as determined by the planning commission or the board of supervisors as provided in this division.

(o)

For the protection of present and future improvements and their users and occupants, the following fire safety requirements are recommended, and where appropriate, may be required:

(1)

Safe Ingress and Egress. Area development should provide for ready access as to fire and other emergency equipment and for routes of escape to safely handle evacuations. Therefore, road and street system designs should provide maximum circulation consistent with topography to meet fire safety needs and the following conditions or such of them as are appropriate may be imposed:

(A)

Require at least two different routes of entrance and egress to the subdivision or lot split.

(B)

Require a sixty-foot right-of-way for the construction of two twelve-foot traffic lanes, two eight-foot parking lanes, and two ten-foot roadside strips upon which the fire hazard should be abated.

(C)

Limit cul-de-sacs to six hundred feet terminated by a turn-around right-of-way of not less than ninety feet in diameter.

(D)

Street grades should be limited to ten percent except for such distances as topographic conditions make greater grades practical.

(E)

No street or road should have a centerline radius of less than fifty feet.

(F)

The responsible fire agency may remove and clear within twenty feet on each side of every roadway all flammable vegetation or other combustible growth and may enter upon private property to do so. This should not apply to single specimens of trees, ornamental shrubbery or cultivated ground cover such as green grass, ivy, succulents or similar plants used as ground covers provided that they do not form a means of readily transmitting fire. As used in this section "roadway" means that portion of a highway or private street improved, designed, or ordinarily used for vehicular travel.

(2)

Street Names and Numbers. To facilitate fire location and to avoid delays in response, all roads, streets, and buildings shall be designated by name or number clearly visible from the main traveled roadway.

(3)

Community Firebreaks. Firebreaks separating communities or clusters of structures from the native vegetation may be required. Such firebreaks would be more properly termed "fuel-breaks" or "green belts" because all vegetation need not be removed, but thinned out or landscaped so as to reduce the volume of fuel.

(A)

All easements for firebreaks for fire safety of built-up areas shall encompass access for fire fighting personnel and equipment, which may mean motorized travel in some cases; such easement shall be dedicated to this specific purpose by being recorded.

(B)

Community firebreaks shall be coordinated with overall firebreak and fuelbreak plans of the mountain area.

(4)

Fire Protection Water Facilities. Water is the most important single factor in fighting structural fires. Therefore, to assure adequate and reliable water supplies for community fire protection in hazardous areas, the following requirements or such of them as are appropriate may be imposed:

(A)

Except in rural desert and rural mountain areas with a planned population density of one or less dwelling per acre, the minimum size of water distribution mains on which fire hydrants are located shall be a minimum six inches in a system designed to permit circulating water flow as may be practical. Hydrant spacing shall not exceed six hundred and sixty feet with minimum fire flow of five hundred and fifty gallons per minute required for population densities of two or less single family residences per acre; for population densities of more than two dwellings per acre hydrant spacing shall not exceed three hundred and thirty feet with a minimum fire flow of seven hundred and fifty gallons per minute, and more where structural conditions require. Water source facilities shall have the capacity to support the required fire flow for a minimum duration of two hours in addition to the maximum daily flow requirements for other consumptive uses. Water storage may be required to assure the required minimum duration fire flow of two hours with the single most serious interruption to power lines, water mains, and to pump units.

The local fire authority may adjust the water quantities set forth on the basis of local conditions, exposure, congestion, and construction of buildings.

(B)

The size, type and location of fire hydrants shall meet the approval of the responsible fire authority and of applicable state and county regulations, with a minimum size of waterway not smaller than the size of the street main up to a nominal 6-inch size. A gate shall be placed on the connection between main and hydrants.

(C)

Those rural mountain and rural desert areas planned for a population density on one or less dwelling per acre shall be encouraged to obtain water service from a single system which shall conform to minimum state regulations as to pipe size and supply. Fire hydrants shall be installed at least each one-fourth mile with individual locations as near as possible to structures to be protected—specific locations to be approved by the responsible fire authority.

(D)

Those separately developed dwellings with an individual private water supply shall provide an acceptable guaranteed minimum supply of water, above the amount required for domestic needs, that will be adequate in the judgment of the fire authority for fire protection of the structures.

(5)

Refuse Disposal. All areas planned for intensive development shall include a suitable plan for the disposal of flammable refuse. Refuse disposal shall be in accord with county or local plans or ordinances, and shall not be less than state requirements. Where practical, disposal shall be by methods other than open burning.

(Ord. No. 1751, § 2)

Sec. 21-48. - Special sewage disposal provisions.

(a)

The purposes of this section are to insure that in special treatment areas there will be adequate and sanitary methods provided for the disposal of sewage which will not pollute water supplies, bathing and swimming areas, permit sewage to come onto the surface of the land, create erosion or earth subsidence or slippage problems and generally prevent other hazards to health and safety.

(b)

In order to protect lift stations, manholes and other appurtenances of community sewer systems from flooding, land movement and other possible sources of damages, locations and protective measures may be prescribed. In order to insure adequate operation, the type and method of operation of lift stations may be prescribed. Such conditions may be in addition to those required by other governmental agencies.

(c)

The use of individual sewage disposal systems may be limited to prohibit where pollution of the underground water table will endanger supplies of domestic water, where seepage of water into unstable or potentially unstable soil or rock formations is likely to cause earth movements dangerous to life or property, and in other cases where a danger to life, limb or health may result from use of individual sewage disposal systems.

(Ord. No. 1751, § 2)

Sec. 21-49. - Special water supply provisions.

Where the elevation of all or a portion of the land proposed to be subdivided is such that tanks, pumps or reservoirs need to be installed, this fact must be indicated at the time the tentative map is filed, although the exact locations of such facilities need not be indicated prior to submission of the final subdivision map.

(Ord. No. 1751, § 2)

Sec. 21-50. - Special road provisions.

The provisions relating to special road requirements are to be found in division nine of this article and in policy resolutions of the board of supervisors. Any one or more of such special provisions relating to roads may be applied when appropriate and reasonable in order to carry out the purposes of this division.

(Ord. No. 1751, § 2)

Division 9. - Classification of Streets

Sec. 21-51. - Alley.

An alley is a secondary means of access usually lying along the rear of lots or property, the front of which abuts on and has primary access from a street.

(Ord. No. 1722, pt. 9, § 14)

Sec. 21-52. - Arterial road.

An arterial road is a street so designated by a general or specific plan adopted by the board of supervisors, or any street which by reason of its through-route characteristics or uses of land served now carries, or is expected to carry in the next twenty years, more than ten thousand vehicles per day.

(Ord. No. 1722, pt 9, § 3)

Sec. 21-53. - Boundary street.

A boundary street is a street lying along a subdivision boundary.

(Ord. No. 1722, pt. 9, § 12)

Sec. 21-54. - Collector street.

A collector street is a primary residential street designed to connect streets of a higher classification (carrying more traffic) designed to have a minimum interference of traffic from driveways.

(Ord. No. 1722, pt. 9, § 9)

Sec. 21-55. - Commercial street.

A commercial street is a street which is to provide access to abutting property zoned for commercial purposes.

(Ord. No. 1722, pt. 9, § 11)

Sec. 21-56. - Expressway.

An expressway is a divided arterial highway for through traffic which may provide "at grade" crossings or may have partial control of access.

(Ord. No. 1722, pt. 9, § 2)

Sec. 21-57. - Freeway.

A freeway is a divided arterial highway for through traffic having full control of access with no "at grade" crossings.

(Ord. No. 1722, pt. 9, § 1)

Sec. 21-58. - Frontage road.

A frontage road is a road which is auxiliary to and located adjacent to a freeway, or other highway, and which may provide service to abutting property on only one side of the road and with controlled access to the adjacent major route. A frontage road may be of any classification.

(Ord. No. 1722, pt. 9, § 13)

Sec. 21-59. - Hillside residential street.

A hillside residential street is a street used as a residential, residential cul-de-sac, or residential loop street with special design features deemed appropriate by the road commissioner on the basis of slope and terrain. In general, this shall include areas where the natural cross-slope to be graded for the street exceeds fifteen percent.

(Ord. No. 1722, pt. 9, § 16)