The Draft IS/MND's analysis of project impacts identified potentially less than significant impacts which will be avoided by adhering to the following Project Features (PFs) and Avoidance and Minimization Measures (AMMs):

•    PF-AES-1, Minimize Vegetation Impacts. Impacts on vegetation would be minimized to the greatest extent possible during construction. Vegetation to remain would be protected from construction activities through the installation of temporary fencing when it is close to construction work. 

•    PF-AES-2, Temporary Fencing. Temporary fencing would be used to protect the roots and canopies of nearby trees.

•    PF-AES-3, Tree Trimming. Where the pruning of trees is required to accommodate construction operations, pruning would be performed under the supervision of a certified arborist.

•    PF-AES-4, Staging Areas Positioning. Construction materials and equipment would be stored in a staging area beyond direct view of the motoring public and residential properties to the extent feasible.

•    PF-AES-5, RSP Treatment. If it is determined that RSP would be visible to highway users, the Office of Landscape Architecture would determine if aesthetic treatment of the RSP is needed. This may include staining and/or other measures.

•    PF-AQ-1, Control Measures for Construction Emissions of Fugitive Dust. Dust control measures would be implemented to minimize airborne dust and soil particles generated from graded areas. For disturbed soil areas, the use of an organic tackifier to control dust emissions would be included in the construction contract. Watering guidelines would be established by the contractor and approved by the Caltrans resident engineer. Any material stockpiled during construction would be watered, sprayed with tackifier, or covered to minimize dust production and wind erosion.

•    PF-AQ-2, Construction Vehicles and Equipment. Construction vehicles and equipment would be maintained and tuned in accordance with manufacturer’s specifications. In addition, solar-powered traffic control lights would be used if feasible.

•    PF-AQ-3, Minimize Idling. Idling times would be minimized either by shutting equipment off when not in use or reducing the maximum idling time to 5 minutes.

•    PF-AQ-4, Recycle Waste and Materials. If practicable, nonhazardous waste and excess material would be recycled. If recycling is not practicable, dispose of material according to applicable regulations.

•    PF-BIO-1, Delineated Construction Areas, Environmentally Sensitive Areas, and Equipment and Material Storage Sites: A biological monitor would delineate construction areas, environmentally sensitive areas (ESAs), and equipment materials and storage sites. ESAs are areas containing sensitive habitats adjacent to or within the Project footprints, in which ground-disturbing activities are not allowed. ESAs would be delineated on the final Project plans. A biological monitor would be onsite to direct the installation of high-visibility, orange ESA fencing to prevent the encroachment of construction personnel, materials, and equipment into ESAs during construction-related activities, as needed. Construction equipment and materials would be stored outside of designated ESAs, as specified by a biological monitor, to avoid construction-related impacts to natural communities. At the discretion of the biological monitor, ESA fencing would be removed when construction is no longer active in the delineated construction areas.

•    PF-BIO-2, Construction Site Management Practices: Construction BMPs for biological resources may include, but are not limited to, the following: 

     o    Construction vehicles would be restricted to SR 1 and delineated construction areas. Construction vehicles would observe a 15-mile-per-hour speed limit within the Project footprints, except when on the SR 1 travel lanes.
     o    Construction access, staging, storage, and parking areas would be delineated outside of designated ESAs within the Project footprints and limited to the minimum area necessary to construct the Project.
     o    All construction-related waste, such as wrappers, cans, bottles, and food scraps, would be disposed of or recycled in closed containers and removed at least once daily from the Project footprint.
     o    All pets would be prohibited from entering the Project footprint.
     o    Firearms would be prohibited within the Project footprint, except for those carried by authorized security personnel or local, state, or federal law enforcement officials.

•    PF-BIO-3, Pre-construction Surveys for Nesting Birds: If clearing and grubbing vegetation should occur between February 1 and September 30, a biological monitor would conduct pre-construction surveys for nesting birds within the ground areas to be disturbed prior to beginning construction-related activities. The survey would include a perimeter buffer of approximately 50 feet for non-game migratory birds and approximately 300 feet for raptors. All nest avoidance requirements of the Migratory Bird Treaty Act, USFWS, and California Department of Fish and Wildlife (CDFW) codes would be observed. If an active nest is found, an appropriate protection buffer would be established until the young fledge. USFWS and/or CDFW would be contacted if a special-status species is discovered within the Project footprints within 24 hours.

•    PF-BIO-4, Noxious Weeds: Noxious weeds would be controlled in accordance with Caltrans Highway Design Manual Topic 110.5, Control of Noxious Weeds—Exotic and Invasive Species, and Executive Order 13112, Invasive Species, and by methods approved by a Caltrans-approved landscape architect. 

•    PF-CUL-1, Unanticipated Archaeological Discovery. If cultural materials are discovered during construction, all earthmoving activity within and around the immediate discovery area would be diverted until a qualified archaeologist can assess the nature and significance of the find in consultation with the State Historic Preservation Officer (SHPO).

•    PF-CUL-2, Unanticipated Human Remains Discovery. If human remains are discovered, State Health and Safety Code Section 7050.5 states that further disturbances and activities would cease in any area or nearby area suspected to overlie the remains and the county coroner would be contacted. Pursuant to PRC Section 5097.98, if the remains are thought to be Native American, the coroner would notify the NAHC, which would then notify the MLD. At that time, the person who discovered the remains would contact the Environmental Senior and PQS, which would work with the MLD to ensure respectful treatment and disposition of the remains. Further provisions of PRC Section 5097.98 would be followed, as applicable. 

•    PF-WQ-1, Construction and Implementation of Best Management Practices: Erosion control BMPs would be included in the final Project plans, and Standard Special Provisions (SSPs) would be included in the final construction package to comply with the conditions of the Caltrans National Pollutant Discharge Elimination System (NPDES) permit. The Caltrans BMP Guidance Handbook (Caltrans 2017) would provide guidance for provisions to be included in the construction contract for measures to protect ESAs and avoid or minimize stormwater and non-stormwater discharges. Construction BMPs for stormwater may include, but are not limited to, the following:
     o    Construction tracking control practices
     o    Job site management
     o    Sediment control (fiber rolls and silt fencing)
     o    Waste management and materials pollution control
     o    Materials stockpile management
     o    Dust and wind erosion controls
     o    DI protection
     o    Non-stormwater management
     o    Water quality monitoring
     o    Maintaining and tuning construction vehicles and equipment approximately 50 feet away from Yellow Creek and Schell Creek
     o    Locating designated fueling areas approximately 50 feet from downslope drainage facilities, as well as Yellow Creek and Schell Creek

•    PF-HYD-2, Water Pollution Control Program. A Water Pollution Control Program (WPCP) would be prepared by the contractor and approved by Caltrans, pursuant to the 2018 Caltrans Standard Specifications Section 13, Water Pollution Control, and the Caltrans WPCP Preparation Manual (Caltrans 2021a). The WPCP would be implemented prior to the beginning of construction.

•    PF-WQ-3, Temporary Stream Diversions. Temporary stream diversions would be used when necessary for culvert replacements. If needed, stream diversions would be determined during the design phase of the Project.

•    PF-WQ-4, Permanent BMPs. To minimize and avoid potential post-construction impacts on water quality, the Project would consider design pollution prevention BMPs. Design pollution prevention BMPs would be used to minimize runoff, maximize infiltration, maximize vegetation (depending on the location), and reduce erosion.

•    PF-NOI-1, Public Outreach. Public outreach would be required before Project construction and throughout the Project construction to update residents, businesses, and others with upcoming activities and time frame of Project. Public outreach may entail sending notices to nearby residents, notifying the city, and posting a notice on the Project website.

•    PF-NOI-2, Construction Noise Levels. The following measures would be implemented to reduce noise levels during construction where feasible:
     o    The Contract Specifications should include a Special Provision requiring Noise Monitoring and Noise Control Measures. 
     o    Measures in the Special Provision may include a temporary noise barrier and other methods (i.e., scheduling), including the following:
     o    Equip an internal combustion engine with a manufacturer-recommended muffler that is in good condition. Do not operate an internal combustion engine within the Project footprint without the appropriate muffler.
     o    Do not idle construction equipment unnecessarily.
     o    Maximize the distance between stationary noise-generating construction equipment, such as air compressors and portable power generators, and noise-sensitive receptors.
     o    Locate staging and storage areas away from residential areas.
     o    Consider reducing impact of detours.
     o    Use quieter alternative methods of equipment.
     o    If feasible, use solar or electricity as power source instead of diesel generators.
     o    Ensure all construction equipment conforms to Section 14-8. 02, Noise Control, of the latest Caltrans Standard Specifications.

•    PF-TRF-1, Traffic Management Plan. A TMP would be prepared prior to the beginning of construction to minimize impacts on the public while traveling on SR 1 and ensure their safety. One-way alternating traffic control would maintain traffic operations through all three culvert replacement work areas by using the lane that is not currently under construction. Flaggers would be used to stop traffic at either end of the work area as well as access points along the lane-closure area (e.g., driveways, parking lots, roadways). Temporary traffic barriers or traffic cones would be used to separate the open lanes from the closed lanes.

•    AMM-AES-1, Staging Areas Impact Reduction. Staging areas would not be located where they require the removal of vegetation or result in ground compaction impacting tree roots. 

•    AMM-AES-2, Project Design Compliance. As the design is advanced, any modifications required to ensure compliance with the Guidelines would be implemented as the need becomes apparent.

•    AMM-AES-3, Revegetating. Trees or vegetation removed during construction would be replaced or compensated via in-lieu fee. Consultation with the Office of Biological Science and Permits, the Office of Environmental Analysis, as well as the Office of Landscape Architecture would be necessary regarding potential tree or vegetation loss, avoidance, and replacement.

•    AMM-AES-4, Reseeding. Disturbed areas would be revegetated with a regionally appropriate native seed mix following construction.

•    AMM-BIO-1, Proper Use of Erosion Control Devices. To prevent CRLF from becoming entangled or trapped in erosion control devices, plastic monofilament netting (i.e., erosion control matting) or similar material would not be used within the Project footprints. Acceptable substitutes would include coconut coir matting or tackified hydroseeding compounds.

•    AMM-BIO-2, Pre-construction Surveys for California Red-legged Frog: Pre-construction surveys would be conducted by a USFWS-approved biological monitor. Visual surveys would be conducted immediately prior to the beginning of ground-disturbing activities. Suitable breeding and dispersal habitat within the Project footprints includes refugia habitat (such as in or under shrubs, downed logs, small woody debris, and burrows), which would be inspected. If an individual is observed, it would be evaluated and relocated in accordance with the observation and handling protocols outlined in AMM-BIO-5. Fossorial mammal burrows would be inspected for signs of CRLF usage to the maximum extent practicable. If it is determined that a fossorial mammal burrow may be occupied by a frog, the burrow would be flagged for avoidance.

•    AMM-BIO-3, Conduct Biological Monitoring: A USFWS-approved biological monitor would be present onsite during construction-related activities, including vegetation clearing and grubbing, when special-status species have the highest likelihood of being harmed or harassed. If, at any point, any listed species is discovered within the Project footprint, the USFWS-approved biological monitor may stop work if deemed necessary and a 50-foot-wide work restriction buffer would be applied until the animal moves out of the area or is relocated out of harm’s way. For state-listed species, CDFW would be contacted on how best to proceed. Alternately, other action may be taken as authorized in Project permits.

•    AMM-BIO-4, Conduct Biological Monitoring for California Red-legged Frog. A USFWS-approved biological monitor would be present onsite during construction-related activities that have the potential to result in take of CRLF to monitor for the species. The USFWS-approved biological monitor may stop work if deemed necessary for any reason to protect CRLF and would advise the resident engineer or designee on how to proceed accordingly.

•    AMM-BIO-5, Discovery of a Special-Status Species. The biological monitor would have the authority to halt work through coordination with the resident engineer in the event that a special-status species is discovered in an active construction area or might otherwise be at risk. The resident engineer would ensure construction-related activities remain suspended in any construction area where the biological monitor has determined that the special-status species could be harmed. For CRLF, work may resume when the individual moves away from the construction area of its own volition or is moved out of harm’s way by a USFWS-approved biological monitor. For other federally and state-listed species, USFWS and/or CDFW would be contacted on how to proceed before work is allowed to resume. 

•    AMM-BIO-6, Timing of Construction: Ground-disturbing activities would be restricted to the dry season (i.e., between April 15 and October 31), and work within jurisdictional waters would be further restricted to between June 15 and October 31, when CRLF are anticipated to be estivating in moist refuges and not dispersing through the BSA.

Construction-related activities would not occur during rain events or within 24 hours following a rain event. Prior to resuming construction-related activities, a USFWS-approved biological monitor would inspect the construction area and construction vehicles, equipment, and materials stored onsite for the presence of CRLF. Any discovered CRLF would be allowed to move away from the construction area of their own volition or would be moved by the USFWS-approved biological monitor.

•    AMM-BIO-7, Construction Materials Storage: For onsite storage of construction materials that could provide shelter for CRLF, an open-top trailer would be used to elevate the construction materials above the ground surface to reduce the potential for any CRLF individuals to climb into the construction materials.

•    AMM-BIO-8, Worker Environmental Awareness Training: Construction personnel would attend a mandatory worker environmental awareness training (WEAT) delivered by a qualified biologist prior to beginning construction. WEAT would provide information on special-status species and the construction personnel’s responsibility in reducing, avoiding, or minimizing impacts to special-status species during construction. At a minimum, WEAT would include the following:
     o    A description of special-status species and migratory birds that may occur in the BSA
     o    A discussion of the potential occurrence of special-status species within the Project footprints
     o    An explanation of the status of special-status species and protection measures under federal and state laws and regulations
     o    The description of avoidance or minimization measures to be implemented to conserve special-status species and their habitats as they relate to the Project
Information on special-status species would be provided to construction personnel, along with compliance reminders and relevant contact information. Documentation of WEAT and sign-in sheets would be kept on file and available on request.

•    AMM-BIO-9, Conduct Pre-construction Survey for Viola adunca. A pre-construction surveys for Viola adunca would be conducted by a USFWS-approved biological monitor. Visual surveys would be conducted in the early spring, prior to construction, referencing phenology trends observed at Fort Ross or other nearby reference populations. If Viola adunca are found in the work area, they would be flagged for avoidance. Negative findings for Viola adunca within the BSA would indicate that the footprint does not contain suitable breeding habitat for MSB.

•    AMM-GEO-1, Unanticipated Paleontological Resources. As outlined in Standard Specifications 14-7.03, Discovery of Unanticipated Paleontological Resources, if unanticipated paleontological resources are discovered at the job site in the native Pleistocene terrace deposits, the following measures would be implemented:
1.    Stop all work within a 60-foot radius of the discovery.
2.    Secure the area.
3.    Notify the Project engineer.
The Caltrans Department of Geology Services would investigate the discovery and modify the dimensions of the secured area if needed. Paleontological resources would not be moved or taken from the job site until appropriate coordination and consultation has been completed. Work within the radius of discovery would not resume until authorized by a qualified paleontologist. 

•    AMM-UT-1, Utility Notifications. Caltrans would notify all affected utility companies of the construction schedule for the Project so that relocations can be conducted by each utility company as necessary prior to the start of construction.

 

The Draft IS/MND's analysis of project impacts identified potentially significant impacts which will be mitigated to less than significant levels through the incorporation of the following Mitigation Measures (MMs):

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• MM-BIO-1, Impacts to ESHAs. Temporary Project impacts to ESHAs would be mitigated at a ratio of 1:1 for temporary impacts and permanent impacts to ESHAs, and waters of the United States would be mitigated at a ratio of 3:1, in accordance with the Caltrans Coastal Act Policy. Habitat mitigation would be purchased from a USFWS- and CDFW-approved mitigation bank prior to Project construction. Temporary Project impacts on ESHAs, mitigation ratios, and appropriate compensation would be confirmed with the Sonoma County Local Coastal Program during the Project permitting phase.

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• MM-BIO-2, Tree Replacements. The tree removal required for the Project would be replaced or compensated via an in-lieu fee in accordance with Chart No. 1 of the Tree Protection Ordinance (Section 26-88-010(m)). Appropriate tree replacement locations or in-lieu fee compensation would be confirmed with Sonoma County prior to construction.