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Within the following categories of sensitive lands, only the following uses shall be permitted and the following development standards and criteria shall be met provided, however, that where the extent of environmentally sensitive lands on a particular legal lot is such that no reasonable economic use of such lot would be permitted by these regulations, then an encroachment into such environmentally sensitive lands to the minimum extent necessary to provide for such reasonable use may be allowed:
(a) Wetlands. The following permitted uses shall be allowed:
(1) Aquaculture, provided that it does not harm the natural ecosystem.
(2) Scientific research, educational or recreational uses, provided that they do not harm the natural ecosystem.
(3) Removal of diseased or invasive exotic plant species as identified and quantified in writing by a qualified biologist and approved in writing by the Director of Planning and Development Services, and removal of dead or detached plant material.
(4) Wetland creation and habitat restoration, revegetation and management projects where the primary goal is to restore or enhance biological values of the habitat, and the activities are carried out pursuant to a written management/enhancement plan approved by the Director of Planning and Development Services.
(5) Crossings of wetlands for roads, driveways or trails/pathways dedicated and improved to the limitations and standards under the County Trails Program, that are necessary to access adjacent lands, when all of the following conditions are met:
(aa) There is no feasible alternative that avoids the wetland;
(bb) The crossings are limited to the minimum number feasible;
(cc) The crossings are located and designed in such a way as to cause the least impact to environmental resources, minimize impacts to sensitive species and prevent barriers to wildlife movement (e.g., crossing widths shall be the minimum feasible and wetlands shall be bridged where feasible);
(dd) The least-damaging construction methods are utilized (e.g., staging areas shall be located outside of sensitive areas, work shall not be performed during the sensitive avian breeding season, noise attenuation measures shall be included and hours of operation shall be limited so as to comply with all applicable ordinances and to avoid impacts to sensitive resources);
(ee) The applicant shall prepare an analysis of whether the crossing could feasibly serve adjoining properties and thereby result in minimizing the number of additional crossings required by adjacent development; and
(ff) There must be no net loss of wetlands and any impacts to wetlands shall be mitigated at a minimum ratio of 3:1 (this shall include a minimum 1:1 creation component, while restoration/ enhancement of existing wetlands may be used to make up the remaining requirements for a total 3:1 ratio).
(b) Wetland Buffer Areas. In the wetland buffer areas, permitted uses shall be limited to the following uses provided that there is no overall decrease in biological values and functions of the wetland or wetland buffer:
(1) Improvements necessary to protect adjacent wetlands.
(2) All uses permitted in wetland areas.
(c) Floodways. The development of permanent structures for human habitation or as a place of work shall not be permitted in a floodway. Uses permitted in a floodway shall be limited to agricultural, recreational, and other such low-intensity uses provided, however, that no use shall be permitted which will substantially harm the environmental values of a particular floodway area. Mineral resource extraction shall be permitted subject to an approved Major Use Permit and Reclamation Plan, provided that mitigation measures are required which produce any net gain in the functional wetlands and riparian habitat.
Modifications to the floodway must meet all of the following criteria:
(1) Concrete or rip-rap flood control channels are allowed only where findings are made that completion of the channel is necessary to protect existing buildings from a current flooding problem. Buildings constructed after the enactment of this Ordinance shall not be the basis for permitting such channels.
(2) Modification will not unduly accelerate the velocity of water so as to create a condition which would increase erosion (and related downstream sedimentation) or would be detrimental to the health and safety of persons or property or adversely affect wetlands or riparian habitat.
(3) In high velocity streams where it is necessary to protect existing houses and other structures, minimize stream scour, or avoid an increase in the transport of stream sediment to downstream wetlands and other environmentally sensitive habitat areas, grade control structures, and other erosion control techniques, including the use of rip-rap, that are designed to be compatible with the environmental setting of the river, may be permitted. The use of rip-rap shall be allowed only when there is no other less environmentally damaging alternative feasible.
(d) Floodplain Fringe. All uses permitted by zoning and those that are allowable in the floodway are allowable in the floodplain fringe, when the following criteria are met:
(1) Fill shall be limited to that necessary to elevate the structure above the elevation of the floodway and to permit minimal functional use of the structure (e.g., fill for access ramps and drainage). If fill is placed in the floodplain fringe, the new bank of the creek shall be landscaped to blend with the natural vegetation of the stream and enhance the natural edge of the stream.
(2) Any development below the elevation of the 100 year flood shall be capable of withstanding periodic flooding.
(3) The design of the development shall incorporate the findings and recommendation of a site-specific hydrologic study to assure that the development: (aa) will not cause significant adverse water resource impacts related to quality or quantity of flow or increase in peak flow to downstream wetlands, lagoons and other sensitive habitat lands; and (bb) neither significantly increases nor contributes to downstream bank erosion and sedimentation of wetlands, lagoons or other sensitive habitat lands.
(4) Lot configurations shall be designed in such a manner as to minimize encroachment into the floodplain. The proposed development shall be set back from the floodway boundary a distance equal to 15% of the floodway width (but not to exceed 100 feet), in order to leave an appropriate buffer area adjacent to the floodway. The setback may be greater if required by subparagraph (6) below.
Following review of a site-specific flood analysis, the floodplain setback required by this paragraph may be reduced by the Director of Planning and Development Services or the applicable hearing body, upon making all of the following findings:
(aa) Practical difficulties, unnecessary hardship, or results inconsistent with the general purposes of this Chapter would result from application of the setback; and
(bb) The reduction in setback will not increase flood flows, siltation and/or erosion, or reduce long-term protection of the floodway, to a greater extent than if the required setback were maintained; and
(cc) The reduction in setback will not have the effect of granting a special privilege not shared by other property in the same vicinity; and
(dd) The reduction in setback will not be materially detrimental to the public health, safety, or welfare, or injurious to the property or improvement in the vicinity in which the property is located; and
(ee) The reduction in setback will not be incompatible with the San Diego County General Plan.
(5) In areas where the Director of Public Works has determined that the potential for erosion or sedimentation in the floodplain is significant, all proposed development shall be set back from the floodway so that it is outside the Erosion/Sedimentation Hazard Area shown on County floodplain maps. Development will only be allowed in the Erosion/Sedimentation Hazard Area when the Director of Public Works approves a special study demonstrating that adequate protection can be achieved in a manner that is compatible with the natural characteristics of the river.
(6) If the subject floodplain fringe land also constitutes wetlands, wetland buffer areas, steep slope lands, sensitive habitat lands or significant prehistoric or historic site lands, the use restrictions herein applicable to such areas shall also apply.
(e) Steep Slope Lands.
(1) Density Formula. When a parcel is located within a plan designation which bases lot size on slopes, the number of lots and/or number of dwelling units shall be in conformance with the General Plan Land Use Element.
A Planned Residential Development, lot area averaging, conservation subdivision or cluster development shall be required to use the density allowed a standard subdivision using this density formula.
Projects obtaining a density bonus, pursuant to Section 4120 of the Zoning Ordinance, are subject to the above density formula.
(2) Project Design and Open Space to Protect Steep Slopes. In designing lot configuration on steep slope lands in all land use designations, parcels shall be created in a manner which minimizes encroachment onto steep slope lands. Where 10% or more of a lot contains steep slope lands, that portion of the lot containing such lands shall be placed in an open space easement unless the lot is equal to or greater than 40 acres or a sensitive resource area designator has been applied to that lot pursuant to the Zoning Ordinance.
The open space easement shall not include any area of encroachment within the limits of the encroachment table (2)(aa). The terms of the open space easement shall provide for sufficient encroachments necessary for access, clearing, and all exceptions to the encroachment limitations identified in (2)(bb) and 2(cc). New agricultural operations will also be allowed in such open space easements with approved grading or clearing permits, provided any other type of sensitive lands present are protected as required by the applicable sections of this Chapter.
(aa) For all types of projects, the maximum encroachment that may be permitted into steep slope lands shall be as set forth in the following table. This encroachment may be further reduced due to environmental concerns or other design criteria.
Twenty-Five Percent Slope Encroachment Allowance
Percentage of Lot in Steep Slope Lands
Maximum Encroachment Allowance as Percentage of Area in Steep Slope Lands
75% or less
(bb) Notwithstanding the provisions of paragraph (aa) above, the following types of development shall be allowed on steep slope lands and shall not be subject to the encroachment limitations set forth above:
(i) All public roads identified in the Mobility Element of the County General Plan or adopted community or subregional plans, provided that findings are made by the hearing body approving the application that no less environmentally damaging alternative alignment or non-structural alternative measure exists.
(ii) Local public streets or private roads and driveways which are necessary for primary or secondary access to the portion of the site to be developed on steep slope lands of less than 25%, provided no less environmentally damaging alternative exists. The determination of whether or not a proposed road or driveway qualifies for an exemption, in whole or in part, shall be made by the Director of Planning and Development Services based upon an analysis of the project site.
(iii) Public and private utility systems, provided that findings are made that the least environmentally damaging alignment has been selected. However, septic systems are not included in this exemption unless Department of Health Services has certified that no grading or benching is required.
(iv) Areas with native vegetation, which are cleared or trimmed to protect existing or proposed structures in potential danger from fire, provided that the area of such clearance is the minimum necessary to comply with applicable fire codes or orders of fire safety officials and that such slopes retain their native root stock or are planted with native vegetation having a low fuel content, and provided further that the natural landform is not reconfigured.
(v) Trails for passive recreational use according to approved park plans.
(vi) On any lot created on or before August 10, 1988, a maximum disturbed area of 20% of the entire lot, or sufficient area to accommodate 3,000 square feet of building footprint (whichever is greater) shall be permitted to provide for reasonable use of existing lots.
(vii) Any on-going existing agricultural operation, such as the cultivation, growing and harvesting of crops and animals. Land left fallow for up to four years shall be considered to be an existing agricultural operation. An on-going existing agricultural operation does not include uses located within the agricultural operation that are not in themselves related to agriculture.
(cc) Additional encroachment into steep slopes may be permitted for tentative maps and tentative parcel maps which propose a Planned Residential Development, lot area averaging, conservation subdivision or cluster development when design considerations include encroachment into steep slopes in order to avoid impacts to significant environmental resources that cannot be avoided by other means, provided no less environmentally damaging alternative exists. The determination of whether or not a tentative map or tentative parcel map qualifies for additional encroachment shall be made by the Director of Planning and Development Services based upon an analysis of the project site.
(3) Waiver of Open Space Easement. The steep slope open space easement requirement may be waived when the authority considering an application listed at Section 86.603(a) above makes the following findings:
(aa) The slope is an insignificant visual feature and isolated from other landforms, or surrounding properties have been developed on steep slopes such that this project would be considered "infill"; and
(bb) The property is zoned for 0.5 acre lots or smaller at the time the application was made, or a concurrent Rezone has been filed; and
(cc) The greater encroachment is consistent with the goals and objectives of the applicable community plan; and
(dd) Site Plan review is required to ensure consistency of design with these regulations.
(f) Sensitive Habitat Lands. Development, grading, grubbing, clearing or any other activity or use damaging to sensitive habitat lands shall be prohibited. The authority considering an application listed at Section 86.603(a) above may allow development when all feasible measures necessary to protect and preserve the sensitive habitat lands are required as a condition of permit approval and where mitigation provides an equal or greater benefit to the affected species.
(g) Significant Prehistoric or Historic Sites. Development, trenching, grading, clearing and grubbing, or any other activity or use damaging to significant prehistoric or historic site lands shall be prohibited, except for scientific investigations with an approved research design prepared by an archaeologist certified by the Society of Professional Archaeologists.
(Added by Ord. No. 9842 (N.S.), effective 4-20-07; amended by Ord. No. 10167 (N.S.), effective 10-14-11; amended by Ord. No. 10224 (N.S.), effective 10-25-12; amended by Ord. No. 10705 (N.S.), effective 1-8-21)