Fortuna City Council
April 7, 2025

GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project i 12th Street
Interchange
Modernization Project
Public Circulation Initial Study & Proposed
Mitigated Negative Declaration
City of Fortuna
February 24, 2025
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project ii 12th Street Interchange Modernization
Project
Prepared for:

City of Fortuna
P.O. Box 545
Fortuna, CA 95540
Prepared by:

GHD
718 Third Street
Eureka, CA 95501
© GHD 2024
Table of Contents
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project i Contents
Contents ..................................................................................................................................................i

1. Project Information....................................................................................................................1-1

1.1 CEQA Requirements......................................................................................................1-1

1.2 Purpose..........................................................................................................................1-2

1.3 Implementing Agency.....................................................................................................1-2

1.4 Proposed Project Summary............................................................................................1-2

1.5 Project Location .............................................................................................................1-3

1.6 Surrounding Land Uses and Existing Setting..................................................................1-3

1.7 Project Description .........................................................................................................1-4 Roadway Paving ........................................................................................................................ 1-4 Striping and Signage.................................................................................................................. 1-4 U.S. 101 Ramps......................................................................................................................... 1-4 Roundabout ............................................................................................................................... 1-4 Overcrossing Improvements....................................................................................................... 1-5 Pedestrian and Bicycle Facilities ................................................................................................ 1-5 Drainage Improvements ............................................................................................................. 1-5 Utilities ....................................................................................................................................... 1-5 Vegetation.................................................................................................................................. 1-5 Lighting ...................................................................................................................................... 1-6 Alteration of Rail Infrastructure ................................................................................................... 1-6

1.8 Project Construction.......................................................................................................1-6 Construction Schedule ............................................................................................................... 1-6 Construction Staging, Activities, and Equipment ......................................................................... 1-6 Traffic and Access Control ......................................................................................................... 1-7 Establish Exclusion Areas and Erosion Control........................................................................... 1-7 Vegetation Removal................................................................................................................... 1-7 Stockpiling and Staging.............................................................................................................. 1-7 Groundwater Dewatering............................................................................................................ 1-7

1.9 Maintenance and Operation ...........................................................................................1-8

1.10 Regulatory Permits, CEQA, and NEPA ..........................................................................1-8

1.11 Required Agency Approvals...........................................................................................1-8

1.12 Compliance with Existing Regulations and Standard BMPs ........................................... 1-8 Municipal Separate Storm Sewer System (MS4)......................................................................... 1-8 Stormwater Pollution Prevention Plan (SWPPP)......................................................................... 1-8 Implementation of Geotechnical Design Recommendations........................................................ 1-9

1.13 Tribal Consultation .........................................................................................................1-9

2. Environmental Factors Potentially Affected ..........................................................................2-10

3. Environmental Analysis ............................................................................................................3-1

3.1 Aesthetics ......................................................................................................................3-1

3.2 Agriculture and Forest Resources ..................................................................................3-6 Table of Contents
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project ii

3.3 Air Quality ......................................................................................................................3-9 Mitigation ................................................................................................................................. 3-10 Construction............................................................................................................................. 3-11 Operation................................................................................................................................. 3-12

3.4 Biological Resources....................................................................................................3-15 Special Status Plant Species.................................................................................................... 3-16 Special Status Wildlife Species................................................................................................. 3-16 Mitigation ................................................................................................................................. 3-28

3.5 Cultural Resources.......................................................................................................3-31 Mitigation ................................................................................................................................. 3-33 Mitigation ................................................................................................................................. 3-33

3.6 Energy Resources........................................................................................................3-35

3.7 Geology and Soils ........................................................................................................3-37 Mitigation ................................................................................................................................. 3-40

3.8 Greenhouse Gas Emissions.........................................................................................3-41

3.9 Hazards and Hazardous Materials ...............................................................................3-45 Mitigation ................................................................................................................................. 3-49

3.10 Hydrology and Water Quality........................................................................................3-51

3.11 Land Use and Planning ................................................................................................3-56

3.12 Mineral Resources .......................................................................................................3-57

3.13 Noise............................................................................................................................3-58 Construction............................................................................................................................. 3-59 Mitigation ................................................................................................................................. 3-60 Operation................................................................................................................................. 3-61

3.14 Population and Housing ...............................................................................................3-64

3.15 Public Services.............................................................................................................3-65

3.16 Recreation....................................................................................................................3-66

3.17 Transportation..............................................................................................................3-67 Mitigation ................................................................................................................................. 3-70

3.18 Tribal Cultural Resources.............................................................................................3-72

3.19 Utilities and Service Systems .......................................................................................3-73

3.20 Wildfire.........................................................................................................................3-75

3.21 Mandatory Findings of Significance..............................................................................3-77

4. References .................................................................................................................................4-1

5. Report Preparers........................................................................................................................5-3

5.1 City of Fortuna................................................................................................................5-3

5.2 GHD...............................................................................................................................5-3

5.3 Sub-consultants .............................................................................................................5-3 Roscoe and Associates.............................................................................................................. 5-3 JRP Historical Consulting........................................................................................................... 5-3 Table of Contents
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project iii Table index
Table 3.3-1 Annual Construction Regional Pollutant Emissions. 3-12 Table 3.3-2 Average Daily Construction Regional Pollutant Emissions. 3-12 Table 3.4-1 Special Status Plants with a Moderate Potential to Occur Within the Project Area. 3-16 Table 3.8-1 Consistency analysis between Project and Climate Change Scoping Plan. 3-43 Table 3.9-1 Potentially Significant Sites of Interest 3-48 Table 3.13-1 City of Fortuna General Plan Construction Noise Compatibility Standards. 3-59 Table 3.13-2 City of Fortuna General Plan Traffic and Stationary Source Noise Compatibility Standards. 3-59
Table 3.13-3 Construction Equipment Reference Noise Levels as Measured at 50 Feet. 3-60 Table 3.13-4 Estimated Construction Noise Levels at Sensitive Receptors. 3-60 Table 3.13-5 Typical Vibration Levels for Construction Equipment Used During Project Construction. 3-62
Table 3.21-1 Cumulative Projects Summary. 3-78
Appendices
Appendix A Figures
Figure 1 Vicinity Map
Figure 2 Project Overview
Figure 3 Soils Map
Appendix B Air Quality Modeling Results
Appendix C Botanical Survey Report
Appendix D Natural Environment Study
Appendix E Wetland Delineation
Environmental Factors Potentially Affected
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 1-1

1. Project Information
Project Title 12th Street Interchange Modernization Project Lead Agency Name & Address City of Fortuna
621 11th Street
P.O. Box 545
Fortuna, CA 95540
Lead Agency Contact Information for Key
Staff
Brendan Byrd, Public Works Director
(707) 725-1469
[email protected]
Shari Meads, Community Development Director
(707) 725-1408
[email protected]
Project Location The Project is located in the City of Fortuna, Humboldt County, California. The site is located at the 12th Street, Newburg Road, Riverwalk Drive, and U.S. Route 101 interchange.

Project Sponsor’s Name & Address City of Fortuna
621 11th Street
P.O. Box 545
Fortuna, CA 95540
General Plan Land Use Designation IND: Industrial
MD: Mill District
AG: Agriculture
Zoning CT: Commercial Thoroughfare
M-2: Heavy Industrial
A-E: Agriculture Exclusive

1.1 CEQA Requirements
The 12th Street Interchange Modernization Project (Project) is subject to the requirements of the California Environmental Quality Act (CEQA). The lead agency is the City of Fortuna (City). The purpose of this Initial Study is to provide a basis for deciding whether to prepare an Environmental Impact Report, a Mitigated Negative Declaration, or a Negative Declaration. This Initial Study is intended to satisfy the requirements of CEQA, (Public Resources Code, Division 13, §§ 21000-21189.91), and CEQA Guidelines (California Code of Regulations, Title 14, §§ 15000-15387). CEQA encourages lead agencies and applicants to modify their Projects to avoid significant adverse impacts.

CEQA Guidelines § 15063(d) requires an Initial Study to include:

1. A description of the Project including the location of the Project; Environmental Factors Potentially Affected
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 1-2

2. An identification of the environmental setting;

3. An identification of environmental effects by use of a checklist, matrix, or other method, provided that entries on a checklist or other form are briefly explained to indicate that there is some evidence to support the entries;

4. A discussion of the ways to mitigate the significant effects identified, if any;

5. An examination of whether the Project would be consistent with existing zoning, plans; and other applicable land use controls; and

6. The name of the person or persons who prepared or participated in the Initial Study.

All phases of project planning, implementation, and operation must be considered in the Initial Study.

1.2 Purpose
The 12th Street Interchange Modernization Project (Project) would improve traffic operation and safety at a key highway interchange in Fortuna, California. Highway 101 serves as the primary regional roadway in Humboldt County and is critically important to the residents and economy of Fortuna. The existing intersection controls, roadway geometry, and the high volumes of local and regional traffic on 12th Street result in poor traffic operation at and near the interchange. Under existing conditions, the Project Area experiences traffic delays during peak hours, experiences crash rates above the statewide average, and lacks bicycle and pedestrian facilities, resulting in a barrier to bicycle and pedestrian circulation. Project goals include:
- Simplify and improve navigation and traffic operations on 12th Street between Newburg Road and Riverwalk Drive, including the northbound U.S. 101 off- and on-ramps; - Improve operations, reduce congestion, and minimize conflicts at the 12th Street intersections; - Improve safety at 12th Street intersections; and
- Improve the local and regional bicycle and pedestrian facilities through the 12th Street interchange area.

1.3 Implementing Agency
This document assumes the Project would be implemented by the City. However, if the Project is ultimately implemented by Caltrans, the Project Description as described herein would remain. Environmental impact analysis herein would also remain accurate, independent of which of the two agencies oversees construction of the Project. Required mitigation measures as established in this Initial Study / Mitigated Negative Declaration (ISMND) would not change but would be implemented by Caltrans, in cooperation with the City.

1.4 Proposed Project Summary
The proposed Project would create a five-leg roundabout at the 12th Street/U.S. Hwy 101/northbound ramps intersection that incorporates a realigned Newburg Road as the fifth leg. The existing Newburg Road connection to 12th Street would be closed by creating a local road, terminating in an emergency vehicle access point to 12th Street. This would include reconstruction of the northbound Hwy 101 ramps. As part of the City of Fortuna’s general plan, 12th Street and Newburg Road improvements will include Class II bike lanes. The Great Redwood Trail crosses through the Project Area along the former railroad corridor, and appropriate crossing through the Project Area would be provided. The Project would also include a shared use non-motorized connection over U.S. Hwy 101.

Environmental Factors Potentially Affected
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 1-3 The Project would simplify and improve navigation and traffic operations while reducing congestion and minimizing conflicts on 12th Street between Newburg Road and Riverwalk Drive, including the 12th Street/U.S. 101 interchange. The Project would also create a gateway into central Fortuna that incorporates bicycle and pedestrian facilities, landscaping, and wayfinding.

The Project is being designed in accordance with the Caltrans Highway Design Manual, 7th Edition (2023) and the National Cooperative Highway Research Program (NCHRP) Report 672 entitled “Roundabouts: An Information Guide, 2nd Edition.” In addition, the Project would be designed in accordance with other specific applicable standards, including the California Manual on Uniform Traffic Control Devices (Caltrans 2021); the 2010 Americans with Disabilities Act (ADA) Standards for Accessible Design; and portions of the American Association of State Highway and Transportation Officials (AASHTO) A Policy on Geometric Design of Highways and Streets, 7th Edition (2018).

The Project is being designed to accommodate the expected volume and diversity of users, and mobility modes. The Project includes pavement reconstruction, a paved shared use path, sidewalks/walkways and curb ramps, crosswalks, roundabouts, lighting, landscaping, signage, and stormwater drainage facilities, utility adjustments/relocations and other ancillary infrastructure improvements. Particular constraints within the Project alignment may warrant adjustments to the standards to address site-specific issues.

1.5 Project Location
The proposed Project includes improvements to the U.S. Hwy 101 interchange at 12th Street in Fortuna, Humboldt County, CA (Appendix A – Figure 1). The proposed Project Area is approximately 22 acres and located within Caltrans and the City of Fortuna rights-of-way (Appendix A – Figure 2). Roads within the Project Area includes the 12th Street U.S. 101 northbound off- and on-ramps, the southern terminus of 12th Street to approximately 117 12th Street, the northern terminus of Riverwalk Drive to Dinsmore Drive, the western terminus of Newburg Road to 1498 Newburg Road, approximately 120 feet of Meadowbrook Land and Sunnybrook Drive from Newburg Road, and Pond Street. The Project Area borders the Clendenen’s Cider Works on the north and the former Palco Lumber Mill to the southeast.

In October 2022, the federal Surface Transportation Board authorized the rail corridor within the Project Area to be railbanked. The railbanked right-of-way must be used in a manner consistent with full restoration of potential future railroad use. The Project requires encroachment on Great Redwood Trail Agency (GRTA) property and use of a railbanked railroad corridor planned for the Great Redwood Trail (GRT). The railroad corridor is owned in fee by the GRTA. Project activities within the GRTA right-of-way would require an encroachment permit from the GRTA.

The Project Area is bordered by Strongs Creek to the southwest and Rohner Creek to the north; however, neither creek is inside the Project Area.

1.6 Surrounding Land Uses and Existing Setting
The general setting for the surrounding area can be characterized as rural residential to the northeast and industrial to the east, south, and west. The landscapes are also intermixed with agricultural lands to the north associated with the Clendenen’s Cider Works.

Environmental Factors Potentially Affected
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 1-4

1.7 Project Description
Roadway Paving
The existing roadway, including ramps, would be improved using a variable thickness overlay, or by replacing the existing structural pavement section with new aggregate base and hot mix asphalt pavement.

Excavation would extend into the native subgrade where required to remediate poor soil/subgrade conditions, in order to accommodate any widening/realignments, or changes in the roadway profiles. Any material that cannot be recycled on-site for the Project would be removed and hauled off-site for recycling or legal disposal by the contractor. Project elements necessary for construction are summarized below and shown in Appendix A – Figure 2.

Striping and Signage
The repaved segments would include required striping, pavement markings, and signage in order to comply with California Manual on Uniform Traffic Control Devices (CA MUTCD) requirements. Existing regulatory, advisory, and guide signage would be upgraded and replaced to reflect new traffic flow patterns resulting from the roundabouts and other improvements. Additional decorative or wayfinding signage may be included as part of the Project. These signs would be designed to accommodate the aesthetics of the improvements and would be installed concurrent with any placement requirements of the CA MUTCD.

U.S. 101 Ramps
The existing northbound off- and on-ramps would be shifted and realigned to support the new roundabout configuration proposed for the eastern side of U.S. 101.

Roundabout
A new five-legged roundabout is proposed for the eastern side of U.S. 101 to improve traffic operations and safety (Appendix A – Figure 2). The legs would include the northbound off- and on-ramps, 12th Street, Riverwalk Drive, and Newburg Road, which would be realigned and widened, as necessary. Newburg Road would be realigned to be closed off at its 12th Street intersection and routed south to connect with the roundabout. Pond Street would be realigned to connect to the new Newburg alignment.

Concrete improvements associated with the roundabout include the roundabout aprons, splitter islands, shared use paths, sidewalks/walkways/paths, and curbs. The truck aprons would include integral color to provide contrast from the other concrete features while avoiding a stark visual alteration. The roundabout center island and splitter islands would be landscaped or hardscaped and designed to blend into the existing community aesthetic and character.

The Project would include four new roundabout splitter islands in the following locations:
– On Riverwalk Drive
– On U.S. 101 northbound off-ramp
– On Newburg Road
– On 12th Street
Splitter islands would include pedestrian refuge islands and provide connectivity with new crosswalks (Appendix A – Figure 2).

Environmental Factors Potentially Affected
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 1-5 Overcrossing Improvements
A new pedestrian-only overcrossing bridge wound be installed over U.S. 101 parallel to the existing 12th Street overcrossing. The bridge would be concrete box girder and approximately 185 feet in length with a width of 12 feet with approximately 10 feet distance from the existing overcrossing. Abutments needed would be supported by driven piles. Small retaining structures may be required near the bridge footings.

The bridge would be designed to be visually similar to the existing 12th Street overcrossing.

Pedestrian and Bicycle Facilities
New shared use paths, and curb ramps would be constructed on the west side of 12th Street, providing improved pedestrian and bicycle safety and enhanced connectivity across U.S. 101. Two new shared use paths would also be constructed on the east side of 12th Street to allow for future connectivity to the GRT.

One path would be on the northern portion of the Project Area at the existing 12th Street and Newburg Road intersection. The second would be located at the proposed Newburg Road roundabout arm realignment.

The street crossings associated with the GRT would be colored and/or stamped asphalt or concrete to alert vehicle travelers of the pedestrian usage. Future development and use of the GRT is not under the scope of this IS/MND and would instead be under the jurisdiction of the GRTA. Project operation would not preclude or conflict with the GRT.

Drainage Improvements
The Project would include new drainage facilities, including gutters, inlets, pipes, vegetated retaining areas and rock energy dissipaters. Existing watershed drainage patterns would be maintained to the maximum extent practicable. Excavation depths to install drainage facilities may vary but would typically be limited to 6 feet below existing grade.

Utilities
The following is a preliminary list of utilities within the construction limits:
– Natural gas
– Overhead and underground electric
– Overhead and underground communications
– Potable water
– Sewage
– Storm drainage
Constructing the Project would require the relocation of both above and below ground utilities that conflict with planned Project elements.

Vegetation
The roundabout would include vegetated or hardscaped medians, splitter islands, and truck aprons. In addition, a vegetated buffer strip or concrete barrier would separate the new shared use paths from the west side of 12th Street/Riverwalk Drive and the east side of 12th Street/Newburg Road. Any vegetation incorporated into the Project is anticipated to include low-maintenance planting designed to blend into the surrounding environment without blocking visibility.

Environmental Factors Potentially Affected
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 1-6 Lighting
The Project would provide enhanced lighting to improve roadway visibility for drivers during nighttime hours.

Lighting is anticipated to be installed at ramp merges and diverges along the shoulders of U.S. 101 as well as at conflict points in and out of the roundabout and at pedestrian crossings. Lighting would also be provided at approaches to the intersection to improve visibility of the changing roadway features.

Excavation depths would range from approximately six and ten feet for each light pole.

Lighting would be designed to protect wildlife and nighttime views, including views of the night sky. The Project would be designed to be consistent with the City’s and Caltrans design guidelines. To comply with these requirements, lighting for the Project would be directed downward and shielded except in situations where requirements of lighting for construction or traffic safety may take priority. This would ensure lighting is contained within the site and does not cause significant lighting and glare impacts for surrounding land uses.

Alteration of Rail Infrastructure
Remnant tracks of the Northwest Pacific Railroad, now owned and managed by GRTA, traverse the Project Area paralleling U.S. 101. Approximately 200 feet of tracks located at the 12th Street crossing and the proposed new roundabout arm to Newburg Road would be removed (See Image 1-3.2 and 1-3.3). Track removal would also include ancillary Northwest Pacific Railroad features including two remnants of warning lights and crossing arms with associated electrical control boxes. The section of tracks between 12th Street and the proposed new roundabout arm to Newburg Road would be converted to a trail (See Image 1-3.2).

1.8 Project Construction
Construction Schedule
Construction is anticipated to occur over two construction seasons. The year of construction is not yet known, pending receipt of future funding. If feasible, vegetation clearing outside of the nesting bird season would occur first, by March 15. Construction would require approximately 18 months.

Construction Staging, Activities, and Equipment
All construction activities would be accompanied by both temporary and permanent erosion and sediment control implementation. Project construction would include the following activities:
– Demolition of existing pavements (concrete and asphalt) – Clearing and grubbing
– Grading and excavation
– Paving (concrete and asphalt)
– Retaining wall construction
– Pile driving and pedestrian bridge construction/installation – Utility trenching, relocation, and installation
– Rock slope protection (RSP) installation
– Temporary detour routes and temporary traffic control – Planting, irrigation, and landscaping installation
– Striping, lighting, and signage installation
Environmental Factors Potentially Affected
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 1-7 – Hauling
Equipment required for construction would include, but is not limited to tracked excavators, backhoes, graders, bulldozers, dump trucks, water trucks, skid steers, concrete truck, drill rigs, concrete pump trucks, changeable message signs, cranes, compactors, and pick-up trucks. It is not anticipated that any temporary utility extensions, such as electric power or water, would be required for construction. Water from legal sources would be used for dust control and compaction and re-vegetation.

Traffic and Access Control
Access to the Project Area will be provided via Newburg Road, 12th Street, and U.S. 101. Throughout the construction period, temporary detours, including possible temporary detour roads, will be necessary.

These detours will comply with City and Caltrans requirements for temporary roadway closures, including appropriate signage and public notifications. Construction will be phased to maintain local access to U.S. 101 as much as possible.

Establish Exclusion Areas and Erosion Control
Areas identified by biological studies sensitive habitats near the Project Area would be excluded with protective fencing prior to construction. Erosion control best management practices (BMPs) would also be installed prior to construction.

Vegetation Removal
Vegetation removal would include mowing and brush removal. Tree removal would also be required. The ground would also be grubbed to remove roots. The disturbed roadside areas would be restored to preconstruction conditions or stabilized with a combination of grass seed, straw mulch, rolled erosion control fabric, and other plantings/revegetation.

Stockpiling and Staging
Temporary disturbance for stockpiling and staging would occur within the limits of temporary disturbance of the Project Area and/or nearby developed, upland areas (e.g., parking areas). Within the stockpiling and staging area, BMPs would be utilized to control erosion and prevent sediment and hazardous materials from impacting the environment.

Excess soils, aggregate road base, RSP, and construction materials would be stored within designated stockpiling and staging areas. Excess materials may be re-used on-site for backfill and finished grading.

Excess materials would not be stockpiled on-site once the Project is complete. The contractor would haul additional excess materials off-site for beneficial reuse, recycling, or legal disposal.

Groundwater Dewatering
Groundwater dewatering is generally not expected to be necessary. However, if needed, temporary groundwater dewatering would involve pumping water out of a trench or excavation. Groundwater would typically be pumped into a settling pond, Baker tanks (or other similar type of settling tank), dewatering bags, or discharged to upland areas. Discharge to the City’s stormwater network or Strongs Creek would not occur.

Environmental Factors Potentially Affected
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 1-8

1.9 Maintenance and Operation
Following construction, general operation and maintenance activities associated with the proposed Project would be limited to typical roadway maintenance, including annual inspections, trash/debris removal, vegetation management, repaving, and striping, similar to what is occurring under existing conditions.

1.10 Regulatory Permits, CEQA, and NEPA
The City of Fortuna is the CEQA lead agency for the Project. This ISMND is the proposed CEQA pathway.

Caltrans is the National Environmental Policy Act (NEPA) lead agency; a Categorical Exclusion is the proposed NEPA pathway.

Rohner Creek and Strongs Creek would not be modified. Thus, there is not a requirement to obtain a California Department of Fish and Wildlife (CDFW) Streambed Alteration Agreement. Similarly, consultation with CDFW for California Endangered Species Act (CESA) and the National Marine Fishery Service/NOAA Fisheries (NMFS) under the state and federal Endangered Species Act would not be required. The Project does not impact regulated waters or wetlands and thus does not require permitting under Sections 401 and 404 of the Clean Water Act.

1.11 Required Agency Approvals
The following permits and approvals are required prior to construction:
– Caltrans Encroachment Permit
– Construction stormwater discharge permit (National Pollutant Discharge Elimination System) from the State Water Resources Control Board
– GRTA Encroachment Permit, Engineers’ Review of Design, and Use Agreement

1.12 Compliance with Existing Regulations and Standard BMPs The Project would abide by the following regulations and industry-accepted BMPs to reduce or avoid potential adverse effects that could result from construction or operation of the Project. In addition to these BMPs, mitigation measures are presented in the analysis sections in Chapter 3, Environmental Analysis, to reduce potentially significant environmental impacts below a level of significance. The Project’s Mitigation Monitoring and Reporting Program (MMRP) would include these actions to ensure implementation.

Municipal Separate Storm Sewer System (MS4)
The Project lies within the City’s regulated MS4 permit boundaries and would be required to meet the stormwater requirements contained in the Humboldt Low Impact Development (LID) Standards Manual (North Coast Stormwater Coalition 2021). Based on the type of project, the Project would be required to meet the Regulated Redevelopment, Roads, and Linear Underground Projects standards of the LID Manual.

Stormwater Pollution Prevention Plan (SWPPP)
The Project would obtain coverage under the North Coast Regional Water Quality Control Board (NCRWQCB), Waste Discharge Requirements for Discharges of Storm Water Runoff Associated with Construction Activities (General Permit). The City would submit permit registration documents (notice of intent, risk assessment, site maps, SWPPP, annual fee, and certifications) to the Water Board. The SWPPP would address pollutant sources, BMPs, and other requirements specified in the Order. The SWPPP would Environmental Factors Potentially Affected
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 1-9 include erosion and sediment control measures, dust control practices to prevent wind erosion, sediment tracking, and dust generation by construction equipment. A Qualified SWPPP Practitioner would oversee implementation of the Project SWPPP, including visual inspections, sampling and analysis, and ensuring overall compliance.

Implementation of Geotechnical Design Recommendations
The Project would be designed and constructed in compliance with site-specific geotechnical recommendations. This would include design in accordance with recommendations for earthwork, such as site clearing, cut/fill slopes, subgrade preparation, material for fill, compaction requirements, trenches, and foundations. The geotechnical recommendations would be incorporated into the final plans and specifications for the Project and would be implemented during construction.

1.13 Tribal Consultation
Pursuant to Public Resources Code section 21080.3.1, the City reached out to the California Native American Heritage Commission (NAHC) to receive a consultation list of tribes that are traditionally and culturally affiliated with the geographic area of the Project. The list included the Bear River Band of the Rohnerville Rancheria and the Wiyot Tribe. The City issued tribal notification letters to the tribes on the NAHC list on March 11, 2024. The City received a response from the Bear River Band of the Rohnerville Rancheria on April 22, 2024, requesting ongoing consultation throughout the Project and had a site visit on April 30, 2024. The City received a response from the Wiyot Tribe on May 30, 2024, requesting standard inadvertent archaeological discovery protocols be in place for any ground-disturbing activities.

Environmental Factors Potentially Affected
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 2-10

2. Environmental Factors Potentially Affected
The environmental factors checked below would be potentially affected by this project, involving at least one impact that is a “Potentially Significant Impact” as indicated by the checklist on the following pages:

Aesthetics Greenhouse Gas Emissions Public Services
Agricultural & Forestry Resources Hazards & Hazardous Materials Recreation Air Quality Hydrology & Water Quality Transportation
Biological Resources Land Use & Planning Tribal Cultural Resources Cultural Resources Mineral Resources Utilities & Service Systems Energy Noise Wildfire
Geology & Soils Population & Housing Mandatory Findings of Significance DETERMINATION (To be completed by the Lead Agency)
On the basis of this initial evaluation:

I find that the proposed project COULD NOT have a significant effect on the environment, and a NEGATIVE DECLARATION would be prepared.

I find that although the proposed project could have a significant effect on the environment, there would not be a significant effect in this case because revisions in the project have been made by or agreed to by the project proponent. A MITIGATED NEGATIVE DECLARATION would be prepared.

I find that the proposed MAY have a significant effect on the environment, and an ENVIRONMENTAL IMPACT REPORT is required.

I find that the proposed project MAY have a “potentially significant impact” or “potentially significant unless mitigated” impact on the environment, but at least one effect: (1) has been adequately analyzed in an earlier document pursuant to applicable legal standards, and (2) has been addressed by mitigation measures based on the earlier analysis as described on attached sheets. An ENVIRONMENTAL IMPACT REPORT is required, but it must analyze only the effects that remain to be addressed.

I find that the proposed project MAY have a “potentially significant impact” or “potentially significant unless mitigated” impact on the environment, but at least one effect: (1) has been adequately analyzed in an earlier document pursuant to applicable legal standards, and (2) has been avoided or mitigated pursuant to that earlier EIR or NEGATIVE DECLARATION, including revisions or mitigation measures that are imposed upon the proposed project, nothing further is required. _______________________________ ____________________
Shari Meads Date
Director of Community Development
Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-1

3. Environmental Analysis

3.1 Aesthetics
Potentially
Significant
Impact
Less than
Significant w/
Mitigation
Incorporated
Less than
Significant
Impact
No
Impact
Except as provided in Public Resources Code Section 21099, would the project:
a) Have a substantial adverse effect on a scenic
vista? 
b) Substantially damage scenic resources, including,
but not limited to, trees, rock outcroppings, and
historic buildings within a state scenic highway?

c) In non-urbanized areas, substantially degrade the
existing visual character or quality of public view
of the site and its surroundings? (Public Views are
those that are experienced from publicly
accessible vantage point). If the project is in an
urbanized area, would the project conflict with
applicable zoning and other regulations governing
scenic quality?

d) Create a new source of substantial light or glare
which would adversely affect day or nighttime
views in the area?

Aesthetic impact assessment is based on the Visual Resource Assessment prepared for the Project (GHD 2024b). The visual setting within the Project Area includes existing roads within Caltrans right-of-way, including U.S. 101, and views of local landmarks and resources from the Project corridor. These areas include Clendenen’s Cider Works, an out of service railroad track crossing 12th Street, and a mix of open green space and forested areas (Image 1-3.1). The Project Area is located in a relatively rural setting characterized by the existing roadway corridor bordered by tall trees, open grassy areas, and ruderal vegetation. Roads that can be seen from the Project Area include 12th Street, Riverwalk Drive, Newburg Road, Pond Street, Meadowbrook Lane, Sunnybrook Drive, and U.S. 101. The Project would be accessed via these roads, with minor realignments, and no new access roads would need to be constructed to implement the Project. The Eel River is approximately 1,200 feet west of the Project Area but is visually independent and cannot be seen from the Project Area or vice versa.

Viewers of the Project include the general public traveling the corridor, including vehicle users, pedestrian, and cyclists. Viewers of the Project also include local residents living adjacent to or near the Project corridor and individuals employed at places of work based in or near the Project corridor. Visual changes may be more noticeable to local residents and non-vehicular users than vehicle-based users (Image 1-3.2, Image 1-3.3).

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-2 Image 1-3.1 Aerial view of the Project Area looking south from the southern limits of the Project Area with general existing site conditions, local landmarks, existing roads, and resources are shown.

Image 1-3.2 3D rendering of current Project design looking south along 12th Street.

Clendenen’s Cider
Works
Riverwalk Drive
Abandoned
Railroad Tracks
US 101
12th Street
Newburg
Road
Former Palco
Lumber Mill
Proposed Roundabout
Location Trees
Pond Street
Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-3 Image 1-3.3 3D rendering of current Project design looking north along Pond Street. a) Have a substantial adverse effect on a scenic vista? (Less Than Significant Impact) For purposes of determining significance under CEQA, a scenic vista is defined as a viewpoint that provides expansive views of a highly valued landscape for the benefit of the general public. The visual setting within which the proposed Project is in consists of a developed roadway corridor adjacent to residential units with some mixed use/industrial and agricultural views. The Project Area and Eel River are visually independent, as the Eel River cannot be seen from the Project Area and vice versa due to elevation differences between the two features. None of the proposed Project features would obstruct the available scenic views of the Eel River or other rural scenic areas that surround the Project Area.

Construction activities or operation of the Project would not obstruct scenic views. The visual impacts of the proposed Project would be compatible with the existing visual character of the corridor. Any vegetation incorporated into the Project would include low-maintenance planting designed to blend into the surrounding environment without blocking visibility for safe vehicular operation. The disturbed roadside areas would be restored/stabilized with a combination of grass seed (broadcast or hydroseed), straw mulch, rolled erosion control fabric, and, if needed, other plantings/revegetation. Though the Project would expand the footprint of the interchange, the Project would be designed to minimize removal of trees and established vegetation.

Opportunity for new greenspace would enhance the visual character of the interchange while maintaining composition and unity of the site as well as providing safety improvements to better manage the levels of vehicular traffic. Center medians on 12th Street, Newburg Road, northbound U.S. 101 off-ramp, and Riverwalk Drive would also serve as pedestrian refuge islands and provide connectivity with new crosswalks. Furthermore, the proposed at-grade pedestrian improvements and installation of a Class I bike path through the Project Area would enhance multimodal connectivity, thus increasing accessibility for the public while improving the visual appearance of the interchange.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-4 A new pedestrian-only overcrossing bridge wound be installed over U.S. 101 parallel to the existing Riverwalk Drive overcrossing. The bridge would be concrete box girder and would be designed to be visually similar to the existing Riverwalk Drive overpass. New shared use paths and curb ramps would be constructed on the west side of 12th Street and Riverwalk Drive, providing improved pedestrian and bicycle safety and enhanced connectivity to the opposite side of U.S. 101. All retaining walls would be colorized and texturized to have similar facings to maintain conformity and enhance the visual aesthetic throughout the interchange corridor. The enhanced pedestrian access would improve public access through this interchange while maintaining the rustic/natural aesthetic of the area and safety improvements to better manage the levels of pedestrian and bicycle traffic.

The Project would not impair views of the nearby developed areas as the proposed interchange improvements are consistent with the current land use of the area within and near the Project. The Project would improve the visual setting of the existing dilapidated roadway and interchange. The Project includes incorporation of greenspace into the improved roadway corridor, which would enhance the overall aesthetic of the Project Area. As such, there would be a less than significant impact to scenic vistas and visual resources.
b) Substantially damage scenic resources, including, but not limited to, trees, rock outcroppings, and historic buildings within a state scenic highway? (Less Than Significant Impact)
The Project is not located within or near a state scenic highway (Caltrans 2019). U.S. 101 occurs within the Project Area and is eligible for listing on the California State Scenic Highway list. Though the proposed Project would result in temporary construction impacts to improve and expand the interchange, the Project once complete, would result in an aesthetically improved roadway and improved traffic flow. As such, impacts to the aesthetic environment or scenic roadway resources would not result. Additionally, the Project Area does not include any historic trees or rock outcroppings. There are no historic buildings within the Project Area. A less than significant impact on scenic resources would occur. c) In non-urbanized areas, substantially degrade the existing visual character or quality of public view of the site and its surroundings? (Public Views are those that are experienced from publicly accessible vantage point). If the Project is in an urbanized area, would the Project conflict with applicable zoning and other regulations governing scenic quality? (Less Than Significant Impact)
The visual quality of the roadway corridor would not be significantly altered by the Project. Views of local landmarks and resources from the Project corridor include the Clendenen’s Cider Works, an out of service railroad track crossing 12th Street, and a mix of open green space and forested areas (GHD 2024b). Views of and access to these local landmarks and resources would not be negatively impacted by the proposed Project. The visual quality resulting from the Project would not be diminished or be inconsistent with the existing visual character of pre-Project viewsheds from local landmarks.

Although there would be visual modifications to the interchange as compared to existing conditions, the overall view-scape surrounding the Project Area would not be impeded or altered by structures or other Project elements. As such, impacts to the visual character or quality of public view of the Project Area and surrounding environment would be less than significant.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-5 d) Create a new source of substantial light or glare which would adversely affect day or nighttime views in the area? (Less Than Significant Impact) The Project does include temporary and permanent sources of light. The Project would provide enhanced lighting to improve roadway visibility for drivers during nighttime hours. Lighting is anticipated to be installed at ramp merges and diverges along the shoulders of U.S. 101 as well as at conflict points in and out of the roundabout and at pedestrian crossings. Lighting would also be provided at approaches to the intersection to improve visibility of the changing roadway features.

Lighting would be designed to protect wildlife and nighttime views, including views of the night sky. The Project would be designed to be consistent with the City’s design guidelines, which includes standards for fixtures, shielding, wattage, placement, height, and illumination levels. To comply with these requirements, lighting for the Project would be directed downward and shielded except in situations where requirements of lighting for construction or traffic safety may take priority. This would ensure lighting is contained within the site and does not cause significant lighting and glare impacts for surrounding land uses. The Project would enhance and improve the existing lighting within the roadway corridor with the intention of improving the safety of the interchange for pedestrians as well as motorists. However, the new lighting improvements would not substantially degrade the environment within/near the roadway corridor, nor should these improvements have a substantial impact on glare for nighttime driving. As such, impacts associated with light, glare and nighttime views in the area would be less than significant.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-6

3.2 Agriculture and Forest Resources
Potentially
Significant
Impact
Less than
Significant w/
Mitigation
Incorporated
Less than
Significant
Impact
No
Impact
Would the project:
a) Convert Prime Farmland, Unique Farmland, or
Farmland of Statewide Importance (Farmland), as
shown on the maps prepared pursuant to the
Farmland Mapping and Monitoring Program of the
California Resources Agency, to non-agricultural
use?

b) Conflict with existing zoning for agricultural use, or a Williamson Act contract? 
c) Conflict with existing zoning for, or cause rezoning of, forest land (as defined in Public Resources Code
section 12220(g)), timberland (as defined by Public
Resources Code section 4526), or timberland zoned
Timberland Production (as defined by Government
Code section 51104(g))?

d) Result in the loss of forest land or conversion of
forest land to non-forest use? 
e) Involve other changes in the existing environment
which, due to their location or nature, could result in conversion of Farmland, to non-agricultural use or
conversion of forest land to non-forest use?

Within the Project Area, areas to the north associated with the out of service railroad are zoned as Agriculture Exclusive (A-E) with a land use of Agriculture (AG) (Fortuna 2009, 2018). The Project Area within the City of Fortuna does not include forest resources. Clendenen’s Cider Works is located adjacent to but outside of the Project Area. The Project would improve the existing parking area for the property but would not modify or reduce any agricultural property. The Clendenen’s Cider Works is zoned A-E.

Applicable policies from the City of Fortuna General Plan are summarized below.

NCR‐3.2 Retain Agricultural Lands. The City shall support and encourage the retention of active cultivation operations until such time that these areas are needed for planned urban or suburban expansion or mitigation for flood projects.

NCR‐3.3 Urban/Agricultural Conflicts. The City shall ensure that new developments adjacent to agricultural areas are informed about nearby agricultural operations and the potential for noise, dust, aerial spraying, and odor.

NCR‐3.4 Agricultural Buffers. The City shall require proposed development to assess potential impacts from adjacent agricultural uses and recommend buffers and other design features to mitigate the impacts, including air quality impacts.

NCR‐3.8 The City shall support agricultural land conservation and encourage minimal conflicts between agricultural and nonagricultural uses through all of the following:
– By promoting in‐filling to achieve a more logical urban/agricultural boundary; Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-7 – By developing available lands not suited for agriculture, or those located within Urban Study Areas, prior to the conversion of agricultural lands outside of those areas; – By assuring that public service facility expansions and non‐agricultural development do not inhibit agricultural viability, either through increased assessment costs or degraded air or water quality; – By broadening the utility of agricultural preserves and the Williamson Act Program; – By not allowing residential subdivision of lands planned Agriculture; and – By allowing lot‐line adjustments for agriculturally designated lands only where planned densities remain constant and there is no resulting increase in the number of building sites.

NCR‐3.10 The City shall require clustering where development is proposed on Prime Farmland, Unique Farmland, or Farmland of Statewide Importance pursuant to the California Resources Agency’s Farmland Mapping and Monitoring Program, to retain the amount of farmland. a) Convert Prime Farmland, Unique Farmland, or Farmland of Statewide Importance)? (No Impact)
Lands within the Project Area have not been formally analyzed by the California Department of Conservation to determine if they meet the criteria for being designated as Prime Farmland, Unique Farmland, or Farmland of Statewide Importance, because the Farmland Mapping and Monitoring Program has not been completed for Humboldt County. Potential impacts would be related to construction, and not operations, thus operations are not discussed further.

The Natural Resources Conservation Service (NRCS) Soil profile indicates a 1010 Urban land-Friendlycity association with 0 to 2 percent slopes and 220 Ferndale with 0 to 2 percent slopes are present within the Project Area (Appendix A – Figure 3). According to the NRCS, the entire Project Area is classified as Prime Farmland if irrigated. The City General Plan defines prime agricultural land as an area of land that has not been developed for a use other than agriculture and meets certain criteria related to soil classification or crop and livestock carrying capacity (Fortuna 2010). No portion of the Project Area is currently irrigated nor used for agricultural uses. Therefore, no impact would occur. b) Conflict with Agricultural Zoning or Williamson Act Contract? (No Impact) The Project would not be located on lands under a Williamson Act contract (Humboldt County 2024). The northern portion of the Project Area associated with the out of service railroad is zoned as Agriculture Exclusive (A-E) (Fortuna 2018). This area is within the right-of-way for the GRTA and, as analyzed above in section a), is not used for agricultural uses. Therefore, no impact would occur. c, d) Conflict with Forest Land Zoning or Convert Forest Land? (No Impact) There are no forest lands, timberland, or timberland zoned Timberland Production in the Project Area; therefore, no forest land or timberland would be converted to non-forest or non-timberland use. No impact would occur.
e) Convert Farmland or Forest? (No Impact)
The Project would include the removal of some small trees. However, these trees not considered forest resources. Potential biological impacts associated with tree removal are discussed in Section 3.4 (Biological Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-8 Resources). The Project involves a portion of a parcel zoned as agricultural exclusive. The parcel is used for farming. As mentioned above, no farmland exists within the Project Area. No impact would occur.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-9

3.3 Air Quality
Potentially
Significant
Impact
Less than
Significant w/
Mitigation
Incorporated
Less than
Significant
Impact
No Impact
Where available, the significance criteria established by the applicable air quality management district or air pollution control district may be relied upon to make the following determinations. Would the project:
a) Conflict with or obstruct implementation of the
applicable air quality plan? 
b) Result in a cumulatively considerable net increase
in any criteria pollutant for which the project region
is non-attainment under an applicable federal or
state ambient air quality standard?

c) Expose sensitive receptors to substantial pollutant
concentrations? 
d) Result in other emissions (such as those leading to
odors) adversely affecting a substantial number of
people?

The Project is located within the North Coast Air Basin (Air Basin) which is managed by the North Coast Unified Air Quality Management District (NCUAQMD). The NCUAQMD monitors air quality; enforces local, state, and federal air quality regulations for counties within its jurisdiction; inventories and assesses the health risks of Toxic Air Contaminants (TACs); and adopts rules that limit pollution.

For construction emissions, the NCUAQMD has indicated that emissions are not considered regionally significant for Projects whose construction would be relatively short in duration, lasting less than one year.

For Project construction lasting more than one year or that involves above average construction intensity in volume of equipment or area disturbed, construction emissions may be compared to the stationary source thresholds. Construction is anticipated to last for approximately 18 months. Since construction is anticipated to last more than one year, construction-related emissions were calculated using California Emissions Estimator Model (CalEEMod) version 2022.1.1.29. See Appendix B for air quality modeling results. a) Conflict with or obstruct implementation of the applicable air quality plan? (Less than Significant with Mitigation)
This impact relates to consistency with an adopted attainment plan. The NCUAQMD is responsible for monitoring and enforcing local, state, and federal air quality standards. Humboldt County is designated ‘attainment’ for all National Ambient Air Quality Standards. Pursuant to California Ambient Air Quality Standards, Humboldt County is designated attainment for all criteria air pollutants except PM10. Humboldt County is designated as “non-attainment” for the State’s PM10 standard.

PM10 refers to inhalable particulate matter with an aerodynamic diameter of less than 10 microns. PM10 includes emission of small particles that consist of dry solid fragments, droplets of water, or solid cores with liquid coatings. The particles vary in shape, size, and composition. PM10 emissions include unpaved road dust, smoke from wood stoves, construction dust, open burning of vegetation, and airborne salts and other particulate matter naturally generated by ocean surf. Therefore, any use or activity that generates airborne particulate matter may be of concern to the NCUAQMD. The proposed Project would create PM10 Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-10 emissions in part through vehicles coming and going to the Project Area and the construction activity associated with the Project.

To address non-attainment for PM10, the NCUAQMD adopted a Particulate Matter Attainment Plan in 1995.

This plan presents available information about the nature and causes of PM10 standard exceedances and identifies cost-effective control measures to reduce PM10 emissions to levels necessary to meet California Ambient Air Quality Standards. However, the NCUAQMD states that the plan, “should be used cautiously as it is not a document that is required in order for the [NCUAQMD] to come into attainment for the state standard” (NCUAQMD 2022). Therefore, compliance with applicable NCUAQMD PM10 rules is applied as the threshold of significance for the purposes of analysis. NCUAQMD Rule 104 Section D, Fugitive Dust Emissions, is applicable to the Project.

Rule 104, Section D – Fugitive Dust Emissions is used by the NCUAQMD to address non-attainment for PM10. Pursuant to Rule 104 Section D, the handling, transporting, or open storage of materials in such a manner, which allows or may allow unnecessary amounts of particulate matter to become airborne, shall not be permitted. Reasonable precautions shall be taken to prevent particulate matter from becoming airborne, including, but not limited to covering open bodied trucks when used for transporting materials likely to give rise to airborne dust and the use of water during the grading of roads or the clearing of land.

During earth moving activities, fugitive dust (PM10) would be generated. The amount of dust generated at any given time would be highly variable and is dependent on the size of the area disturbed at any given time, amount of activity, soil conditions, and meteorological conditions. Unless controlled, fugitive dust emissions during construction of the Project could be a potentially significant impact, therefore, Mitigation Measure AQ-1 would be incorporated to comply with NCUAQMD’s Rule 104 Section D.

Operation of the Project would not include the handling, transporting, or open storage of materials in which particulate matter may become airborne. Due to the absence of handling, transport, or open storage of materials that would generate particulate matter, operation of the Project is not expected to conflict with NCUAQMD’s Rule 104 Section D. No impact from operation of the Project would occur.

Mitigation
Implementation of Mitigation Measures AQ-1 is proposed to reduce the potential impact related to PM10 fugitive dust by requiring BMPs.

Mitigation Measure AQ-1: BMPs to Reduce Air Pollution
The contractor shall implement the following BMPs during construction:
- Disturbed surfaces (e.g., staging areas, soil piles, active graded areas, excavations, and unpaved access roads) shall be watered as needed for dust suppression. - All visible mud or dirt track-out onto adjacent public roads shall be removed using street sweepers as needed to alleviate dust and debris on the roadway. - All vehicle speeds on unpaved roads shall be limited to 15 miles per hour, unless the unpaved road surface has been treated for dust suppression with water, rock, wood chip mulch, or other dust prevention measures.
- All areas to be paved shall be completed as soon as practical. - Idling times shall be minimized either by shutting equipment off when not in use or reducing the maximum idling time to five minutes.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-11 With implementation of Mitigation Measure AQ-1, the Project would implement relevant fugitive dust (PM10) controls during construction and would not conflict with applicable air quality plans. This impact would be reduced to a less than significant level with mitigation. b) Result in a cumulatively considerable net increase in any criteria pollutant for which the Project region is non-attainment under an applicable federal or state ambient air quality standard? (Less than Significant with Mitigation)
This impact is related to regional criteria pollutant impacts. As identified in Section 3.3 Impact (a), Humboldt County is designated non-attainment of the State’s PM10 standard. The Project Area is designated attainment for all other state and federal standards. Potential impacts of concern would be exceedances of state standards for PM10. Localized PM10 is of concern during construction because of the potential to emit fugitive dust during earth-disturbing activities.

Construction
Localized PM10
The Project would include clearing and grubbing, grading, and paving activity to replace the existing intersection of U.S. 101 and 12th Street. Generally, the most substantial localized air pollutant emissions would be dust generated from site clearing, demolition, grading, placement of subgrade and paving. If uncontrolled, these emissions could lead to both health and nuisance impacts. Construction activities would also temporarily generate emissions of equipment exhaust and other air contaminants. The Project’s potential impacts from equipment exhaust are assessed separately below.

The NCUAQMD does not have formally adopted thresholds of significance for fugitive, dust-related particulate matter emissions above and beyond Rule 104, Section D which does not provide quantitative standards. For the purposes of analysis, this document uses the Bay Area Air Quality Management District (BAAQMD) approach to determining significance for fugitive dust emissions from Project construction. The BAAQMD bases the determination of significance for fugitive dust on a consideration of the control measures to be implemented. If all appropriate emissions control measures recommended by BAAQMD are implemented for a project, then fugitive dust emissions during construction are not considered significant.

BAAQMD recommends a specific set of “Basic Construction Measures” to reduce emissions of construction-generated PM10 to less than significant. Without incorporation of these Basic Construction Measures, the Project’s construction-generated fugitive PM10 (dust) would result in a potentially significant impact.

The Basic Construction Measure controls recommended by the BAAQMD are incorporated into Mitigation Measure AQ-1. These controls are consistent with NCUAQMD Rule 104 Section D, Fugitive Dust Emission and provide supplemental, additional control of fugitive dust emissions beyond that which would occur with Rule 104 Section D compliance alone. Therefore, with incorporation of Mitigation Measure AQ-1, the Project would result in a less than significant impact for construction period PM10 generation and would not violate or substantially contribute to an existing or projected air quality violation.

Regional Criteria Pollutants
For construction emissions, the NCUAQMD has indicated that emissions are not considered regionally significant for projects whose construction would be of relatively short duration, lasting less than one year.

For project construction lasting more than one year or that involves above average construction intensity in volume of equipment or area disturbed, construction emissions may be compared to the stationary source Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-12 thresholds. Since this Project’s construction is anticipated to last longer than one year, comparison to stationary sources would be used as the threshold of significance.

The NCUAQMD does not have established CEQA significance criteria to determine the significance of impacts that would result from projects such as the proposed Project; however, the NCUAQMD does have criteria pollutant significance thresholds for new or modified stationary source projects proposed within the NCUAQMD’s jurisdiction. NCUAQMD has indicated that it is appropriate for lead agencies to compare proposed construction emissions that last more than one year to its Best Available Control Technology (BACT) thresholds for stationary sources identified in Rule 110(E)(1), which are:
– Nitrogen Oxides – 40.0 tons per year, 50.0 pounds per day – Reactive Organic Gases – 40.0 tons per year, 50.0 pounds per day – PM10 – 15.0 tons per year, 80.0 pounds per day
– Carbon Monoxide – 100 tons per year, 50.0 pounds per day CalEEMod version 2022.1.1.29 was used to estimate air pollutant emissions from Project construction (Appendix B – Air Quality Modeling Results). Detailed construction equipment activity and material hauling volumes were provided by the Project’s Design Team. The Project’s estimated construction emissions are provided in Table 3.3-1 and 3.3-2 for annual and daily emission rates, respectively. As shown in the tables, the Project would not exceed the NCUAQMD’s thresholds of significance. Therefore, the Project’s construction emissions are considered to have a less than significant impact specific to regional criterial pollutants.

Table 3.3-1 Annual Construction Regional Pollutant Emissions.

Parameter Total Emissions (tons/project)
ROG NOX CO PM10
Project Construction 0.13 1.03 1.26 0.10
NCUAQMD Stationary Source Thresholds 40.0 40.0 100 15.0 Table 3.3-2 Average Daily Construction Regional Pollutant Emissions.

Parameter Maximum Daily Emissions (pounds/day)
ROG NOX CO PM10
Project Construction 0.69 5.66 6.89 0.55
NCUAQMD Stationary Source Thresholds 50.0 50.0 80.0 50.0 Operation
Following construction, the Project would not include any stationary sources of air emissions, traffic capacity enhancements, or result in an increase in traffic volumes or increased delay over existing conditions. The proposed roadway improvements would likely increase multimodal use of the roadway which may decrease vehicle trips and associated emissions. Traffic flow would improve; thus, the Project would result in less vehicle idling and an associated reduction in exhaust emissions. Vehicle trips associated with operation and maintenance of the road would be the same as under existing conditions, include annual inspections, repaving, painting, and repairs as needed. Operation and maintenance of the Project would generate less than one traffic trip per week on average; the location of the Project is Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-13 incidental to other maintenance routes currently performed by the City and Caltrans. However, larger repairs to the road or sidewalk facilities may take several weeks to complete depending on the extent of damage and other circumstances. However, the potential need for larger repair would remain the same as under existing conditions. The Project would not result in an increase in operational emissions of criteria air pollutants above existing conditions. Therefore, the Project would not result in a cumulatively considerable net increase of any criteria pollutant for which the region is in non-attainment. The Project’s operational impact would be less than significant.
c) Expose sensitive receptors to substantial pollutant concentrations? (Less than Significant) Sensitive receptors include school-aged children (schools, daycare, playgrounds), the elderly (retirement community, nursing homes), the infirm (medical facilities and offices), and those who exercise outdoors regularly (public and private exercise facilities, parks). There are 20 residential sensitive receptors located directly adjacent (within 50 feet) to the Project Area along Newburg Road and 12th Street. Additional sensitive receptors are the Great Beginning Preschool located approximately 0.22 miles east, and the Fortuna High School approximately 0.25 miles north.

Construction of the Project would be short in duration, vary in location, and not result in concentrated pollutants in any one area. Because of the distance to potential sensitive receptors, limited construction period, and geographical distribution of construction activities, exposure of sensitive receptors to substantial pollutant concentrations during Project construction would be less than significant.

For Project operations, the Project would modify the path of travel for vehicles. For reference, the 2005 California Air Resources Board’s (CARB) Air Quality and Land Use Handbook: A Community Health Perspective (Land Use Handbook) provides CARB’s recommendations regarding the siting of new sensitive land uses near facilities that are associated with health risks, particularly from air toxic emissions. The Land Use Handbook has siting guidance for freeways, distribution centers, rail yards, ports, refineries, chrome plating facilities, dry cleaners, and gasoline dispensing facilities. Although this guidance is for siting new locations of sensitive receptors, the facility distance and size guidance may be used as a screening level to identify when additional analysis is warranted during environmental review, including CEQA.

The Land Use Handbook advisory recommendation for freeways and high traffic roads includes avoidance of siting new sensitive land uses within 500 feet of a freeway, urban roads with 100,000 vehicles/day, or rural roads with 50,000 vehicles/day.

The nearest sensitive receptors are homes located within 50 feet of the Project. The Traffic Operations & Intersection Control Evaluation (TOAR & ICE) Report prepared for the Project includes Level of Service (LOS) analysis on vehicle counts conducted in 2022 (GHD 2024a). At the 12th Street & Newburg Road intersection, the Project component closest to the residences northeast of the Project, the LOS was E and did not operate acceptably in the AM peak hour. The Project would not substantially reduce the distance between travel lanes and sensitive receptors. Additionally, the Project would have no effect on vehicle mix through the Project Area. The Project meets the Land Use Handbook’s advisory guidance for an appropriate separation of the Project location and sensitive receptors. Therefore, additional analysis is not warranted. This impact would be less than significant.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-14 d) Result in other emissions (such as those leading to odors) adversely affecting a substantial number of people? (Less than Significant)
Implementation of the Project would not result in major sources of odor. The Project type is not one of the common types of facilities known to produce odors (i.e., landfill, coffee roaster, wastewater treatment facility, etc.). Minor odors from the use of equipment during construction activities would be intermittent and temporary and would dissipate rapidly from the source with an increase in distance. This impact would be less than significant.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-15

3.4 Biological Resources
Potentially
Significant
Impact
Less than
Significant w/
Mitigation
Incorporated
Less than
Significant
Impact
No
Impact
Would the project:
a) Have a substantial adverse effect, either directly or through habitat modifications, on any species
identified as a candidate, sensitive, or special
status species in local or regional plans, policies, or regulations, or by the California Department of Fish
and Game or U.S. Fish and Wildlife Service?

b) Have a substantial adverse effect on any riparian
habitat or other sensitive natural community
identified in local or regional plans, policies,
regulations or by the California Department of Fish
and Game or U.S. Fish and Wildlife Service?

c) Have a substantial adverse effect on state or
federally protected wetlands (including, but not
limited to, marsh, vernal pool, coastal, etc.) through
direct removal, filling, hydrological interruption, or
other means?

d) Interfere substantially with the movement of any
native resident or migratory fish or wildlife species
or with established native resident or migratory
wildlife corridors, or impede the use of native
wildlife nursery sites?

e) Conflict with any local policies or ordinances
protecting biological resources, such as a tree
preservation policy or ordinance?

f) Conflict with the provisions of an adopted Habitat
Conservation Plan, Natural Community
Conservation Plan, or other approved local,
regional, or state habitat conservation plan?

A Botanical Report, Natural Environment Study (NES), and Wetland Delineation Report were prepared to assess baseline environmental conditions within the Project Area and are included as Appendix C, Appendix D, and Appendix E, respectively. These studies evaluate the potential for any special status plants, wildlife species, or any sensitive natural communities (SNCs) or aquatic resources to occur. The Biological Study Area (BSA), or the area directly or indirectly impacted by the proposed Project, encompasses a 500-foot radius around the Project Area.
a) Have a substantial adverse effect, either directly or through habitat modifications, on any species identified as a candidate, sensitive, or special status species in local or regional Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-16 plans, policies, or regulations, or by the California Department of Fish and Game or U.S. Fish and Wildlife Service? (Less than Significant with Mitigation) Special Status Plant Species
Special status plant species under state jurisdiction include those listed as endangered, threatened, or as candidate species by the CDFW under the CESA. All plant species on California Native Plant Society (CNPS) California Rare Plant Ranking (CRPR) Lists 1A, 1B, 2A, and 2B are considered eligible for state listing as endangered or threatened pursuant to the California Fish and Game Code and CDFW has oversite of these special status plant species as a trustee agency. As part of the CEQA process, such species should be considered as they meet the definition of threatened or endangered under Sections 2062 and 2067 of the California Fish and Game Code. There are occasions where CRPR List 3 or 4 species might be considered eligible for state listing as endangered or threatened particularly for the type locality of a plant, for populations at the periphery of a species range, or in areas where the taxon is especially uncommon or has sustained heavy losses, or from populations exhibiting unusual morphology. Additionally, CDFW maintains lists of special status plant species. These lists include a species conservation ranking status from multiple sources, including Federal Endangered Species Act (FESA), CESA, federal departments with unique jurisdictions, CNPS, and other non-governmental organizations.

Based on database searches, historical records, and an overview of the primary literature, seven special status species have a moderate potential of occurring in the Project Area, none of which are state or federally listed (Table 3.4-1) (Appendix C, Appendix D). Due to the developed and disturbed nature of the Project Area, no special status plants have a high potential to occur. Eleven additional special status species were classified as having a low likelihood of occurring within the Project Area (Appendix C).

Table 3.4-1 Special Status Plants with a Moderate Potential to Occur Within the Project Area.

Common Name Scientific Name CRPR Status
Harlequin lotus Hosackia gracilis 4.2
Maple-leaved checkerbloom Sidalcea malachroides 4.2
Siskiyou checkerbloom Sidalcea malviflora ssp. patula 1B.2 Kellogg’s lily Lilium kelloggii 4.3
Leafy stemmed mitrewort Mitellastra caulescens 4.2
Pacific golden saxifrage Chrysosplenium glechomifolium 4.3 Trailing black currant Ribes laxiflorum 4.3
GHD conducted two seasonally appropriate floristic surveys for special status plants and vegetation assessments in the Project Area on May 9 and June 29, 2023, which is within the blooming season for all special status plant species with potential to occur in the Project Area. These surveys followed CDFW (2018) and USFWS (2002) protocols and guidelines. No special status plant species were observed in either botanical survey of the Project Area. Given that required protocol level plant surveys are completed with no detections of sensitive plant species and the available roadside habitat is generally disturbed and low quality, no impact on special status plants would occur.

Special Status Wildlife Species
A database search of the California Natural Diversity Database (CNDDB), Biogeographical Information and Observation System (BIOS), CDFW’s Special Animals of California List, U.S. Fish and Wildlife Service Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-17 (USFWS) Information for Planning and Consultation (IPaC), and USFWS Critical Habitat Portal was conducted (Appendix D). CDFW’s lists include a species conservation ranking status from multiple sources, including FESA, CESA, federal departments with unique jurisdictions, CNPS, and other non-governmental organizations. Special status mammal species include species that are (1) listed as threatened or endangered under the CESA or the ESA; (2) proposed for federal listing as threatened or endangered; (3) state or federal candidates for listing as threatened or endangered; and/or (4) identified by the CDFW as SSC, California FP species, or species on their SAL (Appendix D).

The Project Area and BSA does not overlap designated or proposed critical habitat for any federally listed plants or wildlife species. A reconnaissance-level biological field survey was conducted by GHD on March 8, 2023, which included an assessment of the Project Area and BSA, including adjacent private property.

No special status wildlife species were observed (Appendix D). The potential for species to occur was determined at the level of the BSA. Mitigations measures to reduce potential impacts to listed and special status species are provided below.

Special Status Amphibian and Reptiles Species
There are two special status amphibian species recorded in the CNDDB as known to occur nearby and that the BSA likely provides suitable habitat for: the Northern Red-legged Frog (Rana aurora) and Foothill Yellow-legged Frog (Rana boylii pop. 1). Additionally, there is one special status reptile species, the Western Pond Turtle (Emys marmorata), that has suitable habitat within the BSA. No special status species were observed during the reconnaissance-level biological survey (Appendix D). The Project Area and BSA do not overlap designated or proposed critical habitat for any federally listed amphibian or reptile species.

Northern Red-legged Frogs, a State Species of Concern, occur along the west coast of North America from British Columbia to California. The geographic range split between the Northern and California Red-legged Frog species occurs just south of Elk Creek in Mendocino County where both species overlap. Northern Red-legged Frogs are typically found near freshwater sources (e.g., wetlands, ponds, streams, etc.).

However, they can range widely and inhabit damp places far from water. Northern Red-legged Frogs reproduce in water from December to February in Humboldt County, with some breeding occurring as late as March. Preferred egg laying locations are in “vegetated shallows with little water flow in permanent wetlands and temporary pools” (Appendix D). Northern Red-legged Frogs are relatively common in and near coastal portions of Humboldt County and the closest known occurrence record is from 2011 approximately 4.3 miles southeast of the Project Area (Appendix D). The BSA includes potentially suitable breeding, foraging, and dispersal habitat, especially within the riparian habitat associated with Rohner Creek and Strongs Creek. Thus, the potential impact associated with Northern Red-legged Frogs would be potentially significant.

Foothill Yellow-legged Frogs, a State Species of Special Concern, occur from sea level to elevations of 7,000 feet and range from the Willamette River in Oregon south to the Upper San Gabriel River in California, including the coast ranges and Sierra Nevada Foothills (Appendix D). The species prefers open to partially shaded, perennial streams with rocky substrate, often near riffles. These rivers and streams are typically bordered by chaparral, riparian habitat, mixed conifer forest, or wet meadows. Streams are usually small to mid-sized with shallow pools and slow-moving water (Appendix D). They are also found at river edges, in calm pools, and vegetated backwaters. Rocky cobble substrate (3 in or larger) is preferred, particularly for egg laying sites (Appendix D). The closest known occurrence record is from within the BSA from 2018 at the mouth of Strongs Creek on the Eel River near the Fortuna Wastewater Treatment Plant (Appendix D). Thus, the potential impact associated with Foothill Yellow-legged Frogs would be potentially significant.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-18 Western Pond Turtles, a State Species of Concern, occur in a variety of permanent and semi-permanent freshwater aquatic habitats including lakes, rivers, ponds, creeks, and marshes. Nesting occurs on land in areas of loose to hard-packed soils on south or west facing slopes (Appendix D). The species is frequently observed basking on exposed banks, logs, and rocks. Winter activity is possible but limited to unusually warm, sunny days. Normally pond turtles are dormant during winter months on the north coast, which typically involves the turtle burrowing into loose substrate above the high water mark (Appendix D). The closest known record is from 2011 approximately 4.45 miles north of the Project Area (Appendix D). There are no suitable aquatic or nesting habitat within the Project Area. However, the BSA includes suitable aquatic habitat within the Rohner and Strongs Creek, and marginal nesting habitat is available. Thus, the potential impact associated with Western Pond Turtles would be potentially significant.

Mitigation
Implementation of Mitigation Measure BIO-1 would reduce the impact on special status amphibians and reptiles by implementing specific efforts to minimize construction impacts.

Mitigation Measure BIO-1: Avoidance and Minimization Measures to Protect Special Status Amphibians and Reptiles
As well as adhering to the sediment reduction, spill prevention measures, and efforts to minimize disturbances to vegetation, the footprint of the proposed Project when in proximity to aquatic habitat will be restricted to the minimum area necessary.

A qualified biologist will conduct environmental awareness training for contractors prior to construction detailing special status amphibians and reptiles that could be encountered within the Project Area during construction. If special status amphibian or reptile species are encountered during construction, construction-related activities shall cease within 100 feet of the individual until it has left the Project Area upon its own volition. If necessary, a qualified biologist may relocate the individual or individuals into otherwise suitable habitat nearby and outside of harm’s way.

With the implementation of Mitigation Measure BIO-1, potential impacts to the Northern Red-legged Frog, Foothill Yellow-legged Frog, and the Western Pond Turtle, would remain less than significant.

Special Status, Migratory, and Nesting Bird Species
There are 11 special status bird species known to occur nearby and in which the BSA likely provides suitable habitat for: Cooper’s Hawk (Accipiter cooperi), Sharp-shinned Hawk (Accipiter striatus), Great Egret (Ardea alba), Great Blue Heron (Ardea herodias), Northern Harrier (Circus hudsonius), Snowy egret (Egretta thula), Yellow-breasted Chat (Icteria virens), Black-crowned Night-heron (Nycticorax nycticorax), Osprey (Pandion haliaetus), Black-capped Chickadee (Poecile atricapillus), and Yellow Warbler (Setophaga petechia). One special status avian species, the Great Blue Heron, was observed flying through the Rohner Creek riparian corridor during the reconnaissance-level biological survey (Appendix D). The Project Area and BSA do not overlap designated or proposed critical habitat for any federally listed avian species.

Western Yellow-billed Cuckoos, listed federally threatened and state endangered, are an uncommon to rare summer resident of valley foothill and desert riparian habitats in scattered locations in California. They nest in dense riparian cover and the nest consists of a flimsy, open cup of twigs built on horizontal limb of tree or shrub. Formerly much more common and widespread throughout lowland California, but numbers drastically reduced by habitat loss. This species is typically associated with larger riparian forests of the Central Valley. The closest known occurrence of this species is from 2013 approximately 6.1 miles west of the Project Area (Appendix D). The BSA contains only marginal foraging and nesting habitat typically Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-19 suitable for this species within riparian habitat associated with Rohner Creek and Strongs Creek. There would be no alteration or modification to riparian habitat. No impact to the Western Yellow-billed Cuckoo would occur.

Cooper’s Hawks, a CDFW Watch List Species, are year-round residents across most temperate areas in North America. In California, migrants from more northern climes (southern Canada) pass through the state during the fall months (August-November). Some of these northern populations of Cooper’s Hawks likely winter in the state. Cooper’s Hawks may be found in a variety of forested habitats included deciduous, mixed, or evergreen forests in urban, suburban, or rural areas. Cooper’s Hawk populations have increased over the past few decades in urban and suburban areas, likely as a result of readily available prey populations in these habitats (e.g., European Starling and Rock Pigeon flocks). Cooper’s Hawks build their nests in any number of tree species including pines, oaks, firs, eucalyptus, etc. Nest site selection is most likely related to dense prey availability in the surrounding area as well as canopy cover and the adjacent habitat structure. Their nests are constructed out of sticks and bark and may be built on top of existing squirrel or other raptor nests. There are known occurrences of this species within 5 miles of the Project Area, and suitable nesting and foraging habitat are present within the BSA (Appendix D). Thus, the potential impact associated with Cooper’s Hawks would be potentially significant.

Sharp-shinned Hawks, a CDFW Watch List Species, are year-round residents across most densely forested areas of western and eastern North America. In California, migrants from more northern climes (southern Canada) pass through the state during the fall months (August-November). Some of these northern populations of Sharp-shinned Hawks winter in the state. Sharp-shinned Hawks may be found in a variety of forested habitats including coniferous forests, deciduous forests, woodlots, and transitional/forested edges. They prefer to nest in dense stands of a diversity of tree species. There are known occurrences of this species within 5 miles of the Project Area, and suitable nesting and foraging habitat are present within the BSA (Appendix D). Thus, the potential impact associated with Sharp-shinned Hawks would be potentially significant.

Great Egrets, a CDFW Special Animals List species, are year-round residents in western California, with breeders concentrated in the Klamath and Warner basin in Siskiyou and Modoc Counties, along the coast in Humboldt County, the San Francisco Bay area, Monterey County, the Salton Sea, and the Central Valley.

This species favors wetlands, estuaries, lakes, rivers, ponds, streams, marshes, and tidal flats. Great Egrets nest communally or in mixed-species colonies. They are opportunistic foragers, wading in shallow water to feed on fish, amphibians, and invertebrates (Appendix D). They also hunt on shore for reptiles, birds, and small mammals. There are known occurrences of this species within 5 miles of the Project Area, and suitable foraging habitat is present within the BSA within Rohner and Strongs Creek; marginal nesting habitat may be present within the BSA (e.g., riparian corridor) (Appendix D). Thus, the potential impact associated with Great Egrets would be potentially significant.

Great Blue Herons, a CDFW Special Animals List species, are year-round residents in the majority of coastal and central California. Nesting habitat includes trees, bushes, or artificial structures. Nest platforms are typically constructed out of locally available sticks and lined with material such as grass, moss, and reeds. Great Blue Herons are colonial nesters in mixed-species colonies. They are opportunistic foragers, wading in shallow water to feed on fish, amphibians, and invertebrates. They also hunt on shore for reptiles, birds, and small mammals, as well to scavenge carrion (Appendix D). There are known occurrences of this species within 5 miles of the Project Area, and suitable foraging habitat is present within the BSA within Rohner and Strongs Creek with marginal nesting habitat that may be present. Thus, the potential impact associated with Great Blue Herons would be potentially significant.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-20 Northern Harriers, a State Species of Special Concern, are permanent resident of the northeastern plateau and coastal areas, and less commonly residents of the Central Valley. Northern Harriers nest on the ground in shrubby vegetation, usually at marsh edge (Appendix D). Mostly nests in emergent wetland or along rivers or lakes, but may nest in grasslands, grain fields, or on sagebrush flats several miles from water.

There are known occurrences of this species within 5 miles of the Project Area, and suitable foraging habitat is present within the BSA (Appendix D). Marginal nesting habitat may be present within the BSA.

Thus, the potential impact associated with Northern Harriers would be potentially significant.

Snowy Egrets, a State Species of Special Concern, are widespread in California along shores of coastal estuaries, fresh and saline emergent wetlands, ponds, slow-moving rivers, irrigation ditches, and wet fields.

Dense marshes are required for nesting, of which are built of sticks. There are known occurrences of this species within 5 miles of the Project Area, and marginal foraging and nesting habitat is present within the BSA. Thus, the potential impact associated with Snowy Egrets would be potentially significant.

Yellow-breasted Chats are an uncommon summer resident and migrant in coastal California and in the foothills of the Sierra Nevada. They can be uncommon along the coast of northern California east to Cascades and occur only locally south of Mendocino County (Appendix D). They nest above ground in dense shrubs along a stream or river. There are no known occurrences of this species within 5 miles of the Project Area; however suitable foraging and nesting habitat is present within the BSA within Rohner and Strongs Creek (Appendix D). Thus, the potential impact associated with Yellow-breasted Chats would be potentially significant.

Black-crowned Night Herons, a CDFW Special Animals List species, are a common yearlong resident in lowlands and foothills throughout most of California and common in large nesting colonies. They feed along the margins of lacustrine, large riverine, and fresh and saline emergent habitats and, rarely, on kelp beds in marine subtidal habitats. They nest in dense foliaged trees, dense fresh or brackish emergent wetlands, or dense shrubbery or vine tangles, usually near aquatic or emergent feeding areas, with nests built of twigs and/or marsh plants (Appendix D). There are known occurrences of this species within 5 miles of the Project Area along Rohner Creek, with suitable foraging habitat present within the BSA and marginal nesting habitat that may be present within the BSA. Thus, the potential impact associated with Blackcrowned Night Herons would be potentially significant.

Ospreys, a CDFW Watch List Species, breed in northern California from Cascade Ranges south to Lake Tahoe and along the coast south to Marin County. They are associated strictly with large, fish-bearing waters, primarily in ponderosa pine through mixed conifer habitats. Nests on platform of sticks at the top of large snags, dead-topped trees, on cliffs, or on human made structures (Appendix D). There are known occurrences of this species within 5 miles of the Project Area, and marginal foraging and nesting habitat may be present within the BSA (Appendix D). Thus, the potential impact associated with Ospreys would be potentially significant.

Black-capped Chickadees, a CDFW Watch List Species, are an uncommon resident restricted to Del Norte, Humboldt, and Siskiyou counties in northern California. They occur in montane riparian habitat from coast into mountainous areas inland. It nests in rotten snags, branches, or stumps, or in old woodpecker holes.

There are known occurrences of this species within 5 miles of the API, and suitable foraging and nesting habitat is present within the BSA (Appendix D). Thus, the potential impact associated with Black-capped Chickadees would be potentially significant.

Yellow Warblers, a State Species of Special Concern, breeding distribution includes from the coast range in Del Norte County, east to Modoc plateau, south along coast range to Santa Barbara and Ventura counties and along western slope of Sierra Nevada south to Kern County. They breed in riparian woodlands from Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-21 coastal and desert lowlands, montane chaparral, and in open ponderosa pine and mixed conifer habitats with substantial amounts of brush. They nest is an open cup in a deciduous sapling or shrub (Appendix D).

There are known occurrences of this species within 5 miles of the Project Area, and suitable foraging and nesting habitat is present within the BSA (Appendix D). Thus, the potential impact associated with Yellow Warblers would be potentially significant.

In addition, common, protected migratory bird may also nest in the Project Area or greater BSA.

Construction-related disturbance (noise and visual disturbance, as well as possible nest destruction during clearing and grubbing) during the nesting season could result in the loss of fertile eggs or nestlings or otherwise lead to nest abandonment. Loss of fertile eggs or any activities resulting in nest abandonment may have the potential to affect these species. However, most disturbances will occur in the roadway or directly adjacent to the roadway, where nesting habitat is marginal. Riparian habitat within the BSA would not be impacted by the Project. It is likely that the majority of nesting activity would occur outside of the Project Area in adjacent habitat within the BSA. Thus, the potential impact associated with migratory or nesting birds would be potentially significant.

Mitigation
Implementation of Mitigation Measure BIO-2 would reduce the impact on special status, migratory, and nesting bird species by implementing specific efforts to minimize construction impacts.

Mitigation Measure BIO-2: Avoidance and Minimization Measures to Protect Special Status, Migratory, and Nesting Bird Species
Contractors will remove trees and other vegetation that could potentially contain nesting birds outside the bird nesting season (March 15 to August 15). If vegetation removal occurs outside the bird nesting season, no further mitigation is necessary. If vegetation removal or construction work occur adjacent to suitable nesting habitat between March 15 and August 15 a qualified wildlife biologist shall conduct pre-construction surveys within the vicinity of the Project to check for nesting activity of native birds and to evaluate the site for presence of raptors and special status bird species.

As specified by CDFW, a qualified wildlife biologist shall be defined as a person who is 1) knowledgeable in distribution, habitat, nesting behavior, and life history of northern California birds; 2) can correctly identify bird species found in northern California; 3) has conducted previous field surveys of nesting birds; and 4) is knowledgeable in survey protocols and has obtained the necessary state and federal authorization for any potential take of listed birds, if necessary.” The qualified wildlife biologist will conduct at minimum a pre-construction survey within the 7-day period prior to vegetation removal and ground-disturbing activities. If ground disturbance and vegetation removal work lapses for seven days or longer during the breeding season, a qualified wildlife biologist will conduct a supplemental avian pre-construction survey before Project work is reinitiated.

If active nests are detected within the Project Area or up to 500 feet from construction activities, the qualified wildlife biologist will flag a buffer around each nest (assuming property access).

Construction activities will avoid nest sites until the qualified wildlife biologist determines that the young have fledged, or nesting activity has ceased. If nests are documented outside of the construction footprint, but within 500 feet of the construction area, buffers will be implemented as needed (buffer size dependent on species). In general, the buffer size for common species would be determined on a case-by-case basis in consultation with the CDFW and, if applicable, with USFWS. Buffer sizes will take into account factors such as (1) noise and human disturbance levels at the construction site at the time of the survey and the noise and disturbance expected during the construction activity; (2) distance and amount of vegetation or other screening between the Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-22 construction site and the nest; and (3) sensitivity of individual nesting species and behaviors of the nesting birds. An absolute minimum buffer size of 30 feet will be used as a starting point of discussion for common species, with larger buffers for special status species and raptors.

If active nests are detected during the survey within the construction footprint or surrounding 500 feet, the qualified wildlife biologist shall monitor all nests at least once per week to determine whether birds are being disturbed. Activities that might, in the opinion of the qualified wildlife biologist, disturb nesting activities (e.g., excessive noise), shall be prohibited within the buffer zone until such a determination is made. If signs of disturbance or distress are observed, the qualified wildlife biologist shall immediately implement adaptive measures to reduce disturbance. These measures may include, but are not limited to, increasing buffer size, halting disruptive construction activities in the vicinity of the nest until fledging is confirmed or nesting activity has ceased, placement of visual screens or sound dampening structures between the nest and construction activity, reducing speed limits, replacing and updating noisy equipment, queuing trucks to distribute idling noise, locating vehicle access points and loading and shipping facilities away from noisesensitive receptors, reducing the number of noisy construction activities occurring simultaneously, and/or reorienting and/or relocating construction equipment to minimize noise at noise-sensitive receptors.

With the implementation of Mitigation Measure BIO-2, potential impacts to special status, migratory, and nesting birds would remain less than.

Special Status Fish Species
There are three state and federally listed anadromous salmonids and three other special status fish species that the BSA, specifically Rohner Creek and Strongs Creek, provides suitable habitat for: the Pacific Lamprey (Entosphenus tridentatus), Western Brook Lamprey (Lampetra richardsoni), Coastal Cutthroat Trout (Oncorhynchus clarkii clarkii), southern Oregon / northern California (SONCC) Coho Salmon (Oncorhynchus kisutch pop. 2), California coastal Chinook Salmon (Oncorhynchus tshawytscha pop. 17), and northern California Steelhead (Oncorhynchus mykiss irideus pop. 16) (Appendix D).

Although no fish surveys were conducted as part of the reconnaissance-level biological survey, previous stream inventory reports have been completed by CDFW in Rohner Creek and Strongs Creek, and juvenile Steelhead were recorded in the lower reaches of both creeks (Appendix D). The presence of Coho Salmon, Chinook Salmon, Steelhead, and Pacific Lamprey has also been well documented in the Eel River (Appendix D). The Eel River and its tributaries are considered Essential Fish Habitat for Chinook Salmon and Coho Salmon, and is also considered critical habitat for Coho Salmon, Chinook Salmon, and Steelhead (Appendix D).

Pacific Lamprey, a State Species of Special Concern, range from the Japan to the Bering Sea in Alaska and along the west coast of North America to central Baja, California. Pacific Lamprey are anadromous with typical spawning from March through July. Pacific Lamprey are common in the Eel River year-round and are known to occur in the Strongs Creek watershed (Appendix D). Suitable rearing and migratory habitat and potentially spawning habitat are present for Pacific Lamprey in Rohner Creek and Strongs Creek within the BSA. Based on suitable aquatic habitat, the species may be present in the BSA within Rohner Creek and Strongs Creek, although no suitable habitat is present in the Project Area (Appendix D). Thus, the potential impact associated with Pacific Lamprey would be potentially significant.

Western Brook Lamprey, a State Species of Special Concern, are a small non-migratory lamprey that resides in freshwater. They inhabit coastal streams along the Pacific Coast from Alaska to California, with spawning typically occurring March-July. Western Brook Lamprey are known to occur in the Strongs Creek Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-23 watershed. Suitable rearing and potentially spawning habitat are present in Rohner Creek and Strongs Creek within the BSA although no suitable habitat is present in the Project Area. (Appendix D). Thus, the potential impact associated with Western Brook Lamprey would be potentially significant.

Coastal Cutthroat Trout, a State Species of Special Concern, range from the southernmost extent of its range in the Eel River (California) to Prince Williams Sound in Alaska. Coastal Cutthroat Trout usually occupy smaller tributary streams. Spawning can occur from December through May. Despite widespread decline throughout its range, Coastal Cutthroat Trout populations are present in the Eel River as well as Lower Eel River tributaries. Additionally, the species is known to occur in the Strongs Creek watershed. The closest known occurrence record is from 1995 in Strongs Creek within the BSA (Appendix D). Suitable rearing and migratory habitat are present in Rohner Creek and Strongs Creek within the BSA. However, no spawning habitat (based on lack of graveled stream bottom in Rohner Creek and Strongs Creek) is present in the BSA. Based on suitable aquatic habitat, the species may be present in the BSA within Rohner Creek and Strongs Creek, although no suitable habitat is present in the Project Area (Appendix D). Thus, the potential impact associated with Coastal Cutthroat Trout would be potentially significant.

SONCC Coho Salmon, a federal and state threatened species, occupies streams between Punta Gorda in northern California (Humboldt County) and Cape Blanco in southern Oregon. Coho Salmon spend their adult lives in marine environments, returning to freshwater at the age of four or five to spawn, usually in their stream of origin. Juveniles remain in fresh water for over a year before migrating to the ocean in spring. The Eel River supports populations of Coho Salmon; however, Coho Salmon are not known to occur in the Strongs Creek watershed historically or currently (Appendix D). This species is unlikely to be present within the BSA in Rohner Creek and Strongs Creek; however, given the absence of fish passage barriers between the Eel River and the BSA, presence cannot be ruled out. Thus, the potential impact associated with SONCC Coho Salmon would be potentially significant.

California coastal Chinook Salmon, a federally threatened species, ranges from Redwood Creek in Humboldt County south to the Russian River in Sonoma County. Ocean-type Chinook (fall run) rear for less than one year in freshwater, while stream-type Chinook (spring run) remain in freshwater for one year or more before emigrating to forage in coastal and marine zones of California for two to five years. The Eel River supports populations of Chinook Salmon and are also known to occur in the Strongs Creek watershed (Appendix D). This species may be present within the BSA in Rohner Creek and Strongs Creek. Thus, the potential impact associated with California coastal Chinook Salmon would be potentially significant.

Northern California Steelhead, a federal and state threatened species, occupies river basins from Redwood Creek in Humboldt County to the Gualala River (near the Mendocino/Sonoma County line). Both summer and winter-run Steelhead are included in this distinct population segment (DPS). Steelhead spend their adult lives in marine environments, returning to freshwater at the age of four or five to spawn, usually in their stream of origin. Juveniles remain in fresh water for one or two years before returning to saltwater, with emigration typically occurring from March through June. Juvenile Steelhead have been documented in Rohner Creek and Strongs Creek in 2009, and both winter-run and summer-run Steelhead are found in the Eel River (Appendix D). Suitable rearing and migratory habitat are present in Rohner Creek and Strongs Creek within the BSA; however, no spawning habitat (based on lack of graveled stream bottom in Rohner Creek and Strongs Creek) is present in the BSA. Based on suitable aquatic habitat, the species may be present in the BSA within Rohner Creek and Strongs Creek, although no suitable habitat is present in the Project Area. Thus, the potential impact associated with northern California Steelhead would be potentially significant.

Given that no in-water work within Rohner Creek and Strongs Creek would occur, direct impacts to special status fish would not result, however indirect impacts could still occur. Sediment associated with Project Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-24 construction in discrete areas near tributaries has the potential to enter Rohner Creek and Strongs Creek during construction, increasing water turbidity and suspended sediments. Additionally, Project construction has the potential to spill hazardous materials (i.e., oil, grease, fuels, and coolants) that could have detrimental effects on fisheries resources downstream of the Project. Operating construction equipment in or adjacent to any watercourse, whether it is wet or dry, poses the risk of serious environmental damage if a spill were to occur. The Project would require daily on-site refueling of construction equipment. As a result of that activity, minor fuel and oil spills can occur, and there is always the risk of larger releases. Thus, the potential impact associated with special status fish would be potentially significant.

Mitigation
Implementation of Mitigation Measure BIO-3 would reduce the impact on special status fish species by implementing specific efforts to minimize construction impacts.

Mitigation Measure BIO-3: Avoidance and Minimization Measures to Protect Special Status Fish Species
The City shall implement the following avoidance and protection measures in areas adjacent to Rohner Creek and Strongs Creek during Project construction. - Sediment and/or erosion control will be established to avoid sedimentation and runoff into Strongs Creek and Rohner Creek. The location of sediment and/or erosion control measures will be included on the final construction plan set.
- Equipment will be cleaned of deleterious materials before working within 100 feet of either creek.
- Equipment will be staged, and materials stockpiled, outside Rohner Creek and Strongs Creek riparian habitat, in designated staging and stockpile areas. - Any construction equipment operating adjacent to a creek shall be inspected daily for leaks.

Any oil, fuel, and grease residue that has the potential to fall from machinery shall be removed and properly disposed of. Refueling and equipment maintenance would occur in designated staging and stockpiling areas only.
- Spill containment booms will be available on-site at all times during construction operations and/or staging of equipment or during fueling when work occurs over live waterbodies. Fueling trucks will at all times be equipped with sealed spill kits. - City contractors will develop and implement site-specific measures and an emergency spill control plan. The contractor shall be responsible for immediate spill containment and cleanup, as well as proper disposal of hazardous materials and BMPs used during spill recovery.

With the implementation of Mitigation Measure BIO-3, potential impacts to special status fish species would remain less than significant.

Special Status Invertebrate Species
There are six special status invertebrate species, including one federal listing candidate, that the BSA likely provides suitable habitat: California Floater (Anodonta californiensis), Western Ridged Mussel (Gonidea angulata), Western Pearlshell (Margaritifera falcata), Obscure Bumble Bee (Bombus caliginosus), Western Bumble Bee (Bombus occidentalis), and the Monarch Butterfly (Danaus plexippus). No special status invertebrates were observed during the reconnaissance-level biological survey site visits. However, this survey was not targeted towards detection of the full range of invertebrates. The Project Area and BSA do not overlap designated or proposed critical habitat for any federally listed invertebrate species.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-25 California Floaters, a CDFW Special Animals List species, historic range may have spanned from British Columbia to Mexico; however, it is considered extirpated from the Central Valley of California and its current range is disjunct. One large population has been recorded in the Eel River, though there are no known occurrences within the Project Area, BSA, or the surrounding five miles (Appendix D). Based on suitable aquatic habitat, the species may be present in the BSA within Rohner Creek and Strongs Creek, although no suitable habitat is present in the Project Area. There would be no alteration or modification to riparian or creek habitat and no in-water work would occur. No impact would to the California Floater would occur.

Western Ridged Mussels, a CDFW Special Animals List species, were historically known from rivers and creeks across western North America including California, Oregon, Washington, Idaho, Nevada, and British Columbia, and recent studies have documented their presence in northern California and southern Oregon rivers. There are no known occurrences within the Project Area, BSA, or the surrounding five miles; however, suitable aquatic habitat may be present in the BSA within Rohner Creek and Strongs Creek though no suitable habitat is present in the Project Area (Appendix D). There would be no alteration or modification to riparian or creek habitat and no in-water work would occur. No impact would to the Western Ridged Mussel would occur.

Western Pearlshells, a CDFW Special Animals List species, is an aquatic freshwater mussel. Its geographic distribution spans the western U.S. including Alaska, California, Idaho, Montana, Nevada, Oregon, Utah, Washington, and Wyoming. There are no known occurrences within the Project Area, BSA, or the surrounding five miles (Appendix D). Based on suitable aquatic habitat, the species may be present in the BSA within Rohner Creek and Strongs Creek, although no suitable habitat is present in the Project Area (Appendix D). There would be no alteration or modification to riparian or creek habitat and no in-water work would occur. No impact would to the Western Pearlshells would occur.

Obscure Bumble Bees, a CDFW Special Animals List species, occur in coastal habitat within the fog belt from British Columbia to southern California. Preferred plants for foraging include the following genera:

Baccharis, Cirsium, Lupinus, Lotus, Grindelia, Phacelia. The closest known record is from 1968 in Ferndale, approximately 6 miles west of the Project Area (Appendix D). The Project Area and BSA fall within the species current range. In addition, the Project Area and BSA are within the coastal fog belt and includes several of the species' food plants. The API largely consists of ruderal habitat conditions and impacts to the Obscure Bumble Bee would be temporary in nature and less than significant.

Western Bumble Bees, a state candidate species, as well as a CDFW Special Animals List species, were historically widespread in coastal valleys and foothills throughout western North America. However, the species has experienced precipitous declines, and they are now regionally rare. Western Bumble Bees are habitat generalists but require reliable sources of nectar plants and pollen resources (blooming periods from spring through fall). The closest known record is from 1970 in Fortuna, within 1 mile of the Project Area (Appendix D). There are no recent documented occurrences of this species within the BSA or nearby.

Although the Project Area and BSA fall within the species’ pre-2002 range, the range has contracted significantly in the last decade and now primarily includes the intermountain west and cascade regions of the U.S. This being the case, the species is not expected to occur in the Project Area or BSA during construction. Impacts to the Western Bumble Bee would be less than significant.

The California overwintering Monarch Butterfly, a federal candidate species, has over 400 known overwintering sites along the coast of California from Mendocino County to Baja California, Mexico. They rely on milkweed for larval development and various nectar plants for adult food. Monarchs are relatively rare in Humboldt County, although a few observations have been reported generally concentrated between Trinidad and Fortuna from 2015 to 2023 (Appendix D). No Monarch roosts have been recorded in Humboldt Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-26 County, though the closest confirmed Monarch record is from July 2016 in Fortuna. The Project Area does not include habitat suitable for Monarch overwintering. Given the lack of suitable overwintering habitat within the API, no impact to the Monarch Butterfly would occur.

Special Status Terrestrial Mammal Species
The only special status terrestrial mammal species with the potential to occur in the Project Area is the North American Porcupine (Erethizon dorsatum), which is a state special status species and whose potential to occur in the Project Area was assessed in the NES (Appendix D). North American Porcupines are primarily nocturnal but can sometimes be seen during the day. Their range extends across mainland Canada, Alaska, and the western and northeastern United States. They use a wide variety of habitats, but are most common in montane conifer, Douglas fir, alpine dwarf‐shrub. A population in Del Norte County, centered in Tolowa Dunes State Park, is especially known to concentrate in riparian areas. Porcupines are herbivores and feed on a variety of plant materials depending on the season. They feed on berries, seeds, grasses, leaves, roots and stems during the spring and summer. In contrast, they primarily feed on evergreen needles and tree bark during the winter.

The closest known record is from 2014 along U.S. 101, approximately 4.5 miles north of the Project Area (Appendix D). The Project Area does not provide suitable foraging or denning habitat for the North American Porcupine. However, habitat within the greater BSA may serve as suitable habitat for these species. Thus, the potential impact associated with special status mammal species would be potentially significant.

Mitigation
Implementation of Mitigation Measure BIO-4 would reduce the impact on the North American Porcupine by implementing specific efforts to minimize construction impacts.

Mitigation Measure BIO-4: Avoidance and Minimization Measures to Protect Special Status Mammals
The Project footprint shall be restricted to the minimum necessary. Deep steep-sided excavations will be covered or ramped if left overnight to avoid the risk of a nocturnally dispersing terrestrial mammals (e.g., North American Porcupine) becoming trapped. Food waste and other trash will be removed from the site at the end of each workday to avoid attractants. Pets (e.g., dogs) will not be permitted on the construction site.

With the implementation of Mitigation Measure BIO-4, potential impacts to the North American Porcupine would remain less than significant.

Special Status Bats
The BSA includes suitable habitat for three special status bat species: Silver-haired Bat (Lasionycteris noctivagans), Hoary Bat (Lasiurus cinereus), and Yuma Myotis (Myotis yumanensis) (Appendix D). No special status bats were detected during the reconnaissance-level biological survey site visits. However, this survey occurred during daylight hours when bat activity is known to be very low, and the survey methods were not focused on documenting bat presence. The Project Area and BSA do not overlap designated or proposed critical habitat for any federally listed bat species.

Silver-haired Bats, a CDFW Special Animals List species, is a medium sized vespertilionid with black or dark brown hairs which are silver-tipped. Maternity roosts appear to be almost exclusively in trees, inside natural hollows and bird excavated cavities or under loose bark of large diameter snags. This species has Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-27 been found hibernating in hollow trees, under sloughing bark, in rock crevices, and occasionally under wood piles, in leaf litter, under foundations, and in buildings, mines and caves. Silver-haired bat forages above the canopy, over open meadows, and in the riparian zone along water courses. The closest known recent record is from 2017 in Humboldt Redwoods State Park, approximately 15 miles south of the Project Area (Appendix D). Suitable roosting habitat may be present in the BSA, and foraging habitat may be present in the API and BSA.

Hoary Bats, a CDFW Special Animals List species, are found throughout North, Central and South America, but not usually in great densities. The species is found throughout California with the exception of xeric desert habitats in the southeast. The species breeds in inland forest habitat and winters along the coast and in the southern portion of the state. Preferred habitat includes a mosaic of forested habitat for roosting and open/edge habitat for foraging. Hoary Bats are insectivorous and feed primarily on moths (usually over water or over the forest canopy). The species roosts solitarily in dense tree foliage typically near water (species requires water for drinking) (Appendix D). The closest known recent record is historic (1934) record from Ferndale, approximately 4.7 miles west of the Project Area (Appendix D). Suitable roosting habitat may be present in the BSA, and foraging habitat may be present in the API and BSA.

Yuma Myotis, a CDFW Special Animals List species, is widespread and common throughout western North America from southern British Columbia to southern Mexico. In California, the species is widespread throughout the state except for the desert regions. The species feeds on moths and insects over water and other open habitat types. Roosts include bridges, swallow nests, rock crevices, tunnels, tree cavities, and buildings. Maternity roots may include several thousand individuals and are most common in mines and caves. The closest known occurrence record is from 1999 in Humboldt Redwoods State Park, approximately 12 miles south of the Project Area (Appendix D). Suitable roosting habitat may be present in the BSA, and foraging habitat may be present in the API and BSA.

The Project Area is unlikely to provide high-quality foraging and roosting habitat for sensitive bat species.

However, the greater BSA is likely to provide foraging and roosting habitat for bats. The largest trees (>12- inch diameter at breast height [dbh]) that may be removed during Project implementation are located directly adjacent to U.S. 101 and would not be suitable for bat habitat due to the highly disturbed setting associated with car lights and noise. Thus, it is unlikely that any physical impacts to bat or bat roosting sites would occur. As construction activities would be limited to daytime work hours between 7:00 a.m. to 7:00 p.m., indirect impacts would be less than significant.
b) Have a substantial adverse effect on any riparian habitat or other sensitive natural community identified in local or regional plans, policies, regulations or by the California Department of Fish and Game or U.S. Fish and Wildlife Service? (Less than Significant with Mitigation)
CDFW protocol level vegetation assessments and mapping of SNCs occurred on May 9 and June 29 of 2023 (Appendix C). One vegetation association qualified as a SNC, and vegetation communities within the Project Area were comprehensively assessed in the NES (Appendix C). Salal – Berry Brambles – California blackberry association (Gaultheria shallon – Rubus [ursinus]) a SNC, occur in four stands within the Project Area. This community was observed in two stands adjacent to the U.S. 101 northbound off-ramp, U.S. 101 southbound, and along Riverwalk Drive (Appendix C).

The Salal-berry brambles alliance (GNR, S4) is not considered sensitive at the alliance level; however, the Rubus ursinus association (GNR, SNR) within this alliance is designated sensitive by the CDFW (Appendix Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-28 D) This association is characterized by a dominant cover or California blackberry (Rubus ursinus) with no other trees or shrubs.

Mapped sensitive natural communities would be avoided to the greatest extent practicable; however, the Project would result in temporary or permanent impacts that may unavoidably occur to the SNC. This impact to the Salal-berry brambles alliance SNC would be potentially significant.

Mitigation
Implementation of Mitigation Measure BIO-1 would reduce the impact on special status amphibians and reptiles by implementing specific efforts to minimize construction impacts.

Mitigation Measure BIO-5: Compensatory Mitigation for Sensitive Natural Communities If impacts to Salal-berry brambles cannot be avoided, this SNC shall be replaced either on or offsite at no less than a 1:1 ratio. Removal of nuisance litter and invasive species will also be acceptable to offset Salal-berry bramble removal if replanting within or near the Project Area is infeasible. Where feasible Himalayan blackberry will be removed from remaining stands of berry brambles within the Project Area as mitigation for Project impacts.

Mitigation Measure BIO-3 requires avoidance and minimization of permanent impacts and temporary impacts to SNCs during construction, restoration of pre-Project conditions at the conclusion of construction, and compensation (replacement) of SNCs, thereby reducing potential impacts to natural communities to a less than significant level.
c) Have a substantial adverse effect on state or federally protected wetlands (including, but not limited to, marsh, vernal pool, coastal, etc.) through direct removal, filling, hydrological interruption, or other means? (No Impact)
A wetland delineation was completed on January 26, 2023 to determine the extent of wetlands and other waters within the Project Area based on hydrophytic vegetation, hydric soils, and wetland hydrology using methods and indicators outlined in the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (Appendix E). During the site survey, no watercourses, Ordinary High Water Marks, or wetland conditions were observed within the Project Area.

Therefore, no impact would occur.
d) Interfere substantially with the movement of any native resident or migratory fish or wildlife species or with established native resident or migratory wildlife corridors, or impede the use of native wildlife nursery sites? (No Impact)
Project construction and operations do not include in-water work or any other activity that might impede fish migration. Terrestrial Project construction and operations do not include construction of any barriers to wildlife migration (e.g., fencing, highly developed roadway, or large structures). No impact would occur. e) Conflict with any local policies or ordinances protecting biological resources, such as a tree preservation policy or ordinance? (No Impact)
The entirety of the Project is within the limits of the City of Fortuna. The City of Fortuna General Plan’s Resource Management and Conservation Element establishes policies to protect biological resources Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-29 within City limits including protected streams and wetlands (City of Fortuna 2010). Applicable policies include:

Policy NCR-2.1: Riparian Corridor Protection
The City shall establish riparian buffers to provide for fish and terrestrial wildlife habitat protection, enhancement, and movement along riparian corridors through the Planning Area. Activities within these buffers shall be limited to passive recreational uses (hiking, biking, sightseeing, horseback riding) and the movement of wildlife.

Policy NCR-2.8: Native Vegetation
The City shall coordinate with resource agencies to require the preservation of native vegetation, while managing areas with high concentrations of invasive species and/or noxious weeds and preventing their encroachment into new areas.

Policy NCR-2.10: Wetland Identification and Protection
In considering new development projects, the City shall conduct an initial screening, as described in Policy NCR‐2.6 in order to determine whether the proposal would have the potential to impact wetlands. If the initial screening indicates the potential presence of wetlands, a wetland assessment/ delineation shall be prepared to determine the presence of jurisdictional wetlands. The assessment/delineation, with proposed mitigation, shall be submitted to the City, and appropriate state (CDF&G) and federal (USCOE) agencies for concurrence prior to permitting. Mitigation may include, but may not be limited to, avoidance, minimization of impacts, restoration, off‐site replacement, and/or the use of buffers.

Policy NCR-2.12: Permitted Activities with ESHAs
The following activities shall be permitted in Environmentally Sensitive Habitat Areas (ESHAs) with approval from the Fortuna Planning Department and after consultation with Responsible and Trustee agencies:

THPs; removal of dead, dying or diseased trees or downed vegetation within the streambed or streambank; the removal of vegetation obstructing streamflow or causing streambed or streambank erosion; and road crossings.

Policy NCR-15b: Streamside Management and Wetland Protection New development/activities within SMAs shall be limited to: (1) activities for wildlife enhancement/ restoration, flood control or drainage, new fencing so long as it would not impede natural drainage or wildlife, and bank protection; (2) commercial timber management and harvest activities regulated by the Forest Practices Act; (3) road and bridge replacement or construction, when it can be demonstrated that it would not degrade fish and wildlife resources or water quality; (4) removal of vegetation for disease control or public safety; and (5) management and maintenance of trees, shrubs and other plant life.

Policy NC-2.13: Watercourse, Wetland and Riparian Buffers The City shall require appropriate watercourse, wetland, and riparian area buffers to protect water quality and biologic values.

Section 17.06.171 (B) (Removal of natural materials) of the City’s Zoning Code address tree removal and states that the removal of trees shall occur in accordance with applicable sections of the California Forest Practices Act. If the Forest Practices Act is applicable, a Use Permit must be obtained from the planning commission prior to any removal of trees. The Project Area does not include forest resources; thus, the Forest Practices Act is not applicable.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-30 The Project is consistent with the biological policies NCR-2.1, NCR-2.8, NCR-2.10, NCR-2.12, NCR-2.13, and NCR-15 in the City of Fortuna General Plan. No in-water work, culvert replacement or modification, or channel alteration within Rohner Creek or Strongs Creek would occur. Primary construction activities would not occur within riparian corridors, and Mitigation Measure BIO-3 would be implemented to avoid indirect impacts associated with sedimentation and accidental spills. A delineation of all potential aquatic resources within the Project Area was conducted (Appendix E). No watercourses, Ordinary High Water Marks, or wetland conditions were observed within the Project Area. Therefore, there are no conflicts with NCR-15.

Thus, a less than significant impact would occur.
f) Conflict with the provisions of an adopted Habitat Conservation Plan, Natural Community Conservation Plan, or other approved local, regional, or state habitat conservation plan? (No Impact)
There are no adopted Habitat Conservation, Community Conservation, or approval local, regional, or state habitat conservation plans that apply to the Project Area. No impact would occur.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-31

3.5 Cultural Resources
Potentially
Significant
Impact
Less than
Significant w/
Mitigation
Incorporated
Less than
Significant
Impact
No
Impact
Would the project:
a) Cause a substantial adverse change in the
significance of a historical resource pursuant to
§15064.5?

b) Cause a substantial adverse change in the
significance of an archaeological resource
pursuant to §15064.5?

c) Disturb any human remains, including those
interred outside of formal cemeteries? 
The cultural resources study area within this section is described as the Area of Potential Effect (APE). An Archaeological Resources Study (ASR) was prepared for the Project by Roscoe and Associates (Roscoe 2024). A Historical Resources Evaluation report (HRER) was prepared by JRP Historical Consulting (JRP 2024b). Additionally, a Historic Property Survey Report (HPSR) was prepared by JRP and Roscoe (2024).

The studies assessed the potential for surficial and/or buried archaeological and historical resources in the proposed improvement area through the completion of the following:
– Records and literature search at the Northwest Information Center (NWIC) of the California Historical Resources Information Center (CHRIS);
– Further literature review of publications, files, and maps for ethnographic, historic-era, and prehistoric resources and background information;
– Communication with the NAHC to request a review of the Sacred Lands File and contact information for the appropriate tribal communities;
– Contact with the appropriate local Native American Tribes; and – Pedestrian survey of the Project Area.

Study results were used as a technical basis for evaluating potential impacts to historic and cultural resources under CEQA.
a) Cause a substantial adverse change in the significance of a historical resource pursuant to §15064.5? (Less than Significant)
A HPSR was completed in 2024 by Roscoe and Associates (Roscoe 2024). The APE has been subject to five previous studies by Abacus Archaeological Associates (1995); Caltrans North Region District 3 (2008); Far Western Anthropological Research Group, Inc. (2008); California Office of Historic Preservation and California Department of Transportation (2008); and Roscoe & Associates (2012). Seven other studies have been conducted within 0.5 mile of, but outlying, the current APE. The NWIC record search identified no previously inventoried and/or evaluated built environment resources within or near the Project APE.

Additional background research identified one linear resource, the former Northwestern Pacific Railroad, within the APE.

The HRER completed by JRP Historical Consulting identified and evaluated historic built resources within the APE (JRP 2024b). Results found one historic built resource, a segment of the former Northwestern Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-32 Pacific Railroad (NWPRR). A Finding of No Adverse Effect (FNAE) was prepared to analyze the impact to the NWPRR as it is considered eligible under NRHP Criteria A and C. The FNAE concluded that removal of tracks in this short segment would constitute a miniscule portion of the overall railroad, which spans approximately 300 miles, and that no adverse effect would result. Additionally, the State Historic Preservation Officer (SHPO) has concurred at least five times that segments of the NWPRR in Humboldt County (outside the APE) are not eligible for listing in the National Register of Historic Places (NRHP) and are thus not considered a historic property (JRP 2024b). The APE also includes the 12th Street Overcrossing (Bridge 04 0130), constructed in 1962. Caltrans previously determined the overcrossing ineligible for listing in the NRHP and CRHR (JRP 2024b). Based on the findings of the HRER, there are no historical resources within the Project Area. This impact would be less than significant. b) Cause a substantial adverse change in the significance of an archaeological resource pursuant to §15064.5? (Less than Significant with Mitigation) An ASR was completed in 2024 by Roscoe and Associates (Roscoe 2024). The CHRIS record search concluded that no previously recorded resources are present within the APE and no pre-contact era resources are documented within 0.5 mile of the APE. A pedestrian survey was conducted of the APE, as well as areas directly adjacent, on December 6, 2022. The archaeological field survey found no evidence of archaeological deposits; however, the potential for inadvertent discovery remains, resulting in a potentially significant impact.

Native American tribes and individuals and the NAHC were contacted by Caltrans to discuss the proposed Project through the AB 52 consultation process on November 10, 2023 (see Section 3.18). Letters were sent to the Bear River Band of Rohnerville Rancheria, Big Lagoon Rancheria, Blue Lake Rancheria, Hoopa Valley Tribe, Cher-Ae Heights Indian Community of the Trinidad Rancheria, Wiyot Tribe, and the Yurok Tribe. The Tribal Historic Preservation Officer (THPO) for the Blue Lake Rancheria responded on November 20, 2023, stating that the Project is outside of the Rancheria’s area of interest. As part of the AB52 process, the City issued tribal notification letters to the tribes on the NAHC list on March 11, 2024. The City received a response from the Bear River Band of the Rohnerville Rancheria on April 22, 2024, requesting ongoing consultation throughout the Project and had a site visit on April 30, 2024. The City received a response from the THPO for the Wiyot Tribe on May 30, 2024, requesting standard inadvertent archaeological discovery protocols be in place for any ground-disturbing activities which is incorporated as Mitigation Measure CR-1.

Additionally, Roscoe and Associates, as part of the ASR, conducted correspondence with the NAHC on November 23, 2022, to search the Sacred Lands Inventory File and to provide a list of Native American representatives for the Project Area. The NAHC replied on December 5, 2022, that no sacred lands were present and provided a list of Native American tribes. Roscoe and Associates contacted the Bear River Band of Rohnerville Rancheria, Big Lagoon Rancheria, Blue Lake Rancheria, Cher-Ae Heights Indian Community of the Trinidad Rancheria, Hoopa Valley Tribe, Karuk Tribe, Round Valley Reservation/Covelo Indian Community, Tsnungwe Council, Wiyot Tribe, and the Yurok Tribe. Following correspondence, the THPO of the Bear River Band of Rohnerville Rancheria requested to participate in the field survey and was present on the pedestrian survey conducted December 6, 2022. Following the survey, the THPO requested inadvertent discovery measures which specified that representatives of the Bear River Band of Rohnerville Rancheria be contacted directly regarding the discovery. Roscoe and Associates also received correspondence from the Wiyot Tribe also requesting inadvertent discovery measures be included.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-33 To ensure potential impacts to cultural resources remain less than significant, Mitigation Measure CR-1 would be implemented to establish protocols from Roscoe and Associates and Native American consultation for inadvertent archaeological discovery.

Mitigation
Implementation of Mitigation Measure CR-1 would reduce the potential impact to archaeological resources by requiring procedures that follow tribal consultation, and what shall occur in the event of inadvertent discovery.

Mitigation Measure CR-1: Inadvertent Discovery of Archaeological Material If cultural materials for example: chipped or ground stone, historic debris, building foundations, or bone are discovered during ground disturbance activities, work shall be stopped within 66 feet of the discovery, per the requirements of CEQA (Revised Guidelines, Title 14 CCR 15064.5 (f)). Work near the archaeological finds shall not resume until a professional archaeologist, who meets the Secretary of the Interior’s Standards and Guidelines, has evaluated the materials, and offered recommendations for further action. Tribal representatives, including representatives of the Bear River Band of Rohnerville Rancheria, shall be notified.

Implementation of Mitigation Measure CR-1 would reduce the potential impacts to a less than significant level during construction because a plan would be implemented to address discovery of unanticipated archaeological resources and to preserve and/or record those resources consistent with appropriate laws and requirements.
c) Disturb any human remains, including those interred outside of formal cemeteries? (Less than Significant with Mitigation)
While the Archaeological Survey Report did not determine archaeological resources were likely to be present within the APE, inadvertent discovery of human remains may still occur (Roscoe 2024). In the event that human remains are encountered during construction, Mitigation Measure CR-2 would be implemented to ensure any potential impact would be less than significant.

Mitigation
Implementation of Mitigation Measure CR-2 would reduce the potential impact to human remains by requiring procedures that shall be taken in the event of inadvertent discovery.

Mitigation Measure CR-2: Inadvertent Discovery of Human Remains If human remains are discovered during Project construction, work will stop at the discovery location, within 66 feet, and any nearby area reasonably suspected to overlie adjacent to human remains (PRC, Section 7050.5). The Humboldt County Coroner will be contacted to determine if the cause of death must be investigated. If the Coroner determines that the remains are of Native American origin, it is necessary to comply with State laws relating to the disposition of Native American burials, which fall within the jurisdiction of the NAHC (PRC, Section 5097). The coroner will contact the NAHC. The descendants or most likely descendants of the deceased will be contacted, and work will not resume until they have made a recommendation to the landowner or the person responsible for the excavation work for means of treatment and disposition, with appropriate dignity, of the human remains and any associated grave goods, as provided in PRC, Section 5097.98.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-34 Implementation of Mitigation Measure CR-2 would reduce the potential impacts to a less than significant level during construction because a plan would be implemented to address discovery of unanticipated human remains and to preserve and/or record those resources consistent with appropriate laws and requirements.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-35

3.6 Energy Resources
Potentially
Significant
Impact
Less than
Significant w/
Mitigation
Incorporated
Less than
Significant
Impact
No
Impact
Would the project:
a) Result in potentially significant environmental
impacts due to wasteful, inefficient, or unnecessary
consumption of energy resources, during project
construction or operation?

b) Conflict with or obstruct a state or local plan for
renewable energy or energy efficiency? 
a) Result in potentially significant environmental impacts due to wasteful, inefficient, or unnecessary consumption of energy resources, during Project construction or operation? (Less than Significant with Mitigation)
Construction
Temporary energy use in connection with Project construction would entail consumption of diesel fuel and gasoline by construction equipment and by the transportation of earth moving equipment, construction materials, supplies, and construction personnel. Given the short construction period and implementation of state regulations regarding vehicle emission and fuels standards, such as the Low Carbon Fuel Standard and anti-idling regulations, energy use related to construction would not be wasteful or inefficient.

Inefficient construction-related fuels use would also be avoided due to the measures in Mitigation Measure AQ-1 (BMPs to Reduce Air Pollution). Equipment idling times would be minimized either by shutting equipment off when not in use or reducing the maximum idling time to five minutes or less (as required by Mitigation Measure AQ-1). Because construction would not encourage activities that would result in the use of large amounts of fuel and energy in a wasteful manner, and the incorporation of Mitigation Measure AQ-1 would reduce idling time, impacts related to the inefficient use of construction-related fuels would be less than significant with mitigation.

Operation
Operation of the Project would include periodic maintenance. These activities would generally be supported by vehicles and the use of hand-held tools. The use of fossil-fuel powered equipment to support these operational and maintenance activities would be periodic and short-term (occurring intermittently). However, the potential need for larger repair and maintenance would remain the same as under existing conditions, as would the types of equipment and equipment used. These activities would not result in a substantial increase in energy use, and would not result in inefficient, wasteful, or unnecessary consumption of fuels or other energy resources.

Lighting enhancements would be installed to improve visibility for drivers during nighttime hours. As identified in Section 1.7, lighting for the Project would be the minimum lumens necessary. Lighting fixtures would be energy efficient, and as they are being installed for driver and pedestrian safety, would not be wasteful.

The Project would not result in an increase in vehicle trips, traffic volumes or increased delays over existing conditions. The proposed roadway improvements would likely increase multimodal use of the roadway Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-36 which may decrease vehicle trips and associated fuel consumption. Traffic flow would improve; thus, the Project would result in less vehicle idling and an associated reduction in fuel consumption. Vehicle trips associated with operation and maintenance of the road would be the same as under existing conditions and would include annual inspections, repaving, striping, and repairs as needed. The Project would not result in an increase in operational energy consumption above existing conditions. Operation of the Project would not result in wasteful, inefficient, or unnecessary consumption of energy resources; the impact would be less than significant.
b) Conflict with or obstruct a state or local plan for renewable energy or energy efficiency? (No Impact)
There are no local plans for renewable energy that would apply to the Project. The Humboldt County Climate Action Plan remains in development. Implementation of the Project would not obstruct a state plan for renewable energy. The Project would not conflict with or inhibit the implementation of the State Energy Action Plan, or other state regulations. The Project would not inefficiently utilize energy due to incorporation of Mitigation Measure AQ-1, which limits idling time and provides measures to protect air quality. The Project would temporarily require the use of equipment to construct the components of the Project; however, these activities would be temporary and would not interfere with the broader energy goals of the state. Operationally, the Project would not increase operational automobile-related energy consumption and would support multimodal non-automobile transit. Project lighting would be limited and energy efficiency.

The majority of California’s energy-related plans are not directly applicable to the Project or its operations; however, the vehicles that would utilize the Project alignment would comply with plan requirements applicable to vehicles. The Project would therefore not conflict with or obstruct a state or local plan for renewable energy or energy efficiency. No impact would occur.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-37

3.7 Geology and Soils
Potentially
Significant
Impact
Less than
Significant w/
Mitigation
Incorporated
Less than
Significant
Impact
No
Impact
Would the project:
a) Directly or indirectly cause potential substantial
adverse effects, including the risk of loss, injury, or death involving:
i. Rupture of a known earthquake fault, as
delineated on the most recent Alquist-Priolo
Earthquake Fault Zoning Map issued by the
State Geologist for the area or based on other
substantial evidence of a known fault? Refer to
Division of Mines and Geology Special
Publication 42?

ii. Strong seismic ground shaking? 
iii. Seismic related ground failure, including
liquefaction? 
iv. Landslides? 
b) Result in substantial soil erosion or the loss of
topsoil? 
c) Be located on a geologic unit or soil that is
unstable, or that would become unstable as a
result of the project, and potentially result in on, or off, site landslide, lateral spreading, subsidence,
liquefaction or collapse?

d) Be located on expansive soil, as defined in Table
18-1-B of the Uniform Building Code (1994),
creating substantial direct or indirect risks to life or property?

e) Have soils incapable of adequately supporting the
use of septic tanks or alternative wastewater
disposal systems where sewers are not available
for the disposal of wastewater?

f) Directly or indirectly destroy a unique
paleontological resource or site or unique geologic
feature?

The Project is located on generally flat and gently sloping Eel River valley. Regional geology is likely influenced by seismic activity as a result of the relatively close proximity of the Mendocino Triple Junction to the Project. The Project is located near the Little Salmon Fault Zone (CGS 2024). The Project Area is predominantly comprised of Urban land-Friendlycity association with 0 to 2 percent slopes at 93.5%, one other soil associations that covers less than 7% of the Project (Appendix A – Figure 3). a, i) Rupture of a known earthquake fault, as delineated on the most recent Alquist-Priolo Earthquake Fault Zoning Map issued by the State Geologist for the area or based on other Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-38 substantial evidence of a known fault? Refer to Division of Mines and Geology Special Publication 42. (No Impact)
According to the California Geological Survey (CGS), there are no Alquist-Priolo Fault Zones in the Project Area (CGS 2024). The Project would have no impact with regard to the rupture of a known earthquake fault, as delineated on the most recent Alquist-Priolo Earthquake Fault Zoning Map. The nearest fault zone is the Holocene-age Little Salmon Fault Zone approximately 1.6 miles east of the Project (CGS 2024). Project activities, which include shallow excavation and repaving, would not rupture faults in any known fault.

Additionally, the Project does not include structures designed for human occupancy. No impact related to fault rupture would occur.
a, ii) Strong seismic ground shaking? (Less Than Significant) The Project is situated within a seismically active area close to several seismic sources capable of generating moderate to strong ground motions. Because the Project is located within a seismically active area, the probability that strong ground shaking associated with large magnitude earthquakes would occur during the design life of the Project is high. The Humboldt County coast is a highly active tectonic region that has been subjected to numerous earthquakes of low to moderate strength and occasionally to very strong earthquakes. Seismicity in the region is attributed primarily to the Mendocino Triple Junction, or the interaction between the Pacific, Gorda, and North American plates. Project implementation would not increase risk of strong seismic ground shaking above existing conditions.

Project implementation would not increase risk of strong seismic ground shaking or exposure to strong seismic ground shaking above existing conditions. If strong seismic ground shaking were to damage the proposed Project, it is unlikely that human lives would be put at risk because the Project does not involve the construction of habitable structures. The Project would be designed and constructed in conformance with the site-specific recommendations contained in the geotechnical report prepared for the Project, and any subsequent Project-related geotechnical reports. The geotechnical report would reference California seismic requirements applicable to specific Project structural elements such as retaining walls. These recommendations would include, but not be limited to, reinforced road embankment, limited subdrainage elements, and slope toe protection. By following the recommendations contained in the geotechnical report, the construction and operation of the Project would meet Caltrans standards and would result in a less than significant impact. Therefore, the impact to people and structures from strong seismic ground shaking would be less than significant.
a.iii, a.iv, c, d) Liquefaction, landslides, or otherwise unstable soils? (Less Than Significant Impact) Liquefaction is a phenomenon involving loss of soil strength and resulting in fluid mobility through the soil.

Liquefaction typically occurs when loose, uniformly sized, saturated sands or silts are subjected to repeated shaking in areas where the groundwater is less than 50 feet below ground surface. In addition to the necessary soil and groundwater conditions, the ground acceleration must be high enough, and the duration of the shaking must be sufficient, for liquefaction to occur. The Project is located in a mapped liquefaction hazard zone (Humboldt County 2024). Project implementation would not increase risk of liquefaction or exposure to liquefaction above existing conditions and no impact would occur.

Installation of the proposed pedestrian U.S. 101 overcrossing may include retaining walls to support structure footings on the western side of the Project Area, which would be visible on Dinsmore Drive. The design for the retaining walls would be consistent with the Project’s geotechnical recommendations. Thus, Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-39 landslides within or near the Project are unlikely to occur, and the potential for landslide occurrence is not increased by the Project.

Expansive soils can cause considerable distress to roads and building foundations as they “rise-and-fall” in accordance with the cycles of soil wetting (swelling) and drying (shrinking). Soils with high percentages of silicate clays are those that have the potential for shrinking and swelling. Expansive soils can also be defined as those with a Plasticity Index (PI) of greater than 12 (Caltrans 2023). Mapping by the NRCS shows the Project Area to have the highest percentage of clay content is 21.6 percent with a PI value of 8.1 (Appendix E). Thus, soils have a low potential for expansion. Implementation of the Project would not exacerbate potential liquefaction or landslides, rather the potential for liquefaction or landslides would decrease.

The Project would comply with the seismic requirements of the Caltrans Highway Design Manual, 7th Edition (Caltrans 2023). The Project would be designed and constructed in conformance with the sitespecific recommendations contained in the geotechnical report prepared for the Project and any subsequent Project-related geotechnical reports. Project adherence to geotechnical design recommendations during construction and operation would result in a less than significant impact with mitigation in regard to landslide, lateral spreading, subsidence, or collapse. b) Result in substantial soil erosion or the loss of topsoil? (Less Than Significant Impact) Construction activities, including cut, fill, removal of vegetation, directional drilling, and operation of heavy machinery would disturb soil and, therefore, have the potential to cause erosion. Erosion and sediment control provisions prescribed in the Fortuna Municipal Code and NCRWQCB regulations would be required as part of the Project. BMPs may include silt fences, straw wattles, soil stabilization controls, site watering for controlling dust, and sediment detention basins. Section 1.12 outlines existing regulations that the Project would develop and implement, including a SWPPP in accordance with the State General Construction Permit. These mandatory ordinance requirements and permits are designed to maintain potential water quality impacts at a less than significant level during and post construction. Therefore, the potential soil erosion impact would be less than significant. e) Have soils incapable of adequately supporting the use of septic tanks or alternative wastewater disposal systems where sewers are not available for the disposal of wastewater? (No Impact)
The Project does not propose the installation or modification of septic tanks or wastewater disposal systems. Therefore, construction and operation of the Project would have no impact. f) Directly or indirectly destroy a unique paleontological resource or site or unique geologic feature? (Less than Significant with Mitigation)
Paleontological resources are the remains or traces of prehistoric animals and plants. Paleontological resources, which include fossil remains and geologic sites with fossil-bearing strata are non-renewable, scarce, and are a sensitive resource afforded protection under environmental legislation in California. State law requires reasonable mitigation of adverse environmental impacts that result from development of public land and affect paleontological resources (PRC § 30244).

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-40 It is unlikely that Project construction will impact potentially significant paleontological resources because most of the Project occurs in relatively newly deposited alluvium. However, the possibility of encountering a paleontological resource during construction cannot be completely discounted; therefore, the impact related to the potential disturbance or damage of previously undiscovered paleontological resources, if present, is considered potentially significant.

Mitigation
Implementation of Mitigation Measure GEO-1 would reduce the impact of construction activities on potentially unknown paleontological resources by addressing discovery of unanticipated buried resources and preserving and/or recording those resources consistent with appropriate laws and requirements.

Mitigation Measure GEO-1: Inadvertent Discovery of Paleontological Resources In the event that fossils are encountered during construction (i.e., bones, teeth, or unusually abundant and well-preserved invertebrates or plants), construction activities shall be diverted away from the discovery within 50 feet of the find, and a professional paleontologist shall be notified to document the discovery as needed, to evaluate the potential resource, and to assess the nature and importance of the find. Based on the scientific value or uniqueness of the find, the paleontologist may record the find and allow work to continue, or recommend salvage and recovery of the material, if it is determined that the find cannot be avoided. The paleontologist shall make recommendations for any necessary treatment that is consistent with currently accepted scientific practices. Any fossils collected from the area shall then be deposited in an accredited and permanent scientific institution where they will be properly curated and preserved.

With the implementation of Mitigation Measure GEO-1, potential impacts to unique paleontological resources, sites, or unique geologic features would remain less than significant.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-41

3.8 Greenhouse Gas Emissions
Potentially
Significant
Impact
Less than
Significant w/
Mitigation
Incorporated
Less than
Significant
Impact
No
Impact
Would the project:
a) Generate greenhouse gas emissions, either
directly or indirectly, that may have a significant
impact on the environment?

b) Conflict with an applicable plan, policy or regulation adopted for the purpose of reducing the emissions
of greenhouse gases?

a) Generate greenhouse gas emissions, either directly or indirectly, that may have a significant impact on the environment? (Less than Significant)
NCUAQMD has not adopted regulations regarding the evaluation of greenhouse gas (GHG) emissions in a CEQA document and has not established CEQA significance criteria to determine the significance of impacts with regard to GHGs. The NCUAQMD has stated that they would not comment adversely on the use of thresholds of significance from the BAAQMD for projects within Humboldt County. However, the BAAQMD has recently revised their adopted recommended CEQA thresholds of significance for GHG. The BAAQMD’s Justification Report for the newly adopted greenhouse gas thresholds identify the thresholds as specific for ‘development projects’ of commercial/residential development and other projects. Per the Draft Justification Report:

The Air District has developed these thresholds of significance based on typical residential and commercial land use projects and typical long-term communitywide planning documents such as general plans and similar long-range development plans. As such, these thresholds may not be appropriate for other types of projects that do not fit into the mold of a typical residential or commercial project or general plan update.

Lead agencies should keep this point in mind when evaluating other types of projects. A lead agency does not necessarily need to use a threshold of significance if the analysis and justifications that were used to develop the threshold do not reflect the particular circumstances of the project under review. Accordingly, a lead agency should not use these thresholds if it is faced with a unique or unusual project for which the analyses supporting the thresholds as described in this report do not squarely apply. In such cases, the lead agency should develop an alternative approach that would be more appropriate for the particular project before it, considering all of the facts and circumstances of the project on a case-by-case basis. (emphasis added) Additionally, the BAAQMD’s Justification Report states:

There is no proposed construction-related climate impact threshold at this time. Greenhouse gas emissions from construction represent a very small portion of a project’s lifetime GHG emissions.

The proposed thresholds for land use projects are designed to address operational GHG emissions which represent the vast majority of Project GHG emissions. (BAAQMD 2022) Therefore, as the BAAQMD and NCUAQMD do not have recommended thresholds of significance to apply to construction period emissions or roadway/infrastructure projects, the Sacramento Metropolitan Air Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-42 Quality Management District’s (SMAQMD) and South Coast Air Quality Management District’s (SCAQMD) recommended GHG methodology and thresholds for construction impacts were applied. For Project construction, SMAQMD has a threshold of 1,100 metric tons of carbon dioxide (MTCO2e) per year threshold of significance (SMAQMD 2020). SCAQMD recommends a threshold of 1,100 MTCO2e applied to construction and operation; SCAQMD recommends that construction emissions be amortized over the life of the Project, defined as 30 years, and added to the operational emissions for comparison against the threshold of significance.

In order to assess the potential impact of construction-generated emissions, the construction GHG emissions are annualized over an assumed 30-year project lifespan, added to operational emissions, and compared against a threshold of 1,100 MTCO2e.

Project construction activities would result in exhaust emissions from on-road trucks, worker commute vehicles, and off-road heavy-duty equipment. Construction would require clearing, earthmoving, and delivery equipment, as used for similar Projects. Construction emissions were estimated using CalEEMod version 2022.1.1.29 and were estimated to be approximately 253 MTCO2e annually from all construction activities. The Project is not capacity enhancing and would not result in an increase in vehicle trips.

Additionally, improved traffic flow through the roundabouts would reduce vehicular idling and therefore result in a reduction in GHG emissions compared to existing conditions. Required maintenance of the Project would be similar to existing conditions. Therefore, the Project would not generate an increase in operation-related emissions.

Project emissions of 253 MTCO2e per year would be less than the 1,100 MTCO2e threshold. Therefore, the Project’s impact would be less than significant.
b) Conflict with an applicable plan, policy, or regulation adopted for the purpose of reducing the emissions of greenhouse gases? (No Impact)
The CARB 2022 Scoping Plan for Achieving Carbon Neutrality provides California’s climate policy portfolio and recommended strategies to put California on a pathway to achieve a 2045 target. The scenario includes ongoing and statutorily required programs, continuing the Cap-and-Trade Program, and high level objectives and goals to reduce GHGs across multiple economic sectors. Existing programs, also known as “known commitments,” identified by the 2022 Scoping Plan for Achieving Carbon Neutrality include: SB 350, the Low Carbon Fuel Standard, CARB’s Mobile Source Strategy, SB 1383 for short-lived climate pollutants and California’s Sustainable Freight Action Plan. The high level objective and goals recommendations cover the energy, transportation, industry, water, waste management, agriculture, and natural and working lands, and are to be implemented by a variety of state agencies.

Project construction would cause a temporary increase in GHGs; however, as discussed above Project emissions would not exceed the identified emission thresholds. The Project is analyzed for consistency with the 2022 Scoping Plan for Achieving Carbon Neutrality in Table 3.8-1 – Consistency Analysis Between Project and Climate Change Scoping Plan. As shown in the table, the Project is consistent with AB 32, as outlined in the 2022 Scoping Plan for Achieving Carbon Neutrality. Therefore, the Project would not conflict with AB 32 or the 2022 Scoping Plan for Achieving Carbon Neutrality and would result in no impact.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-43 Table 3.8-1 Consistency analysis between Project and Climate Change Scoping Plan.

Scoping Plan Reduction Measures Consistency/Applicability Determination California Cap‐and‐Trade Program Linked to Western
Climate Initiative. Implement a broad‐based California
cap‐and‐trade program to provide a firm limit on
emissions. Link the California cap‐and‐trade program with other Western Climate Initiative Partner programs to
create a regional market system to achieve greater
environmental and economic benefits for
California. Ensure California’s program meets all
applicable AB 32 requirements for market‐based
mechanisms.

Not Applicable. This is a statewide measure that
cannot be implemented by the Project or lead agency.

California Light‐Duty Vehicle Greenhouse Gas
Standards. Implement adopted standards and planned
second phase of the program. Align zero‐emission
vehicle, alternative and renewable fuel, and vehicle
technology programs with long‐term climate change goals.

Consistent. This is a statewide measure that cannot
be implemented by the Project or lead agency.

However, the standards would be applicable to the
light‐duty vehicles that would access the Project Area
during construction and operation.

Energy Efficiency. Maximize energy efficiency building
and appliance standards; pursue additional efficiency
including new technologies, policy, and implementation
mechanisms. Pursue comparable investment in energy
efficiency from all retail providers of electricity in
California.

Not Applicable. This is a measure for the state to
increase its energy efficiency standards in new
buildings. The Project would not result in new
habitable buildings subject to the energy efficiency
standards.

Renewable Portfolio Standard. Achieve 33 percent
renewable energy mix statewide. Renewable energy
sources include (but are not limited to) wind, solar,
geothermal, small hydroelectric, biomass, anaerobic
digestion, and landfill gas.

Not Applicable. This is a statewide measure that
cannot be implemented by the Project or lead agency.

Low Carbon Fuel Standard. Develop and adopt the Low
Carbon Fuel Standard.

Consistent. This is a statewide measure that cannot
be implemented by the Project or lead agency. The
standard would be applicable to the fuel used by
vehicles that would access the Project Area during
construction and operation.

Regional Transportation-Related Greenhouse Gas
Targets. Develop regional greenhouse gas emissions
reduction targets for passenger vehicles. This measure
refers to SB 375.

Not applicable. This is a statewide measure calling
for the development of GHG emission reduction
targets.

Vehicle Efficiency Measures. Implement light-duty
vehicle efficiency measures.

Not applicable. This is a statewide measure that
cannot be implemented by the Project or lead agency.

Goods Movement. Implement adopted regulations for the
use of shore power for ships at berth. Improve efficiency in goods movement activities.

Not applicable. The Project does not propose any
changes to modes of transportation of goods.

Million Solar Roofs Program. Install 3,000 MW of solar‐ electric capacity under California’s existing solar
programs.

Not Applicable. The Project does not involve
structures with roofs.

Medium/Heavy‐Duty Vehicles. Adopt medium and
heavy‐duty vehicle efficiency measures.

Not applicable. This is a statewide measure that
cannot be implemented by the Project or lead agency.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-44 Scoping Plan Reduction Measures Consistency/Applicability Determination Industrial Emissions. Require assessment of large
industrial sources to determine whether individual sources within a facility can cost‐ effectively reduce greenhouse gas emissions and provide other pollution reduction co‐ benefits. Reduce greenhouse gas emissions from fugitive emissions from oil and gas extraction and gas
transmission. Adopt and implement regulations to control fugitive methane emissions and reduce flaring at
refineries.

Not applicable. This measure would apply to the
direct GHG emissions at major industrial facilities. The Project is not industrial.

High Speed Rail. Support implementation of a high‐
speed rail system.

Not applicable. This is a statewide measure that
cannot be implemented by the Project or lead agency.

The Project does not involve a high speed rail system.

Green Building Strategy. Expand the use of green
building practices to reduce the carbon footprint of
California’s new and existing inventory of buildings.

Not Applicable. This is a measure for the state to
increase its energy efficiency standards in new
buildings. The Project would not result in new
habitable buildings subject to the energy efficiency
standards.

High Global Warming Potential Gases. Adopt measures
to reduce high global warming potential gases.

Not Applicable. The Project would not include air
conditioners or commercial refrigerators.

Recycling and Waste. Reduce methane emissions at
landfills. Increase waste diversion, composting, and
commercial recycling. Move toward zero‐waste.

Consistent. The Project does not include a landfill.

The Project would reduce construction waste with
implementation of state mandated recycling and reuse
mandates.

Sustainable Forests. Preserve forest sequestration and
encourage the use of forest biomass for sustainable
energy generation.

Not Applicable. Although the Project is located in a
rural setting, it would not adversely affect forestland.

Additionally, the Project would not include areas
suitable for reforestation. The Project would replant
most native trees removed during construction.

Water. Continue efficiency programs and use cleaner
energy sources to move and treat water.

Not Applicable. The Project would not include an
increase in water consumption or energy use
associated with water treatment or transport.

Agriculture. In the near‐term, encourage investment in
manure digesters and at the five‐ year Scoping Plan
update determine if the program should be made
mandatory by 2020.

Not applicable. The Project does not include
agricultural production.

Source of Scoping Plan Reduction Measures: CARB 2022
Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-45

3.9 Hazards and Hazardous Materials
Potentially
Significant
Impact
Less than
Significant w/
Mitigation
Incorporated
Less than
Significant
Impact
No
Impact
Would the project:
a) Create a significant hazard to the public or the
environment through the routine transport, use, or
disposal of hazardous materials?

b) Create a significant hazard to the public or the
environment through reasonably foreseeable upset
and accident conditions involving the release of
hazardous materials into the environment?

Emit hazardous emissions or handle hazardous or
acutely hazardous materials, substances, or waste
within one-quarter mile of an existing or proposed
school?

Be located on a site which is included on a list of
hazardous materials sites compiled pursuant to
Government Code Section 65962.5 and, as a result,
would it create a significant hazard to the public or the environment?

For a project located within an airport land use plan or, where such a plan has not been adopted, within two
miles of a public airport or public use airport, would the project result in a safety hazard or excessive noise for people residing or working in the project area?

Impair implementation of or physically interfere with an adopted emergency response plan or emergency
evacuation plan?

Expose people or structures, either directly or
indirectly, to a significant risk of loss, injury or death involving wildland fires?

To evaluate the Project Area with respect to the presence and location of existing and/or historical soil and groundwater contamination, GHD completed an initial site assessment (ISA) and regulatory database review of available online government records (GHD 2023). The ISA was completed to identify areas of potentially impacted soil and/or groundwater within and near the Project Area that could potentially pose an exposure risk to humans and/or the environment during construction of the Project. a) Create a significant hazard to the public or the environment through the routine transport, use, or disposal of hazardous materials? (Less Than Significant Impact) Construction of the Project would include the transport and use of common hazardous materials inherent to the construction process, including petroleum products such as fuel and lubricants for construction equipment and vehicles, paints, concrete curing compounds, and solvents for construction of Project improvements. These materials are commonly used during construction, are not acutely hazardous, and would be used in relatively small quantities.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-46 Hazardous materials storage, handling, and transportation must comply with an interconnected matrix of local, state, and federal laws. Hazardous materials used during construction of the Project would be subject to applicable regulations, including California Health and Safety Code Section 25531, Division 20, Chapter

6.5, and other standards enforced by the various departments and boards under the California Environmental Protection Agency (Cal/EPA). The Project would be subject to Cal/EPA hazardous materials regulations consolidated under the State’s Unified Program enforced by the Department of Toxic Substances Control (DTSC), the State Water Resources Control Board (SWRCB), NCRWQCB, NCUAQMD, and the Department of Resources Recycling and Recovery (CalRecycle). The Cal/EPA administers the Unified Program via local Certified Unified Program Agencies (CUPAs). The CUPA for Humboldt County is the Humboldt County Division of Environmental Health (HCDEH). The HCDEH Hazardous Materials Unit has jurisdiction over the Project Area and is tasked with local CUPA inspections and compliance. Project activities involving the transport, use, storage, and disposal of hazardous materials would be in accordance with established rules and regulations.

Project construction specifications would require the management of hazardous materials to comply with applicable laws, rules, and regulations. During Project construction, the contractor would be required to contain hazardous materials and avoid exposure to workers, the public, and surrounding environment during construction. An appropriate facility would be utilized for the legal disposal of any hazardous materials generated.

The Project would be required to implement stormwater management requirements during construction in accordance with the SWRCB General Construction Storm Water Permit (Section 1.9). Stormwater management requirements for addressing materials management would be required, including proper material delivery and storage, spill prevention and control, and management of concrete and other wastes, as described in Section 3.10 (Hydrology and Water Quality).

The established regulatory framework, BMPs, and requisite construction protocols provide appropriate risk mitigation and hazard protections; thus, the Project would not create a significant hazard to the public or environment from hazardous materials. Because the City and its contractors would be required to comply with existing and future hazardous materials laws and regulations addressing the transport, storage, use, and disposal of hazardous materials, the potential to create a significant hazard to the public or the environment during Project construction would be less than significant.

Following construction, operation of the Project would require intermittent maintenance and repair, which could involve hazardous materials. The operational risk posed by intermittent maintenance and repair of the road specific to hazardous materials is low. The potential to create a significant hazard to the public or the environment during Project operation would be less than significant. b) Create a significant hazard to the public or the environment through reasonably foreseeable upset and accident conditions involving the release of hazardous materials into the environment? (Less Than Significant Impact)
The Project would utilize heavy machinery to perform some construction-related tasks including grading, drilling, excavation, and transportation of materials. There is always the possibility when equipment is operating that an accident could occur, and fuel could be released onto the soil. Equipment on-site during construction would be required to have emergency spill cleanup kits immediately accessible in the case of any fuel or oil spills. Equipment would not be refueled near the Strongs Creek, Rohner Creek, or any perennial wetland. If equipment must be washed, it would be washed off-site.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-47 During Project operation, no hazardous materials would be stored on-site. The risk of hazardous materials being released into the environment would be consistent with current use. The potential impact would be less than significant.
c) Emit hazardous emissions or handle hazardous or acutely hazardous materials, substances, or waste within one-quarter mile of an existing or proposed school? (Less Than Significant Impact)
The Great Beginning Preschool is located approximately 0.22 miles east, and the Fortuna High School is approximately 0.25 miles north of the Project. Construction activities are assumed to include the use of hazardous materials such as fuels, lubricants, degreasers, paints, and solvents. These materials are commonly used during construction, are not acutely hazardous, and would be used in small quantities.

Numerous laws and regulations ensure the safe transportation, use, storage, and disposal of hazardous materials (see Impact discussion in Section 3.9 (a) and (b) above). Although construction activities could result in the inadvertent release of small quantities of hazardous substances, a spill or release at a construction area is not expected to endanger individuals at nearby schools given the nature of the materials, the small quantities that would be used, and the distance of the schools from the Project Area.

Therefore, because the City and its contractors would be required to comply with existing and future hazardous materials laws and regulations covering the transport, use, and disposal of hazardous materials, and because of the nature and quantity of the hazardous materials to be potentially used by the Project, the impact related to the use of hazardous materials during construction adjacent to the schools would be less than significant. Project operations would have a less than significant impact on Great Beginning Preschool, Fortuna High School, or any other school.
d) Be located on a site which is included on a list of hazardous materials sites compiled pursuant to Government Code § 65962.5 and, as a result, would it create a significant hazard to the public or the environment? (Less than Significant with Mitigation) The Project Area includes two closed cleanup sites, as mapped in the GeoTracker database, which are associated with the former Palco Lumber Mill: Leaking Underground Storage Tank (LUST) T0602300147 and cleanup site T0602391193 (SWRCB 2024). These sites were closed in 1993 and 2020, respectively.

There are an additional 76 other closed cleanup sites located within one mile of the Project Area, as well as two open sites. The open sites are the LUST Fortuna Veterans Memorial Building (T10000009538) located approximately 0.6-mile north, and the cleanup site Unocal Bulk Plant (T0602393213) located approximately

0.7-mile northwest. Off-site construction activities are not planned, and impacts related to these two off-site open cleanup sites would not occur. The Project Area is also not located on a site listed in the DTSC EnviroStor database; however, it is located within one mile of World Oil Environmental Services (CAL930256136) (DTSC 2024). Hazards related to the sites identified within the GeoTracker and EnviroStor databases, as well as nearby properties not included in database listings, have been addressed within the ISA, and are discussed below (GHD 2023).

The ISA identified no Recognized Environmental Conditions (RECs) within the Project Area. A REC is defined in the American Society for Testing and Materials (ASTM) Standard as:

1. The presence of hazardous substances or petroleum products in, on, or at the subject property due to a release to the environment; or

2. The likely presence of hazardous substances or petroleum products in, on, or at the subject property due to a release or likely release to the environment; or Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-48

3. The presence of hazardous substances or petroleum products in, on, or at the subject property under conditions that pose a material threat of a future release to the environment.

However, the ISA identified Sites of Interest (SOI’s) within one-quarter mile from the Project Area that could potentially impact the Project due to existing hazards. The ISA identified six SOI’s within the one-quarter mile which are summarized in Table 3.9-1 below.

Contaminates of concern (COC) include total petroleum hydrocarbons (TPH) including gasoline (TPHg), diesel (TPHd), motor oil (TPHmo), volatile organic compounds (VOC), semi-volatile organic compounds (SVOC), Aerially Deposited Lead (ADL), polycyclic aromatic hydrocarbons (PAH), dioxins and furans, and metals.

At the City of Fortuna Corporation Yard site, historical documentation shows that there was contamination of the surrounding soil that was caused from an underground storage tank. The tank was removed, and subsequent investigations were below regulatory thresholds for contamination (GHD 2023). No work would occur on Dinsmore Drive adjacent to this site. At the Oil Well Lube Center, Busted Knuckle, The Dipstick, Adams Oil and Repair site, historical documentation shows that there was contamination of the surrounding soil that was caused from an underground storage tank. The tank was removed, and subsequent investigations were mostly non-detect for contamination (GHD 2023). Thus, the potential impact associated with hazardous materials at the two sites above would not be potentially significant.

At the former Palco Lumber Mill site, there is known contamination due to leaking underground storage tanks, however the tanks have been removed. Additionally, contamination impacts to the site occur from historical lumber operations and has land use restrictions regarding future use of the site. This site is listed as being topographically higher than the Project Area and historical groundwater monitoring reports indicate that groundwater direction can flow west from the site, toward the Project Area (GHD 2023).

The U.S. Hwy 101 Corridor immediately adjacent to the Project Area was constructed since approximately 1968 (GHD 2023). Leaded fuels were beginning to be phased out in the 1970s, however, they were not completely banned until 1996 under the Clean Air Act. This means that the current configuration of U.S. 101 adjacent to the Project Area has potentially been exposed to ADL from the use of leaded fuels (GHD 2023).

The NWPRR Corridor is no longer operational through this area; however, there may be contamination of the soil due to potential impacts from contaminants typically associated with railroads and associated debris (GHD 2023).

For these reasons, these SOI’s warrant subsequent pre-construction soil and groundwater sampling near the identified site. Thus, the potential impact associated with hazardous materials sites would be potentially significant.

Table 3.9-1 Potentially Significant Sites of Interest
Site Name Contaminant of Concern
Former Palco Lumber Mill TPH, dioxins and furans, TPHg, TPHmo, and waste oil
U.S. Hwy 101 Corridor immediately adjacent to the Project Area
TPH and metals
NWPRR Corridor TPH, metals including ADL, SVOCs and PAHs Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-49 Mitigation
Implementation of Mitigation Measure HAZ-1 would reduce the impact of construction activities to ensure currently present hazardous materials do not inadvertently impact the public or environment.

Mitigation Measure HAZ-1: Inadvertent Discovery of Hazardous Soils A Preliminary Site Investigation (PSI) will be required prior to the start of construction activities within the following portions of the Project Area:
- Areas of excavation adjacent to the U.S. 101 on- and off-ramps will be characterized for Total Petroleum Hydrocarbons (TPH) and California Administrative Manual (CAM) 17 metals (including Aerially Deposited Lead [ADL]).
- Areas of excavation adjacent to or overlapping the railroad corridor will be characterized for TPH, CAM 17 metals, semi-volatile organic compounds (SVOCs), and polycyclic aromatic hydrocarbons (PAH).
- Areas of excavation adjacent to or overlapping the former Palco Lumber Mill will be characterized for TPH and dioxins and furans.

If construction activities are predicted to encounter groundwater, groundwater will also be characterized as part of the PSI.

If contaminants are identified in the PSI, a Construction Soil and Groundwater Management Plan (SGMP) will be developed prior to the start of construction to identify protocols to proactively manage potentially impacted soil and groundwater within the Project Area and reduce exposure to site workers.

The Construction SGMP will specifically cover applicable soil reuse strategies, potentially unknown hazards related to nearby historical sites, hazards associated with the nearby, open LUST cases, and potential biohazards from illegal camping and garbage dumping. All workers will be trained according to the safe handling instructions included in the Construction SGMP and a copy of the Construction SGMP will be kept on-site at all times during construction.

If final design and construction activities include demolition of concrete infrastructure (bridges, overcrossings, box culverts, etc.), a hazardous materials assessment may be warranted to maintain compliance with National Emission Standard for Hazardous Air Pollutant (NESHAP) as included under 40 CFR Part 61 and/or 40 CFR Part 63.

If construction activities include dewatering, and if laboratory analysis of pre-construction soil borings indicate elevated Total Threshold Limit Concentration (TTLC) of 1,000 ppm and 5 mg/L, respectively, Solubility Threshold Limit Concentration (STLC) characterization will occur. Additional pre-construction soil and groundwater characterization will occur as required by regulatory thresholds.

If pre-construction characterization indicates contaminants of concern impacts above STLC levels to soil and/or groundwater, it is required that site workers involved in excavation activities be Hazardous Waste Operations and Emergency Response (HAZWOPER) trained (Occupational Safety and Health Administration (OSHA) 1910.120).

With implementation of Mitigation Measure HAZ-1, any potential impact due to hazardous soils during both construction and operation would be less than significant.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-50 e) For a Project located within an airport land use plan or, where such a plan has not been adopted, within two miles of a public airport or public use airport, would the Project result in a safety hazard or excessive noise for people residing or working in the Project Area? (No Impact)
The nearest airport is the Rohnerville Airport (KFOT), which is located approximately 2.1 miles southeast from the Project Area. The KFOT is covered by the 2021 Airport Land Use Compatibility Plan (ALUCP) prepared for the Humboldt County Airport Land Use Commission (ALUC) by ESA. Per the ALUCP, the Project Area is located within Review Area 2 of the Airport Influence Areas, which consists of areas within the combined airspace surfaces and overflight notification area (ESA 2021). However, no aspect of the Project would result in an airport-related safety hazard for people residing or working in the Project Area.

Therefore, no impact would occur.
f) Impair implementation of or physically interfere with an adopted emergency response plan or emergency evacuation plan? (No Impact)
The City does not have an independent emergency response plan. However, the City does have hazardous material response plans associated with the regulatory requirements for their wastewater treatment, water treatment plant facilities and operations, and an emergency response plan that establishes chain-ofcommand and response procedures between the emergency services, public works, City staff and board, and other essential departments and outside organizations. The Project does not conflict with these plans.

Additionally, the Project would not increase public use, significantly increase risk of hazard occurrence, or construct facilities that may pose a hazard to people or the environment. No impact would occur. g) Expose people or structures, either directly or indirectly, to a significant risk of loss, injury or death involving wildland fires? (Less Than Significant Impact) Wildland fire is addressed in Section 3.20 (Wildfire). As noted in Section 3.20, the Project would not expose people or structures to a significant risk from wildland fires, thus a less than significant impact would occur.

Please see Section 3.20 for further discussion of the Project as it relates to wildland fire risks.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-51

3.10 Hydrology and Water Quality
Potentially
Significant
Impact
Less than
Significant w/
Mitigation
Incorporated
Less than
Significant
Impact
No
Impact
Would the project:
a) Violate any water quality standards or waste
discharge requirements or otherwise substantially
degrade surface or ground water quality?

b) Substantially decrease groundwater supplies or
interfere substantially with groundwater recharge
such that the project may impede sustainable
groundwater management of the basin?

c) Substantially alter the existing drainage pattern of the site or area, including through the alteration of
the course of a stream or river or through the
addition of impervious surfaces, in a manner which
would:
i. Result in substantial erosion or siltation on- or
off-site? 
ii. Substantially increase the rate or amount of
surface runoff in a manner which would result in
flooding on- or off-site?

iii. Create or contribute runoff water which would
exceed the capacity of existing or planned
stormwater drainage systems or provide
substantial additional sources of polluted runoff?

iv. Impede or redirect flood flows? 
d) In flood hazard, tsunami, or seiche zones, risk
release of pollutants due to project inundation? 
e) Conflict with or obstruct implementation of a water
quality control plan or sustainable groundwater
management plan?

The Project is located in the Lower Eel River watershed. The Project Area is between the perennial Strong’s Creek to the south, and the perennial Rohner Creek to the north. Both creeks are excluded from the Project Area (Appendix E).
a) Violate any water quality standards or waste discharge requirements or otherwise substantially degrade surface or ground water quality? (Less than Significant with Mitigation)
Construction activities such as site clearing, grading, excavation, material stockpiling, placement of aggregate base, and related construction activities, could leave soils exposed to rain or surface water runoff that may carry soil contaminants (e.g., nutrients or other pollutants) into waterways adjacent to the site, degrade water quality, and potentially violate water quality standards for specific chemicals, dissolved oxygen, suspended sediment, or nutrients to surface waters. The greatest potential Project impacts to water Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-52 quality would result from sediment mobilization during construction. This impact is considered to be potentially significant without mitigation.

The proposed Project is anticipated to disturb over one (1) acre of land, therefore compliance with State Water Board Order No. 2009-0009 would be required which would regulate stormwater runoff from Project construction activities. Project operations would obtain coverage under SWRCB Order No. 2009-0009- DWQ, Waste Discharge Requirements for Discharges of Storm Water Runoff Associated with Construction and Land Disturbance Activities, as amended by Order No. 2012-0006. In compliance with the National Pollutant Discharge Elimination System requirements, a Notice of Intent would be prepared and submitted to the NCRWB prior to undertaking construction, providing notification and intent to comply with the State of California Construction General Permit (CGP). In addition, a SWPPP would be prepared for pollution prevention and control prior to initiating site construction activities as explained in Section 1.12.

The Construction SWPPP would be written by a Qualified SWPPP Developer. The SWPPP would identify and specify the use of BMPs erosion control, sediment control, off-site tracking control, wind erosion control, non-stormwater management control, and waste management and materials pollution control. A sampling and monitoring program would be included in the Construction SWPPP that meets the requirements of the CGP to ensure the BMPs are effective. A Qualified SWPPP Practitioner would oversee implementation of the Plan, including visual inspections, sampling and analysis, and overall compliance with the SWPPP and CGP.

Implementation of a SWPPP combined with Mitigation Measures BIO-3 would reduce potential water quality impacts during Project construction activities to a less than significant level by requiring measures to minimize erosion, sediment, and pollutant contribution to surface waters.

Following construction, operation and maintenance of the Project would not result in a new point discharge or a substantial increase in impervious surfaces relative to the surrounding area. Section 1.12 outlines existing regulations that the Project would implement, including MS4 requirements. Due to the MS4 requirements contained in the LID Standards Manual for stormwater treatment, the water discharging from the Project Area to adjacent creeks is anticipated to be of a higher quality compared to current discharges under existing conditions. Therefore, less than significant operational impact would occur. b) Substantially decrease groundwater supplies or interfere substantially with groundwater recharge such that the Project may impede sustainable groundwater management of the basin? (No Impact)
The Project is located in the Eel River Valley Groundwater Basin 1-010, which has a SGMA Basin Priority of Medium and is not listed as Critically Overdrafted (DWR 2004). Contractor-supplied water would be used during construction for dust suppression on local roadways and work areas. Use of groundwater is not necessary for construction of the Project. Similarly, the Project would not decrease groundwater supplies or interfere with groundwater management. During roadway construction, isolated and short duration groundwater dewatering may occur as needed and would be small in scale and limited to shallow groundwater only. The construction-related impact on groundwater levels would not result.

Following construction, the Project would not utilize groundwater and would not result in an increase in population or employment that would indirectly increase groundwater demand. The Project would not alter groundwater recharge. Therefore, the Project would not create a deficit in aquifer volume or a lowering of water levels. Additionally, the amount of impervious surface created by the Project is minimal since the current road is paved, and the Project road would be generally consistent with the previous conditions in the Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-53 area. The Project is not expected to result in any change in the use or recharge of groundwater. No construction or operational impact to groundwater resources would occur. c, i) Substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river or through the addition of impervious surfaces, in a manner which would result in substantial erosion or siltation on- or off-site? (Less Than Significant Impact)
The Project would add approximately 3.41 acres of impervious surfaces to the Project Area through the road realignment and paving and roundabout installation. Existing roadway drainage patterns would be maintained to the maximum extent practicable. Excavation depths to install drainage facilities may vary but would typically be limited to six feet below existing grade. The Project design will include post construction stormwater facilities to the degree required by the City’s MS4 permit and Caltrans operational stormwater requirements. No in-water work would occur and the two creeks near the Project Area (Rohner Creek and Strongs Creek) would not be modified in any way.

Erosion and sediment prevention defined within Mitigation Measures BIO-3 would be implemented during construction to avoid impacts to water quality, including those related to siltation (see impact “a”, above).

The Project would be required to adhere to measures and conditions to be included in a SWPPP to prevent erosion-related impacts during construction. Substantial on- or off-site erosion and siltation would not result, and the potential construction-related impact regarding erosion and siltation would be less than significant.

Therefore, the impact would also be less than significant. c, ii) Substantially increase the rate or amount of surface runoff in a manner which would result in flooding on- or off-site? (No Impact)
The Project would have a net increase of approximately 3.41 acres impervious surface. However, beneficial environmental impacts of the Project include neutral or better effect on existing local drainage, flooding, and implementation of LID stormwater design to contemporary standards to, or near, the Eel River, Rohner Creek, Strongs Creek, or any other tributary. The Project would not alter topography or drainage patterns in a manner that would increase on- or off-site flooding. Aside from the increase impervious surface area, the Project does not include elements that would increase stormwater drainage or necessitate significant design features to accommodate stormwater management. Per MS4 requirements, stormwater would be directed to new vegetated bioretention medians incorporated into the Project design and into existing ruderal open spaces bordering the roadway to support stormwater infiltration. This bioretention would be designed to ensure no increased stormwater runoff during 2-year storm events. Additionally, as explained in Section 1.12, the Project would develop a SWPPP to be approved by the NCRWQCB, and the Project would be designed to meet NCRWQCB storm water requirements. The Project would not cause on- or offsite flooding. The impact would be less than significant. c, iii) Create or contribute runoff water which would exceed the capacity of existing or planned stormwater drainage systems or provide substantial additional sources of polluted runoff? (Less Than Significant)
The Project would include new drainage facilities, including gutters, inlets, pipes, rock energy dissipaters, and bioretention features. This includes replacing and upgrading an existing 48-inch stormwater drainage pipe that has been identified as undersized within the City of Fortuna Storm Drain Master Plan (Fortuna Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-54 2005). Existing watershed drainage patterns would be maintained to the maximum extent practicable. The Project includes impervious surface elements that would increase stormwater drainage; however, design requirements required within the MS4 permit, particularly the bioretention features, would not significantly increase off-site drainage. The Project would require relocations of existing 48 inch reinforced concrete pipe with a 48 inch high-density polyethylene that would increase service life of the drainage system.

Additionally, as detailed in Section 1.12, the Project would develop a SWPPP to be approved by the NCRWQCB, and the Project would be designed to meet NCRWQCB storm water requirements. No in-water work would occur. The Project would not cause on- or off-site flooding. The impact would be less than significant.
c, iv) Impede or redirect flood flows? (Less Than Significant) Approximately half of the Project Area is located within the Eel River’s FEMA 100-year flood zone (Appendix E). However, the Project design does not include any features that would impede or redirect flood flows. Existing topography would not be significantly altered in such a manner as to redirect flood flows. Any potential impact on the impediment or redirection of flood flows would be less than significant. d) In flood hazard, tsunami, or seiche zones, risk release of pollutants due to Project inundation? (Less Than Significant)
Approximately half the Project Area is located within the Eel River’s FEMA 100-year flood zone (Appendix E). The Project does not include unsecured elements that could be washed away during a flood. Any potential construction-related impact would be less than significant.

The Project Area is not located near a larger isolated body of water that may be affected by a seiche. The Project Area is not located within a tsunami hazard zone (Humboldt County 2024). No impact from a seiche or tsunami would occur.

Operational maintenance of the road may involve occasional repair, trash/debris removal, and vegetation maintenance (e.g., mowing), which could involve hazardous materials (e.g., small equipment fuel).

However, these materials would not be stored within the Project Area and thus would not be released into the environment in the event of a flood event. Any potential operational related impact would be less than significant.
e) Conflict with or obstruct implementation of a water quality control plan or sustainable groundwater management plan? (No Impact)
The relevant water quality control plan is the NCRWQCB’s Basin Plan which establishes thresholds for key water resource protection objectives for both surface waters and groundwater. The Project is consistent with the Basin Plan because it does not directly involve the surface waters of Strongs Creek or Rohner Creek and also excludes impacts to wetlands. Conversely, the Project includes stormwater drainage retention features that would increase water quality to the creeks compared to existing conditions. The Project does not involve the use of groundwater resources and would not impact the quantity or quality of groundwater availability in the Eel River Valley Groundwater Basin.

The Project would be required to obtain coverage under SWRCB’s CGP, which would include development and implementation of a SWPPP. Adherence to these regulatory requirements and associated requisite monitoring would ensure a conflict with the Basin Plan does not occur.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-55 The Project would meet and/or support the following City of Fortuna General Plan goals and policies that regulate water resources during construction and operation of the Project: Watershed Protection (Policy NCR-1.1), Stormwater Runoff (Policy NCR-1.5), Polluted Runoff (Policy NCR-1.6), and Clean Water Act Requirements (Policy NCR-1.8). No impact would occur.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-56

3.11 Land Use and Planning
Potentially
Significant
Impact
Less than
Significant w/
Mitigation
Incorporated
Less than
Significant
Impact
No
Impact
Would the project:
a) Physically divide an established community? 
b) Cause a significant environmental impact due to a
conflict with any land use plan, policy, or regulation
adopted for the purpose of avoiding or mitigating
an environmental effect?

This section evaluates the potential impacts related to land use, as it applies to construction and operation of the Project. The Project is entirely within the limits of the City of Fortuna. a) Physically divide an established community? (No Impact) The proposed Project would not divide an existing neighborhood or community. Rather, the Project would enhance community connectivity by better-reconnecting the City’s downtown neighborhoods to the Riverwalk area (that was severed by Highway 101 in the 1950’s) by establishing and promoting bicycle and pedestrian use and providing enhanced safety for all modes of transportation. Temporary detours would be required throughout construction. Temporary detours would follow City and Caltrans requirements for temporary roadway closures, including signage and public noticing. Construction would be phased in order to maintain local access to U.S. 101. No impact would occur. b) Cause a significant environmental impact due to a conflict with any land use plan, policy, or regulation adopted for the purpose of avoiding or mitigating an environmental effect? (No Impact)
The Project Area is located entirely within the city limits of Fortuna, and no portions are located in the Coastal Zone. Therefore, the only applicable land use plans covering the Project is the City of Fortuna General Plan.

The southeast of the Project Area is zoned Commercial Thoroughfare (CT) and Heavy Industrial (M-2) with a land use of Industrial (IND) and Mill District (MD) as sourced from the Fortuna General Plan. The northern portion of the Project Area includes areas zoned as Agriculture Exclusive (A-E) with a land use of Agriculture (AG) along the existing railroad corridor in order to support connections to and from the future GRT.

The Project is consistent with the City of Fortuna municipal code Title 17 regulating land use and zoning designations. Therefore, the proposed Project would not conflict with any land use plan, policy, or regulation. No impact would occur.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-57

3.12 Mineral Resources
Potentially
Significant
Impact
Less than
Significant w/
Mitigation
Incorporated
Less than
Significant
Impact
No
Impact
Would the project:
a) Result in the loss of availability of a known mineral resource that would be of value to the region and
the residents of the state?

b) Result in the loss of availability of a locallyimportant mineral resource recovery site delineated on a local general plan, specific plan or other land
use plan?

This section evaluates the potential impacts related to mineral resources associated with the Project. a, b) Result in the loss of availability of a known mineral resource that would be of value to the region and the residents of the state, or a locally-important mineral resource recovery site delineated on a local general plan, specific plan or other land use plan? (Less than Significant)
The Project would require minor use of rock, gravel, sand, and other similar materials for construction, but is not expected to have any significant impact on locally available minerals or mineral resources valuable to the region or the state. Additionally, the Project Area is also not designated by the City of Fortuna General Plan, or other local land use plan as having locally-important mineral resources within the Project Area (Fortuna 2010). The impact would be less than significant.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-58

3.13 Noise
Potentially
Significant
Impact
Less than
Significant w/
Mitigation
Incorporated
Less than
Significant
Impact
No
Impact
Would the project:
a) Result in generation of a substantial temporary or
permanent increase in ambient noise levels in the
vicinity of the project in excess of standards
established in the local general plan or noise
ordinance, or applicable standards of other
agencies?

b) Result in generation of excessive groundborne
vibration or noise levels? 
c) For a project located within the vicinity of a private airstrip or an airport land use plan or, where such a
plan has not been adopted, within two miles of a
public airport or public use airport, would the
project expose people residing or working in the
project area to excessive noise levels?

Current noise conditions on the Project Area consist of road noise associated with vehicles on U.S. 101, 12th Street, Riverwalk Drive, Pond Street, and Newburg Road. There are 20 residential sensitive receptors located directly adjacent (within 50 feet) to the Project Area along Newburg Road and 12th Street. Additional sensitive receptors are the Great Beginning Preschool located approximately 0.22 mile east, and the Fortuna High School approximately 0.25 mile north.

Applicable policies from the City of Fortuna General Plan are summarized below.

Policy HS-4.7: Noise Barriers
The City shall consider the use of noise barriers (as a means of achieving the noise standards) only if all other practical design‐related noise mitigation measures have been insufficient.

Policy HS-4.8: Noise Reduction/Design
The City shall lessen noise increases along the City’s arterial and collector roads through project design of streets (including providing buffers to the extent feasible and screening), coordination of routing, and other traffic control measures.

Policy HS-6: Hours of Construction
The City shall limit the hours and days of major construction activities throughout the City to the hours between 7:00 a.m. to 8:00 p.m., Monday through Saturday, except for emergencies and other special permitted circumstances.

Policy HS-7: Noise Compatibility Standards by Land Use Type The City shall adopt the noise compatibility standards by land use type identified in Tables 3.13‐1 and 3.13‐

2. Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-59 Table 3.13-1 City of Fortuna General Plan Construction Noise Compatibility Standards.

Zoning District Maximum Noise Level (dBA Lmax)
1 Daytime Exterior
(7:00 a.m. to 8:00 p.m.)
Nighttime Exterior
(8:00 p.m. to 7:00 a.m.)
Residential 65 60
Hotels, motels, transient lodging 70 60
Schools, libraries, churches,
hospitals, nursing homes
75 65
Commercial, office buildings 80 70
Industrial, manufacturing, agriculture 85 75
Source: Fortuna 2010
Table 3.13-2 City of Fortuna General Plan Traffic and Stationary Source Noise Compatibility Standards.

Zoning District Maximum Noise Level (dBA Lmax)
Daytime Exterior
(7:00 a.m. to 8:00 p.m.)
Nighttime Exterior
(8:00 p.m. to 7:00 a.m.)
Residential 45 60
Hotels, motels, transient lodging 45 60
Schools, libraries, churches,
hospitals, nursing homes
45 60
Commercial, office buildings 50 70
Industrial, manufacturing, agriculture 60 75
Source: Fortuna 2010
a) Result in generation of a substantial temporary or permanent increase in ambient noise levels in the vicinity of the Project in excess of standards established in the local general plan or noise ordinance, or applicable standards of other agencies? (Less than Significant with Mitigation)
Construction
Construction of the Project would result in a temporary noise increase associated with the use of construction equipment. Construction is expected to require approximately 18 months to two years to complete. Construction activities would be limited to daytime work hours between 7:00 a.m. to 7:00 p.m., Monday through Friday with occasional work that may occur on Saturdays. Construction noise levels would vary based on the type of equipment as summarized in Table 3.13-3 below. 1 “dB” decibel is a unit used to measure the intensity of a sound. “dBA” is a weighted decibel measurement of the relative loudness of sounds as perceived by the human ear and is the standard for determining hearing damage and noise pollution.
“dBA Lmax” is the highest sound level measured during a single noise event in which the sound level changes value as time goes on.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-60 Table 3.13-3 Construction Equipment Reference Noise Levels as Measured at 50 Feet.

Equipment Noise Level (dB) Equipment Noise Level (dB)
Drill rig truck 84 Jackhammer 85
Horizontal Boring Hydraulic Jack 80 Large Generator 82
Front end loader or Backhoe 80 Paver or Roller 85
Excavator 85 Dump truck 84
Source: Federal Highway Administration, 2006
Sound from a point source is known to attenuate at a rate of -6 dB for each doubling of the distance to the receptor. For example, a noise Equivalent Continuous Level (Leq) of 84 dB as measured at 50 feet from the noise source would attenuate to 78 dB Leq at 100 feet from the source and to 72 dB Leq at 200 feet from the source to the receptor. Based on the reference noise levels in Table 3.13-1, the noise levels generated by construction equipment at the Project site may reach a maximum of approximately 85 dB Leq at 50 feet during site excavation and construction.

City Policy HS-6 limits the hours of construction between 7:00 a.m. and 8:00 p.m., Monday through Saturday. Planned construction hours are consistent with the City of Fortuna Policy HS‐6. City Policy HS-7 establishes construction noise standards that vary by land use (Table 3.13-1). Construction noise standards have been applied to the four sensitive receptors in proximity to the Project (Table 3.13-4) to evaluate consistency with City Policy HS-7.

Table 3.13-4 Estimated Construction Noise Levels at Sensitive Receptors.

Sensitive Receptor Proximity to Construction Estimated Max.

Noise Level (dB)
Consistent with City
General Plan Policy HS7?
Great Beginning Preschool 0.22 east of east of the
eastern leg of Newburg Road
58 dB Yes
Fortuna High School 0.25 mile north of the northern
leg of 12th Street
57 dB Yes
20 Residences on Newburg
Road and 12th Street
Adjacent to construction
(within 50 feet)
85 dB No (above the 65 dBA Lmax
limit)
Great Beginning Preschool and Fortuna High School would attenuate to approximately 57-58 dB, lower than the dBA Lmax of 75 dB for school zones and thus consistent with the City’s Policy HS-7. The 20 residences along Newburg Road and 12th Street are immediately adjacent to the Project Area; therefore, reference noises from Table 3.13-1 are not diminished by distance. Though construction near the residences would be short-term in duration and with BMP construction techniques, these impacts are potentially significant to the residents during periods when construction is occurring near the property. To reduce this potential impact to a less than significant level, Mitigation Measure NOI-1 has been incorporated into the Project.

Mitigation
Implementation of Mitigation Measure NOI-1 would reduce the impact of construction activities to ensure noise does not inadvertently impact the public or the environment.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-61 Mitigation Measure NOI-1: Reduce Construction Noise Levels The City and its contractor shall implement measures to reduce construction noise levels emanating from construction activities and minimize disruption and annoyance to adjacent residences. Specific measures that can be feasibly implemented include, but are not limited to, the following:
- Construction will only occur between 7:00 a.m. and 8:00 p.m. Monday through Saturday. - Provide advance notice to nearby residents within 250 feet prior to starting work, with information regarding anticipated schedule, hours of operation and a Project contact person. - Best available noise control practices (including mufflers, intake silencers, ducts, engine enclosures, and acoustically attenuating shields or shrouds) will be used for equipment and trucks to minimize construction noise impacts.
- Stationary noise sources shall be located as far from sensitive noise receptors as feasible. If they must be located near receptors, adequate muffling (with enclosures where feasible and appropriate) shall be used. Enclosure openings or venting shall face away from sensitive noise receptors.

With implementation of Mitigation Measure NOI-1, construction noise levels would be reduced to a less than significant level.

Operation
Operationally, the Project would have similar vehicle noise to current conditions and would not include any new stationary noise sources.

City Policy HS-4.8 requires strategies to lessen noise along arterial and collector roads through Project design elements, such as buffers. The Project’s design does include an enhanced sidewalk between 12th Street, Newburg Road, and Riverwalk Drive. The proposed roundabout would decrease operational noise by reducing the amount of acceleration and braking associated with stopping, turning, and reaccelerating at the current intersections. The realignment of Newburg Road would eliminate cross traffic, further reducing traffic noise to adjacent residences. The Project would also eliminate several existing turning movements that have turn angles greater than 90 degrees, which currently generates noise (squealing tires).

Additionally, operational noise throughout the Project Area is expected to decrease due to a quieter, smoother roadway surface that is in better condition. Therefore, the Project is consistent with City Policy HS-4.8.

City Policy HS-7 establishes operational noise standards that vary by land use (Table 3.13-2). The Project would reduce operational noise as a result of a quieter, smoother roadway, and reduced breaking / acceleration. Therefore, there Project is consistent with City Policy HS-7.

City Policy HS-4.7 allows the use of noise barriers only if all other practical design-related noise mitigation measure have been insufficient. The Project does not result in an operational noise impact. Therefore, a noise barrier is not required.

Given the Project is consistent with the City’s operational noise-related general plan policies and would not increase operational noise in the vicinity of sensitive receptors, any potential impact would be less than significant.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-62 b) Result in generation of excessive groundborne vibration or noise levels? (Less Than Significant Impact)
The City has not established vibration limits to minimize the potential for cosmetic damage to buildings.

However, Caltrans recommends a vibration limit of 0.5 inches/second peak particle velocity (PPV) for buildings structurally sound and designed to modern engineering standards, 0.3 inches/second PPV for buildings that are found to be structurally sound but where structural damage is a major concern, and a conservative limit of 0.08 inches/second PPV for ancient buildings or buildings that are documented to be structurally weakened. No known buildings that are documented to be structurally weakened or historic adjoin the Project Area. Therefore, the 0.5 inches/second PPV limit would apply when considering the potential for groundborne vibration levels to result in a significant vibration impact.

The noise and vibration evaluation assessed typical vibration levels that could be expected from construction equipment at a distance of 25 feet, inclusive of required equipment and methods for all four potential construction options. Project construction activities, such as drilling, the use of jackhammers, and other high-power or vibratory tools, and rolling stock equipment (tracked vehicles, compactors, etc.) may generate substantial vibration in the immediate vicinity.

Table 3.13-5 presents typical vibration levels that could be expected from construction equipment at a distance of 25 feet (Caltrans 2023). Vibration levels are highest close to the source and attenuate with increasing distance. Vibration levels would vary depending on soil conditions, construction methods, and equipment used.

Table 3.13-5 Typical Vibration Levels for Construction Equipment Used During Project Construction.

Equipment Reference PPV at 25 ft. (in/sec)
Crack-and-seat operations (specific pavement rehabilitation process) 2.4 Vibratory Roller 0.210
Large Bulldozer 0.089
Caisson drilling 0.089
Loaded trucks 0.076
Jackhammer 0.035
Small bulldozer 0.003
Source: Caltrans 2023
Project-related activities would not involve the use of explosives or other intensive construction techniques that could generate significant ground borne vibration or noise. The Project may utilize a vibratory roller, large bulldozer, and jackhammer.

The proposed Project would comply with Fortuna General Plan Policy HS-6 and Humboldt County general plan policy N-IM6, which requires limiting construction activity to specified daytime hours and regulate vibration sources.

Nearby residences are located within 50 feet of the Project Area. Vibration impacts to are anticipated to be a maximum of 0.2 inches/second PPV, below the Caltrans vibration limit of 0.5 inches/second PPV. Minor vibration adjacent to mechanized equipment and road treatments during construction work would also be generated only on a short-term basis. Therefore, groundborne vibration and noise during construction would have a less than significant impact.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-63 Following construction, operation of the Project would result in groundborne vibration or groundborne noise consistent with current use. Project operation would not generate new sources of vibration, except in instances where larger repairs to the road might be required. These conditions would be short-term and temporary (taking from one to several weeks to complete depending on the extent of damage or other circumstances). Therefore, no operational groundborne vibration and noise impact would occur. c) For a Project located within the vicinity of a private airstrip or an airport land use plan or, where such a plan has not been adopted, within two miles of a public airport or public use airport, would the Project expose people residing or working in the Project Area to excessive noise levels? (No Impact)
The nearest airport is the Rohnerville Airport (KFOT), which is located approximately 2.1 miles southeast from the Project Area. The KFOT is covered by the 2021 ALUCP prepared for the Humboldt County ALUC by ESA. The Project is not located within the ALUCP Noise Contours for KFOT (ESA 2021). Therefore, Project construction would not exacerbate existing airport noise. No impact would occur.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-64

3.14 Population and Housing
Potentially
Significant
Impact
Less than
Significant w/
Mitigation
Incorporated
Less than
Significant
Impact
No
Impact
Would the project:
a) Induce substantial unplanned population growth in
an area, either directly (for example, by proposing
new homes and businesses) or indirectly (for
example, through extension of roads or other
infrastructure)?

b) Displace substantial numbers of existing people or
housing, necessitating the construction of
replacement housing elsewhere?

As of 2020, the City of Fortuna’s population is approximately 12,516 (US Census 2020). a) Induce substantial unplanned population growth in an area, either directly (for example, by proposing new homes and businesses) or indirectly (for example, through extension of roads or other infrastructure)? (No Impact)
The key elements of the Project are the creation of a roundabout, the reconfiguration of the U.S. 101 ramps, and the realignment of Newburg Road to enhance traffic operations and safety. New shared use paths and curb ramps would be constructed between 12th Street, Newburg Road, and Riverwalk Drive, providing improved pedestrian and bicycle safety and enhanced connectivity to the opposite side of U.S. 101.

The Project does not include the construction of new homes or businesses in the area. The Project would not indirectly induce population growth because it would not extend infrastructure into new areas not already served by the communities of Fortuna. It would not result in the extension of utilities or roads or other infrastructure into outlying areas and would not directly or indirectly lead to the development of new sites that would induce population growth. In addition, implementation of the Project would not result in a direct or indirect increase in employment opportunities that could lead to an increase in the local population.

No impact would occur.
b) Displace substantial numbers of existing people or housing, necessitating the construction of replacement housing elsewhere? (No Impact)
The proposed Project would not displace people or housing or otherwise effect housing because there is no housing located within the Project Area, and the Project does not include modification or construction of housing. Residences adjacent to the Project would maintain connectivity during construction. Displacement would not occur. No impact would occur.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-65

3.15 Public Services
Potentially
Significant
Impact
Less than
Significant w/
Mitigation
Incorporated
Less than
Significant
Impact
No
Impact
Would the project:
a) Result in substantial adverse physical impacts
associated with the provision of new or physically
altered governmental facilities, need for new or
physically altered governmental facilities, the
construction of which could cause significant
environmental impacts, in order to maintain
acceptable service ratios, response times or other
performance objectives for any of the public
services:

Fire protection? 
Police protection? 
Schools? 
Parks? 
Other public facilities? 
The Project would result in an overall benefit to public services by improving traffic safety for vehicles, bicycles, and pedestrians within the Project Area.
a) Would the project result in substantial adverse physical impacts associated with the provision of new or physically altered governmental facilities, need for new or physically altered governmental facilities, the construction of which could cause significant environmental impacts, in order to maintain acceptable service ratios, response times or other performance objectives for public services? (No Impact) While the Project would alter the 12th Street intersection with the addition of a roundabout, such actions would not increase the need for additional public services in the Project Area. This would enhance public service capabilities in the surrounding area by enhancing connectivity and safety. The Project Area currently receives fire protection services from the Fortuna Volunteer Fire Department consistent with the rest of Fortuna. The Project would not result in the need to increase staffing, create new hazardous conditions, or result in a modification to the road system that would restrict access for emergency services.

The Project would not result in an increase in student population, and therefore, no new or expanded schools would be required. The Project would not necessitate any related new or altered public service facilities. There would be no impact.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-66

3.16 Recreation
Potentially
Significant
Impact
Less than
Significant w/
Mitigation
Incorporated
Less than
Significant
Impact
No
Impact
Would the project:
a) Increase the use of existing neighborhood and
regional parks or other recreational facilities such
that substantial physical deterioration of the facility would occur or be accelerated?

b) Include recreational facilities or require the
construction or expansion of recreational facilities,
which might have an adverse physical effect on the
environment?

Recreational facilities near the Project Area include the Fortuna Dog Park approximately 0.1 mile west and the Riverwalk Trail approximately 0.2 mile southwest. The Project includes elements to support connectivity of the future GRT.
a) Increase the use of existing neighborhood and regional parks or other recreational facilities such that substantial physical deterioration of the facility would occur or be accelerated? (Less Than Significant Impact)
The proposed Project would create new shared use paths to enhance safety for all transit, including pedestrian and bicycle. Any minimal increases in pedestrian and bicycle use would be attributed to a reduction in vehicle use due to the shared use paths increasing accessibility. The Fortuna Dog Park is an established park located near the northern terminus of the River Walk Trail and west of the Project. The future GRT would be located on the eastern portion of the Project Area, however future use of the GRT is not under the scope of this IS/MND and would instead be under the jurisdiction of the GRTA. Project operation would not preclude or conflict with the GRT. Because the Project would not increase residential uses in the vicinity of the Project, the Fortuna Dog Park and the River Walk Trail would not experience an increase in usage due to the Project. There would be a less than significant impact. b) Include or require the construction or expansion of recreational facilities, which might have an adverse physical effect on the environment? (No Impact) The construction or expansion of recreational facilities would not be required by the Project or included in the Project. There would be no impact.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-67

3.17 Transportation
Potentially
Significant
Impact
Less than
Significant w/
Mitigation
Incorporated
Less than
Significant
Impact
No
Impact
Would the project:
a) Conflict with a program plan, ordinance or policy
addressing the circulation system, including transit,
roadway, bicycle and pedestrian facilities?

b) Conflict or be inconsistent with CEQA Guidelines
section 15064.3, subdivision (b)? 
c) Substantially increase hazards due to a geometric
design feature (e.g., sharp curves or dangerous
intersections) or incompatible uses (e.g., farm
equipment)?

d) Result in inadequate emergency access? 
The Project consists of the installation of a roundabout and the installation of new shared use paths. 12th Street, Riverwalk Drive, Newburg Road, and ramps of U.S. 101 would be realigned and widened as necessary to support the new roundabouts.

Applicable policies from the City of Fortuna General Plan are summarized below.

Goal TC-1: Roadways & Highways
To develop a safe, convenient, and uncongested road network.

Policy TC‐1.1: Reducing Mode Conflicts
The City shall seek to minimize conflicts between pedestrians, automobiles, and bicycles.

Policy TC‐1.3: Balanced Transportation System.

The City shall strive to meet the Level of Service (LOS) standards through a balanced transportation system that provides alternatives to the automobile and by promoting pedestrian, bicycle, and transit connections between employment areas and major residential and commercial areas.

TC‐1.20 Interchange Improvements
The City shall encourage the realignment of the Highway 101 southbound on‐ and off-ramps, together with Riverwalk Drive and Dinsmore Drive at the 12th Street interchange as new development increases the level of traffic using this interchange.

Goal TC-4: Pedestrian Facilities
To develop safe and pleasant pedestrian ways that provide recreation opportunities as well as alternatives to the automobile.

Goal TC-5: Bicycle and Trail Facilities
To provide an interconnected and effective system of bikeways, bicycle parking facilities, and trails for people wishing to walk or bicycle for commuting and/or recreational trips.

Policy TC‐5.4: Bicyclists’ Needs
Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-68 The City shall consider bicyclist needs in new roadways construction and existing roadway upgrades.

Policy TC‐5.6 Bicycle and Pedestrian Linkages
The City shall seek opportunities to strengthen and expand bicycle and pedestrian linkages across U.S. 101.

Policy TC‐5.13 Existing Railroad Lines
The City shall view the NWPRR right‐of‐way as a community asset and design accordingly for the future.

Policy TC‐5.14 Future Rail Options
The City shall require that new development adjacent to the NWPRR right‐of‐way, where appropriate, be designed for future bicycle/pedestrian trail or light rail station access.

Policy TC‐5.15 Bicycle and Pedestrian Paths
The City shall develop, establish, and maintain a system of bicycle and pedestrian paths on suitable transportation corridors with trail linkages to park facilities and existing bicycle and pedestrian paths.

Policy TC‐5.17 Riverwalk District Access
The City shall work with Caltrans to identify solutions for both reconnecting Fortuna with the Riverwalk District and for improving pedestrian and bicycle travel options affected by State Highway 101.

Program TC‐13
The City shall create and maintain a comprehensive list of specific corridors throughout Fortuna in need of sidewalks. This list should include, but not be limited to:
– Enhanced pedestrian safety devices on 12th Street;
a) Conflict with a program plan, ordinance or policy addressing the circulation system, including transit, roadway, bicycle and pedestrian facilities? (No Impact) The Project would install a roundabout and new shared use paths for pedestrians and bicycles. The existing U.S. 101 northbound off-ramps and on-ramps would be realigned to support the new proposed roundabout configuration. These activities do not conflict with a circulation-related program plan, ordinance, or policy of the City of Fortuna. In fact, they are in line with the City’s plan to develop pedestrian and bicycle connectivity on 12th Street with connectivity for the GRT. In addition, the Humboldt County Association of Governments regional bicycle plan lists the 12th Street intersection as a proposed Class III bike path, and the Project would not conflict with this designation (HCAOG 2018).

The Project Area would be accessed via 12th Street, Newburg Road, Riverwalk Drive, and U.S. 101.

Temporary detours roads and temporary traffic control would be required throughout construction which would follow City and Caltrans requirements for temporary roadway closures, including signage and public noticing. No impact would occur.
b) Conflict or be inconsistent with CEQA Guidelines § 15064.3, subdivision (b)? (Less Than Significant Impact)
Pursuant to SB 743 and the current CEQA Guidelines, evaluation of a project's potential transportation impact requires consideration of vehicle miles traveled (VMT), which refers to the amount and distance of automobile travel attributable to a project. Section 15064.3, subdivision (b), of the CEQA Guidelines lists Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-69 the criteria for analyzing transportation impacts from proposed projects. The criteria are broken into four categories, including land use projects, transportation projects, qualitative analysis, and methodology.

Transportation projects that reduce, or have no impact on, VMT should be presumed to cause a less than significant transportation impact. This section was recently added by the state legislature in an attempt to separate CEQA’s purpose and role from traffic or other issues related to ease of use of single occupancy vehicles.

Examples of projects that result in the potential to increase VMT include:
– Changes in land use.
– Expanded roadways (e.g., new roads, additional lanes). – Private development.
– Expanded public service facilities, such as new police stations, new fire stations, or new administrative buildings.
– Residential development, such as a new subdivision.

The proposed Project includes none of the above-listed elements, as it would be installing one roundabout to the existing roadway and realignment of existing roadways and U.S. 101 ramps. These elements do not include any component that could be characterized as resulting in a potential increase to VMT. Per the California Office of Planning and Research’s guidelines for evaluating transportation impacts in CEQA, for roadway capacity projects, agencies have discretion to determine the appropriate measure of transportation impact consistent with CEQA and other applicable requirements (OPR 2019).

Other applicable considerations in the California Office of Planning and Research (OPR) guidance note the criteria for determining the significance to transportation impacts must promote the development of multimodal transportation networks. One of the stated goals of this Project is to create access to safe pedestrian use, including walking and biking, by creating paved sidewalks, walkways and crosswalks, where almost none exist currently. This Project would also create a safe and robust pedestrian facility across the freeway, which would allow for and promote none-vehicular access between the City’s downtown area and the Riverwalk area, which can currently only be accessed safety be vehicle.

Because the proposed Project would not increase the length of roadway, add new roadways, or increase the number of travel lanes outside of historic conditions, there would be no increase in VMT. The impact would be less than significant.
c) Substantially increase hazards due to a geometric design feature (e.g., sharp curves or dangerous intersections) or incompatible uses (e.g., farm equipment)? (No Impact) The Project would change the geometry of the existing northbound off-ramps and on-ramps of U.S. 101 to support the new roundabout configuration proposed, improve use compatibility, and increase safety. The geometry along 12th Street, Riverwalk Drive, and Pond Street would also be adjusted for roundabout ingress and egress to reduce hazards and enhance safety. Newburg Road would be realigned to be closed off at its 12th street intersection. These changes would consolidate traffic intersections, minimize sharp curves entering the roundabouts, and would enhance overall safety within the Project Area.

The Project is being designed in accordance with the Caltrans Highway Design Manual, 7th Edition (2023) and the NCHRP Report 672 entitled “Roundabouts: An Information Guide, 2nd Edition”. In addition, the Project would be designed in accordance with other specific applicable standards, including the California Manual on Uniform Traffic Control Devices (Caltrans 2021); the 2010 ADA Standards for Accessible Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-70 Design; the 2019 California Building Code and portions of the American Association of State Highway and Transportation Officials (AASHTO) A Policy on Geometric Design of Highways and Streets, 7th Edition (2018). No impact would occur.
d) Result in inadequate emergency access? (Less than Significant with Mitigation) The Project would involve modification to 12th Street, a minor arterial road, and Newburg Road, a collector road, within the City of Fortuna (City of Fortuna 2010). Principal arterial roadways emphasize mobility with limited access. These include freeways, expressways, and those arterials specifically designed to provide a high level of mobility with limited access to adjoining properties. Minor arterials interconnect with, and augment, the principal arterial system while providing a somewhat lower level of travel mobility due to less stringent access limitations. Collectors provide a balanced function of land access and mobility within residential neighborhoods and commercial and industrial areas. The Project would also involve modification to Riverwalk Drive and Pond Street, classified as local roads and streets within the Project Area (City of Fortuna 2010).

Emergency access to the Project Area already exists and would continue to exist under the proposed Project during both construction and operation. Temporary detours would be required throughout construction which would follow City and Caltrans requirements for temporary roadway closures, including signage and public noticing. Construction would be phased in order to maintain local access to U.S. 101, though lane and/or roadway closures could result in delays for emergency response vehicles.

Since the Project Area is already served by emergency and law enforcement personnel, the proposed Project would not require additional emergency services, though emergency access through lane and/or roadway closures could result in delays during construction. Thus, the potential impact associated with emergency access during construction would be potentially significant and is addressed by Mitigation Measure TR-1.

Following construction, the surrounding area would continue to have emergency access. Newburg Road would be modified to create a new dead-end at the existing 12th Street intersection, which would include removable bollards to allow a direct connection for emergency access. A less than significant operational impact on emergency access would occur.

Mitigation
Implementation of Mitigation Measure TR-1 would reduce the temporary impact of construction activities on emergency access by requiring the City and its contractors to have ready at all times the means necessary to accommodate access by emergency vehicles, as well as to notify emergency responders in advance of construction activities.

Mitigation Measure TR-1: Maintain Emergency Access and Notify Emergency Responders
The City shall require contractors to provide adequate emergency access to all properties along the corridor during the construction process. At locations where access to a nearby property is temporarily blocked, the contractor shall be required to have ready the means necessary to accommodate access by emergency vehicles to such properties, such as plating over excavations.

As construction progresses, emergency providers shall be notified in advance of the timing, location, and duration of construction activities and the locations and durations of any temporary lane closures.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-71 With implementation of Mitigation Measure TR-1, any potential impact to emergency access during construction would be less than significant.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-72

3.18 Tribal Cultural Resources
Potentially
Significant
Impact
Less than
Significant w/
Mitigation
Incorporated
Less than
Significant
Impact
No
Impact
Would the project:
a) Cause a substantial adverse change in the
significance of a tribal cultural resource listed or
eligible for listing in the California Register of
Historic Resources, or in a local register of historic
resources as defined in Public Resources Code
section 5020.1(k)?

b) Cause a substantial adverse change in the
significance of a tribal cultural resource that is a
resource determined by the lead agency, in its
discretion and supported by substantial evidence,
to be significant pursuant to the criteria set forth in subdivision (c) of the Public Resources Code
section 5024.1? In applying the criteria set forth in
subdivision (c) of the Public Resources Code
section 5024.1, the lead agency shall consider the
significance of the resource to a California Native
American Tribe.

a, b) Cause a substantial adverse change in the significance of a tribal cultural resource? (Less than Significant with Mitigation)
CEQA requires lead agencies to determine if a proposed Project would have a significant effect on tribal cultural resources. The CEQA Guidelines define tribal cultural resources as: (1) a site, feature, place, cultural landscape, sacred place, or object with cultural value to a California Native American Tribe that is listed or eligible for listing on the California Register of Historical Resources, or on a local register of historical resources as defined in Public Resources Code section 5020.1(k); or (2) a resource determined by the lead agency, in its discretion and supported by substantial evidence, to be significant according to the historical register criteria in Public Resources Code section 5024.1(c), and considering the significance of the resource to a California Native American Tribe.

Under Assembly Bill (AB) 52, notification letters were sent to the tribes on the NAHC list on March 11, 2024.

The City received a response from the Bear River Band of the Rohnerville Rancheria on April 22, 2024, requesting ongoing consultation throughout the Project which has included a site visit on April 30, 2024.

The City also received a response from the Wiyot Tribe on May 30, 2024, requesting standard inadvertent archaeological discovery protocols be in place for any ground-disturbing activities which is incorporated as Mitigation Measure CR-1.

No specific tribal cultural resources were identified within the APE. Implementation of Mitigation Measures CR-1 and CR-2 (see Section 3.5 – Cultural Resources) would reduce the potential impact to tribal cultural resources to a less than significant level.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-73

3.19 Utilities and Service Systems
Potentially
Significant
Impact
Less than
Significant w/
Mitigation
Incorporated
Less than
Significant
Impact
No
Impact
Would the project:
a) Require or result in the relocation or construction of new or expanded water, wastewater treatment or
storm water drainage, electrical power, natural gas,
or telecommunications facilities, the construction or
relocation of which could cause significant
environmental effects?

b) Have sufficient water supplies available to serve
the project and reasonably foreseeable future
development during normal, dry and multiple dry
years?

c) Result in a determination by the wastewater
treatment provider which serves or may serve the
project that it has adequate capacity to serve the
project’s projected demand in addition to the
provider’s existing commitments?

d) Generate solid waste in excess of State or local
standards, or in excess of the capacity of local
infrastructure, or otherwise impair the attainment of
solid waste reduction goals?

e) Comply with federal, state, and local management
and reduction statutes and regulations related to
solid waste?

a) Require or result in the relocation or construction of new or expanded water, wastewater treatment or storm water drainage, electrical power, natural gas, or telecommunications facilities, the construction or relocation of which could cause significant environmental effects? (Less than Significant Impact)
The following is a preliminary list of utilities within the construction limits:
– Natural gas
– Overhead and underground electric
– Overhead and underground communications
– City water
– City wastewater
– Storm drainage
The Project involves the installation of one roundabout within the 12th street intersection. This would require discrete relocations of both above and below ground utilities that conflict with work. The majority of the relocations would be to return utility access to the new road grade; however, utility and street light poles would be relocated. This would not involve the construction of new water, electrical, natural gas, or telecommunications infrastructure/facilities. A less than significant result would occur.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-74 b) Have sufficient water supplies available to serve the Project and reasonably foreseeable future development during normal, dry and multiple dry years? (No Impact) The proposed Project would not create an increased demand for domestic water service. The Project would require relatively small quantities of water during the construction phase (e.g., for dust control and concrete/asphalt applications). The Project’s water demands would not be substantial and can be met by existing entitlements and resources. The Project would not induce population growth or result in land uses that would increase demand for water supplies. Therefore, the Project would not result in the need for the construction of new water facilities, or the expansion of existing facilities. No impact would occur. c) Result in a determination by the wastewater treatment provider which serves or may serve the Project that it has adequate capacity to serve the Project’s Projected demand in addition to the provider’s existing commitments? (Less than Significant Impact) The Project does not involve sewerage facilities or wastewater treatment and would not result in a demand increase for existing wastewater treatment capacity. The Project would potentially require minor relocations of existing municipal sewerage covers to final grade during construction, but it would not significantly impact existing municipal sewerage infrastructure. A less than significant impact would occur. d, e) Generate solid waste in excess of State or local standards, or in excess of the capacity of local infrastructure, or otherwise impair the attainment of solid waste reduction goals? (Less Than Significant)
The solid waste providers in the area are Recology Eel River (Recology) and the Humboldt Waste Management Authority (HWMA). The Project is not expected to generate a significant increase in services for solid waste disposal needs. The proposed Project would generate limited solid waste during construction and no waste during operation. Construction solid waste would include the one-time temporary generation of construction waste associated with the proposed construction. Excess soils, aggregate road base, RSP, and construction materials would be stored within designated staging areas. Excess materials may be re-used on-site for backfill and finished grading. Excess materials would not be stockpiled on-site once the Project is complete. The contractor would haul additional excess materials off-site for beneficial reuse, recycling, or legal disposal. Solid waste collected as a part of the Project would be disposed of via Recology or HWMA. Solid waste produced in the County is trucked to state licensed landfills located in Anderson, California and Medford, Oregon in compliance with local, state, and federal regulations pertaining to solid waste disposal. These facilities have sufficient capacity to serve the Project’s solid waste disposal needs; therefore, a less than significant impact is anticipated.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-75

3.20 Wildfire
Potentially
Significant
Impact
Less than
Significant w/
Mitigation
Incorporated
Less than
Significant
Impact
No
Impact
Would the project:
a) Substantially impair an adopted emergency
response plan or emergency evacuation plan? 
b) Due to slope, prevailing winds, and other factors,
exacerbate wildfire risks, and thereby expose
project occupants to pollutant concentrations from
a wildfire or the uncontrolled spread of a wildfire?

c) Require the installation or maintenance of
associated infrastructure (such as roads, fuel
breaks, emergency water sources, power lines or
other utilities) that may exacerbate fire risk or that
may result in temporary or ongoing impacts to the
environment?

d) Expose people or structures to significant risks,
including downslope or downstream flooding or
landslides as a result of runoff, post-fire slop
instability, or drainage changes?

This section evaluates potential impacts related to wildfire risk; no portion of the Project Area is located within or near a State Responsibility Area (SRA) where Cal Fire is the primary emergency response agency responsible for fire suppression and prevention. The Project is located approximately 1.0 mile from the nearest SRA (Calfire 2007a). Therefore, the CEQA Guidelines Appendix G Checklist section for wildfire is not applicable to the Project, but the section below is provided for additional context. The Project is located within a Local Responsibility Area (LRA) rated as either unzoned or moderate Fire Hazard Severity Zone (FHSZ) (Calfire 2007b). There are no very high FHSZs within the LRA. Fortuna Volunteer Fire Department serves the Project Area located within the LRA. The nearest land classified as a high FHSZ is approximately 0.70 mile northeast of the Project Area, and the nearest very high FHSZ is approximately

10.80 miles east (Calfire 2007a, 2007b).

The closest fire station to the Project Area is the Fortuna Fire Station located approximately 0.30 mile east of the Project, and the Campton Heights Station located approximately 1.65 miles south. a) Substantially impair an adopted emergency response plan or emergency evacuation plan (No Impact)
The City does not have an independent emergency response plan. A review of the Humboldt County Emergency Operations Plan (EOP) (Humboldt County 2015) and the Tsunami Inundation Map for Emergency Planning – County of Humboldt (CGS 2024a) indicates that the Project would not permanently impair emergency response activities nor established evacuation routes. The Project operation would not impair implementation or physically interfere with an established emergency response or evacuation plan; see Section 3.9 (Hazards and Hazardous Materials, Impact (f)) for discussion of the Project’s effect on emergency response and evacuation plans.) Once constructed, the Project would enhance transportation safety along the 12th Street intersection, thus emergency response or evacuation would not be impeded.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-76 The Project would not permanently impede access to any existing roads or pedestrian ways within the Project Area. No impact would occur.
b) Due to slope, prevailing winds, and other factors, exacerbate wildfire risks, and thereby expose project occupants to pollutant concentrations from a wildfire or the uncontrolled spread of a wildfire? (Less than Significant Impact)
The Project Area includes topography that is relatively flat and where windy conditions are common. Fire ignition risk associated with construction activities is low and limited to accidental ignition associated with a potential heavy machinery-related incident. The majority of work is planned to occur within paved areas, further reducing the potential for fire ignition. The Project would not otherwise increase exposure to wildlife fire above existing conditions. The impact would be less than significant. c) Require the installation or maintenance of associated infrastructure (such as roads, fuel breaks, emergency water sources, power lines or other utilities) that may exacerbate fire risk or that may result in temporary or ongoing impacts to the environment? (No Impact) Development of the Project would not result in a need to expand infrastructure to the Project Area or in the immediate vicinity of the Project. The entirely of the Project Area is already readily accessible via the existing roadway network. New roads for fire defense, expanded water sources, or new power lines would not be required. No impact would occur.
d) Expose people or structures to significant risks, including downslope or downstream flooding or landslides as a result of runoff, post-fire slope instability, or drainage changes? (Less than Significant Impact)
Project construction would not expose people or structures to significant risk. The Project is located in the low-lying, generally flat developed lands adjacent to the Eel River. The immediate Project Area is not forested, although some vegetation is present. Fire ignition risk associated with construction activities is low. Because the Project is located in flat lands and due to low fire ignition risk, the risk of flooding or landslides associated with post-fire slope instability or changes in drainage is low. The impact is less than significant.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-77

3.21 Mandatory Findings of Significance
Potentially
Significant
Impact
Less than
Significant w/
Mitigation
Incorporated
Less than
Significant
Impact
No
Impact
Does the project:
a) Have the potential to substantially degrade the
quality of the environment, substantially reduce the
habitat of a fish or wildlife species, cause a fish or
wildlife population to drop below self-sustaining
levels, threaten to eliminate a plant or animal
community, substantially reduce the number or
restrict the range of a rare or endangered plant or
animal or eliminate important examples of the
major periods of California history or prehistory?

b) Have impacts that are individually limited, but
cumulatively considerable? (“Cumulatively
considerable” means that the incremental effects of
a project are considerable when viewed in
connection with the effects of past projects, the
effects of other current projects, and the effects of
probable future projects)?

c) Have environmental effects which would cause
substantial adverse effects on human beings,
either directly or indirectly?

a) Does the project have the potential to substantially degrade the quality of the environment, substantially reduce the habitat of a fish or wildlife species, cause a fish or wildlife population to drop below self-sustaining levels, threaten to eliminate a plant or animal community, substantially reduce the number or restrict the range of a rare or endangered plant or animal or eliminate important examples of the major periods of California history or prehistory? (Less than Significant with Mitigation)
As evaluated in this IS/MND, the Project would not substantially degrade the quality of the environment; substantially reduce the habitat of a fish or wildlife species; cause a fish or wildlife population to drop below self-sustaining levels; threaten to eliminate a plant or animal community; reduce the number or restrict the range of an endangered, rare, or threatened species; or eliminate important examples of the major periods of California history or prehistory
Mitigation measures are listed herein to reduce impacts related to Air Quality, Biological Resources, Cultural Resources, Energy Resources, Geology and Soils, Hazards and Hazardous Materials, Hydrology and Water Quality, Noise, Transportation, and Tribal Cultural Resources. With implementation of the required mitigation measures, impacts would be less than significant. b) Does the Project have impacts that are individually limited, but cumulatively considerable? (“Cumulatively considerable” means that the incremental effects of a Project are Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-78 considerable when viewed in connection with the effects of past Projects, the effects of other current Projects, and the effects of probable future Projects)? (Less than Significant) Cumulative impacts are defined as “two or more individual effects which, when considered together, are considerable or which compound or increase other environmental impacts” (CEQA Guidelines § 15355).

Cumulative impacts can result from individually minor but collectively significant actions taking place over a period of time.

Table 3.21-1 provides a list of past, present, and reasonably foreseeable future projects within and near the Project Area, including their anticipated construction schedules (if known). Efforts to identify cumulative projects included outreach to Caltrans and the City of Fortuna.

Table 3.21-1 Cumulative Projects Summary.

Agency Project Construction Year
Caltrans Kenmar Road Interchange Roundabouts 2027 or beyond Caltrans Construct Materials Lab 2024
Caltrans Fortuna Median Paving/Fortuna Median Roadside
Safety Project
2026
Caltrans Rehabilitate Drainage/HUM-101 Drainage North 2026 Caltrans Fortuna Maintenance Station Crane/Hoist Not programmed for construction
Private Development Hotel off Riverwalk Drive Near the River Lodge Unknown City of Fortuna Secondary Entry to Old Mill Site Long-term future City of Fortuna Expired Approved Subdivision for 39 Homes on 23 acres
TBD
City of Fortuna Generator Repair Shop in Commercial Zone TBD, Building Permit Pending
City of Fortuna Brewery Expansion in Commercial Zone TBD City of Fortuna Development of the former Palco Lumber Mill Long-term future The impacts associated with the proposed Project analyzed in this IS/MND would not add appreciably to any existing or foreseeable future significant cumulative impact, such as visual quality, cultural resources, biological, traffic impacts, or air quality degradation. All identified projects are adjacent to the roadway corridor on appropriately zoned parcels suitable for development and generally lacking habitat or other environmental resources at risk of impairment. Specifically, development of the former Palco Lumber Mill is being programmatically analyzed with a Supplemental EIR, and thus any development would be considered in a separate CEQA process. Incremental impacts, if any, would be negligible and undetectable. Any applicable cumulative impacts to which this Project would contribute would be mitigated to a less than significant level. Incremental impacts, if any, would be very small, and the cumulative impact would be less than significant. Because the proposed Project would not result in significant impacts after mitigation, and because the proposed Project is a roundabout rather than a development project that could add to existing and future population growth and development in the area, the proposed Project would not contribute to any significant cumulative impacts which may occur in the area in the future. Therefore, the impact would be less than significant.

Environmental Analysis
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 3-79 c) Does the Project have environmental effects which would cause substantial adverse effects on human beings, either directly or indirectly? (Less Than Significant) The Project has been planned and designed to avoid significant environmental impacts. As discussed in the analysis throughout Section 3 of this IS/MND, the Project would not have environmental effects that would cause substantial adverse direct or indirect effects on human beings. The impact would be less than significant.

Appendices
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 4-1

4. References
Bay Area Air Quality Management District (BAAQMD). 202217. Justification Report: CEQA Thresholds for Evaluating the Significance of Climate Impacts From Land Use Projects and Plans. Accessed August 2022. Available at https://www.baaqmd.gov/plans-and-climate/california-environmental-quality-act-ceqa/updated-ceqa-guidelines California Environmental Quality Act Air Quality Guidelines.

California Air Resources Board (CARB). 2005. Air Quality and Land Use Handbook: A Community Health Perspective.

April.

California Department of Forestry and Fire Protection (CAL FIRE). 2007a. Humboldt County Fire Hazard Severity Zones in SRA.

California Department of Forestry and Fire Protection (CAL FIRE). 2007b. Humboldt County Draft Fire Hazard Severity Zones in LRA.

California Department of Toxic Substances Control (DTSC). 2024. EnviroStor Hazardous Waste and Substances Site List (Cortese). Accessed: June 2022. https://www.envirostor.dtsc.ca.gov California Department of Transportation (Caltrans). 2019. State Scenic Highway List. Available online:
https://dot.ca.gov/-/media/dot-media/programs/design/documents/2017-03desigandeligible-a11y.xlsx California Department of Transportation (Caltrans). 2020. Transportation and Construction Vibration Guidance Manual.

California Department of Transportation (Caltrans). 2023. Highway Design Manual, 7th Edition.

California Department of Transportation (Caltrans). 2021. California Manual on Uniform Traffic Control Devices (CA MUTCD) 2014 Edition Revision 6.

California Geological Survey (CGS). 2024. Earthquake Zones of Required Investigation. Accessed: February 2024. https://maps.conservation.ca.gov/cgs/EQZApp/app/
California Geological Survey (CGS). 2024a. Tsunami Inundation Map for Emergency Planning. Accessed: February 2024. https://www.conservation.ca.gov/cgs/tsunami/maps/ City of Fortuna. 2005. 2005 Storm Drainage Master Plan.

City of Fortuna. 2010. General Plan 2030.

Department of Water Resources (DWR). 2004. Department of Water Resources Bulletin 118 Alluvial Groundwater Basins/Subbasins Humboldt County, California. Eel River Valley Groundwater Basin.

ESA. 2021. Airport Land Use Compatibility Plan. Prepared for the Humboldt County Airport Land Use Commission (ALUC). https://humboldtgov.org/DocumentCenter/View/95080/2021-Airport-Land-Use-Compatibility-Planadopted-04132021-33-MB.

Federal Highway Administration. 2006. FHWA Highway Construction Noise Handbook.

GHD Inc. (GHD). 2023. 12th Street Interchange Modernization Project Initial Site Assessment. Prepared for the City of Fortuna. GHD, Eureka, California, USA.

GHD Inc. (GHD). 2024a. 12th Street Interchange Modernization Project Traffic Operations & Analysis Report and Intersection Control Evaluation. Prepared for the City of Fortuna. GHD, Eureka, California, USA.

GHD Inc. (GHD). 2024b. 12th Street Interchange Modernization Project Visual Impact Assessment Memorandum.

Prepared for the City of Fortuna. GHD, Eureka, California, USA.

Appendices
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 4-2 Humboldt County. 2015. Emergency Operations Plan, Humboldt Operational Area. Humboldt County, CA https://humboldtgov.org/DocumentCenter/View/51861/Humboldt-County-Emergency-Operations-Plan-2015 Humboldt County. 2024. Humboldt County WebGIS. Layers Accessed: Williamson AG Preserves, Area of Potential Liquefaction, Tsunami Hazard Area
JRP Historical Consulting. 2024a. Historical Resources Evaluation Report 12th Street Interchange Modernization Project Fortuna, Humboldt County, California. CONFIDENTIAL.

JRP Historical Consulting. 2024b. Finding of No Adverse Effect 12th Street Interchange Modernization Project Fortuna, Humboldt County, California. CONFIDENTIAL.

JRP Historical Consulting, Roscoe and Associates (JRP and Roscoe). 2024. Historic Property Survey Report 12th Street Interchange Modernization Project Fortuna, Humboldt County, California. CONFIDENTIAL.

North Coast Stormwater Coalition. 2021. Humboldt Low Impact Development Stormwater Manual v3.0.

Office of Planning and Research (OPR). 2019. Technical Advisory on Evaluating Transportation Impacts in CEQA.

December. Available online at: https://opr.ca.gov/docs/20190122-743_Technical_Advisory.pdf Roscoe and Associates (Roscoe). 2024. Archaeological Survey Report 12th Street Interchange Modernization Project.

CONFIDENTIAL.

Sacramento Metropolitan Air Quality Management District. (SMAQMD) 2021. SMAQMD Thresholds of Significance Table. Accessed April 2024. Available at https://www.airquality.org/residents/ceqa-land-use-planning/ceqaguidance-tools State Water Resources Control Board (SWRCB). 2024. GeoTracker. Accessed: February 2024. https://geotracker.waterboards.ca.gov/map/
U.S. Census Bureau. "RACE." Decennial Census, DEC Redistricting Data (PL 94-171), Table P1, 2020, https://data.census.gov/table/DECENNIALPL2020.P1?g=160XX00US0625296. Accessed: February 2024 Appendices
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 5-3

5. Report Preparers

5.1 City of Fortuna
Merritt Perry, City Manager
Brendan Byrd, Deputy City Engineer

5.2 GHD
Andrea Hilton, Environmental Planner
Christian Hernandez, Environmental Scientist
Chryss Meier, Air Quality Planner

5.3 Sub-consultants
Roscoe and Associates
James Roscoe, Principal
Melinda Salisbury, Research Associate
Kelly Hughes, Research Associate
JRP Historical Consulting
Christopher McMorris, Principal and Architectural Historian Toni Webb, Architectural Historian
Abigail Lawton, Research Assistant
Appendices
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 5-4 Appendices
Appendix A........................................................................................................................ Figures Figure 1 ................................................................................................................ Vicinity Map Figure 2 ......................................................................................................... Project Overview Figure 3 ....................................................................................................................Soils Map Appendix B........................................................................................ Air Quality Modeling Results Appendix C............................................................................................... Botanical Survey Report Appendix D...........................................................................................Natural Environment Study Appendix E......................................................................................................Wetland Delineation Appendices
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 5-5 Appendix A
Figures
Figure 1 Vicinity Map
Figure 2 Project Overview
Figure 3 Soils Map
Appendices
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 5-6 Appendix B
Air Quality Modeling Results
Appendices
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 5-7 Appendix C
Botanical Survey Report
Appendices
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 5-8 Appendix D
Natural Environment Study
Appendices
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 5-9 Appendix E
Wetland Delineation
Appendices
GHD | City of Fortuna | 12577017 | 12th Street Interchange Modernization Project 5-10 ghd.com The Power of Commitment