Article XXXVIII. - Site Development and Erosion Control Standards.

Sec. 26C-382.Site development standards.

To preserve and protect sensitive areas through appropriate development guidelines when grading, fill, or construction is necessary.

(Ord. No. 5318 § 1, 2001.)

Sec. 26C-380. - Application.

The regulations contained in this article shall be the minimum requirements and shall apply within a sensitive area, riparian corridor, scenic corridor, critical habitat area or unique feature designated in the general plan or coastal plan, and as defined in this chapter.

Where the policies of the coastal plan apply to a development they shall take precedence over these standards. Where the policies and standards of the general plan are more restrictive than those of the coastal plan or any of the standards below, the general plan standards and policies shall apply.

(Ord. No. 5318 § 1, 2001.)

Sec. 26C-381. - Exceptions.

Site development and erosion control standards shall apply to all new and existing uses permitted by Chapter 26C of the Sonoma County Code, with the following exceptions:

(a) Alterations or additions exceeding neither twenty-five percent (25%) of the floor or site area; nor twenty-five percent (25%) of the market value of the structure(s) being altered or added as established by a licensed appraiser; or

(b) Cumulative projects conducted after the effective date of this chapter that exceed the criteria in (a) above, shall be subject to this article.

(d) Waivers, exceptions, or deletions adopted as part of the coastal plan or general plan amendment approved by the board of supervisors.

(Ord. No. 5318 § 1, 2001.)

Sec. 26C-382. - Site development standards.

(a)   Access roads, driveways, turnarounds.
            (1)   All residential uses and all other uses involving structures exceeding one thousand (1,000) square feet of floor area shall
               be served by an all-weather road or driveway adequate to provide fire and emergency equipment access.
            
(2)   All required roads and driveways shall have a minimum cleared width of twelve feet (12′) with an all-weather surface.
(3)   Required roads less than two (2) travel lanes in width shall include not less than one (1) turnout for each three hundred
               feet (300′) of length.
            
(4)   Maximum permitted grade on required roads shall be fifteen percent (15%) providing that a variance permit may be issued to
               allow road grades up to twenty percent (20%) for distances not exceeding 250 feet in any single instance and not exceeding
               two hundred fifty feet (250′) in each one thousand two hundred fifty feet (1,250) of total roadway when required by local
               topography.
            
(5)   Turnaround areas sufficient to accommodate fire and emergency equipment shall be provided adjacent to each residential structure
               and at the end of any dead-end roadways. Circular turnarounds shall be a minimum diameter of ninety feet (90′). Hammerhead
               configurations shall require minimum centerline radii of curvature of fifty feet (50′).
            
(6)   No required roads shall have a centerline radius of curvature of less than fifty feet (50′).
(7)   All weather surface on required roads shall utilize sufficient class I sub-base or class II base or equivalent native material
               to provide for unimpaired emergency equipment access during wet weather conditions.
            
(8)   Bridges and culverts shall be constructed to support a load of not less than twenty (20) tons with a surfaced travel land
               of not less than twelve feet (12′).
            
(9)   All roads shall be designed and constructed in accordance with the grading, drainage, erosion and sediment control standards
               of this chapter.
            

(b) Water supply, storage, and distribution.

(1) Domestic water supply must be provided from either an approved public water system or from an individual water supply system.

(2)   Individual water supply systems shall meet the following minimum standards:
               a.   The water source shall yield a minimum flow of one (1) gallon per minute for a sustained period of not less than four (4)
                  hours as tested between July 15th and October 1st.
               
b.   Individual water systems utilizing water sources with a sustained yield of less than five (5) gallons per minute shall include
                  a minimum of four thousand (4,000) gallons of storage capacity.
               
c.   Water quality shall meet all requirements of the environmental health department.
d.   Water distribution systems shall meet the requirements of the latest edition of the uniform plumbing code adopted by the county.
e.   A minimum two thousand (2,000) gallon water storage tank, swimming pool, or pond shall be provided with two and one-half inch
                  (2-″) National Standard thread with two and one-half inch (2-″) pipes, and should be accessible to fire equipment. A plan for each tank must be submitted with building plans for these
                  sites and installation will occur prior to final inspection.
               

(c)   Sewage disposal.
            (1)   All structures for human occupancy shall be served by a public sewage disposal system, an individual septic tank and leach
               line system, or an alternative sewage disposal system approved by the county health officer.
            
(2)   Proof of the availability of an approved means of sewage disposal shall be provided before the issuance of a building permit
               for any structure for human occupancy.
            
(3)   Septic tank and leach line systems shall meet all of the requirements of the county health officer and environmental health
               department adopted herein by reference.
            

(d) Solid waste disposal.

(1) All garbage, refuse, junk, waste products, or other solid waste material shall be recycled, composted or deposited at an approved waste disposal site or transfer station.

(2) Temporary storage of solid waste shall be out of view from public roads.

(e)   Toxic and flammable substances storage and handling.
            (1)   All on-site fuel storage tanks and facilities shall be located and constructed according to the requirements of the applicable
               fire service agency.
            
(2)   All pesticides, herbicides, and other agricultural chemicals shall be stored and handled in accordance with the requirements
               of the county agricultural commissioner.
            
(3)   Any commercial storage or use of toxic, corrosive, or flammable substances or substances issuing toxic fumes and smoke upon
               burning shall require notification of the applicable fire service agency and adherence to all of the requirements of these
               agencies regarding storage, handling, and use of said substances.
            
(4)   Any commercial storage, transfer, use, or disposal of any radioactive substance excepting licensed medical facilities and
               academic institutions shall first require a use permit.
            

(f)   Fire protection.
            (1)   Ability to meet access and water supply storage and distribution standards shall be demonstrated prior to the issuance of
               any building permit.
            
(2)   Vegetation and other flammable material shall be cleared and maintained in accordance with all the requirements of the applicable
               fire service agency.
            
(3)   Within any area designated extreme fire hazard in the general plan or coastal plan, vegetation and other combustible material
               clearance shall extend not less than one hundred fifty feet (150′) on each side of any building or structure.
            
(4)   Every chimney or stovepipe that is attached to any fireplace, stove, or other device that burns any solid or liquid fuel shall
               be provided and maintained with an approved fire screen over the outlet.
            
(5)   All buildings or structures located within areas designated as extreme fire hazards in the general plan or coastal plan shall
               be constructed using fire proof or fire-resistant roofs. All building projections including eaves, overhangs, canopies, balconies,
               decks, and unenclosed under-floor areas shall utilize suitable fire resistant constructions.
            
(6)   All internal combustion engines operated in fire hazardous areas shall be equipped with approved spark arresters.

(g)   Energy conservation.
            (1)   All structures for human occupancy shall be located, sited, and oriented to achieve maximum solar exposure.
(2)   All new residential development shall provide suitable space and clothesline facilities to enable residents to dry their clothes
               using the sun. Such clothesline facilities shall be convenient to washing facilities and oriented so as to receive sufficient
               sun to dry clothes throughout the day and throughout the year.
            
(3)   Any covenant, restriction, or condition contained in any deed, contract, security instrument, or other instrument affecting
               the transfer or sale of or any interest in real property which prohibits the installation or use of clotheslines in any residential
               zone is void and unenforceable. Restrictions may be placed on the location of clotheslines, so long as access to the sun is
               not restricted.
            
(4)   All new swimming pool construction shall include a solar energy system as the primary means of pool heating.
(5)   Variances from setback and height restrictions may be granted when shown essential for the operation of a solar energy system
               or the proper orientation of a passive solar building.
            
(6)   No sign or advertising structure shall be illuminated between the hours of ten p.m. and six a.m. excepting commercial enterprises
               while open for business.
            

(h) Noise.

All development shall comply with the general plan noise standards and policies.

(i)   Air quality.
            (1)   All potential projects resulting in the discharge of air pollutants shall demonstrate the ability to meet the air quality
               standards of the appropriate air pollution control district prior to the issuance of any grading or building permits.
            
(2)   All required roads shall be sufficiently rocked or paved and maintained as necessary to control dust.
(3)   Non-paved roads subject to heavy traffic shall be managed so as to control dust.

(j)   Landscaping and vegetation.
            (1)   Native vegetation shall be retained, protected, and supplemented to the maximum extent possible.
(2)   Fuel wood harvesting, except timber stand improvement, shall be conducted on a sustained yield basis. Harvested areas shall
               be protected from grazing until restocking is assured. Replanting shall be required whenever root sprouting fails to re-establish
               the initial native vegetation density.
            
(3)   Landscaping, screening, and windbreaks shall utilize native species to the maximum extent possible.

(k)   Drainage and flooding.
            (1)   Projects which involve any of the drainage alterations, ponding, or filling activities listed below must be approved by the
               Sonoma County Water Agency before commencing operations. Activities included are those which:
               a.   Impair or impede or obstruct the natural flow of storm waters or other water running in a defined channel, natural or man-made,
                  or cause or permit the obstruction of any such channel;
               
b.   Deposit any material in such channel;
c.   Alter the surface of land so as to reduce the capacity of such channel;
d.   Construct, alter, or repair any storm water drainage structure, facility, or channel without first obtaining a permit therefor,
                  as herein provided;
               
e.   Impair the use of any easement dedicated for drainage purposes;
f.   Construct, alter, or repair any storm water drainage structure, facility, or channel without first obtaining a permit therefor,
                  as herein provided;
               
g.   Impair the use of any easement dedicated for drainage purposes;
h.   Place any material along the sides of any defined channel or so close to the side of said channel as to cause such material
                  to be carried away by flood waters passing through such channel;
               
i.   Construct any structure within one hundred feet (100′) of the top of any embankment, natural or man-made which defines a channel,
                  except structures constructed on a lot in a subdivision where the flood hazard has been found to be remote in the review of
                  the Sonoma County Water Agency;
               
j.   Deposit any material which contains paper, bottles, cans, lumber, garbage, organic matter, or other material which will not
                  readily become an integral part of said channel side.
               
(2)   Dams constructed for the purpose of impounding water when designed or approved by an agency of the federal government or of
               the state of California or when subject to review and approval by the State of California Department of Water Resources, pursuant
               to Part 1 of Division 3 of the California Water Code shall be exempt from Sonoma County Water Agency approval.
            
(3)   Sediment basins, settling ponds, ditches, levees, dikes, culverts, and other structures as well as erosion control and streambank
               protection measures shall be in accordance with recommendations and standards presented in and herein adopted by reference:
               "Erosion and Sediment Control Handbook" and "Flood Control Design Criteria" Perry Y. Amimoto, Sonoma County Water Agency,
               California Division of Mines and Geology, Revised Edition, 1973, State Department of Conservation, 1978.
            

(l)   Geologic hazards.
            (1)   All uses subject to the requirements of the Alquist-Priolo Special Studies Zone Act for protection from fault rupture hazard
               shall demonstrate compliance prior to issuance of any use permit, building permit, or other entitlement.
            
(2)   All structures for human occupancy including mobile homes shall be designed and constructed to withstand without major structural
               damage groundshaking resulting from the maximum credible earthquake event for the area as specified in the Division of Mines
               and Geology Special Report 120 and adopted herein by reference.
            
(3)   No structure for human occupancy shall be placed within the Tsunami Hazard zone as specified in the Division of Mines and
               Geology Special Report 120.
            
(4)   Any structure for human occupancy proposed for construction within any area designated in the Division of Mines and Geology
               Special Report 120 as slope stability categories "Landslides", C or Bf shall require review and approval of all grading, site
               preparation, drainage, and foundation plans by a registered engineering geologist.
            

(m)   Riparian corridors.
            (1)   All clearing of vegetation, grading, excavation, fill, or construction within a riparian corridor designated in the general
               plan or coastal plan shall first require a use permit.
            
(2)   Use permits for development within designated riparian corridors shall not be approved except when it can be determined that
               no reasonable alternative means of accomplishing the project objectives outside of the riparian corridor can be found.
            
(3)   Use permits shall specify by condition the location and extent of vegetation to be disturbed, grading, filling or excavation
               permitted, roads, walkways or structures permitted, bank protection measures, erosion control measures, and revegetation requirements.
            
(4)   No building materials, abandoned vehicles, junk, garbage, or other solid waste shall be stored within any riparian corridor
               designated in the general plan or coastal plan.
            
(5)   No pesticides, liquid fuels, or other toxic substances shall be sorted or applied within any riparian corridor designated
               in the general plan or coastal plan.
            
(6)   Vegetation removal in conjunction with permitted development shall be minimized and in no case shall result in the disruption
               of more than ten percent (10%) of the tree canopy per one hundred (100) linear feet of designated riparian corridor.
            
(7)   Grading, filling, excavation, or construction in conjunction with permitted development shall not diminish or divert any stream
               flow or result in any increase in bank instability or erosion. Erosion and siltation controls as recommended in the Erosion
               and Sediment Control Handbook, Perry Amimoto, Division of Mines and Geology, 1978, shall be required.
            
(8)   Any roadway, stream crossing, walkway, or structure located within a riparian corridor designated in the general plan or coastal
               plan shall be designed and constructed in accordance with all standards and requirements of the Sonoma County Water Agency.
               No building shall be located closer to the top of the bank of any water course than a distance equal to two and one-half (2
               ) times the depth of the channel plus thirty feet (30′) as determined and approved by the Sonoma County Water Agency.
            
(9)   Intermittent stream crossing may be by means of culverts. All stream crossings shall be approved by the Sonoma County Water
               Agency and the State Department Of Fish And Game prior to the issuance of any grading or building permits.
            
(10)   Dams and water impoundments shall be exempt from the riparian standards of this chapter with plans prepared by the U.S. Department
               of Agriculture, soil conservation service, and approved by the local soil conservation district.
            

(n)   Wetlands.
            (1)   No removal of native vegetation, grading, fill, excavation, dredging, construction, damming or diversion of natural water
               flow shall be permitted in any marsh or wetland designated in the general plan or coastal plan.
            
(2)   Grazing within marshes or wetlands designated in the general plan or coastal plan shall be prohibited except as conducted
               and managed as provided in any official farm plan prepared by the U.S. Department of Agriculture, Soil Conservation Service,
               and approved by the local soil conservation district.
            
(3)   New development adjacent to wetlands designated in the general plan or coastal plan shall be designed and constructed to avoid
               any erosion or sediment transport into the wetland.
            
(4)   No removal of native vegetation, grading, fill, excavation, or construction of any roads or structures shall be permitted
               within one hundred feet (100′) of any wetlands designated in the general plan or coastal plan.
            

(o)   Critical habitat.
            (1)   All clearing of vegetation, grading, excavation, fill, or construction within a critical habitat area designated in the general
               plan or coastal plan shall first require a use permit.
            
(2)   Use permits for development within designated critical habitat areas shall not be approved except when it can be determined
               that no reasonable alternative means of accomplishing the project objectives outside of the critical habitat area can be found.
            
(3)   Use permits shall specify by condition the location and extent of vegetation to be disturbed; grading, filling or excavation
               permitted; roads, walkways, or structures permitted; erosion control measures, revegetation requirements and acceptable timing
               for each aspect of the project.
            
(4)   Prior to approval of a use permit for development within a designated critical habitat area, a biological or other scientific
               study may be required to determine the tolerance of the affected species to the proposed development.
            

(p)   Unique Features.
            (1)   All removal of vegetation, grading, fill, excavation, or construction within a unique feature area designated in the coastal
               plan shall first require a use permit.
            
(2)   Use permits for development within designated unique feature areas shall not be approved except when it can be determined
               that no reasonable alternative means of accomplishing the project objectives outside of the unique feature area can be found.
            
(3)   Use permits shall specify by condition the location and extent of vegetation to be disturbed; grading, filling, or excavation
               permitted; roads, walkways, or structures permitted; and specific measures to be undertaken to protect and enhance the unique
               feature area.
            
(4)   Prior to approval of a use permit for development within a designated unique feature area, an archaeological or biological
               or other scientific study may be required to determine the sensitivity of the unique feature area to disturbance and means
               of reducing or mitigating the impact of the project on the unique feature to the maximum feasible extent.
            
(5)   If, during development, subsurface archaeological materials are uncovered, work shall be halted temporarily and a qualified
               archaeologist contacted to evaluate the finds. Such archaeological materials include but are not limited to milling equipment,
               obsidian or chert artifacts and waste flakes, bone, shell, human graves, structure foundations, and/or historic period items
               such as old bottles and ceramics.
            

(q)   Scenic corridor.
            (1)   Ten (10) scenic corridors have been identified in the coastal plan. The extent of land visible from the scenic corridors have
               been mapped on the coastal visual resource maps incorporated by reference and on file in the permit and resource management
               department.
            
(2)   All new development shall conform with coastal plan visual resource element recommendations, applicable scenic view protection
               policies and policies related to landform and vegetation categories, or subsequently approved area design guidelines.
            
(3)   Design review for all new development to be required in accordance with the procedures described in the coastal plan visual
               resource element and coastal administrative manual.
            
(4)   Coastal permits for development within designated scenic corridors shall not be approved except when it can be determined
               that the development will:
               a.   Create a consistent visual relationship with surrounding development and with the natural terrain and vegetation;
b.   Require minimum grading and vegetation removal;
c.   Not significantly obstruct existing public views;
d.   Utilize native plants for required landscaping;
e.   Utilize building material colors and textures complementary to the natural landscape;
f.   Harmonize with the design characteristics of surrounding development;
g.   Minimize outdoor lighting, shielding it sufficiently to assure no glare toward residential areas or roadways.

(r)   Water quality.
            (1)   All uses shall comply with the requirements and regulations of the appropriate regional water quality control board. New uses
               requiring regional water quality board approval of discharge standards shall submit proof of such approval prior to issuance
               of any grading or building permits.
            
(2)   Storage of pesticides, herbicides, liquid fuels, and/or other potentially toxic substances shall require use of a containment
               structure capable of preventing said substances from entering into any waterway or percolating into any groundwater.
            
(3)   Subsurface disposal or reinjection of any liquid waste into the earth excepting approved septic and leach line systems shall
               require a use permit.
            

(Ord. No. 5318 § 1, 2001.)

Sec. 26C-383. - Erosion control.

(a) Grading.

All section references in this section refer to the "Erosion and Sediment Control Handbook" adopted by reference herein.

(1)   Except as indicated below, no person shall commence or perform any grading or filling or clearing of vegetation without having
               first obtained a grading permit:
               a.   The excavation does not exceed four feet (4′) in vertical depth at its deepest point measured from the original surface and
                  does not exceed two hundred (200) square feet in area.
               
b.   The fill does not exceed three feet (3′) in vertical height at its highest point measured from the natural ground surface
                  and does not cover more than two hundred (200) square feet in area.
               
c.   Exploratory excavations do not exceed an aggregate area of two hundred (200) square feet.
d.   An excavation below finished grade for basements and footings of a building if authorized by a valid building permit. This
                  exception does not affect the requirement of a grading permit for any fill made with the material from such excavation.
               
e.   Clearing of vegetation does not exceed one thousand (1,000) square feet in area.
f.   Use of land is for gardening primarily for home consumption.
g.   Agricultural use of land that is operated in accordance with a farm conservation plan approved by the resource conservation
                  district or when it is determined by the resource conservation district that such use will not cause excessive erosion or
                  sediment losses.
               

(2) Grading operations shall be conducted so as to prevent damaging effects of sediment production and dust on the site and on adjoining properties.

(b) Sediment control.

(1) Sediment shall be retained on the site (Section 90).

(2) Sediment basins, sediment traps, or similar sediment control measures shall be installed before extensive clearing and grading operations begin.

(c)   Native vegetation.
            (1)   In no event shall the native vegetative ground cover be destroyed, removed, or disturbed more than fifteen (15) days prior
               to grading unless otherwise approved by the engineer representing the permit-issuing authority.
            
(2)   When vegetation must be removed, the method shall be one that will minimize the erosive effects from the removal (Sections
               10 and 30).
            
(3)   Exposure of soil to erosion by removing vegetation shall be limited to the area required for immediate construction operations.

(d)   Control of runoff.
            (1)   Provisions shall be made to control the increased runoff caused by changed soil and surface conditions during and after development
               (Sections 40 through 100).
            
(2)   To prevent excess runoff the rate of surface water runoff shall be structurally retarded (Sections 90 and 100).
(3)   Each applicant requesting permission to make any surface changes shall be required to:
               a.   Collect on-site surface runoff and dispose of it at nonerosive velocities to a point of discharge into the common natural
                  watercourse of the drainage area.
               
b.   Handle existing and potential off-site runoff through the development by designing for storm runoff from a fully developed
                  area upstream.
               
c.   Pay his proportionate share of the total cost of off-site erosion and sediment control improvements to the common natural
                  watercourse based on a fully developed drainage area.
               
d.   Provide and install at his expense all drainage, erosion, and sediment control practices (temporary and permanent) required
                  by the erosion and sediment control handbook herein adopted by reference.
               
e.   Retain sediment being transported by runoff water on-site through the use of sediment basins, silt traps, or similar measures.
(4)   Concentration of surface water runoff shall only be permitted in swales or watercourses.
(5)   In order to prevent polluting discharges from occurring, approved erosion and sediment control devices shall be required for
               all grading and filling. Control devices and measures which may be required include but are not limited to the following:
               a.   Energy absorbing devices to reduce the velocity of runoff water (Section 100).
b.   Sedimentation controls such as sediment debris basins and sediment traps. Any trapped sediment shall be removed to a disposal
                  site approved by the permit-issuing authority (Section 90).
               
c.   Dispersal of water runoff from developed areas over large undisturbed areas.
d.   Multiple discharge points to reduce the volume of runoff over localized areas.

(e) Slope construction.

(1) Both cut and fill slopes shall not be steeper than two-to-one (2:1) unless a thorough geological and engineering analysis indicates that steeper slopes are safe and erosion control measures are specified.

(2) Slopes shall not be constructed so as to endanger or disturb adjoining property.

(f) Slope surface stabilization.

(1) Temporary mulching, seeding, or other suitable stabilization measures shall be used to protect exposed critical areas during construction or other land disturbance (Sections 20 and 30).

(2) Earth or paved interceptors and diversions shall be installed at the top of cut or fill slopes where there is a potential for surface runoff (Section 40).

(g)   Protection of watercourses.
            (1)   Fills shall not encroach on natural watercourses or constructed channels.
(2)   Fills placed against watercourses shall have suitable protection against erosion during flooding.
(3)   Grading equipment shall not cross or disturb stream channels.
(4)   Excavated materials shall not be deposited or stored in or alongside the river or watercourses where the materials can be
               washed away by high water or storm runoff.
            

(h) Disposal of cleared vegetation.

Vegetation removed during clearing operations shall be disposed of as follows:

(1) Chipping all or some of the cleared vegetation for use as mulch or compost on the site (Section 30).

(2) Burning so thorough that the materials are reduced to ashes. No logs, branches, or charred pieces shall be permitted to remain. Burning shall comply with local air pollution regulations.

(3) Disposing the balance of the material in a manner and at a location approved by the permit-issuing authority.

(j) Disposal of excavated materials.

Excavated materials removed during grading operations shall be disposed of as follows:

(1) Stockpiling all or some of the topsoil on the site for use on areas to be revegetated.

(2) Locating stockpiled soil so that if erosion occurs it would not become a source for off-site sediment damage.

(3) Stockpiling soil far enough from streams or drainageways that surface runoff cannot carry sediment downstream.

(4) Stockpiling material from trenches and pits on the upslope side of the excavations.

(5) Promptly backfilling and compacting stockpiled soil into trenches and pits to reduce the risk of erosion.

(6) Applying mulch or other protective coverings on stockpiled material which will be exposed through the winter season or which faces a high risk of intensive summer rains (Section 30).

(7) Removal of excavated material not be used at the site to a location approved by the permit-issuing authority.

(Ord. No. 5318 § 1, 2001.)