34.5 STMP: SAMOA TOWN PLAN STANDARDS

34.5.1 Purpose. The purpose of these regulations is to provide for the comprehensive planning and orderly development of the community of Samoa.

34.5.2 Applicability. These regulations shall apply within the STMP-LUP, specifically to the entirety of the legal parcel(s) containing APN 401-031-36, APN 401-031-38, APN 401-031-46, APN 401-031-55, APN 401-031-059, APN 401-031-65, APN 401-031-67, and APN 401-031-44, generally depicted on Exhibit 25.

34.5.3 Modifications Imposed by the STMP Regulations. These regulations shall be in addition to regulations imposed by the primary zone, development regulations, and other coastal resource special area regulations. Where a conflict arises between the regulations of the STMP Combining Zone and any other regulation of the zoning ordinance, the regulations of the STMP Combining Zone shall take precedence.

The land use designations and zoning approved by the Commission with suggested modifications in its action on Humboldt County LCPA HUM-MAJ-01-08 shall not become effective unless and until the entirety of the legal parcel(s) containing APN 401-031-36, APN 401-031-38, APN 401-031-46, APN 401-031-55, APN 401-031-059, APN 401-031-65, and APN 401-031-44, generally depicted on Exhibit 25A and described as the Samoa Town Master Plan

The Humboldt County Code is current through Ordinance 2784, passed March 10, 2026.

Page 179 of 1183

Title III Land Use and Development | Humboldt County Code

Land Use Plan (“STMP-LUP”) Overlay Area, excluding APN 401-031-67 which contains the Samoa Processing Center (recycling facility) (Master Parcel 1), are merged and re-subdivided by parcel map into one two (2) master parcels generally depicted on Exhibit 25A. The two resulting parcels shall comprise (1) Master Parcel 2: the combined Public Facilities (PF) area for wastewater treatment and disposal, the Vance Avenue right of way, and the Residential Medium Density (RM) area; and (2) Master Parcel 3: all other STMP lands excluding Master Parcel 1 containing the Samoa Processing Center. If all such property is not merged and re-subdivided by parcel map into Master Parcels 2 and 3 generally depicted on Exhibit 25A, the entirety of the area generally depicted on Exhibit 25A and described as the Samoa Town Master Plan Land Use Plan (“STMP-LUP”) Overlay Area will remain designated as General Industrial, Coastal Dependent Industrial and Natural Resources. If all such property is merged and resubdivided by parcel map into Master Parcels 2 and 3 generally depicted on Exhibit 25A, the land use designations and zoning approved by the Commission with suggested modifications in its action on Humboldt County LCPA HUM-MAJ-01-08 shall become effective upon both: (a) issuance of the coastal development permit for the merger and re-subdivision by parcel map consistent with the certified LCP and (b) recordation of a parcel map consistent with the coastal development permit. Recordation of a parcel map is required and shall not be waived. If a legal lot containing any APN generally depicted on Exhibit 25A straddles the STMP-LUP boundaries generally depicted on Exhibit 25A, the portion of the legal lot containing the APN outside the STMP Overlay Area boundary shall be included within the merger and re-subdivision by parcel map and become part of the immediately adjacent master parcel generally depicted on Exhibit 25A. If the land use designations and zoning approved by the Commission with suggested modification in its action on Humboldt County LCPA HUM-MAJ-01-08 become effective, the Principal Permitted Use of any area subject to the STMP-LUP shall be determined in accordance with the designated Land Uses and in the patterns and locations generally shown on the certified STMP Land Use Map. No minimum or maximum number of lots shall be determined or authorized until or unless a coastal development permit for the comprehensive division of Master Parcel 3 has been approved and issued consistent with all applicable provisions of the certified LCP, including the STMP-LUP. (Ord. 2466, 12/6/2011; Ord. 2549, § 1, 4/ 26/2016)

34.5.4 STMP Development Findings. Coastal development permit approvals for development within the lands subject to the STMP shall only be authorized if the following requirements are met, in addition to any other applicable requirements of the certified Local Coastal Program. Development within the STMP may only be authorized if the decision-making authority adopts specific findings of consistency with the following numbered regulations and provisions and all other applicable requirements of the certified LCP.

34.5.4.1.1 New development authorized within the STMP-LUP including restoration of existing structures shall incorporate the best available practices for the protection of coastal waters. To achieve these standards, the applicant shall provide supplemental information as a filing requirement of any coastal development permit application for development within the area subject to the STMP, and the pertinent decision-makers shall adopt specific findings and attach conditions requiring the incorporation of, and compliance with, these water quality protection measures in approving coastal development permits for subdivision or further development of the lands subject to the standards of the STMP.

The Humboldt County Code is current through Ordinance 2784, passed March 10, 2026.

Page 180 of 1183

Title III Land Use and Development | Humboldt County Code

34.5.4.1.1.1 Construction pollution control plan. A construction-phase erosion, sedimentation, and polluted runoff control plan (“construction pollution control plan”) shall specify interim best management practices (BMPs) that will be implemented to minimize erosion and sedimentation during construction, and prevent contamination of runoff by construction chemicals and materials, to the maximum extent practicable. The construction pollution control plan shall demonstrate that:

34.5.4.1.1.1.1 During construction, development shall minimize site runoff and erosion through the use of temporary BMPs (including, but not limited to, soil stabilization measures), and shall eliminate the discharge of sediment and other stormwater pollution resulting from construction activities (e.g., chemicals, vehicle fluids, asphalt and cement compounds, and debris), to the extent feasible.

34.5.4.1.1.1.2 Land disturbance activities during construction (e.g., clearing, grading, and cutand-fill) shall be minimized, to the extent feasible, to avoid increased erosion and sedimentation. Soil compaction due to construction activities shall be minimized, to the extent feasible, to retain the natural stormwater infiltration capacity of the soil.

34.5.4.1.1.1.3 Construction shall minimize the disturbance of natural vegetation (including significant trees, native vegetation, and root structures), which is important for preventing erosion and sedimentation.

34.5.4.1.1.1.4 Development shall implement soil stabilization BMPs, including but not limited to re-vegetation, on graded or disturbed areas as soon as feasible.

34.5.4.1.1.1.5 Grading operations shall not be conducted during the rainy season (from October 1 to April 15), except in response to emergencies, unless the County determines that soil conditions at the project site are suitable, the likelihood of significant precipitation is low during the period of extension, (not to exceed one week at a time), and adequate erosion and sedimentation control measures will be in place during all grading operations.

ted during the rainy season (from October 1 to April 15), except in response to emergencies, unless the County determines that soil conditions at the project site are suitable, the likelihood of significant precipitation is low during the period of extension, (not to exceed one week at a time), and adequate erosion and sedimentation control measures will be in place during all grading operations.

34.5.4.1.1.1.6 The construction pollution control plan shall be submitted with the final construction drawings. The plan shall include, at a minimum, a narrative report describing all temporary polluted runoff, sedimentation, and erosion control measures to be implemented during construction, including:

34.5.4.1.1.1.6.1 Controls to be implemented on the amount and timing of grading.

34.5.4.1.1.1.6.2 BMPs to be implemented for staging, storage, and disposal of excavated materials.

34.5.4.1.1.1.6.3 Design specifications for structural treatment control BMPs, such as sedimentation basins.

34.5.4.1.1.1.6.4 Re-vegetation or landscaping plans for graded or disturbed areas.

34.5.4.1.1.1.6.5 Other soil stabilization BMPs to be implemented.

The Humboldt County Code is current through Ordinance 2784, passed March 10, 2026.

Page 181 of 1183

Title III Land Use and Development | Humboldt County Code

34.5.4.1.1.1.6.6 Methods to infiltrate or treat stormwater prior to conveyance off-site during construction.

34.5.4.1.1.1.6.7 Methods to eliminate or reduce the discharge of other stormwater pollutants resulting from construction activities (including but not limited to paints, solvents, vehicle fluids, asphalt and cement compounds, and debris) into stormwater runoff.

34.5.4.1.1.1.6.8 BMPs to be implemented for staging, storage, and disposal of construction chemicals and materials.

34.5.4.1.1.1.6.9 Proposed methods for minimizing land disturbance activities, soil compaction, and disturbance of natural vegetation.

34.5.4.1.1.1.6.10 A site plan showing the location of all temporary erosion control measures.

34.5.4.1.1.1.6.11 A schedule for installation and removal of the temporary erosion control measures.

34.5.4.1.1.2 Post-Construction Stormwater Plan. A plan to control post-construction stormwater runoff flows, and maintain or improve water quality (“post-construction stormwater plan”) shall specify site design, source control, and if necessary, treatment control BMPs that will be implemented to minimize stormwater pollution and minimize or eliminate increases in stormwater runoff volume and rate from the development after construction. The post-construction stormwater plan shall demonstrate that:

34.5.4.1.1.2.1 Following construction, erosion on the site shall be controlled to avoid adverse impacts on adjacent properties and resources.

34.5.4.1.1.2.2 Permanent erosion control measures shall be installed, as may be needed, depending upon the intensity of development proposed and the sensitivity of receiving waters.

34.5.4.1.1.2.3 Runoff from the project shall not increase sedimentation in receiving waters.

34.5.4.1.1.2.4 On-site filtering, grease, and/or sediment trapping systems shall be installed, as needed, to capture any pollutants contained in the runoff.

34.5.4.1.1.2.5 Permanent runoff/drainage control improvements, such as subsurface drainage interception, energy dissipaters, recovery/reuse cisterns, detention/retention impoundments, etc. shall be installed, as needed, at the point of discharge.

34.5.4.1.1.2.6 In the application and initial planning process, the applicant shall submit a preliminary post-construction stormwater plan, and prior to issuance of a building permit the applicant shall submit a final post-construction stormwater plan for approval by the County. The plan shall include, at a minimum, the following components:

The Humboldt County Code is current through Ordinance 2784, passed March 10, 2026.

Page 182 of 1183

Title III Land Use and Development | Humboldt County Code

34.5.4.1.1.2.6.1 Proposed site design and source control BMPs that will be implemented to minimize post-construction polluted runoff.

34.5.4.1.1.2.6.2 Proposed drainage improvements (including locations of infiltration basins, and diversions/ conveyances for upstream runoff).

34.5.4.1.1.2.6.3 Measures to maximize on-site retention and infiltration (including directing rooftop runoff to permeable areas rather than to driveways).

34.5.4.1.1.2.6.4 Measures to maximize, to the extent practicable, the percentage of permeable surfaces, and to limit the percentage of directly connected impervious areas, to increase infiltration of runoff.

34.5.4.1.1.2.6.5 Methods to convey runoff from impervious surfaces into permeable areas of the property in a non-erosive manner.

34.5.4.1.1.2.6.6 A site plan showing the location of all permanent erosion control measures.

34.5.4.1.1.2.6.7 A schedule for installation and maintenance of the permanent erosion control measures.

34.5.4.1.1.2.6.8 A schedule for installation and maintenance of the sediment and debris filtration, grease and/or sediment trap, etc., as warranted for the type of development and site.

34.5.4.1.1.2.6.9 A site plan showing finished grades in one-foot contour intervals and associated drainage improvements.

34.5.4.1.1.3 Site design using low impact development techniques. The post-construction

stormwater plan shall demonstrate the preferential consideration of low impact development (LID) techniques in order to minimize stormwater quality and quantity impacts from development. LID is a development site design strategy with a goal of maintaining or reproducing the site’s predevelopment hydrologic functions of storage, infiltration, and groundwater recharge, as well as the volume and rate of stormwater discharges. LID strategies use small-scale integrated and distributed management practices, including minimizing impervious surfaces, infiltrating stormwater close to its source, and preservation of permeable soils and native vegetation. LID techniques to consider include, but are not limited to, the following:

, infiltration, and groundwater recharge, as well as the volume and rate of stormwater discharges. LID strategies use small-scale integrated and distributed management practices, including minimizing impervious surfaces, infiltrating stormwater close to its source, and preservation of permeable soils and native vegetation. LID techniques to consider include, but are not limited to, the following:

34.5.4.1.1.3.1 Development shall be sited and designed to preserve the infiltration, purification, detention, and retention functions of natural drainage systems that exist on the site, to the maximum extent practicable. Drainage shall be conveyed from the developed area of the site in a non-erosive manner.

34.5.4.1.1.3.2 Development shall minimize the creation of impervious surfaces (including pavement, sidewalks, driveways, patios, parking areas, streets, and roof-tops), especially

The Humboldt County Code is current through Ordinance 2784, passed March 10, 2026.

Page 183 of 1183

Title III Land Use and Development | Humboldt County Code

directly connected impervious areas, to the maximum extent practicable. Directly connected impervious areas include areas covered by a building, impermeable pavement, and/or other impervious surfaces, which drain directly into the storm drain system without first flowing across permeable land areas (e.g., lawns).

34.5.4.1.1.3.3 Development shall maintain or enhance, where appropriate and feasible, on-site infiltration of stormwater runoff, in order to preserve natural hydrologic conditions, recharge groundwater, attenuate runoff flow, and minimize transport of pollutants. Alternative management practices shall be substituted where the review authority has determined that infiltration BMPs may result in adverse impacts, including but not limited to where saturated soils may lead to geologic instability, where infiltration may contribute to flooding, or where regulations to protect groundwater may be violated.

34.5.4.1.1.3.4 Development that creates new impervious surfaces shall divert stormwater runoff flowing from these surfaces into permeable areas in order to maintain, or enhance where appropriate and feasible, on-site stormwater infiltration capacity.

34.5.4.1.1.3.5 To enhance stormwater infiltration capacity, development applicants shall use permeable pavement materials and techniques (e.g., paving blocks, porous asphalt, permeable concrete, and reinforced grass or gravel), where appropriate and feasible. Permeable pavements shall be designed so that stormwater infiltrates into the underlying soil, to enhance groundwater recharge and provide filtration of pollutants.

34.5.4.1.1.4 Water quality and hydrology plan for developments of water quality concern. In addition to the information to be provided in the post-construction stormwater plan, applicants for “developments of water quality concern,” shall submit a water quality and hydrology plan and be subject to the additional requirements listed below.

34.5.4.1.1.4.1 “Developments of water quality concern” include the following:

34.5.4.1.1.4.1.1 Housing developments of five (5) or more dwelling units, including but not limited to residential subdivisions.

34.5.4.1.1.4.1.2 Hillside developments on slopes greater than 20 percent, located in areas with highly erodible soil, such as soils deposited in association with dune formation.

34.5.4.1.1.4.1.3 Developments that will cumulatively result in the creation, addition, or replacement of one acre or more of impervious surface area.

34.5.4.1.1.4.1.4 Parking lots with ten thousand (10,000) square feet or more of impervious surface area, potentially exposed to stormwater runoff, or where, combined with adjacent structures, will cumulatively exceed ten thousand (10,000) square feet.

The Humboldt County Code is current through Ordinance 2784, passed March 10, 2026.

Page 184 of 1183

Title III Land Use and Development | Humboldt County Code

34.5.4.1.1.4.1.5 Vehicle service facilities, including retail gasoline outlets, commercial car washes, and vehicle repair facilities, with ten thousand (10,000) square feet or more of impervious surface area.

34.5.4.1.1.4.1.6 Business or Industrial parks, or other commercial or recreational development with ten thousand (10,000) square feet or more of impervious surface area, including associated parking.

34.5.4.1.1.4.1.7 Commercial, recreational or industrial outdoor storage areas of five thousand (5,000) square feet or more, or as determined by the County based on the use of the storage area, where used for storage of materials that may contribute pollutants to the storm drain system or coastal waters.

34.5.4.1.1.4.1.8 Business, industrial, commercial, agricultural, or recreational developments of any size that utilize chemicals that may contribute pollutants to the storm drain system that would adversely affect the functioning of the vegetated filtration fields associated with the waste water treatment plant.

34.5.4.1.1.4.1.9 Streets, roads, bus stops, and adjacent bicycle lanes and sidewalks cumulatively equaling ten thousand (10,000) feet or more of impervious surface area, but not including Class I (stand-alone) pedestrian pathways, trails, and off-street bicycle lanes.

34.5.4.1.1.4.1.10 All developments entailing the creation, addition, or replacement of 5,000 square feet or more of impervious surface area, located within two hundred (200) feet of the ocean or a coastal water body (including estuaries, wetlands, rivers, streams, and lakes), or that discharge directly to the ocean or a water body (i.e., outflow from the drainage conveyance system is composed entirely of flows from the subject development or redevelopment site, and not commingled with flows from adjacent lands.)

34.5.4.1.1.4.2 Additional Requirements for developments of water quality concern:

34.5.4.1.1.4.2.1 Water quality and hydrology plan. The applicant for a development of water quality concern shall be required to submit a water quality & hydrology plan (WQHP), prepared by a California licensed civil engineer or landscape architect, which supplements the post-construction stormwater plan. The WQHP shall include calculations, per County standards, that estimate increases in pollutant loads and changes in stormwater runoff hydrology (i.e., volume and flow rate) resulting from the proposed development, and shall specify the BMPs that will be implemented to minimize postconstruction water quality and hydrologic impacts. The WQHP shall also include operation and maintenance plans for post-construction treatment control BMPs. In the application and initial planning process, the applicant shall be required to submit for approval a preliminary WQHP, and prior to issuance of a building permit the applicant shall submit a final WQHP for approval by the County Engineer.

The Humboldt County Code is current through Ordinance 2784, passed March 10, 2026.

Page 185 of 1183

Title III Land Use and Development | Humboldt County Code

34.5.4.1.1.4.2.2 Selection of structural treatment control BMPs. If the County determines that the combination of site design and source control BMPs is not sufficient to protect water quality and coastal waters, a structural treatment control BMP (or suite of BMPs) shall also be required. developments of water quality concern are presumed to require treatment control BMPs to meet the requirements of the coastal land use plan and state and federal water quality laws, unless the water quality & hydrology plan demonstrates otherwise.

The water quality & hydrology plan for a development of water quality concern shall describe the selection of treatment controls BMPs. Applicants shall first consider the treatment control BMP, or combination of BMPs, that is most effective at removing the pollutant(s) of concern, or provide a justification if that BMP is determined to be infeasible.

34.5.4.1.1.4.2.3 85th percentile design standard for treatment control BMPs. For postconstruction treatment of stormwater runoff in developments of water quality concern, treatment control BMPs (or suites of BMPs) shall be sized and designed to treat, infiltrate, or filter the amount of stormwater runoff produced by all storms up to and including the 85th percentile, 24-hour storm event for volume-based BMPs, and/or the 85th percentile, one-hour storm event (with an appropriate safety factor of 2 or greater) for flow-based BMPs.

34.5.4.1.1.4.2.4 Maintain pre-development hydrograph. In developments of water quality concern where changes in stormwater runoff hydrology (i.e., volume and flow rate) may result in increased potential for stream bank erosion, downstream flooding, or other adverse habitat impacts, hydrologic control measures (e.g., stormwater infiltration, detention, harvest and re-use, and landscape evapotranspiration) shall be implemented in order to ensure that the pre- and post-project runoff hydrographs match within 10% for a two-year return frequency storm.

and flow rate) may result in increased potential for stream bank erosion, downstream flooding, or other adverse habitat impacts, hydrologic control measures (e.g., stormwater infiltration, detention, harvest and re-use, and landscape evapotranspiration) shall be implemented in order to ensure that the pre- and post-project runoff hydrographs match within 10% for a two-year return frequency storm.

34.5.4.1.1.4.3 Content. The water quality and hydrology plan shall contain the following:

34.5.4.1.1.4.3.1 Site design, source control, and treatment control BMPs that will be implemented to minimize post-construction water quality and hydrologic impacts.

34.5.4.1.1.4.3.2 All of the information required in sub-section A for the post-construction stormwater plan.

34.5.4.1.1.4.3.3 Pre-development stormwater runoff hydrology (i.e., volume and flow rate) from the site.

34.5.4.1.1.4.3.4 Expected post-development stormwater runoff hydrology (i.e., volume and flow rate) from the site, with all proposed non-structural and structural BMPs in place.

34.5.4.1.1.4.3.5 Measures to infiltrate or treat runoff from impervious surfaces (including roads, driveways, parking structures, building pads, roofs, and patios) on the site, and to

The Humboldt County Code is current through Ordinance 2784, passed March 10, 2026.

Page 186 of 1183

Title III Land Use and Development | Humboldt County Code

discharge the runoff in a manner that avoids potential adverse impacts. Such measures may include, but are not limited to, structural treatment control BMPs including biofilters, grassy swales, on-site de-silting basins, detention ponds, or dry wells.

34.5.4.1.1.4.3.6 A description of how the BMPs (or suites of BMPs) have been designed to infiltrate and/or treat the amount of storm water runoff produced by all storms up to and including the 85th percentile, 24-hour storm event for volume-based BMPs, and/or the 85th percentile, one-hour storm event (with an appropriate safety factor of two (2) or greater) for flow-based BMPs.

34.5.4.1.1.4.3.7 Appropriate structural post-construction Treatment Control BMPs selected to remove the specific runoff pollutants generated by the development, using processes such as gravity settling, filtration, biological uptake, media adsorption, or any other physical, chemical, or biological process.

34.5.4.1.1.4.3.8 A long-term plan and schedule for the monitoring and maintenance of all structural Treatment Control BMPs. All structural BMPs shall be inspected, cleaned, and repaired as necessary to ensure their effective operation for the life of the development. Owners of these devices shall be responsible for ensuring that they continue to function properly, and additional inspections should occur after storms as needed throughout the rainy season. Repairs, modifications, or installation of additional BMPs, as needed, shall be carried out prior to the next rainy season.

34.5.4.1.1.5.1 All development shall incorporate effective site design and long-term postconstruction source control BMPs, as necessary to minimize adverse impacts to water quality and coastal waters resulting from the development, to the maximum extent practicable. BMPs that protect post-construction water quality and minimize increases in runoff volume and rate shall be incorporated as necessary in the project design of developments in the following order of priority:

34.5.4.1.1.5.1.1 Site design BMPs: Project design features that reduce the creation or severity of potential pollutant sources, or reduce the alteration of the project site’s natural stormwater flow regime. Examples are minimizing impervious surfaces, preserving native vegetation, and minimizing grading.

34.5.4.1.1.5.1.2 Source control BMPs: Methods that reduce potential pollutants at their sources and/or avoid entrainment of pollutants in runoff, including schedules of activities, prohibitions of practices, maintenance procedures, managerial practices, or operational practices. Examples are covering outdoor storage areas, use of efficient irrigation, and minimizing the use of landscaping chemicals.

34.5.4.1.1.5.1.3 Treatment control BMPs: Systems designed to remove pollutants from stormwater, by simple gravity settling of particulate pollutants, filtration, biological uptake,

The Humboldt County Code is current through Ordinance 2784, passed March 10, 2026.

Page 187 of 1183

Title III Land Use and Development | Humboldt County Code

media adsorption, or any other physical, biological, or chemical process. Examples are vegetated swales, detention basins, and storm drain inlet filters.

34.5.4.1.1.5.2 The selection of BMPs shall be guided by the California Stormwater Quality Association (CASQA) Stormwater BMP Handbooks dated January 2003 (or the current edition), or an equivalent BMP manual that describes the type, location, size, implementation, and maintenance of BMPs suitable to address the pollutants generated by the development and specific to a climate similar to Humboldt County’s. Caltrans' 2007 “Storm Water Quality Handbook: Project Planning and Design Guide” (or the current edition) may also be used to guide design of construction-phase BMPs. Additional guidance on BMPs is available from the state water resources and water quality boards, the U.S. Environmental Protection Agency, regional entities such as the Bay Area Stormwater Management Agencies Association’s (BASMAA) “Start at the Source: Design Guidance Manual for Stormwater Quality Protection,” and/or as may be developed from time to time with technological advances in water quality treatment.

ance on BMPs is available from the state water resources and water quality boards, the U.S. Environmental Protection Agency, regional entities such as the Bay Area Stormwater Management Agencies Association’s (BASMAA) “Start at the Source: Design Guidance Manual for Stormwater Quality Protection,” and/or as may be developed from time to time with technological advances in water quality treatment.

34.5.4.1.1.5.3 Where BMPs, are required, BMPs shall be selected that have been shown to be effective in reducing the pollutants typically generated by the proposed land use. The strategy for selection of appropriate BMPs to protect water quality and coastal waters shall be guided by Tables 21-55B-1 through -3, below, or equivalent tables which list pollutants of concern and appropriate BMPs for each type of development or land use. (Ord. 2466, 12/6/2011; Ord. 2549, § 1, 4/26/2016)

34.5.4.2.1 Remediation of contamination, including contaminated soils or residual lead paint on structural surfaces, and/or reinforcement/replacement of the foundations of aging structures associated with the “company town” of Samoa shall be undertaken with special care to preserve the structural integrity and authentic period details (such as original woodwork, windows, and millwork) of the structures, in accordance with the following additional requirements:

34.5.4.2.1.1 Proposals for remediation shall clearly indicate the removal methods that will be used for the soil, groundwater, and the existing structures in the coastal development permit application submitted to the reviewing authority for each project. In addition, such proposals shall include a Standard Operating Procedure for safe implementation of removal methods that will be used on or near the existing structures, and the Standard Operating Procedure shall be incorporated into each applicable removal contract and which shall clearly state the manner in which release of contaminants to the environment will be prevented;

34.5.4.2.1.2 A coastal development permit application for such work shall include a survey of each existing structure (a “Building Survey”) included in the proposed project or within a 25-foot radius of the proposed project. The Building Survey document shall include at a minimum: a section and plan of the proposed site including existing structures and if a soil removal is proposed – a section and plan prepared by a California-licensed professional civil engineer (“civil engineer”) indicating the

The Humboldt County Code is current through Ordinance 2784, passed March 10, 2026.

Page 188 of 1183

Title III Land Use and Development | Humboldt County Code

excavation limits (depth and distance from existing structures), elevation drawings (each façade) of all existing buildings within the proposed project area and the project radius, an evaluation of the structural integrity of each existing structure (including the foundation, exterior walls, and all attached structures such as porches and decks), photographs to support the findings, a description of any prior site disturbance as the result of past remedial actions or naturally occurring earth movement, and provide a written report of the survey conclusions, including recommendations to ensure that the structure remains stable throughout the proposed removal work as well as postremediation. In addition, the civil engineer shall clearly determine whether the existing foundation of each structure will adequately support the building throughout the removal of hazardous materials or if a new foundation is recommended.

en report of the survey conclusions, including recommendations to ensure that the structure remains stable throughout the proposed removal work as well as postremediation. In addition, the civil engineer shall clearly determine whether the existing foundation of each structure will adequately support the building throughout the removal of hazardous materials or if a new foundation is recommended.

34.5.4.2.1.3 In the event that a new foundation is recommended by the civil engineer pursuant to Subparagraph 2 above, the civil engineer shall propose an appropriate foundation which meets current California State building standards. The reviewing authority shall require that the new foundation be installed in accordance with the civil engineer’s recommendations prior to any site disturbance that the civil engineer indicates could compromise the stability of an existing structure. The civil engineer shall provide a post-remediation survey of each historic structure and warrant the continued stability of the structure in a final report submitted to the reviewing authority, including documentation that the recommendations of the civil engineer have been fully implemented, including the construction of the new foundations where such recommendation has been identified. Should unanticipated de-stabilization of any existing structure occur during remedial activities, site disturbance shall be halted, the structure temporarily stabilized, and a civil engineering analysis and recommendations to stabilize the structure permanently shall be obtained by the reviewing authority and implemented before remediation or other site disturbance resumes. All civil

engineering analyses and reports pertaining to these requirements shall be collected and preserved by the reviewing authority and retained in permanent public files. All survey and civil engineering work performed in accordance with these requirements shall be undertaken by a California Statelicensed registered professional civil engineer.

34.5.4.1 Existing structures associated with the historic town shall be restored and maintained in a manner that protects the historic character, period details, and authentic original materials of the original structures. Replacement of period details and features with new materials or methods designed to achieve energy conservation shall not be undertaken in a manner that would replace or distract from the existing period details such as original wood-framed windows and hand-turned wooden decorative details evident in many of the existing Samoa “company town” structures.

34.5.4.4.1 The biological report required by STMP (Wetlands/ESHA) Policy 11 shall include, but is not limited to, the following:

The Humboldt County Code is current through Ordinance 2784, passed March 10, 2026.

Page 189 of 1183

Title III Land Use and Development | Humboldt County Code

34.5.4.4.1.1 A study identifying biological resources existing on the site, and the historical extent of the resources as identified in previous reports, surveys, delineations, maps, or publications, disclosing the history, ecology and habitat requirements of the relevant resources, such as plants and wildlife, in sufficient detail to permit a review of functional relationships, their potential for restoration, the potential location of dormant seedbanks of rare (particularly annual) plants, habitat (including non-native species such as individual trees or groves that provide habitat architecture and other resources for birds or other species, or wetlands that may be used by amphibians during specific lifecycle stages) that may be used during specific lifecycle stages or seasonally by migratory species for roosting, breeding or feeding during specific seasonal windows, and present and potential adverse physical and biological impacts on the identified biological resources or on the associated ecosystem, either individually or cumulatively;

34.5.4.4.1.2 An identification of “fully protected” species and/or “species of special concern,” and an identification of any other species of rarity, including plants designated “List 1B” or “List 2” by the California Native Plant Society, that are present or have the potential to occur on the project site;

34.5.4.4.1.3 Photographs of the site labeled with orientation noted on pertinent maps;

34.5.4.4.1.4 A discussion of the physical characteristics of the site including, but not limited to, topography, soil types, microclimate, and migration corridors;

34.5.4.4.1.5 A site map depicting the location of biological resources, both current and historical. The resources shall be shown within the context of a topographic based map that shall be at a scale sufficiently large to permit clear and accurate depiction of the extent of sensitive resources identified through appropriate field investigations and where pertinent, protocol surveys for sensitive species, vegetation associations and soil types in relation to any and all proposed development (minimum 1:2,400) and other information, such as the locations of specific trees, habitat boundaries, etc. discussed in the text of the subject biological report. Contour intervals shall be five (5) feet, and the map should contain a north arrow, graphic bar scale, and a citation for the source of the base map (including the date).

34.5.4.4.1.6 An analysis of the potential impacts of the proposed development on the identified habitat or species;

34.5.4.4.1.7 An analysis of any unauthorized development, including grading or vegetation removal that may have contributed to the degradation or elimination of habitat area or species that would otherwise be present on the site in a healthy condition (note: vegetation or other resources previously surveyed as present but absent at the time of preparation of the subject biological report shall be explained, and if no reasonable ecological basis for the change exists, the County shall presume that unauthorized disturbance of the pertinent resources may have occurred and shall investigate and respond to this information accordingly and the results of the pertinent investigation shall be presented to the pertinent decision-makers. Development of areas subject to prior unauthorized disturbance shall not be authorized until or unless resolution of the potential violation has been achieved.);

The Humboldt County Code is current through Ordinance 2784, passed March 10, 2026.

Page 190 of 1183

Title III Land Use and Development | Humboldt County Code

34.5.4.4.1.8 Project alternatives, including project modifications and off-site options designed to avoid and minimize impacts to identified habitat or species;

34.5.4.4.1.9 A buffer adequacy analysis consistent with the requirements of STMP (Wetland/ESHA) Policy 4 where an ESHA buffer of less than one hundred (100) feet is proposed. The buffer adequacy analysis shall at a minimum include the following:

34.5.4.4.1.9.1 Biological significance of adjacent lands. The functional relationships among nearby habitat types and areas. Functional relationships may exist if species associated with such areas spend a significant portion of their life cycle on adjacent lands. The degree of significance depends upon the habitat requirements of the species in the habitat area (e.g., nesting, feeding, breeding, or resting). Where a significant functional relationship exists, the land supporting this relationship shall also be considered to be part of the ESHA, and the buffer zone shall be measured from the edge of these lands and be sufficiently wide to protect these functional relationships. Where no significant functional relationships exist, the buffer shall be measured from the edge of the ESHA that is adjacent to the proposed development.

34.5.4.4.1.9.1.2 Sensitivity of species to disturbance. The width of the buffer zone shall be based, in part, on the distance necessary to ensure that the most sensitive species of plants and animals will not be disturbed significantly by the permitted development. Such a determination shall be based on the following after consultation with biologists of the Department of Fish and Game, the U.S. Fish and Wildlife Service, the National Marine Fisheries Service, the Coastal Commission or others with similar expertise:

34.5.4.4.1.9.1.3 Nesting, feeding, breeding, resting, or other habitat requirements of both resident and migratory fish and wildlife species, which may include reliance on non-native species, including trees that provide roosting, feeding, or nesting habitat;

34.5.4.4.1.9.1.4 An assessment of the short-term and long-term adaptability of various species to human disturbance;

34.5.4.4.1.9.1.5 An assessment of the impact and activity levels of the proposed development on the resource.

34.5.4.4.1.9.1.6 Erosion susceptibility. The width of the buffer shall be based, in part, on an assessment of the slope, soils, impervious surface coverage, runoff characteristics, erosion potential, and vegetative cover of the parcel proposed for development and adjacent lands. A sufficient buffer to allow for the interception of any additional material eroded as a result of the proposed development shall be provided.

34.5.4.4.1.9.1.7 Use natural topography. Where feasible, use hills and bluffs adjacent to Environmentally Sensitive Habitat Areas, to buffer these habitat areas. Where otherwise permitted, locate development on the sides of hills away from Environmentally Sensitive Habitat Areas. Include bluff faces in the buffer area.

The Humboldt County Code is current through Ordinance 2784, passed March 10, 2026.

Page 191 of 1183

Title III Land Use and Development | Humboldt County Code

34.5.4.4.1.9.1.8 Required buffer areas shall be measured from the following points, and shall include historic locations of the subject habitat/species that are pertinent to the habitats associated with the STMP-LUP area, as applicable:

34.5.4.4.1.9.1.8.1 The perimeter of the sand dune/permanently established terrestrial vegetation interface for dune-related ESHA.

34.5.4.4.1.9.1.8.2 The upland edge of a wetland.

34.5.4.4.1.9.1.8.3 The outer edge of the canopy of coastal sage or forests plus such additional area as may be necessary to account for underground root zone areas. All root zones shall be protected as part of the associated ESHA.

34.5.4.4.1.9.1.8.4 The outer edge of the plants that comprise the rare plant community for rare plant community ESHA, including any areas of rare annual plants that have been identified in previous surveys and the likely area containing the dormant seed banks of rare plant species.

34.5.4.4.1.9.1.8.5 The outer edge of any habitat used by mobile or difficult to survey sensitive species (such as ground nesting habitat or rare insects, seasonal upland refuges of certain amphibians, etc.) within or adjacent to the lands subject to the STMP-LUP based on the best available data.

34.5.4.4.1.9.1.86 Where established public agency “protocols” exist for the survey of a particular species or habitat, the preparing biologist shall undertake the survey and subsequent analysis in accordance with the requirements of the protocol and shall be trained and credentialed by the pertinent agency to undertake the subject protocol survey. (Ord. 2466, 12/6/2011; Ord. 2549, § 1, 4/26/2016)

34.5.4.5.1 Sea Level Rise Analysis. Applications for development adjacent to the shore or that may be subject to the influence of sea level over the life of the project shall include an analysis of possible impacts from sea level rise. The analysis shall take into account the best available scientific information with respect to the effects of long-range sea level rise for all requisite geologic, geotechnical, hydrologic, and engineering investigations consistent with the best available science on sea-level rise for the Humboldt Bay region and the Coastal Commission’s adopted Sea Level Rise Policy Guidance document. Residential and commercial development at nearshore sites shall analyze potential coastal hazard sensitivities for a range of potential global sea level rise scenarios, from three to six (6) feet per century. The analysis shall also take into consideration regional sea level variability, localized uplift or subsidence, local topography, bathymetry and geologic conditions. A similar sensitivity analysis shall be performed for critical facilities, energy production and distribution infrastructure, and other development projects of major community significance. These hazard analyses shall be used to identify current and future site hazards, to help guide site design and hazard mitigation and to identify sea level thresholds after which limitations to the development’s design and siting would cause the improvements to become

The Humboldt County Code is current through Ordinance 2784, passed March 10, 2026.

Page 192 of 1183

Title III Land Use and Development | Humboldt County Code

significantly less stable. For design purposes, development projects shall assume a minimum sea level rise of three and two tenths (3.2) feet per century and projects of major community-wide significance shall assume a minimum five and three tenths (5.3) feet per century. (Ord. 2466, 12/6/2011; Ord. ____, Section 1, 4/12/2016)

313-35 “T” Combining Zone Designations