§ 25-17. Standards for approval.

The project review and advisory committee shall approve, disapprove, or conditionally approve the subdivision application in accordance with the following standards:

(a)

The information or basis for information shown on the map is complete.

(b)

The proposed division would not constitute a subdivision for which a tentative and final map are required by the Subdivision Map Act or this chapter.

(c)

All parcels and the intended use shall conform to the minimum building site area, allowable lot width, yards and access requirements of the county zoning regulations for the zoning district within which the parcels lie.

(d)

Access to each parcel will be provided by fronting on a county-maintained road or a private road of adequate right-of-way width. When additional right-of-way is necessary it shall be required only from the property of the owner. The required right-of-way width over the lands owned by the applicant shall be fifty feet (50′) unless in the opinion of the committee such width will not be in the public interest presently or in the future. Access is deemed adequate only if it will allow reasonable ingress and egress for emergency vehicles.

(e)

Right-of-way sufficient for the ultimate public facility shall be dedicated where lots front on a county-maintained road of insufficient width, or, when the existing right-of-way is not deeded. No land may be required to be dedicated to the county from the residual parcel unless the residual parcel is itself of ultimate size, and it does not have a permanent structure in the proposed right-of-way or a residential structure located within the setback line and closer than ten feet (10′), if a front yard, and five feet (5′), if a side yard, to the ultimate road right-of-way.

(f)

(1)

Minimum lot size shall be one and one-half acres where individual sewage disposal and water supply systems are necessary, unless the size and shape of the site and surrounding parcels allow for a lesser lot size. Minimum lot size shall be one (1) acre where individual sewage disposal systems are necessary but water is available from an approved public water system. These lot sizes are exclusive of rights-of-way and/or easements. In either case, there shall be sufficient area on the parcel to accommodate a private sewage disposal system for a typical three (3) bedroom house plus unencumbered area to expand or replace this system by two hundred percent (200%);

(2)

Evidence shall be provided of suitable soil percolation characteristics to meet current criteria of the Sonoma County public health service and the basin plan of the appropriate Regional Water Quality Control Board. Some parcels require testing during the official "wet-weather" season;

(3)

Leachfield areas must be located a minimum of one hundred feet (100′) horizontally from the contour of the ten (10) year flood elevation of perennial waterways and fifty feet (50′) horizontally from the top of bank of ephemeral waterways or drainage courses;

(4)

Leachfield areas shall be a minimum of one hundred feet (100′) from existing or proposed well sites, springs, seepage areas, oceans, lakes, or reservoirs. The presence of springs, seepage areas, or shallow water tables may necessitate approval of the proposal by a registered geologist or certified engineer geologist;

(5)

On parcels where drainage may adversely affect septic field function, an approval by a registered civil engineer and/or provision of drainage easements may be required;

(6)

Leachfields shall be located to avoid areas of land slippage or instability and shall not be placed in areas where land slippage or instability could be induced or accelerated by leachfield discharge. In areas designated potentially unstable, an analysis by a registered or engineering geologist will be required;

(7)

Additional conditions necessary to supplement those established for the tentative map to ensure compliance with sewage disposal regulations prior to filing the final map may be required by the project review and advisory committee;

(8)

Preliminary percolation testing and soil profile analysis will be required on major subdivisions prior to filing the tentative map in order to determine whether the proposed density and lot design are feasible. Reports on at least one (1) percolation test hole per lot and one soil profile hole per five (5) lots must be submitted. Soil profile holes may be reduced in conformity to a given soil type can be established. Additional testing will be required prior to filing the final map to substantiate suitable disposal areas;

(9)

Location of leachfields shall not be on slopes of greater than thirty percent (30%).

(g)

(1)

Development and creation of impervious surfaces in a natural recharge area shall be subject to soils investigation and mitigation of potential recharged reduction. Should adequate mitigation not be possible, the project shall be denied;

(2)

In order to reduce the off-site peak storm flow generated by projects with a density greater than one (1) dwelling unit per acre, retention ponds, drainage swales or the use of check dams shall be utilized where deemed necessary by the project review and advisory committee based on density, size of site, shape of site, and topography;

(3)

Drainage improvements for runoff from all roadways and other impervious surfaces shall be engineered to minimize erosion through the use of rocked culvert inlets and outfalls, energy reducers, proper location of culverts, reseeding of exposed slopes, and minimizing the use of artificial slopes.

(h)

Necessary applications for the formation of districts or annexations thereto will be made to the local agency formation commission of the county as required by law.

(i)

Lot design conforms to the same requirements and standards as for subdivisions for which a tentative and final map are required so as not to substantially devalue other parcels in the neighborhood.

(j)

Note: All road base and surfacing standards are considered minimum. The equivalent of class I sub-base may be substituted for the class II base subject to the project review and advisory committee approval.

Private Roads. Projects with a density of one (1) unit per acre or less for which an applicant requests and PRAC approves private road status shall be developed in accordance with the following:

(1)

Eighteen feet (18′) width roadway with six inches (6″) class II base, two inches (2″) asphaltic concrete pavement;

(2)

Shoulders and asphaltic concrete dikes optional except as required for drainage control;

(3)

Roads for projects consisting of ten (10) lots or fewer or where "feeder" roads within a larger project contain ten (10) lots or fewer and where further divisions are not possible may, if approved by PRAC, be only twelve feet (12′) in width with six inches (6″) class II base, two inches (2″) A.C. pavement. A six foot (6′) cleared lane shall adjoin the twelve foot (12′) paved section for additional fire access; said section need not be surfaced or based;

(4)

Rights-of-way shall be a minimum of twenty feet (20′) unless altered by PRAC;

(5)

Where speed on proposed roadways is deemed to be a concern, traffic control devices such as signing and especially road design may be utilized as mitigation measures;

(6)

For projects which assure long-term road maintenance through the use of legal entities (such as homeowner's associations) private road standards may allow the use of a "seal coat" for surfacing; width and base standards are to be consistent with subsections (j)(1) and (j)(3) of this section where applicable. Seal coat shall consist of one (1) one-half-inch layer of #4 rock, one (1) layer of RS-1 sealing oil, and three-eighths inch of #6 rock;

(7)

Where roadway grade is ten percent (10%) or less, the seal coat described in subsection (j)(6) of this section may be substituted for the two inch (2″) A.C. pavement;

(8)

Where private roads require bridges, said bridges shall conform to regulation H-15 of the State Department of Transportation relating to bridge weight requirements;

(9)

When half-width rights-of-way are proposed, improvements shall be in the minimum width of twelve feet (12′) with six inch (6″) class II base and two inches (2″) A.C. pavement;

(10)

Civil engineered drainage plans shall be provided for all roads and driveways of all subdivisions;

(11)

Grades shall not exceed fifteen percent (15%) but with PRAC approval may not exceed twenty percent (20%) for short distances;

(12)

Roads for parcels greater than forty (40) acres shall meet county grade and alignment standards; width and surfacing standards to be determined by PRAC if deemed necessary;

(13)

Driveways (defined as private roads serving two (2) lots or less) off subdivision roads shall meet county grade standards for private roads and may be required by PRAC to be improved depending on terrain, grade, length, and other factors.

(k)

Repealed.

(l)

Repealed.

(m)

Repealed.

(n)

Repealed.

(o)

If the real property is subject to a Williamson Act agreement or contract, all parcels must meet the minimum requirements of the agricultural preserve advisory committee, its designated representatives, or other official who may be designated by resolution of this board of supervisors as to conformity with agricultural preserve regulations.

(p)

Repealed.

(q)

(1)

Domestic water supply must be provided from either an approved public water system or from an individual source for each parcel. Any proposal to share a water source with five (5) or more connections requires compliance with the Pure Water Law (Health and Safety Code, Sec. 4010 et. seq.). Any proposal to share a water source with two (2) to four (4) connections requires establishment of an entity which meets the approval of the health officer to operate and maintain the system. Design of water systems of two (2) or more connections shall be in conformance with Sonoma County water system standards.

(2)

All subdivision applications within area 4 as shown on that certain map entitled "Groundwater Availability" (on file with the Sonoma County permit and resource management department and available for public inspection) and served by individual wells shall meet the following requirements relating to groundwater prior to recordation of the parcel map:

(i)

That a well or wells on each new undeveloped lot yield a minimum of one (1) gallon per minute for a sustained. yield, metered pump test of twelve (12) hours or eight (8) hours in accordance with the Sonoma County permit and resource management department's well pump test guidelines;

(ii)

A note shall be indicated on the parcel map or similar document that this minimum shall be accompanied at the time of residential construction with a requirement of a minimum of one thousand (1,000) gallons of storage capacity. Said capacity shall be stored in storage tanks;

(iii)

A yield of three (3) gallons per minute will require five hundred (500) gallons of storage under the above testing procedure. A yield of five (5) gallons per minute will require no storage;

(iv)

Testing to meet the above yield requirements shall be conducted from July 15th to October 1st. This time may be extended by the project review and advisory committee in the case of successive dry years;

(v)

Pump tests shall be performed by or under the direction of a licensed water well drilling contractor (C57), pumping contractor (C61/D21), a registered civil engineer or a registered geologist. The director of permit and resource management department shall be notified a minimum of twenty-four (24) hours prior to the pump testing of wells or springs;

(vi)

Test wells shall be sealed as required by Section 25B-5 or completed immediately upon completion of the test or before the driller leaves the site in order to prevent accidental injury to people and animals. A well log on each test well shall be submitted to the Sonoma County permit and resource management department upon completion of the test;

(vii)

On lots greater than twenty-five (25) acres (gross) in size, the project review and advisory committee may waive the requirement of test wells. The parcel map or similar document shall contain a note relating to the lack of evidence of groundwater availability;

(3)

All subdivision applications within area 4 as shown on that certain map entitled "Groundwater Availability" (on file with the Sonoma County permit and resource management department and available for public inspection) and served by a water system shall meet the following requirements relating to groundwater prior to recordation of the parcel map:

(i)

That the well or wells supplying the water system yield a minimum of one (1) gallon per minute per dwelling unit by a sustained yield, metered pump test of the following duration:

(a)

Each dwelling unit is a connection to the well. Wells with one (1) to two (2) connections: test of twelve (12) hours or eight (8) hours in accordance with the Sonoma County permit and resource management department's well pump test guidelines.

(b)

Wells with three (3) to four (4) connections: test of twenty-four (24) hours or sixteen (16) hours in accordance with the Sonoma County permit and resource management department's well pump test guidelines.

(c)

Wells with five (5) or more connections: test of at least seventy-two (72) hours after the dynamic pumping level has been established. A reduction of the seventy-two (72) hour metered pumping test may be granted by the administrative authority if it is indicated that the sustained yield well production is two (2) or more times greater than required. Under no circumstances shall the test be less than forty-eight (48) hours.

NOTE: Also see Section 64563 of the California Code of Regulations for determination of source capacity for systems with five (5) or more connections.

(4)

In water scarce areas bordering on known groundwater or recharge basins (generally within five hundred feet (500′)), the project review and advisory committee may waive the well requirement upon submission of evidence of groundwater availability. Such evidence shall include, but not be limited to, geology reports, well log data, and historical documentation.

(5)

The project review and advisory committee, upon reason to believe the existence of salt, bacteriological, mineral or other contamination, shall require a water quality test for such wells to be conducted by a State Department of Health certified laboratory. Test results shall be submitted to the Sonoma County permit and resource management department for approval or disapproval.

(6)

If springs are to be used as the primary domestic water source, yields from springs and the required storage capacity shall meet the same minimum requirements as for wells. Springs shall be perennial. The water collection facilities from the springs shall be designed to the satisfaction of the Sonoma County permit and resource management department.

(7)

In areas designated water scarce area 4 or marginal water availability area 3 on the groundwater availability map, a report by a registered geologist shall be prepared as required by general plan policy RC-3h. Test wells may be required in marginal water availability areas 3 and 4 where doubt exists as to the possibility of developing water.

(8)

An annual review of the groundwater availability map shall be made so that new data and information can be utilized to keep the map up-to-date.

(r)

Protect and encourage agricultural production by establishing a buffer between agricultural production on lands either designated in one (1) of the three (3) agricultural land use categories in the general plan or lands included within the "AR" zoning district, where any such lands abut a nonagricultural land use conducted on land outside the three general plan land use categories. Generally, buffers shall be defined as a physical separation of one hundred (100) to two hundred feet (200′). These may be modified based upon topographic feature, a substantial tree stand, water course or similar existing feature. In some circumstances, a landscaped berm or other man-made feature may enhance the buffer. The requirement for buffer may be modified after hearing by the advisory agency following a written recommendation by the agricultural commissioner.

Notwithstanding the provisions of Chapter 26, Article XXX (nonconforming uses) where the imposition of the buffer creates a nonconforming condition, expansion or modification of such use may be permitted provided that encroachment into the setback does not exceed that of the existing structure.

Agricultural production as used herein means either an existing agricultural operation or an agricultural operation that would be a reasonably anticipated use. No buffer or setback shall be created by the acquisition of a portion of a parcel devoted to an agricultural operation.

(s)

The project review and advisory committee may specify the order in which conditions are to be completed and may require that one (1) or more conditions be fulfilled prior to the commencement of the fulfillment of other conditions.

(t)

Where projects are determined to warrant further geological investigation, a geologist's report shall be required which summarizes and illustrates the following categories:

(1)

Areas where standard foundation and other conventional construction techniques are satisfactory;

(2)

Areas where geological hazards may exist but which in the opinion of the geologist can be mitigated, i.e., foundation design;

(3)

Areas where geologic suitability is uncertain without additional geotechnical and/or subsurface investigation.

(u)

Development allowed in areas designated on the natural resources map of the Sonoma County general plan (on files in the Sonoma County permit and resource management department and available there for inspection) as resource areas shall be permitted subject to the following design-siting requirements:

(1)

Design of projects shall recognize the environmental and resource characteristics of the site and be designed in such a manner which allows for the preservation and continued production of the particular resource;

(2)

Design of projects in resource areas shall utilize the least productive portion of the site, leaving the productive areas intact, where possible. The design of projects shall be consistent with other applicable development standards;

(3)

Development shall not adversely affect the natural course or riparian habitat of any stream. Mitigation measures shall be required of the project where development may result in impacts to such areas;

(4)

Development shall not adversely affect tidal marshes, freshwater marshes, estuaries, or marine waters. Impacts upon these areas by a project shall be mitigated;

(5)

Development shall not adversely affect areas identified as significant wildlife habitat, and impacts upon these areas by a project shall be mitigated;

(6)

Extensive changes or removal of vegetation shall demonstrate minimal adverse impacts on micro-climate conditions. Erosion protection and revegetation shall be required in all cases of vegetation removal;

(7)

Whenever there is reason to suspect significant archaeological or paleontological sites (as noted in the initial study process under the California Environmental Quality Act) within the project area, an appropriate survey by a qualified professional shall be submitted to the Sonoma County permit and resource management department;

(8)

Development shall not adversely affect the existing volume of any water body, substantially increase chemical or nutrient pollution, or otherwise contribute to the deterioration of the quality and quantity of water in any water body.

(v)

(1)

Projects consisting of ten (10) lots or more shall provide a minimum of two thousand (2,000) gallons storage per lot either in the form of a pressurized distribution system with storage, said storage at the building site, or centralized storage equipped to accommodate emergency equipment. In any method used, water flow rates shall be five hundred (500) g.p.m. Total storage need not exceed forty thousand (40,000) gallons plus daily flow. Storage may consist not only in tanks, but also in ponds, lakes, pools, etc., which are accessible for use by emergency equipment.

(2)

For projects consisting of ten (10) lots or fewer, PRAC, after consultation with the local fire district/California Department of Forestry (CDF) may require a note placed on the parcel map/final map stating that a minimum of two thousand (2,000) gallon storage facility for fire protection shall be required at the time of building permit issuance for new dwellings.

(3)

A fire management plan shall be prepared and submitted with the subdivision application that includes (but is not limited to) identification of fire hazards on the site, the development's relationship to these constraints, necessary protection measures, and provision for maintenance of any water system for the project.

(4)

Where projects are proposing a "tie-in" with existing public or mutual water systems, the storage requirement may be adjusted based on the capability and/or storage capacity of the existing system.

(5)

A design for the cleared area at the building site for a two hundred thirty-six inch (236″) wheelbase vehicle shall be required to ensure adequate emergency vehicle circulation.

(6)

Access for fire protection purposes shall be provided consistent with subsection (j) of this section where determined necessary by PRAC, additional emergency access may be required. The extent and improvement of same shall depend on the circumstances of each case as deemed necessary by PRAC in consultation with the local fire district/CDF.

(w)

(1)

In areas such as ridges, hilltops and other key areas judged to be extremely exposed from public roads or other critically visible offsite locations, development shall be prohibited unless adequate mitigation measures are available. In areas of eroding slopes and near drainageways, development shall be prohibited unless adequate mitigating measures are available.

(2)

Grading for development (building pads, leachfield areas, driveways) shall maximize retention of natural land forms such as rolling hills, ridgetops, areas of extensive vegetation and water courses. Grading shall not produce large flat planes or sharp angles of intersection with the natural terrain. Slopes shall be rounded and contoured to blend with existing terrain. Extensive terracing shall be prohibited.

(3)

Development shall be encouraged to use the form of the land and vegetation to ensure separation of building areas and minimal exposure from roads and other building areas.

(4)

The solar exposure of building sites should allow for, at the minimum, basic passive solar heating and cooling design elements consistent with other applicable standards.

(5)

The use of plantings (generally trees) consistent and compatible with those of the area may be required to mitigate the extent of exposure of the development area in conjunction with land forms, existing vegetation and other features. Screening required for shielding of development areas (not necessarily the immediate house site) shall consist of natural materials of the area, preferably using natural vegetation or land form modification similar in form to the natural terrain.

(6)

Developments exceeding a total of fifty (50) lots and with a density greater than one (1) dwelling unit per acre may:

(i)

Provide on-site open space areas for active and passive recreation (active defined as spaces for field and group activities like football, soccer, baseball, tot lots, playgrounds, etc.; passive defined as areas used for sitting, walking, and project form). Said areas, where applicable, may be used for storm water retention, recharge areas, project form, or other multiple uses. Need and size of such areas shall be determined by the planning director taking into account number of units, size and shape of site, drainage, information derived from an EIR, environmental reconnaissance, or other documentation or site characteristics;

(ii)

Provide, where a recreation agency (district, department, etc.) exists, a dedication of land in lieu of developing project related recreation facilities may be approved by PRAC; such approval will be based on the following:

(a)

Dedication shall consist of a minimum of four hundred (400) square feet per lot,

(b)

There shall be a demonstrated lack of need for additional recreation facilities at the time of development of the proposed project;

(7)

Projects shall be analyzed for their relationship to the general plan open space plan and specific plan open space plans and where necessary, any adverse impacts or inconsistencies mitigated.

(8)

Building envelopes and building setback lines may be required by PRAC to achieve consistency with the standards listed in subsections (w)(1) through (w)(7) of this section.

(9)

All roads shall be sited in conformity with subsections (w)(1), (w)(2), (w)(3) and (w)(5) cited above.

(x)

(1)

Utility lines shall be placed underground on projects with a density greater than one (1) unit per three (3) acres; PRAC, after consideration of the visual characteristics of the project site and development plan, may require undergrounding for projects with a density between one (1) unit per three (3) acres to one (1) unit per fifteen (15) acres; projects with a density less than one (1) unit per fifteen (15) acres shall not require undergrounding. Undergrounding shall be in accordance with the rules of the public utility and state public utilities commission.

(2)

Where new main utility lines are required, these lines and service lines to the building areas shall be undergrounded where densities require undergrounding; where main lines already exist, only service lines to the building areas shall be undergrounded.

(y)

The design guidelines set forth in Section 26-90-050 of this code (the Taylor Mountain/Sonoma Mountain Development Guidelines) shall be utilized in addition to the provisions of this section in evaluating subdivision applications for parcels located within the Taylor Mountain/Sonoma Mountain areas as depicted therein. Building envelopes and related map notations consistent with the provisions of Section 26-90-050 of this code shall be required for each building site area.

( Ord. No. 6121, § II(a) , 7-28-2015; Ord. No. 5489 § 2, 2004: Ord. No. 5130 § 1, 1999: Ord. No. 2517 § 1: 2510 §§ 4—12: Ord. No. 2392 § 2: Ord. No. 2525 § 5: Ord. No. 1875 § 2.)