Description: The Riparian Corridor (RC) Combining Zone dataset represents the geographical area established to protect biotic resource communities, including critical habitat areas within and along riparian corridors, for their habitat and environmental value, and to implement the provisions of the General Plan Open Space and Resource Conservation and Water Resources Elements.These provisions are intended to protect and enhance riparian corridors and functions along designated streams, balancing the need for agricultural production, urban development, timber and mining operations, and other land uses with the preservation of riparian vegetation, protection of water resources, floodplain management, wildlife habitat and movement, stream shade, fisheries, water quality, channel stability, groundwater recharge, opportunities for recreation, education and aesthetic appreciation and other riparian functions and values. NOTE: The RC Combining Zone was revised by the Board of Supervisors as part of the Sonoma Developmental Center Specific Plan (File PLP22-0024) adopted by Ordinance 6400 and General Plan Resolution 22-0556 on December 16, 2022. The Sonoma Developmental Center Specific Plan as modified by the Board of Supervisors requires expansion of the RC corridor along Sonoma Creek within parcels 054-150-005 and 054-090-001 from 50ft to 100ft. Since the Sonoma Creek Riparian Corridor was originally defined manually, guided by riparian vegetation observed in aerial photos (i.e. it was no auto-buffered from the USGS centerline as was implemented to create RC Corrdors for most of the County), to accomodate the Board's requirement, the existing riparian corridors within 054-150-005 and 054-090-001 were buffered an additional 50 ft on both sides, to revise the corridor from the manually determined 50 ft width to a new width of 100 ft.NOTE: This version of RC Combining Zone was revised on October 27, 2021 to make the following correction: on January 30, 2020 the USGS added a new blue line stream to the National Hydrography Dataset (NHD). A local consultant had reported to the USGS that a stream in Forestville between Trenton Rd and Sunridge Ave was missing from their maps. Following confirmation by USGS and on the ground confirmation by staff from the California Department of Water Resources, the blue line stream was officially added to the NHD. Since PRMD Riparian Corridors mirror USGS blue line streams, with an additional buffer, a new RC area was added. The stream does not meet any of the criteria to designate it with a 100 ft or 200 ft setback, so by default it was assigned a 50 ft setback. Since all RC buffers are doubled in practice to account for stream misalignments etc., the new RC 50 setback area was given a buffer width of 100 ft on each side of the stream.For a detailed description of the report and location of the stream addition see the correspondence:S:\GIS-DATA\PRMD_BASE\PRMD Department Projects\Comprhensive Planning\Riparian Corridor Combining Zone\RC Corrections\Missing USGS Stream - 20200130\Email Correspondence\Email - add blue line stream Forestville btwn Trenton Rd and Sunridge Ave.pdfAnd for the new stream and RC buffer feature classes as isolated features, see:S:\GIS-DATA\PRMD_BASE\PRMD Department Projects\Comprhensive Planning\Riparian Corridor Combining Zone\RC Corrections\Missing USGS Stream - 20200130\Corrected USGS Stream.gdbSec. 26-65-010. Applicability. The RC combining zone shall be applied to designated streams and include the stream bed and bank and an adjacent streamside conservation area on each side of the stream as measured from the top of the higher bank. The minimum streamside conservation area shall be shown in the zoning database followed by the minimum setback for agricultural cultivation (e.g., RC 100/50). Where the drip line of existing riparian trees with trunks located wholly or partially within the streamside conservation area extends beyond the streamside conservation area boundary, as indicated in the zoning database, the boundary shall be increased to include the outer drip line of the riparian trees. (Ord. No. 6089, 2014). - - - - Sec. 26-65-020. Determination of streamside conservation areas and setbacks for agricultural cultivation. The streamside conservation area indicated in the zoning database is approximate to allow for a parcel-specific determination of the boundary based upon the location of the top of the higher bank and existing riparian vegetation. The streamside conservation area shall be determined by the director. The setback for agricultural cultivation indicated in the zoning database is also approximate to allow for a site-specific determination of the boundary based upon the location of the top of the higher bank, existing riparian vegetation, and, for upland areas of 50-foot riparian corridors, the slope and soil types of the planting area. The setback for agricultural cultivation shall be determined by the agricultural commissioner. (Ord. No. 6089, 2014) - - - -Sec. 26-65-030. - Prohibited uses and exceptions.Except as allowed by Section 26-65-040, grading, vegetation removal, agricultural cultivation, structures, roads, utility lines, and parking lots shall be prohibited within any stream channel or streamside conservation area. A. An exception to this prohibition may be approved by the director with a zoning permit if: 1. It makes a parcel unbuildable, provided vegetation removal is minimized; 2. The use involves the minor expansion of an existing legally established structure in conformance with Article 94 where it is demonstrated that the expansion will be accomplished with minimum vegetation removal and protection of riparian functions; 3. The use involves only the maintenance, restoration, or reconstruction of an existing legally established structure or use in conformance with Article 94; or 4. The director determines that the affected area has no substantial value for riparian functions. B. An exception to this prohibition may be approved with a use permit if a conservation plan is adopted that provides for the appropriate protection of the biotic resources, water quality, floodplain management, bank stability, groundwater recharge, and other applicable riparian functions. Off-site mitigation will be considered only where on-site mitigation is infeasible or would provide superior ecological benefits, as determined by the director. (Ord. No. 6089, § I(d)(Exh. A), 11-24-2014) - - - -Sec. 26-65-040. - Allowed land uses, activities and permit requirements. The following activities and uses may be allowed within a streamside conservation area, if allowed by the base zone and any combining zones, subject to any required permits and the standards specified in this section. These activities and uses shall also be conducted and maintained in compliance with any prohibitions, permits, approvals, or authorizations required by applicable resource agencies. A. Stream maintenance and restoration carried out or overseen by the Sonoma County Water Agency. B. Levee maintenance. C. Invasive plant removal, such as Himalayan blackberry (Rubus armeniacus), giant reed (Arundo donax), salt cedar (Tamrix sp.), and star thistle (Centaurea solstitialis), not exceeding five (5) acres in disturbed area, principally involving hand labor and not using mechanized equipment. D. Streamside maintenance and small riparian habitat restoration not exceeding five (5) acres of disturbed area, principally involving hand labor and not using mechanized equipment, as described by State CEQA Guidelines Section 15333, subject to a zoning permit. E. Stream dams and stream-related water storage systems, subject to a zoning permit. F. Road and utility line crossings in compliance with county road construction standards and maintenance guidelines, subject to a zoning permit. G. Fencing and maintenance of existing outdoor activity areas, such as yards, gardens, and landscaped or natural vegetation, associated with a legally established structure or use and not involving further encroachment into existing riparian vegetation. H. The following agricultural activities, provided that they are conducted and maintained in compliance with agricultural best management practices developed or referenced by the agricultural commissioner, or defined in a farm or ranch water quality plan acceptable to the agricultural commissioner. The agricultural commissioner shall determine the applicable agricultural best management practices and shall enforce the provisions of this subsection. 1. Grazing and similar agricultural production, not involving cultivation or structures. Livestock control fencing and watering facilities are allowed. 2. Agricultural cultivation and related access roads, drainage, planting, seeding, fertilizing, weeding, tree trimming, irrigation, and harvesting that do not involve the removal of existing contiguous riparian vegetation within two hundred feet (200') of the top of the higher bank, and are located as follows: a. No closer than one hundred feet (100') from the top of the higher bank in the 200-foot riparian corridor for the Russian River; b. No closer than fifty feet (50') from the top of the higher bank in the 100-foot riparian corridors designated in the General Plan and the upland areas of the 50-foot riparian corridors; or c. No closer than twenty-five feet (25') from the top of the higher bank in all other riparian corridors. 3. Replanting existing cropland and related access roads, drainage, planting, seeding, fertilizing, weeding, tree trimming, irrigation, and harvesting that are located closer to the top of the higher bank than specified in Subsection 26-65-040.H.2, provided that the existing cropland is under active cultivation and the footprint of the planting area is not increased within the applicable setback for agricultural cultivation. 4. Filter strips, equipment turnarounds, grassy avenues, and fencing associated with agricultural cultivation that does not involve the removal of existing contiguous riparian vegetation within two hundred feet (200') of the top of the higher bank. I. Selective vegetation removal as part of an integrated pest management program administered by the agricultural commissioner. J. Wells in compliance with Sonoma County Code Chapter 25B (Water Wells). K. Fire fuel management in compliance with county fire safe standards, provided that no redwood trees are removed and vegetation removal is limited to the minimum required for fire safety purposes. New development located within one hundred feet (100') of any riparian corridor shall be allowed with a zoning permit only where there are no feasible alternative development locations that do not require vegetation removal for fire protection and fire resistive construction materials are used to avoid or minimize the need for vegetation removal in the riparian corridor. L. Bikeways, trails, and parks on publicly owned land or public use easements, or on private lands, subject to a zoning permit. M. Temporary seasonal gangway and floating dock of up to one hundred twenty square feet (120' sq.) with encapsulated floatation and grated deck, subject to a zoning permit. N. Timber operations conducted in compliance with an approved timber harvest plan. O. Tree removal subject to a zoning permit, to protect life or property from the threat of harm posed by a dead, dying, diseased, or damaged tree likely to die within one (1) year of the date proposed for removal, or a tree at risk of falling when the structural instability cannot be remedied. A report by a certified arborist or registered professional forester documenting the hazardous condition and a tree replacement plan is required. P. Mining operations, subject to a use permit for surface mining activities in compliance with the Chapter 26A (Surface Mining) of this code. Q. Other activities or uses not meeting the above criteria may be permitted with an exception under Section 26-65-030 (Prohibited Uses and Exceptions), subject to a use permit and approval of a conservation plan. (Ord. No. 6089, § I(d)(Exh. A), 11-24-2014) Related Resource: Sonoma County Zoning Regulations Sonoma County General Plan 2020 Index[includes amendments since adoption]